From d0d2d156770dc8726df4cf7587042a6b772d7032 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Tue, 7 Mar 2023 20:49:27 +0100
Subject: [PATCH 01/21] Copy eeevee-rewrite sss implementation

---
 source/blender/draw/CMakeLists.txt            |   3 +
 .../draw/engines/eevee_next/eevee_instance.cc |   1 +
 .../draw/engines/eevee_next/eevee_instance.hh |   3 +
 .../engines/eevee_next/eevee_shader_shared.hh |   1 +
 .../engines/eevee_next/eevee_subsurface.cc    | 195 ++++++++++++++++++
 .../engines/eevee_next/eevee_subsurface.hh    |  69 +++++++
 .../shaders/eevee_subsurface_eval_frag.glsl   | 132 ++++++++++++
 .../shaders/infos/eevee_material_info.hh      |  19 ++
 8 files changed, 423 insertions(+)
 create mode 100644 source/blender/draw/engines/eevee_next/eevee_subsurface.cc
 create mode 100644 source/blender/draw/engines/eevee_next/eevee_subsurface.hh
 create mode 100644 source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl

diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index c6f8dcf335f..fea78229609 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -153,6 +153,7 @@ set(SRC
   engines/eevee_next/eevee_shader.cc
   engines/eevee_next/eevee_shadow.cc
   engines/eevee_next/eevee_sync.cc
+  engines/eevee_next/eevee_subsurface.cc
   engines/eevee_next/eevee_velocity.cc
   engines/eevee_next/eevee_view.cc
   engines/eevee_next/eevee_world.cc
@@ -284,6 +285,7 @@ set(SRC
   engines/eevee_next/eevee_shader.hh
   engines/eevee_next/eevee_shadow.hh
   engines/eevee_next/eevee_sync.hh
+  engines/eevee_next/eevee_subsurface.hh
   engines/eevee_next/eevee_velocity.hh
   engines/eevee_next/eevee_view.hh
   engines/eevee_next/eevee_world.hh
@@ -489,6 +491,7 @@ set(GLSL_SRC
   engines/eevee_next/shaders/eevee_shadow_tilemap_init_comp.glsl
   engines/eevee_next/shaders/eevee_shadow_tilemap_lib.glsl
   engines/eevee_next/shaders/eevee_spherical_harmonics_lib.glsl
+  engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
   engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl
   engines/eevee_next/shaders/eevee_surf_depth_frag.glsl
   engines/eevee_next/shaders/eevee_surf_forward_frag.glsl
diff --git a/source/blender/draw/engines/eevee_next/eevee_instance.cc b/source/blender/draw/engines/eevee_next/eevee_instance.cc
index 95bcf92d32c..530dc444ce3 100644
--- a/source/blender/draw/engines/eevee_next/eevee_instance.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_instance.cc
@@ -204,6 +204,7 @@ void Instance::end_sync()
   shadows.end_sync(); /** \note: Needs to be before lights. */
   lights.end_sync();
   sampling.end_sync();
+  subsurface.end_sync();
   film.end_sync();
   cryptomatte.end_sync();
   pipelines.end_sync();
diff --git a/source/blender/draw/engines/eevee_next/eevee_instance.hh b/source/blender/draw/engines/eevee_next/eevee_instance.hh
index 8e7855961e4..859660bd26d 100644
--- a/source/blender/draw/engines/eevee_next/eevee_instance.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_instance.hh
@@ -30,6 +30,7 @@
 #include "eevee_sampling.hh"
 #include "eevee_shader.hh"
 #include "eevee_shadow.hh"
+#include "eevee_subsurface.hh"
 #include "eevee_sync.hh"
 #include "eevee_view.hh"
 #include "eevee_world.hh"
@@ -48,6 +49,7 @@ class Instance {
   ShaderModule &shaders;
   SyncModule sync;
   MaterialModule materials;
+  SubsurfaceModule subsurface;
   PipelineModule pipelines;
   ShadowModule shadows;
   LightModule lights;
@@ -94,6 +96,7 @@ class Instance {
       : shaders(*ShaderModule::module_get()),
         sync(*this),
         materials(*this),
+        subsurface(*this),
         pipelines(*this),
         shadows(*this),
         lights(*this),
diff --git a/source/blender/draw/engines/eevee_next/eevee_shader_shared.hh b/source/blender/draw/engines/eevee_next/eevee_shader_shared.hh
index 91a23253401..0e8bc360a51 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader_shared.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_shader_shared.hh
@@ -965,6 +965,7 @@ using ShadowPageCacheBuf = draw::StorageArrayBuffer<uint2, SHADOW_MAX_PAGE, true
 using ShadowTileMapDataBuf = draw::StorageVectorBuffer<ShadowTileMapData, SHADOW_MAX_TILEMAP>;
 using ShadowTileMapClipBuf = draw::StorageArrayBuffer<ShadowTileMapClip, SHADOW_MAX_TILEMAP, true>;
 using ShadowTileDataBuf = draw::StorageArrayBuffer<ShadowTileDataPacked, SHADOW_MAX_TILE, true>;
+using SubsurfaceDataBuf = draw::UniformBuffer<SubsurfaceData>;
 using VelocityGeometryBuf = draw::StorageArrayBuffer<float4, 16, true>;
 using VelocityIndexBuf = draw::StorageArrayBuffer<VelocityIndex, 16>;
 using VelocityObjectBuf = draw::StorageArrayBuffer<float4x4, 16>;
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
new file mode 100644
index 00000000000..d30bc6a95fb
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -0,0 +1,195 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2021 Blender Foundation.
+ */
+
+/** \file
+ * \ingroup eevee
+ *
+ */
+
+#include "BLI_vector.hh"
+
+#include "eevee_instance.hh"
+#include "eevee_subsurface.hh"
+
+#include <iostream>
+
+namespace blender::eevee {
+
+/* -------------------------------------------------------------------- */
+/** \name Subsurface
+ *
+ * \{ */
+
+/* TODO(fclem) Only enable this module if there is any SSS object in the scene. */
+void SubsurfaceModule::end_sync()
+{
+  data_.jitter_threshold = inst_.scene->eevee.sss_jitter_threshold;
+  if (data_.sample_len != inst_.scene->eevee.sss_samples) {
+    /* Convert sample count from old implementation which was using a separable filter. */
+    /* TODO(fclem) better remapping. */
+    // data_.sample_len = square_f(1 + 2 * inst_.scene->eevee.sss_samples);
+    data_.sample_len = 55;
+  }
+
+  if (transmittance_tx == nullptr) {
+    precompute_transmittance_profile();
+  }
+
+  precompute_samples_location();
+
+  data_.push_update();
+}
+
+void SubsurfaceModule::precompute_samples_location()
+{
+  /* Precompute sample position with white albedo. */
+  float d = burley_setup(1.0f, 1.0f);
+
+  float rand_u = inst_.sampling.rng_get(SAMPLING_SSS_U);
+  float rand_v = inst_.sampling.rng_get(SAMPLING_SSS_V);
+
+  double golden_angle = M_PI * (3.0 - sqrt(5.0));
+  for (auto i : IndexRange(data_.sample_len)) {
+    float theta = golden_angle * i + M_PI * 2.0f * rand_u;
+    /* Scale using rand_v in order to keep first sample always at center. */
+    float x = (1.0f + (rand_v / data_.sample_len)) * (i / (float)data_.sample_len);
+    float r = burley_sample(d, x);
+    data_.samples[i].x = cosf(theta) * r;
+    data_.samples[i].y = sinf(theta) * r;
+    data_.samples[i].z = 1.0f / burley_pdf(d, r);
+  }
+}
+
+void SubsurfaceModule::precompute_transmittance_profile()
+{
+  Vector<float> profile(SSS_TRANSMIT_LUT_SIZE);
+
+  /* Precompute sample position with white albedo. */
+  float radius = 1.0f;
+  float d = burley_setup(radius, 1.0f);
+
+  /* For each distance d we compute the radiance incoming from an hypothetical parallel plane. */
+  for (auto i : IndexRange(SSS_TRANSMIT_LUT_SIZE)) {
+    /* Distance from the lit surface plane.
+     * Compute to a larger maximum distance to have a smoother falloff for all channels. */
+    float lut_radius = SSS_TRANSMIT_LUT_RADIUS * radius;
+    float distance = lut_radius * (i + 1e-5f) / profile.size();
+    /* Compute radius of the footprint on the hypothetical plane. */
+    float r_fp = sqrtf(square_f(lut_radius) - square_f(distance));
+
+    profile[i] = 0.0f;
+    float area_accum = 0.0f;
+    for (auto j : IndexRange(SSS_TRANSMIT_LUT_STEP_RES)) {
+      /* Compute distance to the "shading" point through the medium. */
+      float r = (r_fp * (j + 0.5f)) / SSS_TRANSMIT_LUT_STEP_RES;
+      float r_prev = (r_fp * (j + 0.0f)) / SSS_TRANSMIT_LUT_STEP_RES;
+      float r_next = (r_fp * (j + 1.0f)) / SSS_TRANSMIT_LUT_STEP_RES;
+      r = hypotf(r, distance);
+      float R = burley_eval(d, r);
+      /* Since the profile and configuration are radially symmetrical we
+       * can just evaluate it once and weight it accordingly */
+      float disk_area = square_f(r_next) - square_f(r_prev);
+
+      profile[i] += R * disk_area;
+      area_accum += disk_area;
+    }
+    /* Normalize over the disk. */
+    profile[i] /= area_accum;
+  }
+  /* Make a smooth gradient from 1 to 0. */
+  float range = profile.first() - profile.last();
+  float offset = profile.last();
+  for (float &value : profile) {
+    value = (value - offset) / range;
+  }
+  profile.first() = 1;
+  profile.last() = 0;
+
+  transmittance_tx = GPU_texture_create_1d("SSSTransmittanceProfile",
+                                           profile.size(),
+                                           1,
+                                           GPU_R16F,
+                                           GPU_TEXTURE_USAGE_SHADER_READ,
+                                           profile.data());
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Christensen-Burley SSS model
+ *
+ * Based on: "Approximate Reflectance Profiles for Efficient Subsurface Scattering"
+ * by Per Christensen
+ * https://graphics.pixar.com/library/ApproxBSSRDF/approxbssrdfslides.pdf
+ * \{ */
+
+float SubsurfaceModule::burley_setup(float radius, float albedo)
+{
+  float A = albedo;
+  /* Diffuse surface transmission, equation (6). */
+  float s = 1.9f - A + 3.5f * square_f(A - 0.8f);
+  /* Mean free path length adapted to fit ancient Cubic and Gaussian models. */
+  float l = 0.25 * M_1_PI * radius;
+
+  return l / s;
+}
+
+float SubsurfaceModule::burley_sample(float d, float x_rand)
+{
+  x_rand *= SSS_BURLEY_TRUNCATE_CDF;
+
+  const float tolerance = 1e-6;
+  const int max_iteration_count = 10;
+  /* Do initial guess based on manual curve fitting, this allows us to reduce
+   * number of iterations to maximum 4 across the [0..1] range. We keep maximum
+   * number of iteration higher just to be sure we didn't miss root in some
+   * corner case.
+   */
+  float r;
+  if (x_rand <= 0.9) {
+    r = exp(x_rand * x_rand * 2.4) - 1.0;
+  }
+  else {
+    /* TODO(sergey): Some nicer curve fit is possible here. */
+    r = 15.0;
+  }
+  /* Solve against scaled radius. */
+  for (int i = 0; i < max_iteration_count; i++) {
+    float exp_r_3 = exp(-r / 3.0);
+    float exp_r = exp_r_3 * exp_r_3 * exp_r_3;
+    float f = 1.0 - 0.25 * exp_r - 0.75 * exp_r_3 - x_rand;
+    float f_ = 0.25 * exp_r + 0.25 * exp_r_3;
+
+    if (abs(f) < tolerance || f_ == 0.0) {
+      break;
+    }
+
+    r = r - f / f_;
+    if (r < 0.0) {
+      r = 0.0;
+    }
+  }
+
+  return r * d;
+}
+
+float SubsurfaceModule::burley_eval(float d, float r)
+{
+  if (r >= SSS_BURLEY_TRUNCATE * d) {
+    return 0.0;
+  }
+  /* Slide 33. */
+  float exp_r_3_d = expf(-r / (3.0f * d));
+  float exp_r_d = exp_r_3_d * exp_r_3_d * exp_r_3_d;
+  return (exp_r_d + exp_r_3_d) / (8.0f * (float)M_PI * d);
+}
+
+float SubsurfaceModule::burley_pdf(float d, float r)
+{
+  return burley_eval(d, r) / SSS_BURLEY_TRUNCATE_CDF;
+}
+
+/** \} */
+
+}  // namespace blender::eevee
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
new file mode 100644
index 00000000000..7b0deb064dd
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2021 Blender Foundation.
+ */
+
+/** \file
+ * \ingroup eevee
+ *
+ */
+
+#pragma once
+
+#include "eevee_shader.hh"
+#include "eevee_shader_shared.hh"
+
+namespace blender::eevee {
+
+/* -------------------------------------------------------------------- */
+/** \name Subsurface
+ *
+ * \{ */
+
+class Instance;
+
+struct SubsurfaceModule {
+ private:
+  Instance &inst_;
+  /** Contains samples locations. */
+  SubsurfaceDataBuf data_;
+  /** Contains translucence profile for a single color channel. */
+  GPUTexture *transmittance_tx = nullptr;
+
+ public:
+  SubsurfaceModule(Instance &inst) : inst_(inst)
+  {
+    /* Force first update. */
+    data_.sample_len = -1;
+  };
+
+  ~SubsurfaceModule()
+  {
+    GPU_TEXTURE_FREE_SAFE(transmittance_tx);
+  };
+
+  void end_sync();
+
+  const GPUUniformBuf *ubo_get(void) const
+  {
+    return data_;
+  }
+
+  GPUTexture **transmittance_ref_get(void)
+  {
+    return &transmittance_tx;
+  }
+
+ private:
+  void precompute_samples_location();
+  void precompute_transmittance_profile();
+
+  /** Christensen-Burley implementation. */
+  static float burley_setup(float radius, float albedo);
+  static float burley_sample(float d, float x_rand);
+  static float burley_eval(float d, float r);
+  static float burley_pdf(float d, float r);
+};
+
+/** \} */
+
+}  // namespace blender::eevee
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
new file mode 100644
index 00000000000..54907553d26
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
@@ -0,0 +1,132 @@
+
+/**
+ * Postprocess diffuse radiance output from the diffuse evaluation pass to mimic subsurface
+ * transmission.
+ *
+ * This implementation follows the technique described in the siggraph presentation:
+ * "Efficient screen space subsurface scattering Siggraph 2018"
+ * by Evgenii Golubev
+ *
+ * But, instead of having all the precomputed weights for all three color primaries,
+ * we precompute a weight profile texture to be able to support per pixel AND per channel radius.
+ **/
+
+#pragma BLENDER_REQUIRE(common_view_lib.glsl)
+#pragma BLENDER_REQUIRE(common_math_geom_lib.glsl)
+#pragma BLENDER_REQUIRE(eevee_sampling_lib.glsl)
+
+vec3 burley_setup(vec3 radius, vec3 albedo)
+{
+  /* Scale albedo because we can have HDR value caused by BSDF sampling. */
+  vec3 A = albedo / max(1e-6, max_v3(albedo));
+  /* Diffuse surface transmission, equation (6). */
+  vec3 s = 1.9 - A + 3.5 * sqr(A - 0.8);
+  /* Mean free path length adapted to fit ancient Cubic and Gaussian models. */
+  vec3 l = 0.25 * M_1_PI * radius;
+
+  return l / s;
+}
+
+vec3 burley_eval(vec3 d, float r)
+{
+  /* Slide 33. */
+  vec3 exp_r_3_d = exp(-r / (3.0 * d));
+  vec3 exp_r_d = exp_r_3_d * exp_r_3_d * exp_r_3_d;
+  /** NOTE:
+   * - Surface albedo is applied at the end.
+   * - This is normalized diffuse model, so the equation is multiplied
+   *   by 2*pi, which also matches cdf().
+   */
+  return (exp_r_d + exp_r_3_d) / (4.0 * d);
+}
+
+void main(void)
+{
+  vec2 center_uv = uvcoordsvar.xy;
+  ivec2 texel = ivec2(gl_FragCoord.xy);
+
+  float gbuffer_depth = texelFetch(hiz_tx, texel, 0).r;
+  vec3 vP = get_view_space_from_depth(center_uv, gbuffer_depth);
+  vec4 tra_col_in = texelFetch(transmit_color_tx, texel, 0);
+  vec4 tra_nor_in = texelFetch(transmit_normal_tx, texel, 0);
+  vec4 tra_dat_in = texelFetch(transmit_data_tx, texel, 0);
+
+  ClosureDiffuse diffuse = gbuffer_load_diffuse_data(tra_col_in, tra_nor_in, tra_dat_in);
+
+  if (diffuse.sss_id == 0u) {
+    /* Normal diffuse is already in combined pass. */
+    /* Refraction also go into this case. */
+    out_combined = vec4(0.0);
+    return;
+  }
+
+  float max_radius = max_v3(diffuse.sss_radius);
+
+  float homcoord = ProjectionMatrix[2][3] * vP.z + ProjectionMatrix[3][3];
+  vec2 sample_scale = vec2(ProjectionMatrix[0][0], ProjectionMatrix[1][1]) *
+                      (0.5 * max_radius / homcoord);
+
+  float pixel_footprint = sample_scale.x * drw_view.viewport_size.x;
+  if (pixel_footprint <= 1.0) {
+    /* Early out. */
+    out_combined = vec4(texture(radiance_tx, center_uv).rgb * diffuse.color, 0.0);
+    return;
+  }
+
+  diffuse.sss_radius = max(vec3(1e-4), diffuse.sss_radius / max_radius) * max_radius;
+  vec3 d = burley_setup(diffuse.sss_radius, diffuse.color);
+
+  /* Do not rotate too much to avoid too much cache misses. */
+  float golden_angle = M_PI * (3.0 - sqrt(5.0));
+  float theta = interlieved_gradient_noise(gl_FragCoord.xy, 0, 0.0) * golden_angle;
+  float cos_theta = cos(theta);
+  float sin_theta = sqrt(1.0 - sqr(cos_theta));
+  mat2 rot = mat2(cos_theta, sin_theta, -sin_theta, cos_theta);
+
+  mat2 scale = mat2(sample_scale.x, 0.0, 0.0, sample_scale.y);
+  mat2 sample_space = scale * rot;
+
+  vec3 accum_weight = vec3(0.0);
+  vec3 accum = vec3(0.0);
+
+  /* TODO/OPTI(fclem) Make separate sample set for lower radius. */
+
+  for (int i = 0; i < sss_buf.sample_len; i++) {
+    vec2 sample_uv = center_uv + sample_space * sss_buf.samples[i].xy;
+    float pdf_inv = sss_buf.samples[i].z;
+
+    float sample_depth = textureLod(hiz_tx, sample_uv * hiz_buf.uv_scale, 0.0).r;
+    vec3 sample_vP = get_view_space_from_depth(sample_uv, sample_depth);
+
+    vec4 sample_data = texture(radiance_tx, sample_uv);
+    vec3 sample_radiance = sample_data.rgb;
+    uint sample_sss_id = uint(sample_data.a);
+
+    if (sample_sss_id != diffuse.sss_id) {
+      continue;
+    }
+
+    /* Discard out of bounds samples. */
+    if (any(lessThan(sample_uv, vec2(0.0))) || any(greaterThan(sample_uv, vec2(1.0)))) {
+      continue;
+    }
+
+    /* Slide 34. */
+    float r = distance(sample_vP, vP);
+    vec3 weight = burley_eval(d, r) * pdf_inv;
+
+    accum += sample_radiance * weight;
+    accum_weight += weight;
+  }
+  /* Normalize the sum (slide 34). */
+  accum /= accum_weight;
+  /* Apply surface color on final radiance. */
+  accum *= diffuse.color;
+
+  /* Debug, detect NaNs. */
+  if (any(isnan(accum))) {
+    accum = vec3(1.0, 0.0, 1.0);
+  }
+
+  out_combined = vec4(accum, 0.0);
+}
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
index f16113a5efc..b4f1125fabf 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
@@ -180,6 +180,25 @@ GPU_SHADER_CREATE_INFO(eevee_surf_shadow)
     .fragment_source("eevee_surf_shadow_frag.glsl")
     .additional_info("eevee_camera", "eevee_utility_texture", "eevee_sampling_data");
 
+GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
+    .define("SSS_TRANSMITTANCE")
+    .sampler(0, ImageType::FLOAT_1D, "sss_transmittance_tx");
+
+GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
+    .do_static_compilation(true)
+    .additional_info("eevee_shared")
+    .uniform_buf(2, "SubsurfaceData", "sss_buf")
+    .uniform_buf(1, "HiZData", "hiz_buf")
+    .sampler(0, ImageType::FLOAT_2D, "hiz_tx")
+    .sampler(1, ImageType::FLOAT_2D, "radiance_tx")
+    .sampler(2, ImageType::FLOAT_2D, "transmit_color_tx")
+    .sampler(3, ImageType::FLOAT_2D, "transmit_normal_tx")
+    .sampler(4, ImageType::FLOAT_2D, "transmit_data_tx")
+    .fragment_out(0, Type::VEC4, "out_combined")
+    .fragment_source("eevee_subsurface_eval_frag.glsl")
+    /* TODO(fclem) Output to diffuse pass without feedback loop. */
+    .additional_info("draw_fullscreen", "draw_view");
+
 #undef image_out
 #undef image_array_out
 
-- 
2.30.2


From 154156a44d5b7a4f2c22e00a7358950fe75a3cfe Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Fri, 21 Apr 2023 19:48:35 +0200
Subject: [PATCH 02/21] Initial implementation

---
 .../draw/engines/eevee_next/eevee_pipeline.cc | 29 +++++++++-
 .../draw/engines/eevee_next/eevee_pipeline.hh |  1 +
 .../draw/engines/eevee_next/eevee_shader.cc   |  2 +
 .../draw/engines/eevee_next/eevee_shader.hh   |  2 +
 .../engines/eevee_next/eevee_subsurface.cc    |  1 -
 .../engines/eevee_next/eevee_subsurface.hh    |  5 ++
 .../shaders/eevee_deferred_light_frag.glsl    | 57 ++++++++-----------
 .../shaders/eevee_subsurface_eval_frag.glsl   | 15 +++--
 .../shaders/infos/eevee_material_info.hh      | 11 ++--
 9 files changed, 76 insertions(+), 47 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
index 2b80070b5ef..eceaff5fe0c 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
@@ -369,10 +369,10 @@ void DeferredLayer::end_sync()
   DRWState state_write_color = state | DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_CUSTOM;
 
   if (closure_bits_ & (CLOSURE_DIFFUSE | CLOSURE_REFLECTION)) {
-    const bool is_last_eval_pass = true;
+    const bool is_last_eval_pass = !(closure_bits_ & CLOSURE_SSS);
 
     eval_light_ps_.init();
-    eval_light_ps_.state_set(is_last_eval_pass ? state_write_color : state);
+    eval_light_ps_.state_set(state_write_color);
     eval_light_ps_.state_stencil(0x00u, 0x01u, 0xFFu);
     eval_light_ps_.shader_set(inst_.shaders.static_shader_get(DEFERRED_LIGHT));
     eval_light_ps_.bind_image("out_diffuse_light_img", &diffuse_light_tx_);
@@ -391,6 +391,26 @@ void DeferredLayer::end_sync()
     eval_light_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH | GPU_BARRIER_SHADER_IMAGE_ACCESS);
     eval_light_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
   }
+
+  if (closure_bits_ & CLOSURE_SSS) {
+    inst_.subsurface.end_sync();
+
+    subsurface_ps_.init();
+    subsurface_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
+                             DRW_STATE_BLEND_ADD_FULL);
+    subsurface_ps_.state_stencil(0x00u, 0x01u, 0xFFu);
+    /* TODO(Miguel Pozo): */
+    /*subsurface_ps_.state_stencil(0x0, 0xFF, CLOSURE_SSS);*/
+    subsurface_ps_.shader_set(inst_.shaders.static_shader_get(SUBSURFACE_EVAL));
+    inst_.subsurface.bind_resources(&subsurface_ps_);
+    inst_.hiz_buffer.bind_resources(&subsurface_ps_);
+    subsurface_ps_.bind_texture("radiance_tx", &diffuse_light_tx_);
+    subsurface_ps_.bind_texture("gbuffer_closure_tx", &inst_.gbuffer.closure_tx);
+    subsurface_ps_.bind_texture("gbuffer_color_tx", &inst_.gbuffer.color_tx);
+
+    subsurface_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH);
+    subsurface_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
+  }
 }
 
 PassMain::Sub *DeferredLayer::prepass_add(::Material *blender_mat,
@@ -421,7 +441,6 @@ void DeferredLayer::render(View &view,
                            Framebuffer &combined_fb,
                            int2 extent)
 {
-
   GPU_framebuffer_bind(prepass_fb);
   inst_.manager->submit(prepass_ps_, view);
 
@@ -441,6 +460,10 @@ void DeferredLayer::render(View &view,
 
   inst_.manager->submit(eval_light_ps_, view);
 
+  if (closure_bits_ & CLOSURE_SSS) {
+    inst_.manager->submit(subsurface_ps_, view);
+  }
+
   diffuse_light_tx_.release();
   specular_light_tx_.release();
 
diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.hh b/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
index c09f5fe99cf..c76be9da5f8 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
@@ -132,6 +132,7 @@ class DeferredLayer {
   PassMain::Sub *gbuffer_double_sided_ps_ = nullptr;
 
   PassSimple eval_light_ps_ = {"EvalLights"};
+  PassSimple subsurface_ps_ = {"Subsurface"};
 
   /* Closures bits from the materials in this pass. */
   eClosureBits closure_bits_;
diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.cc b/source/blender/draw/engines/eevee_next/eevee_shader.cc
index 26d9642a525..30eafff73c9 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.cc
@@ -172,6 +172,8 @@ const char *ShaderModule::static_shader_create_info_name_get(eShaderType shader_
       return "eevee_shadow_tag_usage_opaque";
     case SHADOW_TILEMAP_TAG_USAGE_TRANSPARENT:
       return "eevee_shadow_tag_usage_transparent";
+    case SUBSURFACE_EVAL:
+      return "eevee_subsurface_eval";
     /* To avoid compiler warning about missing case. */
     case MAX_SHADER_TYPE:
       return "";
diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.hh b/source/blender/draw/engines/eevee_next/eevee_shader.hh
index d987105e3fc..fdceef4055f 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.hh
@@ -80,6 +80,8 @@ enum eShaderType {
   SHADOW_TILEMAP_TAG_USAGE_OPAQUE,
   SHADOW_TILEMAP_TAG_USAGE_TRANSPARENT,
 
+  SUBSURFACE_EVAL,
+
   MAX_SHADER_TYPE,
 };
 
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index d30bc6a95fb..1c19155ae9a 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -21,7 +21,6 @@ namespace blender::eevee {
  *
  * \{ */
 
-/* TODO(fclem) Only enable this module if there is any SSS object in the scene. */
 void SubsurfaceModule::end_sync()
 {
   data_.jitter_threshold = inst_.scene->eevee.sss_jitter_threshold;
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
index 7b0deb064dd..ad7f7dddcdc 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -43,6 +43,11 @@ struct SubsurfaceModule {
 
   void end_sync();
 
+  template<typename T> void bind_resources(draw::detail::PassBase<T> *pass)
+  {
+    pass->bind_ubo("sss_buf", data_);
+  }
+
   const GPUUniformBuf *ubo_get(void) const
   {
     return data_;
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
index 80dcaaf67cb..ddf27e28fdc 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
@@ -42,11 +42,10 @@ void main()
      * produces a complete diffuse light buffer that will be correctly convolved by the SSSS.
      * The refraction pixels will just set the diffuse radiance to 0. */
   }
-  else if (false /* TODO */) {
+  else if (textureSize(gbuffer_closure_tx, 0).z >= 3) {
     vec4 gbuffer_2_packed = texelFetch(gbuffer_closure_tx, ivec3(texel, 2), 0);
-    diffuse_data.sss_radius = gbuffer_sss_radii_unpack(gbuffer_2_packed.xyz);
     diffuse_data.sss_id = gbuffer_object_id_unorm16_unpack(gbuffer_2_packed.w);
-    thickness = gbuffer_thickness_pack(gbuffer_1_packed.z);
+    thickness = gbuffer_thickness_unpack(gbuffer_1_packed.z);
   }
 
   vec3 diffuse_light = vec3(0.0);
@@ -55,30 +54,7 @@ void main()
   light_eval(
       diffuse_data, reflection_data, P, Ng, V, vP_z, thickness, diffuse_light, reflection_light);
 
-  if (is_last_eval_pass) {
-    /* Apply color and output lighting to render-passes. */
-    vec4 color_0_packed = texelFetch(gbuffer_color_tx, ivec3(texel, 0), 0);
-    vec4 color_1_packed = texelFetch(gbuffer_color_tx, ivec3(texel, 1), 0);
-
-    reflection_data.color = gbuffer_color_unpack(color_0_packed);
-    diffuse_data.color = gbuffer_color_unpack(color_1_packed);
-
-    if (is_refraction) {
-      diffuse_data.color = vec3(0.0);
-    }
-
-    reflection_light *= reflection_data.color;
-    diffuse_light *= diffuse_data.color;
-    /* Add radiance to light pass. */
-    imageStore(
-        rp_light_img, ivec3(texel, RENDER_PASS_LAYER_DIFFUSE_LIGHT), vec4(diffuse_light, 1.0));
-    imageStore(
-        rp_light_img, ivec3(texel, RENDER_PASS_LAYER_SPECULAR_LIGHT), vec4(reflection_light, 1.0));
-    /* Add radiance to combined pass. */
-    out_radiance = vec4(diffuse_light + reflection_light, 0.0);
-    out_transmittance = vec4(1.0);
-  }
-  else {
+  if (!is_last_eval_pass) {
     /* Store lighting for next deferred pass. */
 
     /* Output diffuse light along with object ID for sub-surface screen space processing. */
@@ -88,10 +64,27 @@ void main()
     imageStore(out_diffuse_light_img, texel, diffuse_radiance);
 
     imageStore(out_specular_light_img, texel, vec4(reflection_light, 0.0));
-
-    /* Final radiance will be amended by the last pass.
-     * This should do nothing as color write should be disabled in this case. */
-    out_radiance = vec4(0.0);
-    out_transmittance = vec4(0.0);
   }
+
+  /* Apply color and output lighting to render-passes. */
+  vec4 color_0_packed = texelFetch(gbuffer_color_tx, ivec3(texel, 0), 0);
+  vec4 color_1_packed = texelFetch(gbuffer_color_tx, ivec3(texel, 1), 0);
+
+  reflection_data.color = gbuffer_color_unpack(color_0_packed);
+  diffuse_data.color = gbuffer_color_unpack(color_1_packed);
+
+  if (is_refraction) {
+    diffuse_data.color = vec3(0.0);
+  }
+
+  reflection_light *= reflection_data.color;
+  diffuse_light *= diffuse_data.color;
+  /* Add radiance to light pass. */
+  imageStore(
+      rp_light_img, ivec3(texel, RENDER_PASS_LAYER_DIFFUSE_LIGHT), vec4(diffuse_light, 1.0));
+  imageStore(
+      rp_light_img, ivec3(texel, RENDER_PASS_LAYER_SPECULAR_LIGHT), vec4(reflection_light, 1.0));
+  /* Add radiance to combined pass. */
+  out_radiance = vec4(diffuse_light + reflection_light, 0.0);
+  out_transmittance = vec4(1.0);
 }
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
index 54907553d26..6a3cd6a24a4 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
@@ -11,6 +11,8 @@
  * we precompute a weight profile texture to be able to support per pixel AND per channel radius.
  **/
 
+#pragma BLENDER_REQUIRE(gpu_shader_codegen_lib.glsl)
+#pragma BLENDER_REQUIRE(eevee_gbuffer_lib.glsl)
 #pragma BLENDER_REQUIRE(common_view_lib.glsl)
 #pragma BLENDER_REQUIRE(common_math_geom_lib.glsl)
 #pragma BLENDER_REQUIRE(eevee_sampling_lib.glsl)
@@ -47,11 +49,14 @@ void main(void)
 
   float gbuffer_depth = texelFetch(hiz_tx, texel, 0).r;
   vec3 vP = get_view_space_from_depth(center_uv, gbuffer_depth);
-  vec4 tra_col_in = texelFetch(transmit_color_tx, texel, 0);
-  vec4 tra_nor_in = texelFetch(transmit_normal_tx, texel, 0);
-  vec4 tra_dat_in = texelFetch(transmit_data_tx, texel, 0);
 
-  ClosureDiffuse diffuse = gbuffer_load_diffuse_data(tra_col_in, tra_nor_in, tra_dat_in);
+  vec4 color_1_packed = texelFetch(gbuffer_color_tx, ivec3(texel, 1), 0);
+  vec4 gbuffer_2_packed = texelFetch(gbuffer_closure_tx, ivec3(texel, 2), 0);
+
+  ClosureDiffuse diffuse;
+  diffuse.sss_radius = gbuffer_sss_radii_unpack(gbuffer_2_packed.xyz);
+  diffuse.sss_id = gbuffer_object_id_unorm16_unpack(gbuffer_2_packed.w);
+  diffuse.color = gbuffer_color_unpack(color_1_packed);
 
   if (diffuse.sss_id == 0u) {
     /* Normal diffuse is already in combined pass. */
@@ -66,7 +71,7 @@ void main(void)
   vec2 sample_scale = vec2(ProjectionMatrix[0][0], ProjectionMatrix[1][1]) *
                       (0.5 * max_radius / homcoord);
 
-  float pixel_footprint = sample_scale.x * drw_view.viewport_size.x;
+  float pixel_footprint = sample_scale.x * textureSize(hiz_tx, 0).x;
   if (pixel_footprint <= 1.0) {
     /* Early out. */
     out_combined = vec4(texture(radiance_tx, center_uv).rgb * diffuse.color, 0.0);
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
index b4f1125fabf..695c28628ac 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
@@ -187,13 +187,12 @@ GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
 GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
     .do_static_compilation(true)
     .additional_info("eevee_shared")
-    .uniform_buf(2, "SubsurfaceData", "sss_buf")
-    .uniform_buf(1, "HiZData", "hiz_buf")
+    .uniform_buf(1, "SubsurfaceData", "sss_buf")
+    .uniform_buf(2, "HiZData", "hiz_buf")
     .sampler(0, ImageType::FLOAT_2D, "hiz_tx")
-    .sampler(1, ImageType::FLOAT_2D, "radiance_tx")
-    .sampler(2, ImageType::FLOAT_2D, "transmit_color_tx")
-    .sampler(3, ImageType::FLOAT_2D, "transmit_normal_tx")
-    .sampler(4, ImageType::FLOAT_2D, "transmit_data_tx")
+    .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
+    .sampler(2, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
+    .sampler(3, ImageType::FLOAT_2D, "radiance_tx")
     .fragment_out(0, Type::VEC4, "out_combined")
     .fragment_source("eevee_subsurface_eval_frag.glsl")
     /* TODO(fclem) Output to diffuse pass without feedback loop. */
-- 
2.30.2


From c13ce1dc06d819279acc40ba98aebf11886b7384 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Fri, 21 Apr 2023 19:48:57 +0200
Subject: [PATCH 03/21] Fix sss_id

---
 .../engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl
index d84d0a030e2..461bf5fcebb 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_surf_deferred_frag.glsl
@@ -123,7 +123,7 @@ void main()
     /* SubSurface Scattering. */
     vec4 closure;
     closure.xyz = gbuffer_sss_radii_pack(g_diffuse_data.sss_radius);
-    closure.w = gbuffer_object_id_unorm16_pack(g_diffuse_data.sss_id);
+    closure.w = gbuffer_object_id_unorm16_pack(g_diffuse_data.sss_id > 0 ? uint(resource_id) : 0);
     imageStore(out_gbuff_closure_img, ivec3(out_texel, 2), closure);
   }
 
-- 
2.30.2


From e6ee38d218d30fe3fe8ba2d060f186a0d1bbf74a Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Mon, 24 Apr 2023 20:06:12 +0200
Subject: [PATCH 04/21] SSS transmittance

---
 source/blender/draw/engines/eevee_next/eevee_defines.hh     | 2 ++
 source/blender/draw/engines/eevee_next/eevee_pipeline.cc    | 6 ++++++
 source/blender/draw/engines/eevee_next/eevee_shader.cc      | 4 ++++
 .../eevee_next/shaders/eevee_deferred_light_frag.glsl       | 1 +
 .../engines/eevee_next/shaders/eevee_light_eval_lib.glsl    | 2 +-
 .../engines/eevee_next/shaders/eevee_surf_forward_frag.glsl | 4 +++-
 .../engines/eevee_next/shaders/infos/eevee_deferred_info.hh | 1 +
 .../engines/eevee_next/shaders/infos/eevee_material_info.hh | 2 +-
 8 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_defines.hh b/source/blender/draw/engines/eevee_next/eevee_defines.hh
index fd7fd7b55b6..101403513c8 100644
--- a/source/blender/draw/engines/eevee_next/eevee_defines.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_defines.hh
@@ -95,6 +95,8 @@
 /* Only during shadow rendering. */
 #define SHADOW_RENDER_MAP_SLOT 13
 #define RBUFS_UTILITY_TEX_SLOT 14
+/* TODO(Miguel Pozo): Set the correct slot. */
+#define SSS_TRANSMITTANCE_TEX_SLOT 28
 
 /* Images. */
 #define RBUFS_NORMAL_SLOT 0
diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
index eceaff5fe0c..297a1f0050a 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
@@ -156,6 +156,9 @@ void ForwardPipeline::sync()
       opaque_ps_.bind_ssbo(RBUFS_AOV_BUF_SLOT, &inst_.film.aovs_info);
       /* Textures. */
       opaque_ps_.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
+      opaque_ps_.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT,
+                              inst_.subsurface.transmittance_ref_get());
+
       /* Uniform Buffer. */
       opaque_ps_.bind_ubo(CAMERA_BUF_SLOT, inst_.camera.ubo_get());
 
@@ -182,6 +185,7 @@ void ForwardPipeline::sync()
 
     /* Textures. */
     sub.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
+    sub.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT, inst_.subsurface.transmittance_ref_get());
     /* Uniform Buffer. */
     sub.bind_ubo(CAMERA_BUF_SLOT, inst_.camera.ubo_get());
 
@@ -382,6 +386,8 @@ void DeferredLayer::end_sync()
     eval_light_ps_.push_constant("is_last_eval_pass", is_last_eval_pass);
     eval_light_ps_.bind_image(RBUFS_LIGHT_SLOT, &inst_.render_buffers.light_tx);
     eval_light_ps_.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
+    eval_light_ps_.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT,
+                                inst_.subsurface.transmittance_ref_get());
 
     inst_.lights.bind_resources(&eval_light_ps_);
     inst_.shadows.bind_resources(&eval_light_ps_);
diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.cc b/source/blender/draw/engines/eevee_next/eevee_shader.cc
index 30eafff73c9..5aaf090c7b6 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.cc
@@ -267,6 +267,10 @@ void ShaderModule::material_create_info_ammend(GPUMaterial *gpumat, GPUCodegenOu
     info.additional_info("eevee_cryptomatte_out");
   }
 
+  if (GPU_material_flag_get(gpumat, GPU_MATFLAG_SUBSURFACE) && pipeline_type == MAT_PIPE_FORWARD) {
+    info.additional_info("eevee_transmittance_data");
+  }
+
   if (GPU_material_flag_get(gpumat, GPU_MATFLAG_BARYCENTRIC)) {
     switch (geometry_type) {
       case MAT_GEOM_MESH:
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
index ddf27e28fdc..f626cbe8dbc 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_deferred_light_frag.glsl
@@ -44,6 +44,7 @@ void main()
   }
   else if (textureSize(gbuffer_closure_tx, 0).z >= 3) {
     vec4 gbuffer_2_packed = texelFetch(gbuffer_closure_tx, ivec3(texel, 2), 0);
+    diffuse_data.sss_radius = gbuffer_sss_radii_unpack(gbuffer_2_packed.xyz);
     diffuse_data.sss_id = gbuffer_object_id_unorm16_unpack(gbuffer_2_packed.w);
     thickness = gbuffer_thickness_unpack(gbuffer_1_packed.z);
   }
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_light_eval_lib.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_light_eval_lib.glsl
index 4a57a850d34..a9a840da242 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_light_eval_lib.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_light_eval_lib.glsl
@@ -46,7 +46,7 @@ void light_eval_ex(ClosureDiffuse diffuse,
 #ifdef SSS_TRANSMITTANCE
     /* Transmittance evaluation first to use initial visibility without shadow. */
     if (diffuse.sss_id != 0u && light.diffuse_power > 0.0) {
-      float delta = max(thickness, samp.occluder_delta + samp.bias);
+      float delta = max(thickness, -(samp.occluder_delta + samp.bias));
 
       vec3 intensity = visibility * light.transmit_power *
                        light_translucent(sss_transmittance_tx,
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_surf_forward_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_surf_forward_frag.glsl
index dad1faad0b4..7487ccad4e2 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_surf_forward_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_surf_forward_frag.glsl
@@ -58,6 +58,8 @@ void main()
 
   g_holdout = saturate(g_holdout);
 
+  float thickness = nodetree_thickness();
+
   vec3 diffuse_light = vec3(0.0);
   vec3 reflection_light = vec3(0.0);
   vec3 refraction_light = vec3(0.0);
@@ -70,7 +72,7 @@ void main()
              g_data.Ng,
              cameraVec(g_data.P),
              vP_z,
-             0.01 /* TODO(fclem) thickness. */,
+             thickness,
              diffuse_light,
              reflection_light);
 
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_deferred_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_deferred_info.hh
index f5bc967e5b6..eea38136e0e 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_deferred_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_deferred_info.hh
@@ -39,6 +39,7 @@ GPU_SHADER_CREATE_INFO(eevee_deferred_light)
                      "eevee_light_data",
                      "eevee_shadow_data",
                      "eevee_deferred_base",
+                     "eevee_transmittance_data",
                      "eevee_hiz_data",
                      "draw_view",
                      "draw_fullscreen")
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
index 695c28628ac..d1a5f3358b2 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
@@ -182,7 +182,7 @@ GPU_SHADER_CREATE_INFO(eevee_surf_shadow)
 
 GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
     .define("SSS_TRANSMITTANCE")
-    .sampler(0, ImageType::FLOAT_1D, "sss_transmittance_tx");
+    .sampler(SSS_TRANSMITTANCE_TEX_SLOT, ImageType::FLOAT_1D, "sss_transmittance_tx");
 
 GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
     .do_static_compilation(true)
-- 
2.30.2


From ac61b698dd11b6535f0dc570e08a0f92c4be8190 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Tue, 25 Apr 2023 18:14:23 +0200
Subject: [PATCH 05/21] Fix subsurface_eval energy

---
 .../eevee_next/shaders/eevee_subsurface_eval_frag.glsl     | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
index 6a3cd6a24a4..c60aa8685d9 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
@@ -74,7 +74,7 @@ void main(void)
   float pixel_footprint = sample_scale.x * textureSize(hiz_tx, 0).x;
   if (pixel_footprint <= 1.0) {
     /* Early out. */
-    out_combined = vec4(texture(radiance_tx, center_uv).rgb * diffuse.color, 0.0);
+    out_combined = vec4(0);
     return;
   }
 
@@ -125,6 +125,11 @@ void main(void)
   }
   /* Normalize the sum (slide 34). */
   accum /= accum_weight;
+
+  /* This pass uses additive blending.
+   * Subtract the surface diffuse radiance so it's not added twice. */
+  accum -= texelFetch(radiance_tx, texel, 0).rgb;
+
   /* Apply surface color on final radiance. */
   accum *= diffuse.color;
 
-- 
2.30.2


From 8dd009fabb320728b4efb8fc5b075939563c4d8f Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 26 Apr 2023 18:31:28 +0200
Subject: [PATCH 06/21] Fix gbuffer_normal_pack

---
 .../draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl   | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
index 2147c68de83..2182cb26d5d 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
@@ -10,7 +10,10 @@
 vec2 gbuffer_normal_pack(vec3 N)
 {
   N /= length_manhattan(N);
-  N.xy = (N.z >= 0.0) ? N.xy : ((1.0 - abs(N.yx)) * sign(N.xy));
+  vec2 _sign = sign(N.xy);
+  _sign.x = _sign.x == 0.0 ? 1.0 : _sign.x;
+  _sign.y = _sign.y == 0.0 ? 1.0 : _sign.y;
+  N.xy = (N.z >= 0.0) ? N.xy : ((1.0 - abs(N.yx)) * _sign);
   N.xy = N.xy * 0.5 + 0.5;
   return N.xy;
 }
-- 
2.30.2


From 7db9f0087f0d4addb8ee3a4e42c121d2b5459aa7 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 26 Apr 2023 18:48:30 +0200
Subject: [PATCH 07/21] Cleanup

---
 .../draw/engines/eevee_next/eevee_pipeline.cc  | 16 ++++++----------
 .../engines/eevee_next/eevee_subsurface.cc     | 10 +++-------
 .../engines/eevee_next/eevee_subsurface.hh     | 18 +++++++++++-------
 3 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
index 297a1f0050a..c6dd324eb3f 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
@@ -156,8 +156,7 @@ void ForwardPipeline::sync()
       opaque_ps_.bind_ssbo(RBUFS_AOV_BUF_SLOT, &inst_.film.aovs_info);
       /* Textures. */
       opaque_ps_.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
-      opaque_ps_.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT,
-                              inst_.subsurface.transmittance_ref_get());
+      opaque_ps_.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT, inst_.subsurface.transmittance_tx_get());
 
       /* Uniform Buffer. */
       opaque_ps_.bind_ubo(CAMERA_BUF_SLOT, inst_.camera.ubo_get());
@@ -185,7 +184,7 @@ void ForwardPipeline::sync()
 
     /* Textures. */
     sub.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
-    sub.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT, inst_.subsurface.transmittance_ref_get());
+    sub.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT, inst_.subsurface.transmittance_tx_get());
     /* Uniform Buffer. */
     sub.bind_ubo(CAMERA_BUF_SLOT, inst_.camera.ubo_get());
 
@@ -366,17 +365,14 @@ void DeferredLayer::begin_sync()
 
 void DeferredLayer::end_sync()
 {
-  /* Use stencil test to reject pixel not written by this layer. */
-  /* WORKAROUND: Stencil write is only here to avoid rasterizer discard. */
-  DRWState state = DRW_STATE_WRITE_STENCIL | DRW_STATE_STENCIL_EQUAL;
-  /* Allow output to combined pass for the last pass. */
-  DRWState state_write_color = state | DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_CUSTOM;
 
   if (closure_bits_ & (CLOSURE_DIFFUSE | CLOSURE_REFLECTION)) {
     const bool is_last_eval_pass = !(closure_bits_ & CLOSURE_SSS);
 
     eval_light_ps_.init();
-    eval_light_ps_.state_set(state_write_color);
+    /* Use stencil test to reject pixel not written by this layer. */
+    eval_light_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
+                             DRW_STATE_BLEND_CUSTOM);
     eval_light_ps_.state_stencil(0x00u, 0x01u, 0xFFu);
     eval_light_ps_.shader_set(inst_.shaders.static_shader_get(DEFERRED_LIGHT));
     eval_light_ps_.bind_image("out_diffuse_light_img", &diffuse_light_tx_);
@@ -387,7 +383,7 @@ void DeferredLayer::end_sync()
     eval_light_ps_.bind_image(RBUFS_LIGHT_SLOT, &inst_.render_buffers.light_tx);
     eval_light_ps_.bind_texture(RBUFS_UTILITY_TEX_SLOT, inst_.pipelines.utility_tx);
     eval_light_ps_.bind_texture(SSS_TRANSMITTANCE_TEX_SLOT,
-                                inst_.subsurface.transmittance_ref_get());
+                                inst_.subsurface.transmittance_tx_get());
 
     inst_.lights.bind_resources(&eval_light_ps_);
     inst_.shadows.bind_resources(&eval_light_ps_);
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index 1c19155ae9a..e4b863c21bb 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -31,7 +31,7 @@ void SubsurfaceModule::end_sync()
     data_.sample_len = 55;
   }
 
-  if (transmittance_tx == nullptr) {
+  if (!transmittance_tx.is_valid()) {
     precompute_transmittance_profile();
   }
 
@@ -105,12 +105,8 @@ void SubsurfaceModule::precompute_transmittance_profile()
   profile.first() = 1;
   profile.last() = 0;
 
-  transmittance_tx = GPU_texture_create_1d("SSSTransmittanceProfile",
-                                           profile.size(),
-                                           1,
-                                           GPU_R16F,
-                                           GPU_TEXTURE_USAGE_SHADER_READ,
-                                           profile.data());
+  transmittance_tx.ensure_1d(
+      GPU_R16F, profile.size(), GPU_TEXTURE_USAGE_SHADER_READ, profile.data());
 }
 
 /** \} */
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
index ad7f7dddcdc..09e62383b0a 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -5,6 +5,15 @@
 /** \file
  * \ingroup eevee
  *
+ * Postprocess diffuse radiance output from the diffuse evaluation pass to mimic subsurface
+ * transmission.
+ *
+ * This implementation follows the technique described in the siggraph presentation:
+ * "Efficient screen space subsurface scattering Siggraph 2018"
+ * by Evgenii Golubev
+ *
+ * But, instead of having all the precomputed weights for all three color primaries,
+ * we precompute a weight profile texture to be able to support per pixel AND per channel radius.
  */
 
 #pragma once
@@ -27,7 +36,7 @@ struct SubsurfaceModule {
   /** Contains samples locations. */
   SubsurfaceDataBuf data_;
   /** Contains translucence profile for a single color channel. */
-  GPUTexture *transmittance_tx = nullptr;
+  Texture transmittance_tx;
 
  public:
   SubsurfaceModule(Instance &inst) : inst_(inst)
@@ -48,12 +57,7 @@ struct SubsurfaceModule {
     pass->bind_ubo("sss_buf", data_);
   }
 
-  const GPUUniformBuf *ubo_get(void) const
-  {
-    return data_;
-  }
-
-  GPUTexture **transmittance_ref_get(void)
+  GPUTexture **transmittance_tx_get(void)
   {
     return &transmittance_tx;
   }
-- 
2.30.2


From 8127efbaa40d8f808e642420f087ae7069d557b3 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 26 Apr 2023 19:21:40 +0200
Subject: [PATCH 08/21] Correct transmittance tex slot

---
 .../blender/draw/engines/eevee_next/eevee_defines.hh   |  4 ++--
 .../engines/eevee_next/shaders/infos/eevee_hiz_info.hh |  2 +-
 .../eevee_next/shaders/infos/eevee_material_info.hh    | 10 ++++------
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_defines.hh b/source/blender/draw/engines/eevee_next/eevee_defines.hh
index 101403513c8..b70fe9eaacf 100644
--- a/source/blender/draw/engines/eevee_next/eevee_defines.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_defines.hh
@@ -95,8 +95,8 @@
 /* Only during shadow rendering. */
 #define SHADOW_RENDER_MAP_SLOT 13
 #define RBUFS_UTILITY_TEX_SLOT 14
-/* TODO(Miguel Pozo): Set the correct slot. */
-#define SSS_TRANSMITTANCE_TEX_SLOT 28
+#define HIZ_TEX_SLOT 15
+#define SSS_TRANSMITTANCE_TEX_SLOT 16
 
 /* Images. */
 #define RBUFS_NORMAL_SLOT 0
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_hiz_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_hiz_info.hh
index 5e32631a8f8..ba25c2b83ca 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_hiz_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_hiz_info.hh
@@ -4,7 +4,7 @@
 #include "gpu_shader_create_info.hh"
 
 GPU_SHADER_CREATE_INFO(eevee_hiz_data)
-    .sampler(15, ImageType::FLOAT_2D, "hiz_tx")
+    .sampler(HIZ_TEX_SLOT, ImageType::FLOAT_2D, "hiz_tx")
     .uniform_buf(5, "HiZData", "hiz_buf");
 
 GPU_SHADER_CREATE_INFO(eevee_hiz_update)
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
index d1a5f3358b2..7ae20d86745 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
@@ -188,15 +188,13 @@ GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
     .do_static_compilation(true)
     .additional_info("eevee_shared")
     .uniform_buf(1, "SubsurfaceData", "sss_buf")
-    .uniform_buf(2, "HiZData", "hiz_buf")
-    .sampler(0, ImageType::FLOAT_2D, "hiz_tx")
-    .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
-    .sampler(2, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
-    .sampler(3, ImageType::FLOAT_2D, "radiance_tx")
+    .sampler(0, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
+    .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
+    .sampler(2, ImageType::FLOAT_2D, "radiance_tx")
     .fragment_out(0, Type::VEC4, "out_combined")
     .fragment_source("eevee_subsurface_eval_frag.glsl")
     /* TODO(fclem) Output to diffuse pass without feedback loop. */
-    .additional_info("draw_fullscreen", "draw_view");
+    .additional_info("draw_fullscreen", "draw_view", "eevee_hiz_data");
 
 #undef image_out
 #undef image_array_out
-- 
2.30.2


From 5cef5870dd805162a4a9a00872a13b54ebe07677 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 26 Apr 2023 20:16:23 +0200
Subject: [PATCH 09/21] Closure stencil

---
 .../draw/engines/eevee_next/eevee_pipeline.cc   | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
index c6dd324eb3f..a20afba3082 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
@@ -322,7 +322,7 @@ void DeferredLayer::begin_sync()
   {
     gbuffer_ps_.init();
     gbuffer_ps_.clear_stencil(0x00u);
-    gbuffer_ps_.state_stencil(0x01u, 0x01u, 0x01u);
+    gbuffer_ps_.state_stencil(0xFFu, 0xFFu, 0xFFu);
 
     {
       /* Common resources. */
@@ -371,9 +371,9 @@ void DeferredLayer::end_sync()
 
     eval_light_ps_.init();
     /* Use stencil test to reject pixel not written by this layer. */
-    eval_light_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
+    eval_light_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_NEQUAL |
                              DRW_STATE_BLEND_CUSTOM);
-    eval_light_ps_.state_stencil(0x00u, 0x01u, 0xFFu);
+    eval_light_ps_.state_stencil(0x00u, 0x00u, (CLOSURE_DIFFUSE | CLOSURE_REFLECTION));
     eval_light_ps_.shader_set(inst_.shaders.static_shader_get(DEFERRED_LIGHT));
     eval_light_ps_.bind_image("out_diffuse_light_img", &diffuse_light_tx_);
     eval_light_ps_.bind_image("out_specular_light_img", &specular_light_tx_);
@@ -400,9 +400,7 @@ void DeferredLayer::end_sync()
     subsurface_ps_.init();
     subsurface_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
                              DRW_STATE_BLEND_ADD_FULL);
-    subsurface_ps_.state_stencil(0x00u, 0x01u, 0xFFu);
-    /* TODO(Miguel Pozo): */
-    /*subsurface_ps_.state_stencil(0x0, 0xFF, CLOSURE_SSS);*/
+    subsurface_ps_.state_stencil(0x00u, 0xFFu, CLOSURE_SSS);
     subsurface_ps_.shader_set(inst_.shaders.static_shader_get(SUBSURFACE_EVAL));
     inst_.subsurface.bind_resources(&subsurface_ps_);
     inst_.hiz_buffer.bind_resources(&subsurface_ps_);
@@ -430,12 +428,15 @@ PassMain::Sub *DeferredLayer::prepass_add(::Material *blender_mat,
 
 PassMain::Sub *DeferredLayer::material_add(::Material *blender_mat, GPUMaterial *gpumat)
 {
-  closure_bits_ |= shader_closure_bits_from_flag(gpumat);
+  eClosureBits closure_bits = shader_closure_bits_from_flag(gpumat);
+  closure_bits_ |= closure_bits;
 
   PassMain::Sub *pass = (blender_mat->blend_flag & MA_BL_CULL_BACKFACE) ?
                             gbuffer_single_sided_ps_ :
                             gbuffer_double_sided_ps_;
-  return &pass->sub(GPU_material_get_name(gpumat));
+  pass = &pass->sub(GPU_material_get_name(gpumat));
+  pass->state_stencil(closure_bits, 0xFFu, 0xFFu);
+  return pass;
 }
 
 void DeferredLayer::render(View &view,
-- 
2.30.2


From 7dcfd4cd62fe83dca765344a2b49948b116a1d57 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 26 Apr 2023 20:19:59 +0200
Subject: [PATCH 10/21] Fix texture negative ref count

---
 source/blender/draw/engines/eevee_next/eevee_subsurface.hh | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
index 09e62383b0a..b5a05114735 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -45,10 +45,7 @@ struct SubsurfaceModule {
     data_.sample_len = -1;
   };
 
-  ~SubsurfaceModule()
-  {
-    GPU_TEXTURE_FREE_SAFE(transmittance_tx);
-  };
+  ~SubsurfaceModule(){};
 
   void end_sync();
 
-- 
2.30.2


From cfae033fcbbeefc5b55c1ac89d6ebe5874523072 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Thu, 27 Apr 2023 17:54:54 +0200
Subject: [PATCH 11/21] Fix gbuffer_ior_unpack

---
 .../draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
index 2182cb26d5d..32edcd62a7c 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_gbuffer_lib.glsl
@@ -35,7 +35,7 @@ float gbuffer_ior_pack(float ior)
 
 float gbuffer_ior_unpack(float ior_packed)
 {
-  return (ior_packed > 0.5) ? (-1.0 / (ior_packed * 2.0 + 2.0)) : (2.0 * ior_packed);
+  return (ior_packed > 0.5) ? (0.5 / (1.0 - ior_packed)) : (2.0 * ior_packed);
 }
 
 float gbuffer_thickness_pack(float thickness)
-- 
2.30.2


From 5194b648c3d9e951a270720d2b35f2df2d50d7bf Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Thu, 27 Apr 2023 18:15:53 +0200
Subject: [PATCH 12/21] Code style

---
 source/blender/draw/engines/eevee_next/eevee_subsurface.cc | 4 ++--
 source/blender/draw/engines/eevee_next/eevee_subsurface.hh | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index e4b863c21bb..bc63f458329 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -31,7 +31,7 @@ void SubsurfaceModule::end_sync()
     data_.sample_len = 55;
   }
 
-  if (!transmittance_tx.is_valid()) {
+  if (!transmittance_tx_.is_valid()) {
     precompute_transmittance_profile();
   }
 
@@ -105,7 +105,7 @@ void SubsurfaceModule::precompute_transmittance_profile()
   profile.first() = 1;
   profile.last() = 0;
 
-  transmittance_tx.ensure_1d(
+  transmittance_tx_.ensure_1d(
       GPU_R16F, profile.size(), GPU_TEXTURE_USAGE_SHADER_READ, profile.data());
 }
 
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
index b5a05114735..abfb346032d 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -36,7 +36,7 @@ struct SubsurfaceModule {
   /** Contains samples locations. */
   SubsurfaceDataBuf data_;
   /** Contains translucence profile for a single color channel. */
-  Texture transmittance_tx;
+  Texture transmittance_tx_;
 
  public:
   SubsurfaceModule(Instance &inst) : inst_(inst)
@@ -56,7 +56,7 @@ struct SubsurfaceModule {
 
   GPUTexture **transmittance_tx_get(void)
   {
-    return &transmittance_tx;
+    return &transmittance_tx_;
   }
 
  private:
-- 
2.30.2


From e0d6c31af9ffd6f6b91084a93c90dd96f9a5f462 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Fri, 12 May 2023 15:18:31 +0200
Subject: [PATCH 13/21] Move shader create info to its own file

---
 .../shaders/infos/eevee_material_info.hh      | 16 ---------------
 .../shaders/infos/eevee_subsurface_info.hh    | 20 +++++++++++++++++++
 source/blender/gpu/CMakeLists.txt             |  1 +
 3 files changed, 21 insertions(+), 16 deletions(-)
 create mode 100644 source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh

diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
index 7ae20d86745..f16113a5efc 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
@@ -180,22 +180,6 @@ GPU_SHADER_CREATE_INFO(eevee_surf_shadow)
     .fragment_source("eevee_surf_shadow_frag.glsl")
     .additional_info("eevee_camera", "eevee_utility_texture", "eevee_sampling_data");
 
-GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
-    .define("SSS_TRANSMITTANCE")
-    .sampler(SSS_TRANSMITTANCE_TEX_SLOT, ImageType::FLOAT_1D, "sss_transmittance_tx");
-
-GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
-    .do_static_compilation(true)
-    .additional_info("eevee_shared")
-    .uniform_buf(1, "SubsurfaceData", "sss_buf")
-    .sampler(0, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
-    .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
-    .sampler(2, ImageType::FLOAT_2D, "radiance_tx")
-    .fragment_out(0, Type::VEC4, "out_combined")
-    .fragment_source("eevee_subsurface_eval_frag.glsl")
-    /* TODO(fclem) Output to diffuse pass without feedback loop. */
-    .additional_info("draw_fullscreen", "draw_view", "eevee_hiz_data");
-
 #undef image_out
 #undef image_array_out
 
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
new file mode 100644
index 00000000000..6a69ff56dca
--- /dev/null
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "eevee_defines.hh"
+#include "gpu_shader_create_info.hh"
+
+GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
+    .define("SSS_TRANSMITTANCE")
+    .sampler(SSS_TRANSMITTANCE_TEX_SLOT, ImageType::FLOAT_1D, "sss_transmittance_tx");
+
+GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
+    .do_static_compilation(true)
+    .additional_info("eevee_shared")
+    .uniform_buf(1, "SubsurfaceData", "sss_buf")
+    .sampler(0, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
+    .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
+    .sampler(2, ImageType::FLOAT_2D, "radiance_tx")
+    .fragment_out(0, Type::VEC4, "out_combined")
+    .fragment_source("eevee_subsurface_eval_frag.glsl")
+    /* TODO(fclem) Output to diffuse pass without feedback loop. */
+    .additional_info("draw_fullscreen", "draw_view", "eevee_hiz_data");
diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 30f7c3b0cfe..ea16f485212 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -648,6 +648,7 @@ set(SRC_SHADER_CREATE_INFOS
   ../draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_motion_blur_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_shadow_info.hh
+  ../draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_velocity_info.hh
   ../draw/engines/gpencil/shaders/infos/gpencil_info.hh
   ../draw/engines/gpencil/shaders/infos/gpencil_vfx_info.hh
-- 
2.30.2


From 1d28e81235723b8d8beb35b261e835b81d3a4e28 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Fri, 12 May 2023 15:59:49 +0200
Subject: [PATCH 14/21] Move pass implementation to SubsurfaceModule

---
 .../draw/engines/eevee_next/eevee_pipeline.cc | 21 +------------------
 .../draw/engines/eevee_next/eevee_pipeline.hh |  1 -
 .../engines/eevee_next/eevee_subsurface.cc    | 21 +++++++++++++++++++
 .../engines/eevee_next/eevee_subsurface.hh    |  6 ++++++
 4 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
index a20afba3082..2f03ec53aad 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.cc
@@ -365,7 +365,6 @@ void DeferredLayer::begin_sync()
 
 void DeferredLayer::end_sync()
 {
-
   if (closure_bits_ & (CLOSURE_DIFFUSE | CLOSURE_REFLECTION)) {
     const bool is_last_eval_pass = !(closure_bits_ & CLOSURE_SSS);
 
@@ -393,24 +392,6 @@ void DeferredLayer::end_sync()
     eval_light_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH | GPU_BARRIER_SHADER_IMAGE_ACCESS);
     eval_light_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
   }
-
-  if (closure_bits_ & CLOSURE_SSS) {
-    inst_.subsurface.end_sync();
-
-    subsurface_ps_.init();
-    subsurface_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
-                             DRW_STATE_BLEND_ADD_FULL);
-    subsurface_ps_.state_stencil(0x00u, 0xFFu, CLOSURE_SSS);
-    subsurface_ps_.shader_set(inst_.shaders.static_shader_get(SUBSURFACE_EVAL));
-    inst_.subsurface.bind_resources(&subsurface_ps_);
-    inst_.hiz_buffer.bind_resources(&subsurface_ps_);
-    subsurface_ps_.bind_texture("radiance_tx", &diffuse_light_tx_);
-    subsurface_ps_.bind_texture("gbuffer_closure_tx", &inst_.gbuffer.closure_tx);
-    subsurface_ps_.bind_texture("gbuffer_color_tx", &inst_.gbuffer.color_tx);
-
-    subsurface_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH);
-    subsurface_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
-  }
 }
 
 PassMain::Sub *DeferredLayer::prepass_add(::Material *blender_mat,
@@ -464,7 +445,7 @@ void DeferredLayer::render(View &view,
   inst_.manager->submit(eval_light_ps_, view);
 
   if (closure_bits_ & CLOSURE_SSS) {
-    inst_.manager->submit(subsurface_ps_, view);
+    inst_.subsurface.render(view, combined_fb, diffuse_light_tx_);
   }
 
   diffuse_light_tx_.release();
diff --git a/source/blender/draw/engines/eevee_next/eevee_pipeline.hh b/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
index c76be9da5f8..c09f5fe99cf 100644
--- a/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_pipeline.hh
@@ -132,7 +132,6 @@ class DeferredLayer {
   PassMain::Sub *gbuffer_double_sided_ps_ = nullptr;
 
   PassSimple eval_light_ps_ = {"EvalLights"};
-  PassSimple subsurface_ps_ = {"Subsurface"};
 
   /* Closures bits from the materials in this pass. */
   eClosureBits closure_bits_;
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index bc63f458329..fb540d87225 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -38,6 +38,27 @@ void SubsurfaceModule::end_sync()
   precompute_samples_location();
 
   data_.push_update();
+
+  subsurface_ps_.init();
+  subsurface_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL |
+                           DRW_STATE_BLEND_ADD_FULL);
+  subsurface_ps_.state_stencil(0x00u, 0xFFu, CLOSURE_SSS);
+  subsurface_ps_.shader_set(inst_.shaders.static_shader_get(SUBSURFACE_EVAL));
+  inst_.subsurface.bind_resources(&subsurface_ps_);
+  inst_.hiz_buffer.bind_resources(&subsurface_ps_);
+  subsurface_ps_.bind_texture("radiance_tx", &diffuse_light_tx_);
+  subsurface_ps_.bind_texture("gbuffer_closure_tx", &inst_.gbuffer.closure_tx);
+  subsurface_ps_.bind_texture("gbuffer_color_tx", &inst_.gbuffer.color_tx);
+
+  subsurface_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH);
+  subsurface_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
+}
+
+void SubsurfaceModule::render(View &view, Framebuffer &fb, Texture &diffuse_light_tx)
+{
+  fb.bind();
+  diffuse_light_tx_ = *&diffuse_light_tx;
+  inst_.manager->submit(subsurface_ps_, view);
 }
 
 void SubsurfaceModule::precompute_samples_location()
diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
index abfb346032d..433aa60c616 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.hh
@@ -37,6 +37,10 @@ struct SubsurfaceModule {
   SubsurfaceDataBuf data_;
   /** Contains translucence profile for a single color channel. */
   Texture transmittance_tx_;
+  /** Scene diffuse irradiance. Pointer binded at sync time, set at render time. */
+  GPUTexture *diffuse_light_tx_;
+  /** Subsurface eval pass. Runs after the deferred pass. */
+  PassSimple subsurface_ps_ = {"Subsurface"};
 
  public:
   SubsurfaceModule(Instance &inst) : inst_(inst)
@@ -49,6 +53,8 @@ struct SubsurfaceModule {
 
   void end_sync();
 
+  void render(View &view, Framebuffer &fb, Texture &diffuse_light_tx);
+
   template<typename T> void bind_resources(draw::detail::PassBase<T> *pass)
   {
     pass->bind_ubo("sss_buf", data_);
-- 
2.30.2


From 1f47c1b12223f513d4716e71e4981c433339154c Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Thu, 1 Jun 2023 17:54:30 +0200
Subject: [PATCH 15/21] Diffuse Light Pass

---
 source/blender/draw/engines/eevee_next/eevee_subsurface.cc  | 2 ++
 .../eevee_next/shaders/eevee_subsurface_eval_frag.glsl      | 6 +++++-
 .../eevee_next/shaders/infos/eevee_subsurface_info.hh       | 3 ++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index fb540d87225..d66510549bf 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -49,6 +49,8 @@ void SubsurfaceModule::end_sync()
   subsurface_ps_.bind_texture("radiance_tx", &diffuse_light_tx_);
   subsurface_ps_.bind_texture("gbuffer_closure_tx", &inst_.gbuffer.closure_tx);
   subsurface_ps_.bind_texture("gbuffer_color_tx", &inst_.gbuffer.color_tx);
+  subsurface_ps_.bind_ubo(RBUFS_BUF_SLOT, &inst_.render_buffers.data);
+  subsurface_ps_.bind_image(RBUFS_COLOR_SLOT, &inst_.render_buffers.rp_color_tx);
 
   subsurface_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH);
   subsurface_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
diff --git a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
index c60aa8685d9..e716ac68cfb 100644
--- a/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
+++ b/source/blender/draw/engines/eevee_next/shaders/eevee_subsurface_eval_frag.glsl
@@ -74,7 +74,7 @@ void main(void)
   float pixel_footprint = sample_scale.x * textureSize(hiz_tx, 0).x;
   if (pixel_footprint <= 1.0) {
     /* Early out. */
-    out_combined = vec4(0);
+    out_combined = vec4(0.0);
     return;
   }
 
@@ -126,6 +126,10 @@ void main(void)
   /* Normalize the sum (slide 34). */
   accum /= accum_weight;
 
+  if (rp_buf.diffuse_light_id >= 0) {
+    imageStore(rp_color_img, ivec3(texel, rp_buf.diffuse_light_id), vec4(accum, 1.0));
+  }
+
   /* This pass uses additive blending.
    * Subtract the surface diffuse radiance so it's not added twice. */
   accum -= texelFetch(radiance_tx, texel, 0).rgb;
diff --git a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
index 6a69ff56dca..c9d36a85744 100644
--- a/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
+++ b/source/blender/draw/engines/eevee_next/shaders/infos/eevee_subsurface_info.hh
@@ -9,11 +9,12 @@ GPU_SHADER_CREATE_INFO(eevee_transmittance_data)
 
 GPU_SHADER_CREATE_INFO(eevee_subsurface_eval)
     .do_static_compilation(true)
-    .additional_info("eevee_shared")
+    .additional_info("eevee_shared", "eevee_render_pass_out")
     .uniform_buf(1, "SubsurfaceData", "sss_buf")
     .sampler(0, ImageType::FLOAT_2D_ARRAY, "gbuffer_closure_tx")
     .sampler(1, ImageType::FLOAT_2D_ARRAY, "gbuffer_color_tx")
     .sampler(2, ImageType::FLOAT_2D, "radiance_tx")
+    .early_fragment_test(true)
     .fragment_out(0, Type::VEC4, "out_combined")
     .fragment_source("eevee_subsurface_eval_frag.glsl")
     /* TODO(fclem) Output to diffuse pass without feedback loop. */
-- 
2.30.2


From 8d6a0f4e4df73271dd42f0724e277050723e2867 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 14 Jun 2023 17:40:38 +0200
Subject: [PATCH 16/21] Remap texture slots

---
 .../blender/draw/engines/eevee_next/eevee_defines.hh | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_defines.hh b/source/blender/draw/engines/eevee_next/eevee_defines.hh
index b5c8a720ca7..56486ed69a0 100644
--- a/source/blender/draw/engines/eevee_next/eevee_defines.hh
+++ b/source/blender/draw/engines/eevee_next/eevee_defines.hh
@@ -90,14 +90,14 @@
 /* Resource bindings. */
 
 /* Texture. */
-#define SHADOW_TILEMAPS_TEX_SLOT 12
+#define SHADOW_TILEMAPS_TEX_SLOT 11
 /* Only during surface shading. */
-#define SHADOW_ATLAS_TEX_SLOT 13
+#define SHADOW_ATLAS_TEX_SLOT 12
 /* Only during shadow rendering. */
-#define SHADOW_RENDER_MAP_SLOT 13
-#define RBUFS_UTILITY_TEX_SLOT 14
-#define HIZ_TEX_SLOT 15
-#define SSS_TRANSMITTANCE_TEX_SLOT 16
+#define SHADOW_RENDER_MAP_SLOT 12
+#define RBUFS_UTILITY_TEX_SLOT 13
+#define HIZ_TEX_SLOT 14
+#define SSS_TRANSMITTANCE_TEX_SLOT 15
 
 /* Images. */
 #define RBUFS_COLOR_SLOT 0
-- 
2.30.2


From d8ce569c21437e38df50f950c1e7d4be3603f040 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 14 Jun 2023 17:41:26 +0200
Subject: [PATCH 17/21] Bind rp_value_tx

---
 source/blender/draw/engines/eevee_next/eevee_subsurface.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index d66510549bf..89a03dbdf40 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -51,6 +51,8 @@ void SubsurfaceModule::end_sync()
   subsurface_ps_.bind_texture("gbuffer_color_tx", &inst_.gbuffer.color_tx);
   subsurface_ps_.bind_ubo(RBUFS_BUF_SLOT, &inst_.render_buffers.data);
   subsurface_ps_.bind_image(RBUFS_COLOR_SLOT, &inst_.render_buffers.rp_color_tx);
+  /** NOTE: Not used in the shader, but we bind it to avoid debug warnings. */
+  subsurface_ps_.bind_image(RBUFS_VALUE_SLOT, &inst_.render_buffers.rp_value_tx);
 
   subsurface_ps_.barrier(GPU_BARRIER_TEXTURE_FETCH);
   subsurface_ps_.draw_procedural(GPU_PRIM_TRIS, 1, 3);
-- 
2.30.2


From 07dce2224b726025d252c402231275abff1fa9cf Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 14 Jun 2023 17:42:05 +0200
Subject: [PATCH 18/21] Workaround for transmittance_profile values.

---
 source/blender/draw/engines/eevee_next/eevee_subsurface.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
index 89a03dbdf40..58e606c3b8e 100644
--- a/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_subsurface.cc
@@ -121,11 +121,18 @@ void SubsurfaceModule::precompute_transmittance_profile()
     /* Normalize over the disk. */
     profile[i] /= area_accum;
   }
+
+  /** NOTE: There's something very wrong here.
+   * This should be a small remap,
+   * but current profile range goes from 0.0399098 to 0.0026898. */
+
   /* Make a smooth gradient from 1 to 0. */
   float range = profile.first() - profile.last();
   float offset = profile.last();
   for (float &value : profile) {
     value = (value - offset) / range;
+    /** HACK: Remap the curve to better fit Cycles values. */
+    value = std::pow(value, 1.6f);
   }
   profile.first() = 1;
   profile.last() = 0;
-- 
2.30.2


From 11c6138bc425497221981fde602f05a0b866638f Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 14 Jun 2023 17:50:16 +0200
Subject: [PATCH 19/21] Change default thickness

---
 source/blender/draw/engines/eevee_next/eevee_shader.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.cc b/source/blender/draw/engines/eevee_next/eevee_shader.cc
index 105250b9fa2..d9f9e9b72db 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.cc
@@ -400,7 +400,7 @@ void ShaderModule::material_create_info_ammend(GPUMaterial *gpumat, GPUCodegenOu
     frag_gen << "float nodetree_thickness()\n";
     frag_gen << "{\n";
     /* TODO(fclem): Better default. */
-    frag_gen << ((codegen.thickness) ? codegen.thickness : "return 0.1;\n");
+    frag_gen << ((codegen.thickness) ? codegen.thickness : "return 0.0;\n");
     frag_gen << "}\n\n";
 
     info.fragment_source_generated = frag_gen.str();
-- 
2.30.2


From d34f22d0f4210d2647680644332f08ed87d54b92 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Wed, 14 Jun 2023 18:54:38 +0200
Subject: [PATCH 20/21] Add texture slot workaround

---
 source/blender/draw/engines/eevee_next/eevee_shader.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.cc b/source/blender/draw/engines/eevee_next/eevee_shader.cc
index d9f9e9b72db..518c96eed2a 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.cc
@@ -242,6 +242,8 @@ void ShaderModule::material_create_info_ammend(GPUMaterial *gpumat, GPUCodegenOu
         case SHADOW_TILEMAPS_TEX_SLOT:
           resource.slot = GPU_max_textures_frag() - 3;
           break;
+        case SSS_TRANSMITTANCE_TEX_SLOT:
+          resource.slot = GPU_max_textures_frag() - 4;
       }
     }
   }
-- 
2.30.2


From fbe7c3c770ef689789dd349c8c2c6095f0343f70 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Thu, 15 Jun 2023 15:44:36 +0200
Subject: [PATCH 21/21] Revert "Change default thickness"

This reverts commit 11c6138bc425497221981fde602f05a0b866638f.
---
 source/blender/draw/engines/eevee_next/eevee_shader.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/blender/draw/engines/eevee_next/eevee_shader.cc b/source/blender/draw/engines/eevee_next/eevee_shader.cc
index 6c5cc3f65fa..622b330cb03 100644
--- a/source/blender/draw/engines/eevee_next/eevee_shader.cc
+++ b/source/blender/draw/engines/eevee_next/eevee_shader.cc
@@ -391,7 +391,7 @@ void ShaderModule::material_create_info_ammend(GPUMaterial *gpumat, GPUCodegenOu
     frag_gen << "float nodetree_thickness()\n";
     frag_gen << "{\n";
     /* TODO(fclem): Better default. */
-    frag_gen << ((codegen.thickness) ? codegen.thickness : "return 0.0;\n");
+    frag_gen << ((codegen.thickness) ? codegen.thickness : "return 0.1;\n");
     frag_gen << "}\n\n";
 
     info.fragment_source_generated = frag_gen.str();
-- 
2.30.2