From 49604f0c16541e893ba86e83e2e9963b492a16eb Mon Sep 17 00:00:00 2001
From: S2S <asier.lakun@gmail.com>
Date: Thu, 7 Nov 2019 22:15:47 +0100
Subject: [PATCH] Write wrap function. Cleanup of combiner code.

---
 .../GLSL/glsl_CombinerProgramBuilder.cpp      | 23 ++++++++++++-------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp b/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
index 19e26b67..2f3cb353 100644
--- a/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
+++ b/src/Graphics/OpenGLContext/GLSL/glsl_CombinerProgramBuilder.cpp
@@ -604,7 +604,7 @@ public:
 	ShaderClamp()
 	{
 		m_part =
-			"  lowp vec4 wrappedColor = cmbRes + 2.0 * step(cmbRes, vec4(-0.51)) - 2.0*step(vec4(1.51), cmbRes); \n"
+			"  lowp vec4 wrappedColor = WRAP(cmbRes, -0.51, 1.51); \n"
 			"  lowp vec4 clampedColor = clamp(wrappedColor, 0.0, 1.0); \n"
 			;
 	}
@@ -623,7 +623,7 @@ public:
 	ShaderSignExtendColorC()
 	{
 		m_part =
-			"  color1 = color1 - 2.0*(vec3(1.0) - step(color1, vec3(1.0)));	\n"
+			" color1 = WRAP(color1, -1.01, 1.01); \n"
 			;
 	}
 };
@@ -634,7 +634,7 @@ public:
 	ShaderSignExtendAlphaC()
 	{
 		m_part =
-			"  alpha1 = alpha1 - 2.0*(1.0 - step(alpha1, 1.0));					\n"
+			" alpha1 = WRAP(alpha1, -1.01, 1.01); \n"
 			;
 	}
 };
@@ -655,7 +655,7 @@ public:
 	ShaderSignExtendColorABD()
 	{
 		m_part =
-			"  color1 = color1 + 2.0*step(color1, vec3(-0.51)) - 2.0*step(vec3(1.51), color1); \n"
+			" color1 = WRAP(color1, -0.51, 1.51); \n"
 			;
 	}
 };
@@ -666,7 +666,7 @@ public:
 	ShaderSignExtendAlphaABD()
 	{
 		m_part =
-			"  alpha1 = alpha1 + 2.0*step(alpha1, -0.51) - 2.0*step(1.51, alpha1); \n"
+			"  alpha1 = WRAP(alpha1, -0.51,1.51); \n"
 			;
 	}
 };
@@ -1252,18 +1252,22 @@ public:
 		m_part =
 			"void main() \n"
 			"{			 \n"
-		;
+			;
 		if (!_glinfo.isGLES2) {
 			m_part +=
 				"  highp float fragDepth = writeDepth();	\n"
-			;
+				;
 		}
 		m_part +=
 			"  lowp vec4 vec_color;				\n"
 			"  lowp float alpha1;				\n"
 			"  lowp vec3 color1, input_color;	\n"
-		;
+			;
+		m_part += "#define WRAP(x, low, high) mod((x)-(low), (high)-(low)) + (low) \n"; // Return wrapped value of x in interval [low, high)
+		// m_part += "#define WRAP(x, low, high) (x) - ((high)-(low)) * floor(((x)-(low))/((high)-(low)))  \n"; // Perhaps more compatible?
+		// m_part += "#define WRAP(x, low, high) (x) + ((high)-(low)) * (1.0-step(low,x)) - ((high)-(low)) * step(high,x) \n"; // Step based version. Only wraps correctly if input is in the range [low-(high-low), high + (high-low)). Similar to old code.
 	}
+
 };
 
 class ShaderFragmentMain2Cycle : public ShaderPart
@@ -1285,6 +1289,9 @@ public:
 			"  lowp float alpha1, alpha2;				\n"
 			"  lowp vec3 color1, color2, input_color;	\n"
 		;
+		m_part += "#define WRAP(x, low, high) mod((x)-(low), (high)-(low)) + (low) \n"; // Return wrapped value of x in interval [low, high)
+		// m_part += "#define WRAP(x, low, high) (x) - ((high)-(low)) * floor(((x)-(low))/((high)-(low)))  \n"; // Perhaps more compatible?
+		// m_part += "#define WRAP(x, low, high) (x) + (2.0) * (1.0-step(low,x)) - (2.0) * step(high,x) \n"; // Step based version. Only wraps correctly if input is in the range [low-(high-low), high + (high-low)). Similar to old code.
 	}
 };