Merge commit 'qt-graphics-team/pixmapfilters-redux' into kinetic-graphicseffect

Conflicts:
	src/opengl/gl2paintengineex/qglengineshadermanager.cpp
	src/opengl/gl2paintengineex/qglengineshadermanager_p.h
	src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
	src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h

Merge custom shader / GL blur pixmap filter implementation from graphics
team repo with implementation from kinetic graphics-team repo.

1 files changed, 93 insertions, 41 deletions

diff --git a/src/opengl/qpixmapdata_gl.cpp b/src/opengl/qpixmapdata_gl.cpp
index e3ee2b2..c0eed4d 100644
--- a/src/opengl/qpixmapdata_gl.cpp
+++ b/src/opengl/qpixmapdata_gl.cpp
@@ -55,6 +55,85 @@ QT_BEGIN_NAMESPACE
 
 extern QGLWidget* qt_gl_share_widget();
 
+/*!
+    \class QGLFramebufferObjectPool
+    \since 4.6
+
+    \brief The QGLFramebufferObject class provides a pool of framebuffer
+    objects for offscreen rendering purposes.
+
+    When requesting an FBO of a given size and format, an FBO of the same
+    format and a size at least as big as the requested size will be returned.
+
+    \internal
+*/
+
+static inline int areaDiff(const QSize &size, const QGLFramebufferObject *fbo)
+{
+    return qAbs(size.width() * size.height() - fbo->width() * fbo->height());
+}
+
+QGLFramebufferObject *QGLFramebufferObjectPool::acquire(const QSize &requestSize, const QGLFramebufferObjectFormat &requestFormat)
+{
+    QGLFramebufferObject *chosen = 0;
+    QGLFramebufferObject *candidate = 0;
+    for (int i = 0; !chosen && i < m_fbos.size(); ++i) {
+        QGLFramebufferObject *fbo = m_fbos.at(i);
+
+        QGLFramebufferObjectFormat format = fbo->format();
+        if (format.samples() == requestFormat.samples()
+            && format.attachment() == requestFormat.attachment()
+            && format.textureTarget() == requestFormat.textureTarget()
+            && format.internalFormat() == requestFormat.internalFormat())
+        {
+            // choose the fbo with a matching format and the closest size
+            if (!candidate || areaDiff(requestSize, candidate) > areaDiff(requestSize, fbo))
+                candidate = fbo;
+        }
+
+        if (candidate) {
+            m_fbos.removeOne(candidate);
+
+            const QSize fboSize = candidate->size();
+            QSize sz = fboSize;
+
+            if (sz.width() < requestSize.width())
+                sz.setWidth(qMax(requestSize.width(), qRound(sz.width() * 1.5)));
+            if (sz.height() < requestSize.height())
+                sz.setHeight(qMax(requestSize.height(), qRound(sz.height() * 1.5)));
+
+            // wasting too much space?
+            if (sz.width() * sz.height() > requestSize.width() * requestSize.height() * 2.5)
+                sz = requestSize;
+
+            if (sz != fboSize) {
+                delete candidate;
+                qDebug() << "Resizing fbo in pool:" << sz;
+                candidate = new QGLFramebufferObject(sz, requestFormat);
+            }
+
+            chosen = candidate;
+        }
+    }
+
+    if (!chosen) {
+        qDebug() << "Creating new fbo in pool:" << requestSize;
+        chosen = new QGLFramebufferObject(requestSize, requestFormat);
+    }
+
+    if (!chosen->isValid()) {
+        delete chosen;
+        chosen = 0;
+    }
+
+    return chosen;
+}
+
+void QGLFramebufferObjectPool::release(QGLFramebufferObject *fbo)
+{
+    m_fbos << fbo;
+}
+
 class QGLShareContextScope
 {
 public:
@@ -332,8 +411,11 @@ struct TextureBuffer
     QGL2PaintEngineEx *engine;
 };
 
-static QVector<TextureBuffer> textureBufferStack;
-static int currentTextureBuffer = 0;
+Q_GLOBAL_STATIC(QGLFramebufferObjectPool, _qgl_fbo_pool)
+QGLFramebufferObjectPool* qgl_fbo_pool()
+{
+    return _qgl_fbo_pool();
+}
 
 void QGLPixmapData::copyBackFromRenderFbo(bool keepCurrentFboBound) const
 {
@@ -380,7 +462,8 @@ void QGLPixmapData::swapBuffers()
     copyBackFromRenderFbo(false);
     m_renderFbo->release();
 
-    --currentTextureBuffer;
+    qgl_fbo_pool()->release(m_renderFbo);
+    delete m_engine;
 
     m_renderFbo = 0;
     m_engine = 0;
@@ -398,19 +481,6 @@ void QGLPixmapData::doneCurrent()
         m_renderFbo->release();
 }
 
-static TextureBuffer createTextureBuffer(const QSize &size, QGL2PaintEngineEx *engine = 0)
-{
-    TextureBuffer buffer;
-    QGLFramebufferObjectFormat fmt;
-    fmt.setAttachment(QGLFramebufferObject::CombinedDepthStencil);
-    fmt.setSamples(4);
-
-    buffer.fbo = new QGLFramebufferObject(size, fmt);
-    buffer.engine = engine ? engine : new QGL2PaintEngineEx;
-
-    return buffer;
-}
-
 bool QGLPixmapData::useFramebufferObjects()
 {
     return QGLFramebufferObject::hasOpenGLFramebufferObjects()
@@ -433,33 +503,15 @@ QPaintEngine* QGLPixmapData::paintEngine() const
             qt_gl_share_widget()->makeCurrent();
         QGLShareContextScope ctx(qt_gl_share_widget()->context());
 
-        if (textureBufferStack.size() <= currentTextureBuffer) {
-            textureBufferStack << createTextureBuffer(size());
-        } else {
-            QSize sz = textureBufferStack.at(currentTextureBuffer).fbo->size();
-            if (sz.width() < w || sz.height() < h) {
-                if (sz.width() < w)
-                    sz.setWidth(qMax(w, qRound(sz.width() * 1.5)));
-                if (sz.height() < h)
-                    sz.setHeight(qMax(h, qRound(sz.height() * 1.5)));
-
-                // wasting too much space?
-                if (sz.width() * sz.height() > w * h * 2.5)
-                    sz = QSize(w, h);
-
-                delete textureBufferStack.at(currentTextureBuffer).fbo;
-                textureBufferStack[currentTextureBuffer] =
-                    createTextureBuffer(sz, textureBufferStack.at(currentTextureBuffer).engine);
-                qDebug() << "Creating new pixmap texture buffer:" << sz;
-            }
-        }
-
-        if (textureBufferStack.at(currentTextureBuffer).fbo->isValid()) {
-            m_renderFbo = textureBufferStack.at(currentTextureBuffer).fbo;
-            m_engine = textureBufferStack.at(currentTextureBuffer).engine;
+        QGLFramebufferObjectFormat format;
+        format.setAttachment(QGLFramebufferObject::CombinedDepthStencil);
+        format.setSamples(4);
+        format.setInternalFormat(m_hasAlpha ? GL_RGBA : GL_RGB);
 
-            ++currentTextureBuffer;
+        m_renderFbo = qgl_fbo_pool()->acquire(size(), format);
 
+        if (m_renderFbo) {
+            m_engine = new QGL2PaintEngineEx;
             return m_engine;
         }