[Bf-blender-cvs] [4074ab361e1] master: Eevee: Fix background alpha regression

[Clément Foucault]

Commit: 4074ab361e13444ae9a5d6b8bdf973fce2302021
Author: Clément Foucault
Date:   Wed Aug 14 14:28:57 2019 +0200
Branches: master
https://developer.blender.org/rB4074ab361e13444ae9a5d6b8bdf973fce2302021

Eevee: Fix background alpha regression

===================================================================

M	source/blender/gpu/intern/gpu_codegen.c
M	source/blender/gpu/shaders/gpu_shader_material.glsl

===================================================================

diff --git a/source/blender/gpu/intern/gpu_codegen.c b/source/blender/gpu/intern/gpu_codegen.c
index 6d9fda1c695..3e635b3198a 100644
--- a/source/blender/gpu/intern/gpu_codegen.c
+++ b/source/blender/gpu/intern/gpu_codegen.c
@@ -929,12 +929,15 @@ static char *code_generate_fragment(GPUMaterial *material,
   /* XXX This cannot go into gpu_shader_material.glsl because main()
    * would be parsed and generate error */
   /* Old glsl mode compat. */
+  /* TODO(fclem) This is only used by world shader now. get rid of it? */
   BLI_dynstr_append(ds, "#ifndef NODETREE_EXEC\n");
   BLI_dynstr_append(ds, "out vec4 fragColor;\n");
   BLI_dynstr_append(ds, "void main()\n");
   BLI_dynstr_append(ds, "{\n");
   BLI_dynstr_append(ds, "\tClosure cl = nodetree_exec();\n");
-  BLI_dynstr_append(ds, "\tfragColor = vec4(cl.radiance, saturate(avg(cl.transmittance)));\n");
+  BLI_dynstr_append(ds,
+                    "\tfragColor = vec4(cl.radiance, "
+                    "saturate(1.0 - avg(cl.transmittance)));\n");
   BLI_dynstr_append(ds, "}\n");
   BLI_dynstr_append(ds, "#endif\n\n");
 
diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 7cb38503039..f077ae55d8f 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -3515,7 +3515,7 @@ void node_output_world(Closure surface, Closure volume, out Closure result)
 {
 #ifndef VOLUMETRICS
   result.radiance = surface.radiance * backgroundAlpha;
-  result.transmittance = vec3(0.0);
+  result.transmittance = vec3(1.0 - backgroundAlpha);
 #else
   result = volume;
 #endif /* VOLUMETRICS */