gsdx-ogl: improve date performance for GL45

If there is no overlap, it is allowed to directly read from the render target.

On SotC testcase with 6x scaling: 30fps -> 40fps

Note: it requires GL_ARB_texture_barrier extension so be sure to have a recent driver

Note2: it requires a lots of testing too

Open question: in case of complex date (written alpha)
Will it be faster to split the draw call into multiple call with no
primitive overlap

plugins/GSdx/GLState.cpp

@@ -54,8 +54,8 @@ namespace GLState {
 
 	GLuint rt = 0;
 	GLuint ds = 0;
-	GLuint tex_unit[2] = {0, 0};
+	GLuint tex_unit[4] = {0, 0, 0, 0};
-	GLuint64 tex_handle[2] = { 0, 0};
+	GLuint64 tex_handle[4] = { 0, 0, 0, 0};
 	bool dirty_ressources = false;
 
 	GLuint ps = 0;
@@ -106,10 +106,10 @@ namespace GLState {
 
 		rt = 0;
 		ds = 0;
-		tex_unit[0] = 0;
+		for (int i = 0; i < 4; i++) {
-		tex_unit[1] = 0;
+			tex_unit[i] = 0;
-		tex_handle[0] = 0;
+			tex_handle[i] = 0;
-		tex_handle[1] = 0;
+		}
 
 		ps = 0;
 		gs = 0;

plugins/GSdx/GLState.h

@@ -56,8 +56,8 @@ namespace GLState {
 
 	extern GLuint rt; // render target
 	extern GLuint ds; // Depth-Stencil
-	extern GLuint tex_unit[2]; // shader input texture
+	extern GLuint tex_unit[4]; // shader input texture
-	extern GLuint64 tex_handle[2]; // shader input texture
+	extern GLuint64 tex_handle[4]; // shader input texture
 
 	extern GLuint ps;
 	extern GLuint gs;

plugins/GSdx/GSDeviceOGL.cpp

@@ -579,7 +579,6 @@ void GSDeviceOGL::InitPrimDateTexture(GSTexture* rt)
 #ifndef ENABLE_GLES
 	gl_BindImageTexture(2, static_cast<GSTextureOGL*>(m_date.t)->GetID(), 0, false, 0, GL_READ_WRITE, GL_R32I);
 #endif
-	gl_BindTextureUnit(3, static_cast<GSTextureOGL*>(rt)->GetID());
 }
 
 void GSDeviceOGL::RecycleDateTexture()

plugins/GSdx/GSDeviceOGL.h

@@ -372,7 +372,7 @@ class GSDeviceOGL : public GSDevice
 				uint32 clr1:1;
 				uint32 fba:1;
 				uint32 aout:1;
-				uint32 date:2;
+				uint32 date:3;
 				uint32 spritehack:1;
 				uint32 tcoffsethack:1;
 				uint32 point_sampler:1;

plugins/GSdx/GSRendererOGL.cpp

@@ -151,6 +151,39 @@ void GSRendererOGL::SetupIA()
 	dev->IASetPrimitiveTopology(t);
 }
 
+bool GSRendererOGL::PrimitiveOverlap()
+{
+	if (m_vertex.next < 4)
+		return false;
+
+	if (m_vt.m_primclass != GS_SPRITE_CLASS)
+		return true;
+
+	// Check intersection of sprite primitive only
+	size_t count = m_vertex.next;
+	GSVertex* v = &m_vertex.buff[0];
+
+	for(size_t i = 0; i < count; i += 2) {
+		// Very bad code
+		GSVector4i vi(v[i].XYZ.X, v[i].XYZ.Y, v[i+1].XYZ.X, v[i+1].XYZ.Y);
+		for (size_t j = i+2; j < count; j += 2) {
+			GSVector4i vj(v[j].XYZ.X, v[j].XYZ.Y, v[j+1].XYZ.X, v[j+1].XYZ.Y);
+			GSVector4i inter = vi.rintersect(vj);
+			if (!inter.rempty()) {
+				//fprintf(stderr, "Overlap found between %d and %d (draw of %d vertices)\n", i, j, count);
+				//vi.print();
+				//vj.print();
+				//inter.print();
+				//exit(0);
+				return true;
+			}
+		}
+	}
+
+	//fprintf(stderr, "Yes, code can be optimized (draw of %d vertices)\n", count);
+	return false;
+}
+
 void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Source* tex)
 {
 	GSDrawingEnvironment& env = m_env;
@@ -160,7 +193,8 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 	const GSVector2& rtscale = rt->GetScale();
 
 	bool DATE = m_context->TEST.DATE && context->FRAME.PSM != PSM_PSMCT24;
-	bool advance_DATE = false;
+	bool DATE_GL42 = false;
+	bool DATE_GL45 = false;
 
 	ASSERT(m_dev != NULL);
 
@@ -208,14 +242,21 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 
 	om_bsel.wrgba = ~GSVector4i::load((int)context->FRAME.FBMSK).eq8(GSVector4i::xffffffff()).mask();
 
-	if (DATE && om_bsel.wa && (!context->TEST.ATE || context->TEST.ATST == ATST_ALWAYS)) {
+	if (DATE) {
-		advance_DATE = GLLoader::found_GL_ARB_shader_image_load_store && !UserHacks_AlphaStencil;
+		if (gl_TextureBarrier && !PrimitiveOverlap()) {
+			DATE_GL45 = true;
+			DATE = false;
+		} else if (om_bsel.wa && (!context->TEST.ATE || context->TEST.ATST == ATST_ALWAYS)) {
+			DATE_GL42 = GLLoader::found_GL_ARB_shader_image_load_store && !UserHacks_AlphaStencil;
+		}
 	}
 
 	// DATE
 
-	if(DATE)
+	if (DATE_GL45) {
-	{
+		gl_TextureBarrier();
+		dev->PSSetShaderResource(3, rt);
+	} else if (DATE) {
 		// TODO: do I need to clamp the value (if yes how? rintersect with rt?)
 		GSVector4 si = GSVector4(rtscale.x, rtscale.y);
 		GSVector4 o = GSVector4(-1.0f, 1.0f); // Round value
@@ -227,8 +268,9 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 
 		// Must be done here to avoid any GL state pertubation (clear function...)
 		// Create an r32ui image that will containt primitive ID
-		if (advance_DATE) {
+		if (DATE_GL42) {
 			dev->InitPrimDateTexture(rt);
+			dev->PSSetShaderResource(3, rt);
 		} else {
 			GSVector4 s = GSVector4(rtscale.x / rtsize.x, rtscale.y / rtsize.y);
 
@@ -349,9 +391,10 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 	// GS_SPRITE_CLASS are already flat (either by CPU or the GS)
 	ps_sel.iip = (m_vt.m_primclass == GS_SPRITE_CLASS) ? 1 : PRIM->IIP;
 
-	if(DATE)
+	if (DATE_GL45) {
-	{
+		ps_sel.date = 5 + context->TEST.DATM;
-		if (advance_DATE)
+	} else if(DATE) {
+		if (DATE_GL42)
 			ps_sel.date = 1 + context->TEST.DATM;
 		else
 			om_dssel.date = 1;
@@ -497,7 +540,7 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 	dev->SetupOM(om_dssel, om_bsel, afix);
 	dev->SetupCB(&vs_cb, &ps_cb, ps_sel.sprite ? &gs_cb : NULL);
 
-	if (advance_DATE) {
+	if (DATE_GL42) {
 		// Create an r32i image that will contain primitive ID
 		// Note: do it at the beginning because the clean will dirty the FBO state
 		//dev->InitPrimDateTexture(rtsize.x, rtsize.y);
@@ -598,7 +641,7 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 			}
 		}
 	}
-	if (advance_DATE)
+	if (DATE_GL42)
 		dev->RecycleDateTexture();
 
 	dev->EndScene();

plugins/GSdx/GSRendererOGL.h

@@ -56,4 +56,6 @@ class GSRendererOGL : public GSRendererHW
 		void UpdateFBA(GSTexture* rt);
 
 		void DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Source* tex);
+
+		bool PrimitiveOverlap();
 };

plugins/GSdx/res/glsl/tfx_fs.glsl

@@ -438,13 +438,13 @@ void ps_main()
 #if !pGL_ES
 void ps_main()
 {
-#if PS_DATE == 1 && !defined(DISABLE_GL42_image)
+#if (PS_DATE & 3) == 1 && !defined(DISABLE_GL42_image)
     // DATM == 0
     // Pixel with alpha equal to 1 will failed
 	float rt_a = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0).a;
 	if ((127.5f / 255.0f) < rt_a) // < 0x80 pass (== 0x80 should not pass)
 		discard;
-#elif PS_DATE == 2 && !defined(DISABLE_GL42_image)
+#elif (PS_DATE & 3) == 2 && !defined(DISABLE_GL42_image)
     // DATM == 1
     // Pixel with alpha equal to 0 will failed
 	float rt_a = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0).a;

plugins/GSdx/res/glsl_source.h

@@ -1189,13 +1189,13 @@ static const char* tfx_fs_all_glsl =
 	"#if !pGL_ES\n"
 	"void ps_main()\n"
 	"{\n"
-	"#if PS_DATE == 1 && !defined(DISABLE_GL42_image)\n"
+	"#if (PS_DATE & 3) == 1 && !defined(DISABLE_GL42_image)\n"
 	"    // DATM == 0\n"
 	"    // Pixel with alpha equal to 1 will failed\n"
 	"	float rt_a = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0).a;\n"
 	"	if ((127.5f / 255.0f) < rt_a) // < 0x80 pass (== 0x80 should not pass)\n"
 	"		discard;\n"
-	"#elif PS_DATE == 2 && !defined(DISABLE_GL42_image)\n"
+	"#elif (PS_DATE & 3) == 2 && !defined(DISABLE_GL42_image)\n"
 	"    // DATM == 1\n"
 	"    // Pixel with alpha equal to 0 will failed\n"
 	"	float rt_a = texelFetch(RtSampler, ivec2(gl_FragCoord.xy), 0).a;\n"