From e1de3407f15fd1e5e2f4494395c3784e613e1acd Mon Sep 17 00:00:00 2001
From: Vincent Pelletier <plr.vincent@gmail.com>
Date: Fri, 22 Jul 2016 06:19:41 +0200
Subject: [PATCH] TINYGL: Make scissors follow Common::Rect semantics.

As per Common::Rect data model, right and bottom border are excluded, so:
- Make FrameBuffer::scissorPixel reject bottom & right borders.
- Update bounding rectangle definition for dirty rectangle operations
  ClearBufferDrawCall::getDirtyRegion is already correct.
- zblit was almost following, except for an off-by-one mistake.
---
 graphics/tinygl/zblit.cpp      |  4 ++--
 graphics/tinygl/zbuffer.h      |  2 +-
 graphics/tinygl/zdirtyrect.cpp | 26 +++++---------------------
 3 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/graphics/tinygl/zblit.cpp b/graphics/tinygl/zblit.cpp
index 063def717d0..99934a1e0d7 100644
--- a/graphics/tinygl/zblit.cpp
+++ b/graphics/tinygl/zblit.cpp
@@ -163,13 +163,13 @@ public:
 			return false;
 		}
 
-		if (dstX + width > c->_scissorRect.right) {
+		if (dstX + width >= c->_scissorRect.right) {
 			clampWidth = c->_scissorRect.right - dstX;
 		} else {
 			clampWidth = width;
 		}
 
-		if (dstY + height > c->_scissorRect.bottom) {
+		if (dstY + height >= c->_scissorRect.bottom) {
 			clampHeight = c->_scissorRect.bottom - dstY;
 		} else {
 			clampHeight = height;
diff --git a/graphics/tinygl/zbuffer.h b/graphics/tinygl/zbuffer.h
index 07fc7497f03..6d6a4de3a07 100644
--- a/graphics/tinygl/zbuffer.h
+++ b/graphics/tinygl/zbuffer.h
@@ -226,7 +226,7 @@ struct FrameBuffer {
 	}
 
 	FORCEINLINE bool scissorPixel(int x, int y) {
-		return x < _clipRectangle.left || x > _clipRectangle.right || y < _clipRectangle.top || y > _clipRectangle.bottom;
+		return !_clipRectangle.contains(x, y);
 	}
 
 	FORCEINLINE void writePixel(int pixel, byte aSrc, byte rSrc, byte gSrc, byte bSrc) {
diff --git a/graphics/tinygl/zdirtyrect.cpp b/graphics/tinygl/zdirtyrect.cpp
index 743b5ea6fa1..b5f5757acb4 100644
--- a/graphics/tinygl/zdirtyrect.cpp
+++ b/graphics/tinygl/zdirtyrect.cpp
@@ -54,11 +54,11 @@ static void tglDrawRectangle(Common::Rect rect, int r, int g, int b) {
 
 	for(int x = rect.left; x < rect.right; x++) {
 		c->fb->writePixel(rect.top * c->fb->xsize + x, 255, r, g, b);
-		c->fb->writePixel(rect.bottom * c->fb->xsize + x, 255, r, g, b);
+		c->fb->writePixel((rect.bottom - 1) * c->fb->xsize + x, 255, r, g, b);
 	}
 	for(int y = rect.top; y < rect.bottom; y++) {
 		c->fb->writePixel(y * c->fb->xsize + rect.left, 255, r, g, b);
-		c->fb->writePixel(y * c->fb->xsize + rect.right, 255, r, g, b);
+		c->fb->writePixel(y * c->fb->xsize + rect.right - 1, 255, r, g, b);
 	}
 }
 #endif
@@ -302,7 +302,7 @@ void RasterizationDrawCall::computeDirtyRegion() {
 	int width = c->fb->xsize;
 	int height = c->fb->ysize;
 
-	int left = width, right = 0, top = height, bottom = 0;
+	int left = width - 1, right = 0, top = height - 1, bottom = 0;
 
 	bool pointInsideVolume = false;
 
@@ -339,37 +339,21 @@ void RasterizationDrawCall::computeDirtyRegion() {
 
 	if (left < 0) {
 		left = 0;
-		if (right < left) {
-			left = 0;
-			right = width - 1;
-		}
 	}
 
 	if (right >= width) {
 		right = width - 1;
-		if (left > right) {
-			left = 0;
-			right = width - 1;
-		}
 	}
 
 	if (top < 0) {
 		top = 0;
-		if (bottom < top) {
-			top = 0;
-			bottom = height - 1;
-		}
 	}
 
 	if (bottom >= height) {
 		bottom = height - 1;
-		if (top > bottom) {
-			top = 0;
-			bottom = height - 1;
-		}
 	}
 
-	_dirtyRegion = Common::Rect(left, top, right, bottom);
+	_dirtyRegion = Common::Rect(left, top, right + 1, bottom + 1);
 	// This takes into account precision issues that occur during rasterization.
 	_dirtyRegion.left -= 2;
 	_dirtyRegion.top -= 2;
@@ -648,7 +632,7 @@ const Common::Rect BlittingDrawCall::getDirtyRegion() const {
 			tglGetBlitImageSize(_image, blitWidth, blitHeight);
 		}
 	}
-	return Common::Rect(_transform._destinationRectangle.left, _transform._destinationRectangle.top, _transform._destinationRectangle.left + blitWidth, _transform._destinationRectangle.top + blitHeight);
+	return Common::Rect(_transform._destinationRectangle.left, _transform._destinationRectangle.top, _transform._destinationRectangle.left + blitWidth + 1, _transform._destinationRectangle.top + blitHeight + 1);
 }
 
 bool BlittingDrawCall::operator==(const BlittingDrawCall &other) const {