[Bf-blender-cvs] [d051dd01eda] master: Workbench: Fix premultiply alpha issue in transparent material

[Clément Foucault]

Commit: d051dd01eda2f893fa3d72a22da3e9bafee91bb1
Author: Clément Foucault
Date:   Thu Feb 13 01:24:40 2020 +0100
Branches: master
https://developer.blender.org/rBd051dd01eda2f893fa3d72a22da3e9bafee91bb1

Workbench: Fix premultiply alpha issue in transparent material

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

M	source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl
M	source/blender/draw/engines/workbench/workbench_deferred.c

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

diff --git a/source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl b/source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl
index 91e1ebabae4..0a4d64b37ad 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_forward_composite_frag.glsl
@@ -25,7 +25,8 @@ void main()
 
   vec3 trans_color = trans_accum.rgb / clamp(trans_accum.a, 1e-4, 5e4);
 
-  fragColor = vec4(trans_color, 1.0 - trans_revealage);
+  fragColor.a = 1.0 - trans_revealage;
+  fragColor.rgb = trans_color * fragColor.a;
 
 #ifdef V3D_SHADING_OBJECT_OUTLINE
   uint object_id = texelFetch(objectId, texel, 0).r;
diff --git a/source/blender/draw/engines/workbench/workbench_deferred.c b/source/blender/draw/engines/workbench/workbench_deferred.c
index dfeb50248df..762eeced176 100644
--- a/source/blender/draw/engines/workbench/workbench_deferred.c
+++ b/source/blender/draw/engines/workbench/workbench_deferred.c
@@ -827,7 +827,7 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
     }
     /* OIT Composite */
     {
-      int state = DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_ALPHA;
+      int state = DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_ALPHA_PREMUL;
       psl->oit_composite_pass = DRW_pass_create("OIT Composite", state);
 
       grp = DRW_shgroup_create(e_data.oit_resolve_sh, psl->oit_composite_pass);