Fix #34966: cycles packed PNG images were showing alpha fringe, packed images

were not properly premultiplied.

1 files changed, 8 insertions, 0 deletions

diff --git a/intern/cycles/blender/blender_session.cpp b/intern/cycles/blender/blender_session.cpp
index 1f1bb830771..f4f9ec548a4 100644
--- a/intern/cycles/blender/blender_session.cpp
+++ b/intern/cycles/blender/blender_session.cpp
@@ -693,6 +693,14 @@ bool BlenderSession::builtin_image_pixels(const string &builtin_name, void *buil
 			}
 		}
 
+		/* premultiply, byte images are always straight for blender */
+		unsigned char *cp = pixels;
+		for(int i = 0; i < width * height; i++, cp += channels) {
+			cp[0] = (cp[0] * cp[3]) >> 8;
+			cp[1] = (cp[1] * cp[3]) >> 8;
+			cp[2] = (cp[2] * cp[3]) >> 8;
+		}
+
 		return true;
 	}