From 12358f839a293d7936e12dbabdd1aca953063b36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20L=C3=BCbking?= <thomas.luebking@gmail.com>
Date: Tue, 19 May 2015 14:35:12 +0200
Subject: [PATCH] no VBO upload for zero vertex count

causes out of bounds segfault

BUG: 347900
REVIEW: 123865
FIXED-IN: 5.3.1
---
 effects/backgroundcontrast/contrast.cpp | 2 ++
 effects/blur/blur.cpp                   | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/effects/backgroundcontrast/contrast.cpp b/effects/backgroundcontrast/contrast.cpp
index 059a5d85fb..882055b651 100644
--- a/effects/backgroundcontrast/contrast.cpp
+++ b/effects/backgroundcontrast/contrast.cpp
@@ -230,6 +230,8 @@ void ContrastEffect::uploadRegion(QVector2D *&map, const QRegion &region)
 void ContrastEffect::uploadGeometry(GLVertexBuffer *vbo, const QRegion &region)
 {
     const int vertexCount = region.rectCount() * 6;
+    if (!vertexCount)
+        return;
 
     QVector2D *map = (QVector2D *) vbo->map(vertexCount * sizeof(QVector2D));
     uploadRegion(map, region);
diff --git a/effects/blur/blur.cpp b/effects/blur/blur.cpp
index e238bd2ed8..fe0d467b12 100644
--- a/effects/blur/blur.cpp
+++ b/effects/blur/blur.cpp
@@ -236,6 +236,8 @@ void BlurEffect::uploadRegion(QVector2D *&map, const QRegion &region)
 void BlurEffect::uploadGeometry(GLVertexBuffer *vbo, const QRegion &horizontal, const QRegion &vertical)
 {
     const int vertexCount = (horizontal.rectCount() + vertical.rectCount()) * 6;
+    if (!vertexCount)
+        return;
 
     QVector2D *map = (QVector2D *) vbo->map(vertexCount * sizeof(QVector2D));
     uploadRegion(map, horizontal);