From 06055add5c225d18290a59d1681e9a7546a6df9a Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Sun, 9 Oct 2016 14:46:55 +0200
Subject: [PATCH] gsdx merge: get a new buffer for the feedback write

---
 plugins/GSdx/GSRenderer.cpp   |  5 ++++-
 plugins/GSdx/GSRenderer.h     |  1 +
 plugins/GSdx/GSRendererHW.cpp | 20 ++++++++++++++++++++
 plugins/GSdx/GSRendererHW.h   |  1 +
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/plugins/GSdx/GSRenderer.cpp b/plugins/GSdx/GSRenderer.cpp
index 6a147b9964..49ace2318b 100644
--- a/plugins/GSdx/GSRenderer.cpp
+++ b/plugins/GSdx/GSRenderer.cpp
@@ -201,7 +201,9 @@ bool GSRenderer::Merge(int field)
 
 	s_n++;
 
-	if(samesrc && fr[0].bottom == fr[1].bottom)
+	bool feedback_merge = m_regs->EXTWRITE.WRITE == 1;
+
+	if(samesrc && fr[0].bottom == fr[1].bottom && !feedback_merge)
 	{
 		tex[0]      = GetOutput(0, y_offset[0]);
 		tex[1]      = tex[0]; // saves one texture fetch
@@ -211,6 +213,7 @@ bool GSRenderer::Merge(int field)
 	{
 		if(en[0]) tex[0] = GetOutput(0, y_offset[0]);
 		if(en[1]) tex[1] = GetOutput(1, y_offset[1]);
+		if(feedback_merge) tex[2] = GetFeedbackOutput();
 	}
 
 	GSVector4 src[2];
diff --git a/plugins/GSdx/GSRenderer.h b/plugins/GSdx/GSRenderer.h
index 06abd0a3dc..08f2b725e9 100644
--- a/plugins/GSdx/GSRenderer.h
+++ b/plugins/GSdx/GSRenderer.h
@@ -52,6 +52,7 @@ protected:
 	GSVector2i m_real_size;
 
 	virtual GSTexture* GetOutput(int i, int& y_offset) = 0;
+	virtual GSTexture* GetFeedbackOutput() { return nullptr; }
 
 public:
 	GSWnd* m_wnd;
diff --git a/plugins/GSdx/GSRendererHW.cpp b/plugins/GSdx/GSRendererHW.cpp
index 1cbffeca37..bb46da8fe9 100644
--- a/plugins/GSdx/GSRendererHW.cpp
+++ b/plugins/GSdx/GSRendererHW.cpp
@@ -252,6 +252,26 @@ GSTexture* GSRendererHW::GetOutput(int i, int& y_offset)
 	return t;
 }
 
+GSTexture* GSRendererHW::GetFeedbackOutput()
+{
+	GIFRegTEX0 TEX0;
+
+	TEX0.TBP0 = m_regs->EXTBUF.EXBP;
+	TEX0.TBW = m_regs->EXTBUF.EXBW;
+	TEX0.PSM = m_regs->DISP[m_regs->EXTBUF.FBIN & 1].DISPFB.PSM;
+
+	GSTextureCache::Target* rt = m_tc->LookupTarget(TEX0, m_width, m_height, /*GetFrameRect(i).bottom*/0);
+
+	GSTexture* t = rt->m_texture;
+
+#ifdef ENABLE_OGL_DEBUG
+	if(s_dump && s_savef && s_n >= s_saven)
+		t->Save(m_dump_root + format("%05d_f%lld_fr%d_%05x_%s.bmp", s_n, m_perfmon.GetFrame(), 3, (int)TEX0.TBP0, psm_str(TEX0.PSM)));
+#endif
+
+	return t;
+}
+
 void GSRendererHW::InvalidateVideoMem(const GIFRegBITBLTBUF& BITBLTBUF, const GSVector4i& r)
 {
 	// printf("[%d] InvalidateVideoMem %d,%d - %d,%d %05x (%d)\n", (int)m_perfmon.GetFrame(), r.left, r.top, r.right, r.bottom, (int)BITBLTBUF.DBP, (int)BITBLTBUF.DPSM);
diff --git a/plugins/GSdx/GSRendererHW.h b/plugins/GSdx/GSRendererHW.h
index 310a38bc2c..229d0c6da6 100644
--- a/plugins/GSdx/GSRendererHW.h
+++ b/plugins/GSdx/GSRendererHW.h
@@ -170,6 +170,7 @@ public:
 	void VSync(int field);
 	void ResetDevice();
 	GSTexture* GetOutput(int i, int& y_offset);
+	GSTexture* GetFeedbackOutput();
 	void InvalidateVideoMem(const GIFRegBITBLTBUF& BITBLTBUF, const GSVector4i& r);
 	void InvalidateLocalMem(const GIFRegBITBLTBUF& BITBLTBUF, const GSVector4i& r, bool clut = false);
 	void Draw();