QOpenGLTextureBlitter: Remove Origin location for the Target rect

The Origin for Target rect was deemed a confusing concept. The current
implementation would translate the target rect to the coordinate system
specified. However, the order and "direction" of the vertices would
always be the same. So drawing a texture in for one target rect defined in
one coordinate system would paint the texture the same way as it would
when a texture was drawn for a target rect drawn in the "opposite"
coordinate system. The point with this was that if you wanted to "flip"
the texture you would specify that with the source coordinate system.

However, this approach breaks on different levels, such as QRect has functions
which expects a top left coordinate system (ie. top() and bottom()).

In the end Qt uses a top left coordinate system, hence QWindow specifies
a top left coordinate system, and hence the api becomes easier if it is
not possible to define the coordinate system of the target viewport.

Change-Id: I7dd59b3718380876e87a4bff88381d7a1c7d58c1
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/src/gui/painting/qplatformbackingstore.cpp b/src/gui/painting/qplatformbackingstore.cpp
index 58fe28bb48..15459dd748 100644
--- a/src/gui/painting/qplatformbackingstore.cpp
+++ b/src/gui/painting/qplatformbackingstore.cpp
@@ -218,8 +218,7 @@ void QPlatformBackingStore::composeAndFlush(QWindow *window, const QRegion &regi
         GLuint textureId = textures->textureId(i);
         glBindTexture(GL_TEXTURE_2D, textureId);
 
-        QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(textures->geometry(i), windowRect,
-                                                                   QOpenGLTextureBlitter::OriginTopLeft);
+        QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(textures->geometry(i), windowRect);
         d_ptr->blitter->blit(textureId, target, QOpenGLTextureBlitter::OriginBottomLeft);
     }
 
@@ -230,8 +229,7 @@ void QPlatformBackingStore::composeAndFlush(QWindow *window, const QRegion &regi
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
-    QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(windowRect, windowRect,
-                                                               QOpenGLTextureBlitter::OriginTopLeft);
+    QMatrix4x4 target = QOpenGLTextureBlitter::targetTransform(windowRect, windowRect);
     d_ptr->blitter->setSwizzleRB(true);
     d_ptr->blitter->blit(textureId, target, QOpenGLTextureBlitter::OriginTopLeft);
     d_ptr->blitter->setSwizzleRB(false);