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

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_);

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:

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);
   }

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,

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);
 

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")

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)