From 5cedc0e6e70cce89032e7e875b99ca3b8b687760 Mon Sep 17 00:00:00 2001
From: Sergey Lipskiy <gonetz@ngs.ru>
Date: Sun, 29 Sep 2013 22:02:50 +0700
Subject: [PATCH] Implement VI emulation: treat main frame buffer as TV screen
 and render FBO buffers on it according to VI registers values.

---
 FrameBuffer.cpp | 41 ++++++++++++++++++++++++++++++++++++++---
 VI.cpp          | 15 ++++++++++++---
 VI.h            |  5 ++++-
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/FrameBuffer.cpp b/FrameBuffer.cpp
index bed89d5f..51b7b841 100644
--- a/FrameBuffer.cpp
+++ b/FrameBuffer.cpp
@@ -324,18 +324,53 @@ void FrameBuffer_SaveBuffer( u32 address, u16 format, u16 size, u16 width, u16 h
 #if 1
 void FrameBuffer_RenderBuffer( u32 address )
 {
+	if (_SHIFTR( *REG.VI_H_START, 0, 10 ) == 0) // H width is zero. Don't draw
+		return;
 	FrameBuffer *current = FrameBuffer_FindBuffer(address);
 	if (current == NULL)
 		return;
+	GLint srcY0, srcY1, dstY0, dstY1;
+	GLint partHeight = 0;
+	dstY0 = 1;
+	const u32 vStart = _SHIFTR( *REG.VI_V_START, 17, 9 );
+	const u32 vEnd = _SHIFTR( *REG.VI_V_START, 1, 9 );
+	const float viScaleY = OGL.height / (float)VI.vHeight;
+
+	if (VI.vStart != vStart)
+		dstY0 += vStart - VI.vStart;
+	dstY1 = dstY0 + vEnd - vStart;
+	srcY0 = ((address - current->startAddress) << 1 >> current->size) / (*REG.VI_WIDTH);
+	srcY1 = srcY0 + VI.real_height;
+	if (srcY1 > VI.height) {
+		partHeight = srcY1 - VI.height;
+		srcY1 = VI.height;
+		dstY1 -= partHeight;
+	}
+
 	ogl_glBindFramebuffer(GL_READ_FRAMEBUFFER, current->fbo);
 	ogl_glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 	glDrawBuffer( GL_FRONT );
 	ogl_glBlitFramebuffer(
-//				0, 0, current->texture->realWidth, current->texture->realHeight,
-		0, 0, OGL.width, OGL.height,
-		0, OGL.heightOffset, OGL.width, OGL.height+OGL.heightOffset,
+		0, (GLint)(srcY0*OGL.scaleY), OGL.width, (GLint)(srcY1*OGL.scaleY),
+		0, OGL.heightOffset + (GLint)(dstY0*viScaleY), OGL.width, OGL.heightOffset + (GLint)(dstY1*viScaleY),
 		GL_COLOR_BUFFER_BIT, GL_LINEAR
 	);
+	if (partHeight > 0) {
+		const u32 size = *REG.VI_STATUS & 3;
+		current = FrameBuffer_FindBuffer(address + (((*REG.VI_WIDTH)*VI.height)<<size>>1));
+		if (current != NULL) {
+			srcY0 = 0;
+			srcY1 = partHeight;
+			dstY0 = dstY1;
+			dstY1 = dstY0 + partHeight;
+			ogl_glBindFramebuffer(GL_READ_FRAMEBUFFER, current->fbo);
+			ogl_glBlitFramebuffer(
+				0, (GLint)(srcY0*OGL.scaleY), OGL.width, (GLint)(srcY1*OGL.scaleY),
+				0, OGL.heightOffset + (GLint)(dstY0*viScaleY), OGL.width, OGL.heightOffset + (GLint)(dstY1*viScaleY),
+				GL_COLOR_BUFFER_BIT, GL_LINEAR
+			);
+		}
+	}
 	glDrawBuffer( GL_BACK );
 	ogl_glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
 	ogl_glBindFramebuffer(GL_DRAW_FRAMEBUFFER, frameBuffer.top->fbo);
diff --git a/VI.cpp b/VI.cpp
index 9ece0002..ef24d4a3 100644
--- a/VI.cpp
+++ b/VI.cpp
@@ -27,9 +27,16 @@ void VI_UpdateSize()
 	u32 vStart = _SHIFTR( *REG.VI_V_START, 17, 9 );
 
 	VI.width = (hEnd - hStart) * xScale;
-	VI.height = (vEnd - vStart) * yScale * 1.0126582f;
+	VI.real_height = (vEnd - vStart) * yScale;
+	VI.height = VI.real_height*1.0126582f;
 
-	if (VI.width == 0.0f) VI.width = 320.0f;
+	if (VI.vStart == 0) {
+		VI.vStart = vStart;
+		VI.vEnd = vEnd;
+		VI.vHeight = VI.height;
+	}
+
+	if (VI.width == 0.0f) VI.width = *REG.VI_WIDTH;
 	if (VI.height == 0.0f) VI.height = 240.0f;
 }
 
@@ -42,10 +49,12 @@ void VI_UpdateScreen()
 		OGL_SaveScreenshot();
 		OGL.captureScreen = false;
 	}
+	if (((*REG.VI_STATUS)&3) == 0)
+		VI.vStart = VI.vEnd = 0;
 
 	if (OGL.frameBufferTextures) {
 		const bool bCFB = (gSP.changed&CHANGED_CPU_FB_WRITE) == CHANGED_CPU_FB_WRITE;
-		const bool bNeedUpdate = bCFB ? true : (*REG.VI_ORIGIN != VI.lastOrigin) && gDP.colorImage.changed;
+		const bool bNeedUpdate = bCFB ? true : (*REG.VI_ORIGIN != VI.lastOrigin);// && gDP.colorImage.changed;
 
 		if (bNeedUpdate) {
 			FrameBuffer * pBuffer = FrameBuffer_FindBuffer(*REG.VI_ORIGIN);
diff --git a/VI.h b/VI.h
index 6f6c0b23..7927ef55 100644
--- a/VI.h
+++ b/VI.h
@@ -4,8 +4,11 @@
 
 struct VIInfo
 {
-	u32 width, height;
+	u32 width, height, real_height;
+	u32 vStart, vEnd, vHeight;
 	u32 lastOrigin;
+
+	VIInfo() : width(0), height(0), real_height(0), vStart(0), vEnd(0), vHeight(0), lastOrigin(0) {}
 };
 
 extern VIInfo VI;