source/blender/draw/CMakeLists.txt

@@ -144,6 +144,7 @@ set(SRC
   engines/eevee_next/eevee_film.cc
   engines/eevee_next/eevee_hizbuffer.cc
   engines/eevee_next/eevee_instance.cc
+  engines/eevee_next/eevee_irradiance_cache.cc
   engines/eevee_next/eevee_light.cc
   engines/eevee_next/eevee_material.cc
   engines/eevee_next/eevee_motion_blur.cc
@@ -275,6 +276,7 @@ set(SRC
   engines/eevee_next/eevee_film.hh
   engines/eevee_next/eevee_hizbuffer.hh
   engines/eevee_next/eevee_instance.hh
+  engines/eevee_next/eevee_irradiance_cache.hh
   engines/eevee_next/eevee_light.hh
   engines/eevee_next/eevee_material.hh
   engines/eevee_next/eevee_motion_blur.hh
@@ -425,6 +427,8 @@ set(GLSL_SRC
   engines/eevee_next/shaders/eevee_colorspace_lib.glsl
   engines/eevee_next/shaders/eevee_cryptomatte_lib.glsl
   engines/eevee_next/shaders/eevee_transparency_lib.glsl
+  engines/eevee_next/shaders/eevee_debug_surfels_vert.glsl
+  engines/eevee_next/shaders/eevee_debug_surfels_frag.glsl
   engines/eevee_next/shaders/eevee_depth_of_field_accumulator_lib.glsl
   engines/eevee_next/shaders/eevee_depth_of_field_bokeh_lut_comp.glsl
   engines/eevee_next/shaders/eevee_depth_of_field_downsample_comp.glsl

source/blender/draw/engines/eevee_next/eevee_instance.cc

@@ -70,6 +70,7 @@ void Instance::init(const int2 &output_res,
   shadows.init();
   motion_blur.init();
   main_view.init();
+  irradiance_cache.init();
 }
 
 void Instance::set_time(float time)
@@ -117,6 +118,7 @@ void Instance::begin_sync()
   main_view.sync();
   world.sync();
   film.sync();
+  irradiance_cache.sync();
 }
 
 void Instance::scene_sync()

source/blender/draw/engines/eevee_next/eevee_instance.hh

@@ -20,6 +20,7 @@
 #include "eevee_depth_of_field.hh"
 #include "eevee_film.hh"
 #include "eevee_hizbuffer.hh"
+#include "eevee_irradiance_cache.hh"
 #include "eevee_light.hh"
 #include "eevee_material.hh"
 #include "eevee_motion_blur.hh"
@@ -60,6 +61,7 @@ class Instance {
   RenderBuffers render_buffers;
   MainView main_view;
   World world;
+  IrradianceCache irradiance_cache;
 
   /** Input data. */
   Depsgraph *depsgraph;
@@ -103,7 +105,8 @@ class Instance {
         film(*this),
         render_buffers(*this),
         main_view(*this),
-        world(*this){};
+        world(*this),
+        irradiance_cache(*this){};
   ~Instance(){};
 
   void init(const int2 &output_res,

source/blender/draw/engines/eevee_next/eevee_irradiance_cache.cc

@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BLI_rand.hh"
+#include "eevee_instance.hh"
+
+#include "eevee_irradiance_cache.hh"
+
+namespace blender::eevee {
+
+void IrradianceCache::generate_random_surfels()
+{
+  const int surfels_len = 256;
+  debug_surfels.resize(surfels_len);
+
+  RandomNumberGenerator rng;
+  rng.seed(0);
+
+  for (DebugSurfel &surfel : debug_surfels) {
+    float3 random = rng.get_unit_float3();
+    surfel.position = random * 3.0f;
+    surfel.normal = random;
+    surfel.color = float4(rng.get_float(), rng.get_float(), rng.get_float(), 1.0f);
+  }
+
+  debug_surfels.push_update();
+}
+
+void IrradianceCache::init()
+{
+  if (debug_surfels_sh_ == nullptr) {
+    debug_surfels_sh_ = inst_.shaders.static_shader_get(DEBUG_SURFELS);
+  }
+
+  /* TODO: Remove this. */
+  generate_random_surfels();
+}
+
+void IrradianceCache::sync()
+{
+  debug_pass_sync();
+}
+
+void IrradianceCache::debug_pass_sync()
+{
+  if (inst_.debug_mode == eDebugMode::DEBUG_IRRADIANCE_CACHE_SURFELS) {
+    debug_surfels_ps_.init();
+    debug_surfels_ps_.state_set(DRW_STATE_WRITE_COLOR | DRW_STATE_WRITE_DEPTH |
+                                DRW_STATE_DEPTH_LESS_EQUAL);
+    debug_surfels_ps_.shader_set(debug_surfels_sh_);
+    debug_surfels_ps_.bind_ssbo("surfels_buf", debug_surfels);
+    debug_surfels_ps_.push_constant("surfel_radius", 0.25f);
+    debug_surfels_ps_.draw_procedural(GPU_PRIM_TRI_STRIP, debug_surfels.size(), 4);
+  }
+}
+
+void IrradianceCache::debug_draw(View &view, GPUFrameBuffer *view_fb)
+{
+  if (inst_.debug_mode == eDebugMode::DEBUG_IRRADIANCE_CACHE_SURFELS) {
+    inst_.info = "Debug Mode: Irradiance Cache Surfels";
+    GPU_framebuffer_bind(view_fb);
+    inst_.manager->submit(debug_surfels_ps_, view);
+  }
+}
+
+}  // namespace blender::eevee

source/blender/draw/engines/eevee_next/eevee_irradiance_cache.hh

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include "eevee_shader_shared.hh"
+
+namespace blender::eevee {
+
+class Instance;
+
+class IrradianceCache {
+ private:
+  Instance &inst_;
+
+  DebugSurfelBuf debug_surfels;
+  PassSimple debug_surfels_ps_ = {"IrradianceCache.Debug"};
+  GPUShader *debug_surfels_sh_ = nullptr;
+
+  /* TODO: Remove this. */
+  void generate_random_surfels();
+
+ public:
+  IrradianceCache(Instance &inst) : inst_(inst){};
+  ~IrradianceCache(){};
+
+  void init();
+  void sync();
+
+  void debug_pass_sync();
+  void debug_draw(View &view, GPUFrameBuffer *view_fb);
+};
+
+}  // namespace blender::eevee

source/blender/draw/engines/eevee_next/eevee_shader.cc

@@ -98,6 +98,8 @@ const char *ShaderModule::static_shader_create_info_name_get(eShaderType shader_
       return "eevee_motion_blur_tiles_flatten_render";
     case MOTION_BLUR_TILE_FLATTEN_VIEWPORT:
       return "eevee_motion_blur_tiles_flatten_viewport";
+    case DEBUG_SURFELS:
+      return "eevee_debug_surfels";
     case DOF_BOKEH_LUT:
       return "eevee_depth_of_field_bokeh_lut";
     case DOF_DOWNSAMPLE:

source/blender/draw/engines/eevee_next/eevee_shader.hh

@@ -30,6 +30,8 @@ enum eShaderType {
   FILM_COMP,
   FILM_CRYPTOMATTE_POST,
 
+  DEBUG_SURFELS,
+
   DOF_BOKEH_LUT,
   DOF_DOWNSAMPLE,
   DOF_FILTER,

source/blender/draw/engines/eevee_next/eevee_shader_shared.hh

@@ -48,6 +48,10 @@ enum eDebugMode : uint32_t {
    * Show incorrectly downsample tiles in red.
    */
   DEBUG_HIZ_VALIDATION = 2u,
+  /**
+   * Display IrradianceCache surfels.
+   */
+  DEBUG_IRRADIANCE_CACHE_SURFELS = 3u,
   /**
    * Show tiles depending on their status.
    */
@@ -821,6 +825,21 @@ static inline ShadowTileDataPacked shadow_tile_pack(ShadowTileData tile)
 
 /** \} */
 
+/* -------------------------------------------------------------------- */
+/** \name Debug
+ * \{ */
+
+struct DebugSurfel {
+  packed_float3 position;
+  int _pad0;
+  packed_float3 normal;
+  int _pad1;
+  float4 color;
+};
+BLI_STATIC_ASSERT_ALIGN(DebugSurfel, 16)
+
+/** \} */
+
 /* -------------------------------------------------------------------- */
 /** \name Hierarchical-Z Buffer
  * \{ */
@@ -928,6 +947,7 @@ using DepthOfFieldDataBuf = draw::UniformBuffer<DepthOfFieldData>;
 using DepthOfFieldScatterListBuf = draw::StorageArrayBuffer<ScatterRect, 16, true>;
 using DrawIndirectBuf = draw::StorageBuffer<DrawCommand, true>;
 using FilmDataBuf = draw::UniformBuffer<FilmData>;
+using DebugSurfelBuf = draw::StorageArrayBuffer<DebugSurfel, 64>;
 using HiZDataBuf = draw::UniformBuffer<HiZData>;
 using LightCullingDataBuf = draw::StorageBuffer<LightCullingData>;
 using LightCullingKeyBuf = draw::StorageArrayBuffer<uint, LIGHT_CHUNK, true>;

source/blender/draw/engines/eevee_next/eevee_view.cc

@@ -136,6 +136,8 @@ void ShadingView::render()
   inst_.hiz_buffer.debug_draw(render_view_new_, combined_fb_);
   inst_.shadows.debug_draw(render_view_new_, combined_fb_);
 
+  inst_.irradiance_cache.debug_draw(render_view_new_, combined_fb_);
+
   GPUTexture *combined_final_tx = render_postfx(rbufs.combined_tx);
 
   inst_.film.accumulate(sub_view_, combined_final_tx);

source/blender/draw/engines/eevee_next/shaders/eevee_debug_surfels_frag.glsl

@@ -0,0 +1,21 @@
+
+void main()
+{
+  DebugSurfel surfel = surfels_buf[surfel_index];
+  out_color = surfel.color;
+
+  /* Display surfels as circles. */
+  if (distance(P, surfel.position) > surfel_radius) {
+    discard;
+    return;
+  }
+
+  /* Display backfacing surfels with a transparent checkerboard grid. */
+  if (!gl_FrontFacing) {
+    ivec2 grid_uv = ivec2(gl_FragCoord) / 5;
+    if ((grid_uv.x + grid_uv.y) % 2 == 0) {
+      discard;
+      return;
+    }
+  }
+}

source/blender/draw/engines/eevee_next/shaders/eevee_debug_surfels_vert.glsl

@@ -0,0 +1,38 @@
+#pragma BLENDER_REQUIRE(common_view_lib.glsl)
+#pragma BLENDER_REQUIRE(common_math_geom_lib.glsl)
+
+void main()
+{
+  surfel_index = gl_InstanceID;
+  DebugSurfel surfel = surfels_buf[surfel_index];
+
+  vec3 lP;
+
+  switch (gl_VertexID) {
+    case 0:
+      lP = vec3(-1, 1, 0);
+      break;
+    case 1:
+      lP = vec3(-1, -1, 0);
+      break;
+    case 2:
+      lP = vec3(1, 1, 0);
+      break;
+    case 3:
+      lP = vec3(1, -1, 0);
+      break;
+  }
+
+  vec3 N = surfel.normal;
+  vec3 T, B;
+  make_orthonormal_basis(N, T, B);
+
+  mat4 model_matrix = mat4(vec4(T * surfel_radius, 0),
+                           vec4(B * surfel_radius, 0),
+                           vec4(N * surfel_radius, 0),
+                           vec4(surfel.position, 1));
+
+  P = (model_matrix * vec4(lP, 1)).xyz;
+
+  gl_Position = point_world_to_ndc(P);
+}

source/blender/draw/engines/eevee_next/shaders/infos/eevee_irradiance_cache_info.hh

@@ -0,0 +1,16 @@
+#include "eevee_defines.hh"
+#include "gpu_shader_create_info.hh"
+
+GPU_SHADER_INTERFACE_INFO(eeve_debug_surfel_iface, "")
+    .smooth(Type::VEC3, "P")
+    .flat(Type::INT, "surfel_index");
+
+GPU_SHADER_CREATE_INFO(eevee_debug_surfels)
+    .additional_info("eevee_shared", "draw_view")
+    .vertex_source("eevee_debug_surfels_vert.glsl")
+    .vertex_out(eeve_debug_surfel_iface)
+    .fragment_source("eevee_debug_surfels_frag.glsl")
+    .fragment_out(0, Type::VEC4, "out_color")
+    .storage_buf(0, Qualifier::READ, "DebugSurfel", "surfels_buf[]")
+    .push_constant(Type::FLOAT, "surfel_radius")
+    .do_static_compilation(true);

source/blender/gpu/CMakeLists.txt

@@ -606,6 +606,7 @@ set(SRC_SHADER_CREATE_INFOS
   ../draw/engines/eevee_next/shaders/infos/eevee_depth_of_field_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_film_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_hiz_info.hh
+  ../draw/engines/eevee_next/shaders/infos/eevee_irradiance_cache_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_light_culling_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_material_info.hh
   ../draw/engines/eevee_next/shaders/infos/eevee_motion_blur_info.hh