[Bf-blender-cvs] [40863623267] temp-compositor-fixes: Compositor: Fix Alpha Over node ignoring emissive colors

[Manuel Castilla]

Commit: 40863623267354f8c2458d224ca4491a45d6d7d3
Author: Manuel Castilla
Date:   Tue Sep 14 17:25:47 2021 +0200
Branches: temp-compositor-fixes
https://developer.blender.org/rB40863623267354f8c2458d224ca4491a45d6d7d3

Compositor: Fix Alpha Over node ignoring emissive colors

It was an issue on Full Frame mode only.

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M	source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc

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diff --git a/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc b/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc
index a57e8c7f8a3..911e8d2df92 100644
--- a/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc
+++ b/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc
@@ -62,7 +62,8 @@ void AlphaOverPremultiplyOperation::update_memory_buffer_row(PixelCursor &p)
     const float *over_color = p.color2;
     const float value = *p.value;
 
-    if (over_color[3] <= 0.0f) {
+    /* Zero alpha values should still permit an add of RGB data. */
+    if (over_color[3] < 0.0f) {
       copy_v4_v4(p.out, color1);
     }
     else if (value == 1.0f && over_color[3] >= 1.0f) {