From c82351488e99d061f2cb361e780a80b03b7afb5e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20H=C3=B6glund?= <fredrik@kde.org>
Date: Fri, 12 Mar 2010 15:56:19 +0000
Subject: [PATCH] Make sure that both the render target and the shader are
 valid before using them.

svn path=/trunk/KDE/kdebase/workspace/; revision=1102465
---
 effects/blur/blur.cpp       |  3 ++-
 effects/blur/blurshader.cpp | 27 +++++++++++++++++++++------
 effects/blur/blurshader.h   |  4 ++++
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/effects/blur/blur.cpp b/effects/blur/blur.cpp
index badf69a82b..354319795a 100644
--- a/effects/blur/blur.cpp
+++ b/effects/blur/blur.cpp
@@ -162,12 +162,13 @@ void BlurEffect::drawWindow(EffectWindow *w, int mask, QRegion region, WindowPai
     bool translated = data.xTranslate || data.yTranslate;
     bool transformed = scaled || translated;
     bool hasAlpha = w->hasAlpha() || (w->hasDecoration() && effects->decorationsHaveAlpha());
+    bool valid = target->valid() && shader->isValid();
 
     QRegion shape;
     if (!effects->activeFullScreenEffect() && hasAlpha && !w->isDesktop() && !transformed)
         shape = blurRegion(w).translated(w->geometry().topLeft()) & screen;
 
-    if (!shape.isEmpty() && region.intersects(shape.boundingRect()))
+    if (valid && !shape.isEmpty() && region.intersects(shape.boundingRect()))
     {
         const QRect r = expand(shape.boundingRect()) & screen;
         const QPoint offset = -shape.boundingRect().topLeft() +
diff --git a/effects/blur/blurshader.cpp b/effects/blur/blurshader.cpp
index 2220697a8a..581ef28917 100644
--- a/effects/blur/blurshader.cpp
+++ b/effects/blur/blurshader.cpp
@@ -29,7 +29,7 @@ using namespace KWin;
 
 
 BlurShader::BlurShader()
-    : mRadius(12)
+    : mRadius(0), mValid(false)
 {
 }
 
@@ -52,6 +52,7 @@ void BlurShader::setRadius(int radius)
     if (mRadius != r) {
         mRadius = r;
         reset();
+        init();
     }
 }
 
@@ -117,10 +118,15 @@ void GLSLBlurShader::reset()
         glDeleteProgram(program);
         program = 0;
     }
+
+    setIsValid(false);
 }
 
 void GLSLBlurShader::setPixelDistance(float val)
 {
+    if (!isValid())
+        return;
+
     float pixelSize[2] = { 0.0, 0.0 };
 
     if (direction() == Qt::Horizontal)
@@ -133,14 +139,17 @@ void GLSLBlurShader::setPixelDistance(float val)
 
 void GLSLBlurShader::setOpacity(float val)
 {
+    if (!isValid())
+        return;
+
     const float opacity[4] = { val, val, val, val };
     glUniform4fv(uOpacity, 1, opacity);
 }
 
 void GLSLBlurShader::bind()
 {
-    if (!program)
-        init();
+    if (!isValid())
+        return;
 
     glUseProgram(program);
     glUniform1i(uTexUnit, 0);
@@ -284,6 +293,8 @@ void GLSLBlurShader::init()
         uPixelSize = glGetUniformLocation(program, "pixelSize");
         uOpacity   = glGetUniformLocation(program, "opacity");
     }
+
+    setIsValid(program != 0);
 }
 
 
@@ -308,6 +319,8 @@ void ARBBlurShader::reset()
         glDeleteProgramsARB(1, &program);
         program = 0;
     }
+
+    setIsValid(false);
 }
 
 void ARBBlurShader::setPixelDistance(float val)
@@ -331,8 +344,8 @@ void ARBBlurShader::setOpacity(float val)
 
 void ARBBlurShader::bind()
 {
-    if (!program)
-        init();
+    if (!isValid())
+        return;
 
     glEnable(GL_FRAGMENT_PROGRAM_ARB);
     glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, program);
@@ -413,7 +426,9 @@ void ARBBlurShader::init()
     if (glGetError()) {
         const char *error = (const char*)glGetString(GL_PROGRAM_ERROR_STRING_ARB);
         kError() << "Failed to compile fragment program:" << error;
-    }
+        setIsValid(false);
+    } else
+        setIsValid(true);
 
     glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, 0); 
 }
diff --git a/effects/blur/blurshader.h b/effects/blur/blurshader.h
index 9340700c78..b42e6f6ce6 100644
--- a/effects/blur/blurshader.h
+++ b/effects/blur/blurshader.h
@@ -33,6 +33,8 @@ public:
 
     static BlurShader *create();
 
+    bool isValid() const { return mValid; }
+
     // Sets the radius in pixels
     void setRadius(int radius);
     int radius() const { return mRadius; }
@@ -53,6 +55,7 @@ public:
 protected:
     float gaussian(float x, float sigma) const;
     QVector<float> gaussianKernel() const;
+    void setIsValid(bool value) { mValid = value; }
     virtual void init() = 0;
     virtual void reset() = 0;
     virtual int maxKernelSize() const = 0;
@@ -60,6 +63,7 @@ protected:
 private:
     int mRadius;
     Qt::Orientation mDirection;
+    bool mValid;
 };