gsdx: GS kinds of support draw without framebuffer

Gow uses 24 bits buffer, so only color is updated but blending is configured as Cd
so it is a NOP

In this case, we don't lookup the target in the texture cache. It reduces the complexity
to handle depth which can be located at same address as RT

Note: please test DX renderer

plugins/GSdx/GS.h

@@ -523,6 +523,7 @@ REG_END2
 	// opaque => output will be Cs/As
 	__forceinline bool IsOpaque() const {return ((A == B || (C == 2 && FIX == 0)) && D == 0) || (A == 0 && B == D && C == 2 && FIX == 0x80);}
 	__forceinline bool IsOpaque(int amin, int amax) const {return ((A == B || amax == 0) && D == 0) || (A == 0 && B == D && amin == 0x80 && amax == 0x80);}
+	__forceinline bool IsCd() { return (A == B) && (D == 1);}
 REG_END2
 
 REG64_(GIFReg, BITBLTBUF)

plugins/GSdx/GSDeviceOGL.cpp

@@ -996,7 +996,6 @@ void GSDeviceOGL::SetupDATE(GSTexture* rt, GSTexture* ds, const GSVertexPT1* ver
 {
 	GL_PUSH("DATE First Pass");
 
-	GSTexture* t = NULL;
 	// sfex3 (after the capcom logo), vf4 (first menu fading in), ffxii shadows, rumble roses shadows, persona4 shadows
 
 	BeginScene();
@@ -1016,7 +1015,7 @@ void GSDeviceOGL::SetupDATE(GSTexture* rt, GSTexture* ds, const GSVertexPT1* ver
 	OMSetDepthStencilState(m_date.dss, 1);
 	OMSetBlendState(m_date.bs, 0);
 	// normally ok without any RT if GL_ARB_framebuffer_no_attachments is supported (minus driver bug)
-	OMSetRenderTargets(t, ds, &GLState::scissor);
+	OMSetRenderTargets(NULL, ds, &GLState::scissor);
 	OMSetColorMaskState(); // TODO: likely useless
 
 	// ia
@@ -1035,9 +1034,7 @@ void GSDeviceOGL::SetupDATE(GSTexture* rt, GSTexture* ds, const GSVertexPT1* ver
 		PSSetSamplerState(m_convert.pt);
 	}
 
-	OMSetWriteBuffer(GL_NONE);
 	DrawPrimitive();
-	OMSetWriteBuffer();
 
 	EndScene();
 
@@ -1179,9 +1176,10 @@ void GSDeviceOGL::OMSetRenderTargets(GSTexture* rt, GSTexture* ds, const GSVecto
 	if (rt == NULL || !RT->IsBackbuffer()) {
 		OMSetFBO(m_fbo);
 		if (rt) {
+			OMSetWriteBuffer();
 			OMAttachRt(RT);
 		} else {
-			// Note: NULL rt is only used in DATE so far.
+			OMSetWriteBuffer(GL_NONE);
 			OMAttachRt();
 		}
 

plugins/GSdx/GSRendererDX.cpp

@@ -47,8 +47,8 @@ void GSRendererDX::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 	GSDrawingEnvironment& env = m_env;
 	GSDrawingContext* context = m_context;
 
-	const GSVector2i& rtsize = rt->GetSize();
+	const GSVector2i& rtsize = ds->GetSize();
-	const GSVector2& rtscale = rt->GetScale();
+	const GSVector2& rtscale = ds->GetScale();
 
 	bool DATE = m_context->TEST.DATE && context->FRAME.PSM != PSM_PSMCT24;
 
@@ -199,7 +199,7 @@ void GSRendererDX::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 	//The resulting shifted output aligns better with common blending / corona / blurring effects,
 	//but introduces a few bad pixels on the edges.
 
-	if(rt->LikelyOffset)
+	if(rt && rt->LikelyOffset)
 	{
 		// DX9 has pixelcenter set to 0.0, so give it some value here
 

plugins/GSdx/GSRendererDX9.cpp

@@ -231,6 +231,9 @@ void GSRendererDX9::SetupIA()
 
 void GSRendererDX9::UpdateFBA(GSTexture* rt)
 {
+	if (!rt)
+		return;
+
 	GSDevice9* dev = (GSDevice9*)m_dev;
 
 	dev->BeginScene();

plugins/GSdx/GSRendererHW.cpp

@@ -334,12 +334,17 @@ void GSRendererHW::Draw()
 	GSDrawingEnvironment& env = m_env;
 	GSDrawingContext* context = m_context;
 
+	// It is allowed to use the depth and rt at the same location. However at least 1 must
+	// be disabled. GoW uses a Cd blending on a 24 bits buffer (no alpha)
+	const bool no_rt = context->ALPHA.IsCd() && PRIM->ABE && (context->FRAME.PSM == 1);
+
 	GIFRegTEX0 TEX0;
 
 	TEX0.TBP0 = context->FRAME.Block();
 	TEX0.TBW = context->FRAME.FBW;
 	TEX0.PSM = context->FRAME.PSM;
-	GSTextureCache::Target* rt = m_tc->LookupTarget(TEX0, m_width, m_height, GSTextureCache::RenderTarget, true);
+
+	GSTextureCache::Target* rt = no_rt ? NULL : m_tc->LookupTarget(TEX0, m_width, m_height, GSTextureCache::RenderTarget, true);
 
 	TEX0.TBP0 = context->ZBUF.Block();
 	TEX0.TBW = context->FRAME.FBW;
@@ -347,7 +352,7 @@ void GSRendererHW::Draw()
 
 	GSTextureCache::Target* ds = m_tc->LookupTarget(TEX0, m_width, m_height, GSTextureCache::DepthStencil, context->DepthWrite());
 
-	if(!rt || !ds)
+	if((!rt && !no_rt) || !ds)
 	{
 		GL_POP();
 		ASSERT(0);
@@ -429,6 +434,7 @@ void GSRendererHW::Draw()
 		{
 			s = format("%05d_f%lld_rt0_%05x_%d.bmp", s_n, frame, context->FRAME.Block(), context->FRAME.PSM);
 
+			if (rt)
 				rt->m_texture->Save(root_hw+s);
 		}
 
@@ -447,7 +453,7 @@ void GSRendererHW::Draw()
 #endif
 	}
 
-	if(m_hacks.m_oi && !(this->*m_hacks.m_oi)(rt->m_texture, ds->m_texture, tex))
+	if(m_hacks.m_oi && !(this->*m_hacks.m_oi)(NULL, ds->m_texture, tex))
 	{
 		s_n += 1; // keep counter sync
 		GL_POP();
@@ -514,7 +520,7 @@ void GSRendererHW::Draw()
 
 	//
 
-	DrawPrims(rt->m_texture, ds->m_texture, tex);
+	DrawPrims(rt ? rt->m_texture : NULL, ds->m_texture, tex);
 
 	//
 
@@ -526,7 +532,7 @@ void GSRendererHW::Draw()
 
 	GSVector4i r = GSVector4i(m_vt.m_min.p.xyxy(m_vt.m_max.p)).rintersect(GSVector4i(context->scissor.in));
 
-	if(fm != 0xffffffff)
+	if(fm != 0xffffffff && rt)
 	{
 		rt->m_valid = rt->m_valid.runion(r);
 
@@ -557,6 +563,7 @@ void GSRendererHW::Draw()
 		{
 			s = format("%05d_f%lld_rt1_%05x_%d.bmp", s_n, frame, context->FRAME.Block(), context->FRAME.PSM);
 
+			if (rt)
 				rt->m_texture->Save(root_hw+s);
 		}
 
@@ -580,6 +587,7 @@ void GSRendererHW::Draw()
 
 	#ifdef DISABLE_HW_TEXTURE_CACHE
 	
+	if (rt)
 		m_tc->Read(rt, r);
 
 	#endif

plugins/GSdx/GSRendererOGL.cpp

@@ -217,13 +217,13 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 {
 	GL_PUSH("GL Draw from %d in %d (Depth %d)",
 				tex && tex->m_texture ? tex->m_texture->GetID() : 0,
-				rt->GetID(), ds->GetID());
+				rt ? rt->GetID() : -1, ds->GetID());
 
 	GSDrawingEnvironment& env = m_env;
 	GSDrawingContext* context = m_context;
 
-	const GSVector2i& rtsize = rt->GetSize();
+	const GSVector2i& rtsize = ds->GetSize();
-	const GSVector2& rtscale = rt->GetScale();
+	const GSVector2& rtscale = ds->GetScale();
 
 	bool DATE = m_context->TEST.DATE && context->FRAME.PSM != PSM_PSMCT24;
 	bool DATE_GL42 = false;
@@ -425,7 +425,7 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 	//The resulting shifted output aligns better with common blending / corona / blurring effects,
 	//but introduces a few bad pixels on the edges.
 
-	if (rt->LikelyOffset)
+	if (rt && rt->LikelyOffset)
 	{
 		ox2 *= rt->OffsetHack_modx;
 		oy2 *= rt->OffsetHack_mody;
@@ -621,7 +621,7 @@ void GSRendererOGL::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sour
 	bool all_sw = !( (ALPHA.A == ALPHA.B) || (ALPHA.C == 2 && afix <= 1.002f) ) && (m_accurate_blend > 1);
 	bool sw_blending = (m_accurate_blend && (bogus_blend & A_MAX)) || acc_colclip_wrap || all_sw;
 
-	if (sw_blending && om_bsel.abe) {
+	if (sw_blending && om_bsel.abe && rt) {
 		GL_INS("!!! SW blending effect used (0x%x from sel %d) !!!", bogus_blend, blend_sel);
 
 		// select a shader that support blending