Added some optimizations to the blur and drop shadow GL filters.

* Use ExpandToTransparentBorderPadMode since we can use GL_CLAMP_TO_EDGE
  to clamp to the texture.

* Shrink the bounding rects reported by the blur
  and drop shadow filters (expanding by 2 * radius isn't needed).

* Use a single-pass blur for radii <= 3 to avoid the overhead of
  rendering to an FBO.

* Made the fast blur setting generate filters for only a predefined set
  of radii, and then use the actual blur radius to spread the sample
  points outwards.

* Optimized the generated program to rely less on temporary variables,
  as those seemed to not be handled very well by certain GLSL compilers.

Reviewed-by: Gunnar Sletta

1 files changed, 7 insertions, 1 deletions

diff --git a/src/gui/effects/qgraphicseffect_p.h b/src/gui/effects/qgraphicseffect_p.h
index dff84a1..1ed7103 100644
--- a/src/gui/effects/qgraphicseffect_p.h
+++ b/src/gui/effects/qgraphicseffect_p.h
@@ -66,7 +66,12 @@ class QGraphicsEffectSourcePrivate : public QObjectPrivate
 {
     Q_DECLARE_PUBLIC(QGraphicsEffectSource)
 public:
-    QGraphicsEffectSourcePrivate() : QObjectPrivate() {}
+    QGraphicsEffectSourcePrivate()
+        : QObjectPrivate()
+        , m_cachedSystem(Qt::DeviceCoordinates)
+        , m_cachedMode(QGraphicsEffectSource::ExpandToTransparentBorderPadMode)
+    {}
+
     virtual ~QGraphicsEffectSourcePrivate() { invalidateCache(); }
     virtual void detach() = 0;
     virtual QRectF boundingRect(Qt::CoordinateSystem system) const = 0;
@@ -88,6 +93,7 @@ public:
 
 private:
     mutable Qt::CoordinateSystem m_cachedSystem;
+    mutable QGraphicsEffectSource::PixmapPadMode m_cachedMode;
     mutable QPoint m_cachedOffset;
     mutable QPixmapCache::Key m_cacheKey;
 };