From 76eb3c3391ddd88d28c73e190ddeb2aee8dda38b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Sun, 26 Jun 2011 13:16:14 +0200
Subject: [PATCH] Remove clipping against the bounding rect of paint region

---
 scene_opengl.cpp | 48 ++++++++++++++----------------------------------
 1 file changed, 14 insertions(+), 34 deletions(-)

diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index 0f83d2c8a6..571cb74462 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -479,44 +479,24 @@ void SceneOpenGL::Window::performPaint(int mask, QRegion region, WindowPaintData
     if (region != infiniteRegion() && !(mask & PAINT_WINDOW_TRANSFORMED)) {
         WindowQuadList quads;
         const QRegion filterRegion = region.translated(-x(), -y());
-        const QRectF bounding = QRectF(filterRegion.boundingRect());
-        // first step: split all quads according to the bounding rect
+        // split all quads in bounding rect with the actual rects in the region
         foreach (const WindowQuad &quad, data.quads) {
-            const QRectF quadRect(QPointF(quad.left(), quad.top()), QPointF(quad.right(), quad.bottom()));
-            // case 1: completely contains
-            if (bounding.contains(quadRect)) {
-                quads << quad;
-                continue;
-            }
-            // case 2: intersection
-            if (bounding.intersects(quadRect)) {
-                const QRectF intersected = bounding.intersected(quadRect);
-                quads << quad.makeSubQuad(intersected.left(), intersected.top(), intersected.right(), intersected.bottom());
-            }
-        }
-        if (filterRegion.numRects() > 1) {
-            // second step: split all quads in bounding rect with the actual rects in the region
-            WindowQuadList tempList;
-            foreach (const WindowQuad &quad, quads) {
-                foreach (const QRect &r, filterRegion.rects()) {
-                    const QRectF rf(r);
-                    const QRectF quadRect(QPointF(quad.left(), quad.top()), QPointF(quad.right(), quad.bottom()));
-                    // case 1: completely contains, include and do not check other rects
-                    if (rf.contains(quadRect)) {
-                        tempList << quad;
-                        break;
-                    }
-                    // case 2: intersection
-                    if (rf.intersects(quadRect)) {
-                        const QRectF intersected = rf.intersected(quadRect);
-                        tempList << quad.makeSubQuad(intersected.left(), intersected.top(), intersected.right(), intersected.bottom());
-                    }
+            foreach (const QRect &r, filterRegion.rects()) {
+                const QRectF rf(r);
+                const QRectF quadRect(QPointF(quad.left(), quad.top()), QPointF(quad.right(), quad.bottom()));
+                // case 1: completely contains, include and do not check other rects
+                if (rf.contains(quadRect)) {
+                    quads << quad;
+                    break;
+                }
+                // case 2: intersection
+                if (rf.intersects(quadRect)) {
+                    const QRectF intersected = rf.intersected(quadRect);
+                    quads << quad.makeSubQuad(intersected.left(), intersected.top(), intersected.right(), intersected.bottom());
                 }
             }
-            data.quads = tempList;
-        } else {
-            data.quads = quads;
         }
+        data.quads = quads;
     }
 
     if (!bindTexture())