From 030b562eb97d9c0c7b791062dfbf4f26ba22cc31 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 14 Jun 2014 17:08:41 -0700
Subject: [PATCH] Support render-to-offset within a framebuffer.

Fixes #6324.
---
 GPU/GLES/Framebuffer.cpp             | 26 ++++++++++++++++++++------
 GPU/GLES/StateMapping.cpp            |  2 ++
 GPU/GPUState.cpp                     |  2 +-
 GPU/GPUState.h                       |  2 +-
 Windows/GEDebugger/VertexPreview.cpp |  2 +-
 5 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/GPU/GLES/Framebuffer.cpp b/GPU/GLES/Framebuffer.cpp
index 9ed88769f6..57716d733e 100644
--- a/GPU/GLES/Framebuffer.cpp
+++ b/GPU/GLES/Framebuffer.cpp
@@ -862,22 +862,36 @@ void FramebufferManager::DoSetRenderFrameBuffer() {
 	// Find a matching framebuffer
 	VirtualFramebuffer *vfb = 0;
 	size_t i;
+	gstate_c.cutRTOffsetX = 0;
 	for (i = 0; i < vfbs_.size(); ++i) {
 		VirtualFramebuffer *v = vfbs_[i];
 		if (MaskedEqual(v->fb_address, fb_address)) {
 			vfb = v;
 			// Update fb stride in case it changed
 			vfb->fb_stride = fb_stride;
-			v->format = fmt;
+			vfb->format = fmt;
 			// In throughmode, a higher height could be used.  Let's avoid shrinking the buffer.
-			if (gstate.isModeThrough() && (int)v->width < fb_stride) {
-				v->width = std::max((int)v->width, drawing_width);
-				v->height = std::max((int)v->height, drawing_height);
+			if (gstate.isModeThrough() && (int)vfb->width < fb_stride) {
+				vfb->width = std::max((int)vfb->width, drawing_width);
+				vfb->height = std::max((int)vfb->height, drawing_height);
 			} else {
-				v->width = drawing_width;
-				v->height = drawing_height;
+				vfb->width = drawing_width;
+				vfb->height = drawing_height;
 			}
 			break;
+		} else if (v->fb_address < fb_address && v->fb_address + v->fb_stride * 4 > fb_address) {
+			// Possibly a render-to-offset.
+			const u32 bpp = v->format == GE_FORMAT_8888 ? 4 : 2;
+			const int x_offset = (fb_address - v->fb_address) / bpp;
+			if (v->format == fmt && v->fb_stride == fb_stride && x_offset < fb_stride && v->height >= drawing_height) {
+				WARN_LOG_REPORT_ONCE(renderoffset, HLE, "Rendering to framebuffer offset: %08x +%dx%d", v->fb_address, x_offset, 0);
+				vfb = v;
+				gstate_c.cutRTOffsetX = x_offset;
+				vfb->width = std::max((int)vfb->width, x_offset + drawing_width);
+				// To prevent the newSize code from being confused.
+				drawing_width += x_offset;
+				break;
+			}
 		}
 	}
 
diff --git a/GPU/GLES/StateMapping.cpp b/GPU/GLES/StateMapping.cpp
index 72b631933b..970bebd9f0 100644
--- a/GPU/GLES/StateMapping.cpp
+++ b/GPU/GLES/StateMapping.cpp
@@ -507,6 +507,8 @@ void TransformDrawEngine::ApplyDrawState(int prim) {
 		renderHeightFactor = renderHeight / 272.0f;
 	}
 
+	renderX += gstate_c.cutRTOffsetX * renderWidthFactor;
+
 	// Scissor
 	int scissorX1 = gstate.getScissorX1();
 	int scissorY1 = gstate.getScissorY1();
diff --git a/GPU/GPUState.cpp b/GPU/GPUState.cpp
index cd3c8e7026..208930a60f 100644
--- a/GPU/GPUState.cpp
+++ b/GPU/GPUState.cpp
@@ -336,5 +336,5 @@ void GPUStateCache::DoState(PointerWrap &p) {
 	p.Do(curRTWidth);
 	p.Do(curRTHeight);
 
-	// curRTBufferWidth and curRTBufferHeight don't need to be saved.
+	// curRTBufferWidth, curRTBufferHeight, and cutRTOffsetX don't need to be saved.
 }
diff --git a/GPU/GPUState.h b/GPU/GPUState.h
index e14f6a62f2..d5381fcf8e 100644
--- a/GPU/GPUState.h
+++ b/GPU/GPUState.h
@@ -474,9 +474,9 @@ struct GPUStateCache
 
 	u32 curRTWidth;
 	u32 curRTHeight;
-
 	u32 curRTRenderWidth;
 	u32 curRTRenderHeight;
+	u32 cutRTOffsetX;
 
 	u32 getRelativeAddress(u32 data) const;
 	void DoState(PointerWrap &p);
diff --git a/Windows/GEDebugger/VertexPreview.cpp b/Windows/GEDebugger/VertexPreview.cpp
index 7c7d795ad6..bfd07c9746 100644
--- a/Windows/GEDebugger/VertexPreview.cpp
+++ b/Windows/GEDebugger/VertexPreview.cpp
@@ -189,7 +189,7 @@ void CGEDebugger::UpdatePrimPreview(u32 op) {
 	};
 
 	Matrix4x4 ortho;
-	ortho.setOrtho(0, frameWindow->TexWidth() * scale[0], frameWindow->TexHeight() * scale[1], 0, -1, 1);
+	ortho.setOrtho(-(int)gstate_c.cutRTOffsetX, (frameWindow->TexWidth() - (int)gstate_c.cutRTOffsetX) * scale[0], frameWindow->TexHeight() * scale[1], 0, -1, 1);
 	glUniformMatrix4fv(previewProgram->u_viewproj, 1, GL_FALSE, ortho.getReadPtr());
 	glEnableVertexAttribArray(previewProgram->a_position);
 	glVertexAttribPointer(previewProgram->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (float *)vertices.data() + 2);