From 7fac25edb093774b274134fff711b9cb0384f10f Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Fri, 8 May 2015 20:27:13 +0200
Subject: [PATCH] glsl: add shader implementation of impossible blend

Issue: I don't know if destination alpha value must be multiplied by 2.0f
---
 plugins/GSdx/res/glsl/tfx_fs.glsl | 41 +++++++++++++++++++++++++++++++
 plugins/GSdx/res/glsl_source.h    | 41 +++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/plugins/GSdx/res/glsl/tfx_fs.glsl b/plugins/GSdx/res/glsl/tfx_fs.glsl
index 64770f6742..5f018dc8c3 100644
--- a/plugins/GSdx/res/glsl/tfx_fs.glsl
+++ b/plugins/GSdx/res/glsl/tfx_fs.glsl
@@ -375,6 +375,43 @@ vec4 ps_color()
 	return c;
 }
 
+void ps_blend(inout vec4 c, in float As)
+{
+	vec4 rt = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);
+	// FIXME Ad or Ad * 2?
+	float Ad = rt.a;
+
+#if PS_BLEND == 1
+	// {4, D3DBLENDOP_SUBTRACT, D3DBLEND_SRCALPHA, D3DBLEND_SRCALPHA},			//*0100: (Cs - Cd)*As + Cs ==> Cs*(As + 1) - Cd*As
+	c.rgb = c.rgb * (As + 1.0f) - rt.rgb * As;
+#elif PS_BLEND == 2
+	// {5, D3DBLENDOP_SUBTRACT, D3DBLEND_DESTALPHA, D3DBLEND_DESTALPHA},		//*0110: (Cs - Cd)*Ad + Cs ==> Cs*(Ad + 1) - Cd*Ad
+	c.rgb = c.rgb * (Ad + 1.0f) - rt.rgb * Ad;
+#elif PS_BLEND == 3
+	// {6, D3DBLENDOP_SUBTRACT, D3DBLEND_BLENDFACTOR, D3DBLEND_BLENDFACTOR},	//*0120: (Cs - Cd)*F  + Cs ==> Cs*(F + 1) - Cd*F
+	c.rgb = c.rgb * (Af.x + 1.0f) - rt.rgb * Af.x;
+#elif PS_BLEND == 4
+	// {7, D3DBLENDOP_ADD, D3DBLEND_SRCALPHA, D3DBLEND_ZERO},					//*0200: (Cs -  0)*As + Cs ==> Cs*(As + 1)
+	c.rgb = c.rgb * (As + 1.0f); // FIXME Not bogus
+#elif PS_BLEND == 5
+	// {8, D3DBLENDOP_ADD, D3DBLEND_DESTALPHA, D3DBLEND_ZERO},					//*0210: (Cs -  0)*Ad + Cs ==> Cs*(Ad + 1)
+	c.rgb = c.rgb * (Ad + 1.0f);
+#elif PS_BLEND == 6
+	// {9, D3DBLENDOP_ADD, D3DBLEND_BLENDFACTOR, D3DBLEND_ZERO},				//*0220: (Cs -  0)*F  + Cs ==> Cs*(F + 1)
+	besoin du fix
+	c.rgb = c.rgb * (Af.x + 1.0f); // FIXME Not bogus
+#elif PS_BLEND == 7
+	// {10,D3DBLENDOP_REVSUBTRACT, D3DBLEND_SRCALPHA, D3DBLEND_SRCALPHA},		//*1001: (Cd - Cs)*As + Cd ==> Cd*(As + 1) - Cs*As
+	c.rgb = rt.rgb * (As + 1.0f) - c.rgb * As;
+#elif PS_BLEND == 8
+	// {11,D3DBLENDOP_REVSUBTRACT, D3DBLEND_DESTALPHA, D3DBLEND_DESTALPHA},	//*1011: (Cd - Cs)*Ad + Cd ==> Cd*(Ad + 1) - Cs*Ad
+	c.rgb = rt.rgb * (Ad + 1.0f) - c.rgb * Ad;
+#elif PS_BLEND == 9
+	// {12,D3DBLENDOP_REVSUBTRACT, D3DBLEND_BLENDFACTOR, D3DBLEND_BLENDFACTOR},//*1021: (Cd - Cs)*F  + Cd ==> Cd*(F + 1) - Cs*F
+	c.rgb = rt.rgb * (Af.x + 1.0f) - c.rgb * Af.x;
+#endif
+}
+
 void ps_main()
 {
 #if (PS_DATE & 3) == 1 && !defined(DISABLE_GL42_image)
@@ -446,6 +483,10 @@ void ps_main()
 	}
 #endif
 
+#if PS_BLEND > 0
+	ps_blend(c, alpha);
+#endif
+
 	SV_Target0 = c;
 	SV_Target1 = vec4(alpha, alpha, alpha, alpha);
 }
diff --git a/plugins/GSdx/res/glsl_source.h b/plugins/GSdx/res/glsl_source.h
index e7125df834..4f86ec2212 100644
--- a/plugins/GSdx/res/glsl_source.h
+++ b/plugins/GSdx/res/glsl_source.h
@@ -1089,6 +1089,43 @@ static const char* tfx_fs_all_glsl =
 	"	return c;\n"
 	"}\n"
 	"\n"
+	"void ps_blend(inout vec4 c, in float As)\n"
+	"{\n"
+	"	vec4 rt = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);\n"
+	"	// FIXME Ad or Ad * 2?\n"
+	"	float Ad = rt.a;\n"
+	"\n"
+	"#if PS_BLEND == 1\n"
+	"	// {4, D3DBLENDOP_SUBTRACT, D3DBLEND_SRCALPHA, D3DBLEND_SRCALPHA},			//*0100: (Cs - Cd)*As + Cs ==> Cs*(As + 1) - Cd*As\n"
+	"	c.rgb = c.rgb * (As + 1.0f) - rt.rgb * As;\n"
+	"#elif PS_BLEND == 2\n"
+	"	// {5, D3DBLENDOP_SUBTRACT, D3DBLEND_DESTALPHA, D3DBLEND_DESTALPHA},		//*0110: (Cs - Cd)*Ad + Cs ==> Cs*(Ad + 1) - Cd*Ad\n"
+	"	c.rgb = c.rgb * (Ad + 1.0f) - rt.rgb * Ad;\n"
+	"#elif PS_BLEND == 3\n"
+	"	// {6, D3DBLENDOP_SUBTRACT, D3DBLEND_BLENDFACTOR, D3DBLEND_BLENDFACTOR},	//*0120: (Cs - Cd)*F  + Cs ==> Cs*(F + 1) - Cd*F\n"
+	"	c.rgb = c.rgb * (Af.x + 1.0f) - rt.rgb * Af.x;\n"
+	"#elif PS_BLEND == 4\n"
+	"	// {7, D3DBLENDOP_ADD, D3DBLEND_SRCALPHA, D3DBLEND_ZERO},					//*0200: (Cs -  0)*As + Cs ==> Cs*(As + 1)\n"
+	"	c.rgb = c.rgb * (As + 1.0f); // FIXME Not bogus\n"
+	"#elif PS_BLEND == 5\n"
+	"	// {8, D3DBLENDOP_ADD, D3DBLEND_DESTALPHA, D3DBLEND_ZERO},					//*0210: (Cs -  0)*Ad + Cs ==> Cs*(Ad + 1)\n"
+	"	c.rgb = c.rgb * (Ad + 1.0f);\n"
+	"#elif PS_BLEND == 6\n"
+	"	// {9, D3DBLENDOP_ADD, D3DBLEND_BLENDFACTOR, D3DBLEND_ZERO},				//*0220: (Cs -  0)*F  + Cs ==> Cs*(F + 1)\n"
+	"	besoin du fix\n"
+	"	c.rgb = c.rgb * (Af.x + 1.0f); // FIXME Not bogus\n"
+	"#elif PS_BLEND == 7\n"
+	"	// {10,D3DBLENDOP_REVSUBTRACT, D3DBLEND_SRCALPHA, D3DBLEND_SRCALPHA},		//*1001: (Cd - Cs)*As + Cd ==> Cd*(As + 1) - Cs*As\n"
+	"	c.rgb = rt.rgb * (As + 1.0f) - c.rgb * As;\n"
+	"#elif PS_BLEND == 8\n"
+	"	// {11,D3DBLENDOP_REVSUBTRACT, D3DBLEND_DESTALPHA, D3DBLEND_DESTALPHA},	//*1011: (Cd - Cs)*Ad + Cd ==> Cd*(Ad + 1) - Cs*Ad\n"
+	"	c.rgb = rt.rgb * (Ad + 1.0f) - c.rgb * Ad;\n"
+	"#elif PS_BLEND == 9\n"
+	"	// {12,D3DBLENDOP_REVSUBTRACT, D3DBLEND_BLENDFACTOR, D3DBLEND_BLENDFACTOR},//*1021: (Cd - Cs)*F  + Cd ==> Cd*(F + 1) - Cs*F\n"
+	"	c.rgb = rt.rgb * (Af.x + 1.0f) - c.rgb * Af.x;\n"
+	"#endif\n"
+	"}\n"
+	"\n"
 	"void ps_main()\n"
 	"{\n"
 	"#if (PS_DATE & 3) == 1 && !defined(DISABLE_GL42_image)\n"
@@ -1160,6 +1197,10 @@ static const char* tfx_fs_all_glsl =
 	"	}\n"
 	"#endif\n"
 	"\n"
+	"#if PS_BLEND > 0\n"
+	"	ps_blend(c, alpha);\n"
+	"#endif\n"
+	"\n"
 	"	SV_Target0 = c;\n"
 	"	SV_Target1 = vec4(alpha, alpha, alpha, alpha);\n"
 	"}\n"