Optimized blur / drop shadow effects for the GL 2 paint engine.

Do the blur in half the resolution in software and then upload the
result as a texture and smooth-scale it on the GPU. This leads to stable
and decent performance regardless of the blur radius, and simplifies the
implementation quite a bit.

Reviewed-by: Bjørn Erik Nilsen

2 files changed, 23 insertions, 0 deletions

diff --git a/src/gui/painting/qmemrotate.cpp b/src/gui/painting/qmemrotate.cpp
index 67dc2c7954..e3a6f78d45 100644
--- a/src/gui/painting/qmemrotate.cpp
+++ b/src/gui/painting/qmemrotate.cpp
@@ -572,5 +572,26 @@ QT_IMPL_MEMROTATE(quint32, qrgb_generic16)
 QT_IMPL_MEMROTATE(quint16, qrgb_generic16)
 #endif
 
+struct qrgb_gl_rgba
+{
+public:
+    inline qrgb_gl_rgba(quint32 v) {
+        if (QSysInfo::ByteOrder == QSysInfo::LittleEndian)
+            data = ((v << 16) & 0xff0000) | ((v >> 16) & 0xff) | (v & 0xff00ff00);
+        else
+            data = (v << 8) | ((v >> 24) & 0xff);
+    }
+
+    inline operator quint32() const { return data; }
+
+private:
+    quint32 data;
+} Q_PACKED;
+
+void Q_GUI_EXPORT qt_memrotate90_gl(const quint32 *src, int srcWidth, int srcHeight, int srcStride,
+                                    quint32 *dest, int dstStride)
+{
+    qt_memrotate90_template(src, srcWidth, srcHeight, srcStride, reinterpret_cast<qrgb_gl_rgba *>(dest), dstStride);
+}
 
 QT_END_NAMESPACE
diff --git a/src/gui/painting/qmemrotate_p.h b/src/gui/painting/qmemrotate_p.h
index 676a880cdf..8aee575fca 100644
--- a/src/gui/painting/qmemrotate_p.h
+++ b/src/gui/painting/qmemrotate_p.h
@@ -81,6 +81,8 @@ QT_BEGIN_NAMESPACE
     void Q_GUI_QWS_EXPORT qt_memrotate180(const srctype*, int, int, int, desttype*, int); \
     void Q_GUI_QWS_EXPORT qt_memrotate270(const srctype*, int, int, int, desttype*, int)
 
+void Q_GUI_EXPORT qt_memrotate90(const quint32*, int, int, int, quint32*, int);
+
 QT_DECL_MEMROTATE(quint32, quint32);
 QT_DECL_MEMROTATE(quint32, quint16);
 QT_DECL_MEMROTATE(quint16, quint32);