gsdx-hw: Implement per pixel alpha blending (PABE).

Fixes Strawberry Shortcake character lighting/face shadow.
Fixes Cartoon Network Racing shadows.

Credits to Kojin.

plugins/GSdx/Renderers/DX11/GSDevice11.h

@@ -233,8 +233,8 @@ public:
 				uint32 blend_c:2; // bit0
 				uint32 blend_d:2;
 				uint32 clr1:1;
-
 				uint32 colclip:1;
+				uint32 pabe:1;
 
 				// Others ways to fetch the texture
 				uint32 channel:3;
@@ -252,7 +252,7 @@ public:
 				uint32 point_sampler:1;
 				uint32 invalid_tex0:1; // Lupin the 3rd
 
-				uint32 _free:15;
+				uint32 _free:14;
 			};
 
 			uint64 key;

plugins/GSdx/Renderers/DX11/GSRendererDX11.cpp

@@ -470,7 +470,9 @@ void GSRendererDX11::EmulateBlending()
 			m_om_bsel.abe = 0;
 		}
 
-		// Breath of Fire Dragon Quarter, Strawberry Shortcake, Super Robot Wars.
+		// Breath of Fire Dragon Quarter, Strawberry Shortcake, Super Robot Wars, Cartoon Network Racing.
+		// fprintf(stderr, "%d: PABE mode ENABLED\n", s_n);
+		m_ps_sel.pabe = 1;
 	}
 
 	m_om_bsel.blend_index = uint8(((ALPHA.A * 3 + ALPHA.B) * 3 + ALPHA.C) * 3 + ALPHA.D);

plugins/GSdx/Renderers/DX11/GSTextureFX11.cpp

@@ -219,6 +219,7 @@ void GSDevice11::SetupPS(PSSelector sel, const PSConstantBuffer* cb, PSSamplerSe
 		sm.AddMacro("PS_BLEND_B", sel.blend_b);
 		sm.AddMacro("PS_BLEND_C", sel.blend_c);
 		sm.AddMacro("PS_BLEND_D", sel.blend_d);
+		sm.AddMacro("PS_PABE", sel.pabe);
 		sm.AddMacro("PS_DITHER", sel.dither);
 		sm.AddMacro("PS_ZCLAMP", sel.zclamp);
 

plugins/GSdx/Renderers/OpenGL/GSDeviceOGL.cpp

@@ -984,7 +984,7 @@ GLuint GSDeviceOGL::CompilePS(PSSelector sel)
 		+ format("#define PS_HDR %d\n", sel.hdr)
 		+ format("#define PS_DITHER %d\n", sel.dither)
 		+ format("#define PS_ZCLAMP %d\n", sel.zclamp)
-		// + format("#define PS_PABE %d\n", sel.pabe)
+		+ format("#define PS_PABE %d\n", sel.pabe)
 	;
 
 	if (GLLoader::buggy_sso_dual_src)

plugins/GSdx/Renderers/OpenGL/GSDeviceOGL.h

@@ -300,7 +300,7 @@ public:
 				uint32 clr1:1; // useful?
 				uint32 hdr:1;
 				uint32 colclip:1;
-				// uint32 pabe:1;
+				uint32 pabe:1;
 
 				// Others ways to fetch the texture
 				uint32 channel:3;
@@ -321,7 +321,7 @@ public:
 				uint32 point_sampler:1;
 				uint32 invalid_tex0:1; // Lupin the 3rd
 
-				uint32 _free2:7;
+				uint32 _free2:6;
 			};
 
 			uint64 key;

plugins/GSdx/Renderers/OpenGL/GSRendererOGL.cpp

@@ -420,14 +420,9 @@ void GSRendererOGL::EmulateBlending(bool& DATE_GL42, bool& DATE_GL45)
 	}
 
 	if (m_env.PABE.PABE) {
-		GL_INS("ERROR: ENV PABE not supported!");
-		if (m_sw_blending >= ACC_BLEND_MEDIUM) {
-			// m_ps_sel.pabe = 1;
-			m_require_full_barrier |= (ALPHA.C == 1);
-			sw_blending = true;
-		}
-		// Breath of Fire Dragon Quarter, Strawberry Shortcake, Super Robot Wars.
-		//ASSERT(0);
+		// Breath of Fire Dragon Quarter, Strawberry Shortcake, Super Robot Wars, Cartoon Network Racing.
+		GL_INS("PABE mode ENABLED");
+		m_ps_sel.pabe = 1;
 	}
 
 	// Compute the blending equation to detect special case

plugins/GSdx/res/glsl/tfx_fs.glsl

@@ -627,6 +627,7 @@ void ps_blend(inout vec4 Color, float As)
 {
 #if SW_BLEND
     vec4 RT = trunc(texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0) * 255.0f + 0.1f);
+    vec4 Color_pabe = Color;
 
 #if PS_DFMT == FMT_24
     float Ad = 1.0f;
@@ -678,6 +679,11 @@ void ps_blend(inout vec4 Color, float As)
     Color.rgb = trunc((A - B) * C + D);
 #endif
 
+    // PABE
+#if PS_PABE
+    Color.rgb = (Color_pabe.a >= 128.0f) ? Color.rgb : Color_pabe.rgb;
+#endif
+
     // Dithering
     ps_dither(Color);
 

plugins/GSdx/res/tfx.fx

@@ -48,6 +48,7 @@
 #define PS_BLEND_B 0
 #define PS_BLEND_C 0
 #define PS_BLEND_D 0
+#define PS_PABE 0
 #define PS_DITHER 0
 #define PS_ZCLAMP 0
 #endif
@@ -685,6 +686,10 @@ void ps_blend(inout float4 Color, float As, float2 pos_xy)
 
 		Cv = (PS_BLEND_A == PS_BLEND_B) ? D : trunc(((A - B) * C) + D);
 
+		// PABE
+		if (PS_PABE)
+			Cv = (Color.a >= 128.0f) ? Cv : Color.rgb;
+
 		// Dithering
 		ps_dither(Cv, pos_xy);