From 3b9f16e8ddce81be8121ce0a29d743807b6d7a41 Mon Sep 17 00:00:00 2001
From: Sergey Lipskiy <gonetz@ngs.ru>
Date: Sun, 30 Jul 2017 22:50:39 +0700
Subject: [PATCH] Fix regression with blending in A Bug's Life, #1488

Hack alert:
The problem blender is used in two cycles mode, but both cycles are the same:
c_in*a_in + c_mem * 1ma
I have no access to c_mem from shader. Therefore, I use c_in instead of c_mem in the first cycle.
Result of the second cycle will be blended with c_mem by GL blender, as usual.
This is pretty good approximation, no problems noticed.
---
 .../GLSL/glsl_CombinerProgramBuilder.cpp      | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp b/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
index c6733fda..9bf876e7 100644
--- a/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
+++ b/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
@@ -10,6 +10,8 @@
 
 using namespace glsl;
 
+u32 g_cycleType = G_CYC_1CYCLE;
+
 /*---------------_compileCombiner-------------*/
 
 static
@@ -468,6 +470,13 @@ public:
 			m_part =
 				"  if (uForceBlendCycle1 != 0) {	\n"
 				"    muxPM[0] = clampedColor;		\n"
+			;
+			if (g_cycleType == G_CYC_2CYCLE) {
+				m_part +=
+					"    muxPM[1] = clampedColor;	\n"
+					;
+			}
+			m_part +=
 				"    muxA[0] = clampedColor.a;		\n"
 				"    lowp float muxa;				\n"
 				"    if (uBlendMux1[1] == 0)		\n"
@@ -514,6 +523,13 @@ public:
 			m_part =
 				"  if (uForceBlendCycle1 != 0) {						\n"
 				"    muxPM[0] = clampedColor;							\n"
+			;
+			if (g_cycleType == G_CYC_2CYCLE) {
+				m_part +=
+					"    muxPM[1] = clampedColor;						\n"
+				;
+			}
+			m_part +=
 				"    muxA[0] = clampedColor.a;							\n"
 				"    muxB[0] = 1.0 - muxA[uBlendMux1[1]];				\n"
 				"    lowp vec4 blend1 = (muxPM[uBlendMux1[0]] * muxA[uBlendMux1[1]]) + (muxPM[uBlendMux1[2]] * muxB[uBlendMux1[3]]);	\n"
@@ -534,6 +550,7 @@ public:
 			m_part =
 				"  if (uForceBlendCycle2 != 0) {	\n"
 				"    muxPM[0] = clampedColor;		\n"
+				"    muxPM[1] = vec4(0.0);			\n"
 				"    muxA[0] = clampedColor.a;		\n"
 				"    lowp float muxa;				\n"
 				"    if (uBlendMux2[1] == 0)		\n"
@@ -581,6 +598,7 @@ public:
 			m_part =
 				"  if (uForceBlendCycle2 != 0) {						\n"
 				"    muxPM[0] = clampedColor;							\n"
+				"    muxPM[1] = vec4(0.0);								\n"
 				"    muxA[0] = clampedColor.a;							\n"
 				"    muxB[0] = 1.0 - muxA[uBlendMux2[1]];				\n"
 				"    lowp vec4 blend2 = muxPM[uBlendMux2[0]] * muxA[uBlendMux2[1]] + muxPM[uBlendMux2[2]] * muxB[uBlendMux2[3]];	\n"
@@ -1685,8 +1703,6 @@ public:
 
 /*---------------ShaderPartsEnd-------------*/
 
-u32 g_cycleType = G_CYC_1CYCLE;
-
 static
 bool needClampColor() {
 	return g_cycleType <= G_CYC_2CYCLE;