From cf3bcc629400ef646e3f3a2806d6f9bf169361cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <kde@martin-graesslin.com>
Date: Sun, 13 Jun 2010 07:40:21 +0000
Subject: [PATCH] Try to get a FBO in the init method of GLRenderTarget. If the
 FBO is incomplete there is no need to claim that the driver supports FBO.
 This is a workaround to the problem that some drivers do not return a
 complete FBO, but support the extension. Which caused the blur effect to get
 loaded without working and in consequence Plasma to use the blur-optimized
 and very translucent backgrounds. CCBUG: 240956

svn path=/trunk/KDE/kdebase/workspace/; revision=1137490
---
 lib/kwinglutils.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/lib/kwinglutils.cpp b/lib/kwinglutils.cpp
index 721e3284cd..3ec98028d0 100644
--- a/lib/kwinglutils.cpp
+++ b/lib/kwinglutils.cpp
@@ -971,6 +971,26 @@ bool GLRenderTarget::mSupported = false;
 void GLRenderTarget::initStatic()
     {
     mSupported = hasGLExtension("GL_EXT_framebuffer_object") && glFramebufferTexture2D;
+    if( mSupported )
+        {
+        // some drivers claim to support the extension, but fail to return a complete FBO (see Bug 240956)
+        // generate a FBO and test if it is valid. If it isn't valid there's no need to claim that FBO's are supported
+        int w = displayWidth();
+        int h = displayHeight();
+        if ( !GLTexture::NPOTTextureSupported() )
+            {
+            w = nearestPowerOfTwo( w );
+            h = nearestPowerOfTwo( h );
+            }
+        GLTexture* tex = new GLTexture( w, h );
+        tex->setFilter( GL_LINEAR );
+        tex->setWrapMode( GL_CLAMP_TO_EDGE );
+        GLRenderTarget* target = new GLRenderTarget( tex );
+        if( !target->valid() )
+            mSupported = false;
+        delete target;
+        delete tex;
+        }
     }
 
 GLRenderTarget::GLRenderTarget(GLTexture* color)