From fdee84fd567a5bb87ee5c4ec0abfd8c79aed4801 Mon Sep 17 00:00:00 2001
From: John Quillan <jquillan>
Date: Thu, 21 Feb 2019 13:26:22 +0100
Subject: [PATCH] Fix T61733: wrong alpha for sequencer screen, multiply, ..
 blend modes.

It was copying the alpha from the foreground instead of background image,
which is not usually what is needed and inconsistent with the compositor.

Differential Revision: https://developer.blender.org/D4371
---
 source/blender/blenkernel/intern/seqeffects.c | 32 +++++++++----------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/source/blender/blenkernel/intern/seqeffects.c b/source/blender/blenkernel/intern/seqeffects.c
index 788935b12e6..57480006439 100644
--- a/source/blender/blenkernel/intern/seqeffects.c
+++ b/source/blender/blenkernel/intern/seqeffects.c
@@ -1318,11 +1318,11 @@ BLI_INLINE void apply_blend_function_byte(
 	rt = out;
 	while (y--) {
 		for (x = xo; x > 0; x--) {
-			achannel = rt2[3];
-			rt2[3] = (unsigned int) achannel * facf0;
+			achannel = rt1[3];
+			rt1[3] = (unsigned int) achannel * facf0;
 			blend_function(rt, rt1, rt2);
-			rt2[3] = achannel;
-			rt[3] = rt2[3];
+			rt1[3] = achannel;
+			rt[3] = rt1[3];
 			rt1 += 4;
 			rt2 += 4;
 			rt += 4;
@@ -1332,11 +1332,11 @@ BLI_INLINE void apply_blend_function_byte(
 		}
 		y--;
 		for (x = xo; x > 0; x--) {
-			achannel = rt2[3];
-			rt2[3] = (unsigned int) achannel * facf1;
+			achannel = rt1[3];
+			rt1[3] = (unsigned int) achannel * facf1;
 			blend_function(rt, rt1, rt2);
-			rt2[3] = achannel;
-			rt[3] = rt2[3];
+			rt1[3] = achannel;
+			rt[3] = rt1[3];
 			rt1 += 4;
 			rt2 += 4;
 			rt += 4;
@@ -1357,11 +1357,11 @@ BLI_INLINE void apply_blend_function_float(
 	rt = out;
 	while (y--) {
 		for (x = xo; x > 0; x--) {
-			achannel = rt2[3];
-			rt2[3] = achannel * facf0;
+			achannel = rt1[3];
+			rt1[3] = achannel * facf0;
 			blend_function(rt, rt1, rt2);
-			rt2[3] = achannel;
-			rt[3] = rt2[3];
+			rt1[3] = achannel;
+			rt[3] = rt1[3];
 			rt1 += 4;
 			rt2 += 4;
 			rt += 4;
@@ -1371,11 +1371,11 @@ BLI_INLINE void apply_blend_function_float(
 		}
 		y--;
 		for (x = xo; x > 0; x--) {
-			achannel = rt2[3];
-			rt2[3] = achannel * facf1;
+			achannel = rt1[3];
+			rt1[3] = achannel * facf1;
 			blend_function(rt, rt1, rt2);
-			rt2[3] = achannel;
-			rt[3] = rt2[3];
+			rt1[3] = achannel;
+			rt[3] = rt1[3];
 			rt1 += 4;
 			rt2 += 4;
 			rt += 4;