From dcd4b15595a63864ee59a19d80f1ba33b4821aa3 Mon Sep 17 00:00:00 2001
From: Rhys Weatherley <rhys.weatherley@nokia.com>
Date: Wed, 16 Sep 2009 09:31:01 +1000
Subject: Only regenerate pixmap filter source if the parameters have changed.

Reviewed-by: trustme
---
 src/opengl/qglpixmapfilter.cpp | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/opengl/qglpixmapfilter.cpp b/src/opengl/qglpixmapfilter.cpp
index e4df69e..43f1990 100644
--- a/src/opengl/qglpixmapfilter.cpp
+++ b/src/opengl/qglpixmapfilter.cpp
@@ -71,6 +71,8 @@ void QGLPixmapFilterBase::drawImpl(QPainter *painter, const QPointF &pos, const
 class QGLPixmapColorizeFilter: public QGLCustomShaderStage, public QGLPixmapFilter<QPixmapColorizeFilter>
 {
 public:
+    QGLPixmapColorizeFilter();
+
     void setUniforms(QGLShaderProgram *program);
 
 protected:
@@ -100,6 +102,8 @@ private:
 class QGLPixmapBlurFilter : public QGLCustomShaderStage, public QGLPixmapFilter<QPixmapBlurFilter>
 {
 public:
+    QGLPixmapBlurFilter();
+
     void setUniforms(QGLShaderProgram *program);
 
 protected:
@@ -111,6 +115,10 @@ private:
     mutable QSize m_textureSize;
 
     mutable bool m_horizontalBlur;
+
+    mutable bool m_haveCached;
+    mutable int m_cachedRadius;
+    mutable Qt::TransformationMode m_cachedQuality;
 };
 
 extern QGLWidget *qt_gl_share_widget();
@@ -182,10 +190,14 @@ static const char *qt_gl_colorize_filter =
         "        return vec4(mix(srcPixel.rgb, colorized * srcPixel.a, colorizeStrength), srcPixel.a);"
         "}";
 
+QGLPixmapColorizeFilter::QGLPixmapColorizeFilter()
+{
+    setSource(qt_gl_colorize_filter);
+}
+
 bool QGLPixmapColorizeFilter::processGL(QPainter *painter, const QPointF &pos, const QPixmap &src, const QRectF &) const
 {
     QGLPixmapColorizeFilter *filter = const_cast<QGLPixmapColorizeFilter *>(this);
-    filter->setSource(qt_gl_colorize_filter);
 
     filter->setOnPainter(painter);
     painter->drawPixmap(pos, src);
@@ -292,10 +304,27 @@ bool QGLPixmapConvolutionFilter::processGL(QPainter *, const QPointF &pos, const
     return true;
 }
 
+QGLPixmapBlurFilter::QGLPixmapBlurFilter()
+    : m_haveCached(false), m_cachedRadius(5),
+      m_cachedQuality(Qt::FastTransformation)
+{
+}
+
 bool QGLPixmapBlurFilter::processGL(QPainter *painter, const QPointF &pos, const QPixmap &src, const QRectF &) const
 {
     QGLPixmapBlurFilter *filter = const_cast<QGLPixmapBlurFilter *>(this);
-    filter->setSource(generateBlurShader(radius(), quality() == Qt::SmoothTransformation));
+
+    int radius = this->radius();
+    Qt::TransformationMode quality = this->quality();
+
+    if (!m_haveCached || radius != m_cachedRadius ||
+            quality != m_cachedQuality) {
+        // Only regenerate the shader from source if parameters have changed.
+        m_haveCached = true;
+        m_cachedRadius = radius;
+        m_cachedQuality = quality;
+        filter->setSource(generateBlurShader(radius, quality == Qt::SmoothTransformation));
+    }
 
     QGLFramebufferObjectFormat format;
     format.setInternalTextureFormat(GLenum(src.hasAlphaChannel() ? GL_RGBA : GL_RGB));
-- 
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