[Bf-blender-cvs] [8845a51e796] greasepencil-object: GPencil: Masking materials using alpha channel

[Antonio Vazquez]

Commit: 8845a51e7966a730e7711167b088ef7d348f57dc
Author: Antonio Vazquez
Date:   Tue Jul 21 13:23:49 2020 +0200
Branches: greasepencil-object
https://developer.blender.org/rB8845a51e7966a730e7711167b088ef7d348f57dc

GPencil: Masking materials using alpha channel

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

M	source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl

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

diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
index db09cf12472..7fa4d05c0ad 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
@@ -89,19 +89,22 @@ void main()
   fragColor *= stroke_round_cap_mask(
       strokePt1, strokePt2, strokeAspect, strokeThickness, strokeHardeness);
 
+  /* Masking materials. */
   if (GP_FLAG_TEST(matFlag, GP_STROKE_MASK | GP_FILL_MASK)) {
-    fragColor = vec4(0.0, 0.0, 0.0, 1.0);
-    revealColor = vec4(1.0, 1.0, 1.0, 1.0);
+    revealColor = vec4(1.0 - fragColor.aaa, fragColor.a);
+    fragColor = vec4(fragColor.rgb, 1.0);
   }
   else {
-    /* For compatibility with colored alpha buffer.
+    /* NOT masking materials.
+     * For compatibility with colored alpha buffer.
      * Note that we are limited to mono-chromatic alpha blending here
      * because of the blend equation and the limit of 1 color target
      * when using custom color blending. */
     revealColor = vec4(0.0, 0.0, 0.0, fragColor.a);
-  }
-  if (fragColor.a < 0.001) {
-    discard;
+
+    if (fragColor.a < 0.001) {
+      discard;
+    }
   }
 
   vec2 fb_size = max(vec2(textureSize(gpSceneDepthTexture, 0).xy),