gsdx ogl: implement an alternate shader for Jak Shadows

The game sets the framebuffer as an input texture. So I did the same for
openGL. Code is protected with a CRC. It is working because the game want to sample
pixels.

For the record, I tested it GTA too, it doesn't work as expected because
the game will resize the framebuffer to a smaller one. So you don't have
the guarantee that pixel will be read before a data write.

Note: it requires at least accurate blending set on basic

Note: I need CRC of all Jak games that suffers of this issue. Thanks you :)

plugins/GSdx/GSCrc.cpp

@@ -515,6 +515,7 @@ CRC::Game CRC::m_games[] =
 	{0XE1BF5DCA, SuperManReturns, US, 0},
 	{0x06A7506A, SacredBlaze, JP, 0},
 	{0x4CE7FB04, ItadakiStreet, JP, 0},
+	{0x12804727, Jak3, PAL, 0},
 };
 
 map<uint32, CRC::Game*> CRC::m_map;

plugins/GSdx/GSCrc.h

@@ -175,6 +175,7 @@ class CRC
 		SacredBlaze,
 		SuperManReturns,
 		ItadakiStreet,
+		Jak3,
 		TitleCount,
 	};
 

plugins/GSdx/GSDeviceOGL.cpp

@@ -943,6 +943,7 @@ GLuint GSDeviceOGL::CompilePS(PSSelector sel)
 		+ format("#define PS_CHANNEL_FETCH %d\n", sel.channel)
 		+ format("#define PS_URBAN_CHAOS_HLE %d\n", sel.urban_chaos_hle)
 		+ format("#define PS_TALES_OF_ABYSS_HLE %d\n", sel.tales_of_abyss_hle)
+		+ format("#define PS_TEX_IS_FB %d\n", sel.tex_is_fb)
 		+ format("#define PS_AEM %d\n", sel.aem)
 		+ format("#define PS_TFX %d\n", sel.tfx)
 		+ format("#define PS_TCC %d\n", sel.tcc)

plugins/GSdx/GSDeviceOGL.h

@@ -292,8 +292,9 @@ class GSDeviceOGL final : public GSDevice
 				uint32 tcoffsethack:1;
 				uint32 urban_chaos_hle:1;
 				uint32 tales_of_abyss_hle:1;
+				uint32 tex_is_fb:1; // Jak Shadows
 
-				uint32 _free2:14;
+				uint32 _free2:13;
 			};
 
 			uint64 key;

plugins/GSdx/GSRendererOGL.cpp

@@ -1142,11 +1142,15 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 
 	// Always check if primitive overlap. The function will return PRIM_OVERLAP_UNKNOW for non sprite primitive
 	m_prim_overlap = PrimitiveOverlap();
-#ifdef ENABLE_OGL_DEBUG
-	if (PRIM->TME && m_sw_blending && (m_prim_overlap != PRIM_OVERLAP_NO) && (m_context->FRAME.Block() == m_context->TEX0.TBP0) && (m_vertex.next > 2)) {
-		GL_INS("ERROR: Source and Target are the same!");
+	if ((m_context->FRAME.Block() == m_context->TEX0.TBP0) && PRIM->TME && m_sw_blending && (m_prim_overlap != PRIM_OVERLAP_NO) && (m_vertex.next > 2)) {
+		if (m_game.title == CRC::Jak3) {
+			GL_INS("ERROR: Source and Target are the same! Let's sample the framebuffer");
+			m_ps_sel.tex_is_fb = 1;
+			m_require_full_barrier = true;
+		} else {
+			GL_INS("ERROR: Source and Target are the same!");
+		}
 	}
-#endif
 
 	EmulateTextureShuffleAndFbmask();
 

plugins/GSdx/res/glsl/tfx_fs.glsl

@@ -75,7 +75,11 @@ layout(early_fragment_tests) in;
 
 vec4 sample_c(vec2 uv)
 {
+#if PS_TEX_IS_FB == 1
+    return texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);
+#else
     return texture(TextureSampler, uv);
+#endif
 }
 
 vec4 sample_p(float idx)

plugins/GSdx/res/glsl_source.h

@@ -995,7 +995,11 @@ static const char* const tfx_fs_all_glsl =
 	"\n"
 	"vec4 sample_c(vec2 uv)\n"
 	"{\n"
+	"#if PS_TEX_IS_FB == 1\n"
+	"    return texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0);\n"
+	"#else\n"
 	"    return texture(TextureSampler, uv);\n"
+	"#endif\n"
 	"}\n"
 	"\n"
 	"vec4 sample_p(float idx)\n"