From 23f8203a22f30f99220a4ce457ca7926ef9597dd Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Fri, 29 May 2015 18:58:26 +0200
Subject: [PATCH] gsdx-ogl: add some shaders to convert depth <-> color

I'm afraid of rounding error
---
 plugins/GSdx/GSDeviceOGL.h         |  2 +-
 plugins/GSdx/res/glsl/convert.glsl | 26 ++++++++++++++++++++++++++
 plugins/GSdx/res/glsl_source.h     | 26 ++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/plugins/GSdx/GSDeviceOGL.h b/plugins/GSdx/GSDeviceOGL.h
index 64f42e9f80..74e9053f30 100644
--- a/plugins/GSdx/GSDeviceOGL.h
+++ b/plugins/GSdx/GSDeviceOGL.h
@@ -486,7 +486,7 @@ class GSDeviceOGL : public GSDevice
 
 	struct {
 		GLuint vs;		// program object
-		GLuint ps[11];	// program object
+		GLuint ps[13];	// program object
 		GLuint ln;		// sampler object
 		GLuint pt;		// sampler object
 		GSDepthStencilOGL* dss;
diff --git a/plugins/GSdx/res/glsl/convert.glsl b/plugins/GSdx/res/glsl/convert.glsl
index a664e87459..3a7fa21f17 100644
--- a/plugins/GSdx/res/glsl/convert.glsl
+++ b/plugins/GSdx/res/glsl/convert.glsl
@@ -151,12 +151,38 @@ void ps_main1()
 #ifdef ps_main10
 void ps_main10()
 {
+	// Convert a GL_FLOAT32 depth texture into a 32 bits UINT texture
 	vec4 c = sample_c();
 	const float exp2_32 = exp2(32.0f);
 	SV_Target1 = uint(exp2_32 * c.r);
 }
 #endif
 
+#ifdef ps_main11
+void ps_main11()
+{
+	const float exp2_32 = exp2(32.0f);
+	const vec4 bitSh = vec4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);
+	const vec4 bitMsk = vec4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);
+
+	// Convert a GL_FLOAT32 depth texture into a RGBA texture
+	vec4 res = fract(vec4(sample_c().r) * bitSh);
+
+	SV_Target0 = (res - res.xxyz * bitMsk) * 256.0f/255.0f;
+}
+#endif
+
+#ifdef ps_main12
+out float gl_FragDepth;
+void ps_main12()
+{
+	// Convert a RRGBA texture into a float depth texture
+	// FIXME: I'm afraid of the accuracy
+	const vec4 bitSh = vec4(1.0/(256.0*256.0*256.0), 1.0/(256.0*256.0), 1.0/256.0, 1.0) * vec4(255.0/256.0);
+	gl_FragDepth = dot(sample_c(), bitSh);
+}
+#endif
+
 #ifdef ps_main7
 void ps_main7()
 {
diff --git a/plugins/GSdx/res/glsl_source.h b/plugins/GSdx/res/glsl_source.h
index 1a6cc4dacd..08a0303ee6 100644
--- a/plugins/GSdx/res/glsl_source.h
+++ b/plugins/GSdx/res/glsl_source.h
@@ -176,12 +176,38 @@ static const char* convert_glsl =
 	"#ifdef ps_main10\n"
 	"void ps_main10()\n"
 	"{\n"
+	"	// Convert a GL_FLOAT32 depth texture into a 32 bits UINT texture\n"
 	"	vec4 c = sample_c();\n"
 	"	const float exp2_32 = exp2(32.0f);\n"
 	"	SV_Target1 = uint(exp2_32 * c.r);\n"
 	"}\n"
 	"#endif\n"
 	"\n"
+	"#ifdef ps_main11\n"
+	"void ps_main11()\n"
+	"{\n"
+	"	const float exp2_32 = exp2(32.0f);\n"
+	"	const vec4 bitSh = vec4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);\n"
+	"	const vec4 bitMsk = vec4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);\n"
+	"\n"
+	"	// Convert a GL_FLOAT32 depth texture into a RGBA texture\n"
+	"	vec4 res = fract(vec4(sample_c().r) * bitSh);\n"
+	"\n"
+	"	SV_Target0 = (res - res.xxyz * bitMsk) * 256.0f/255.0f;\n"
+	"}\n"
+	"#endif\n"
+	"\n"
+	"#ifdef ps_main12\n"
+	"out float gl_FragDepth;\n"
+	"void ps_main12()\n"
+	"{\n"
+	"	// Convert a RRGBA texture into a float depth texture\n"
+	"	// FIXME: I'm afraid of the accuracy\n"
+	"	const vec4 bitSh = vec4(1.0/(256.0*256.0*256.0), 1.0/(256.0*256.0), 1.0/256.0, 1.0) * vec4(255.0/256.0);\n"
+	"	gl_FragDepth = dot(sample_c(), bitSh);\n"
+	"}\n"
+	"#endif\n"
+	"\n"
 	"#ifdef ps_main7\n"
 	"void ps_main7()\n"
 	"{\n"