Use FBOs as pixmap backend in GL graphics system.

We now use FBOs to implement render-to-pixmap for the GL pixmap backend.
A multisample FBO is used for rendering, and is then blitted onto a
non-multisample FBO dynamically bound to the relevant texture.

Reviewed-by: Tom

1 files changed, 37 insertions, 1 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index e166b54..fe70020 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -175,6 +175,8 @@ public:
     // Clipping & state stuff stolen from QOpenGLPaintEngine:
     void updateDepthClip();
     uint use_system_clip : 1;
+
+    QPaintEngine *last_engine;
 };
 
 
@@ -616,7 +618,6 @@ void QGL2PaintEngineExPrivate::fill(const QVectorPath& path)
 
     const QPointF* const points = reinterpret_cast<const QPointF*>(path.points());
 
-
     // Check to see if there's any hints
     if (path.shape() == QVectorPath::RectangleHint) {
         QGLRect rect(points[0].x(), points[0].y(), points[2].x(), points[2].y());
@@ -1034,6 +1035,14 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     qt_resolve_version_1_3_functions(d->ctx);
     qt_resolve_glsl_extensions(d->ctx);
 
+    d->last_engine = d->ctx->d_ptr->active_engine;
+    d->ctx->d_ptr->active_engine = this;
+
+    if (d->last_engine) {
+        QGL2PaintEngineEx *engine = static_cast<QGL2PaintEngineEx *>(d->last_engine);
+        static_cast<QGL2PaintEngineExPrivate *>(engine->d_ptr)->transferMode(DefaultMode);
+    }
+
     if (!d->shaderManager)
         d->shaderManager = new QGLPEXShaderManager(d->ctx);
 
@@ -1054,6 +1063,19 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     d->use_system_clip = !systemClip().isEmpty();
 
     glDisable(GL_DEPTH_TEST);
+    glDisable(GL_SCISSOR_TEST);
+
+    QGLPixmapData *source = d->drawable.copyOnBegin();
+    if (source) {
+        d->transferMode(ImageDrawingMode);
+
+        source->bind();
+
+        glDisable(GL_BLEND);
+
+        QRect rect(0, 0, source->width(), source->height());
+        d->drawTexture(QRectF(rect), QRectF(rect), rect.size());
+    }
 
     updateClipRegion(QRegion(), Qt::NoClip);
     return true;
@@ -1067,6 +1089,20 @@ bool QGL2PaintEngineEx::end()
     d->transferMode(DefaultMode);
     d->drawable.swapBuffers();
     d->drawable.doneCurrent();
+    d->ctx->d_ptr->active_engine = d->last_engine;
+
+    if (d->last_engine) {
+        QGL2PaintEngineEx *engine = static_cast<QGL2PaintEngineEx *>(d->last_engine);
+        QGL2PaintEngineExPrivate *p = static_cast<QGL2PaintEngineExPrivate *>(engine->d_ptr);
+
+        glDisable(GL_DEPTH_TEST);
+        glDisable(GL_SCISSOR_TEST);
+
+        glViewport(0, 0, p->width, p->height);
+        engine->setState(engine->state());
+        p->updateDepthClip();
+    }
+
     return false;
 }