QOpenGLTextureBlitter: fix source rect when origin is top left

This fixes the issue that the blitter required sometimes the
texture wrapping to be repeat

Change-Id: I86150d008422facf9040873b0983b0e44be9ad24
Reviewed-by: Laszlo Agocs <[email protected]>

2 files changed, 4 insertions, 2 deletions

diff --git a/src/gui/opengl/qopengltextureblitter.cpp b/src/gui/opengl/qopengltextureblitter.cpp
index 8085089bce9..b776444347f 100644
--- a/src/gui/opengl/qopengltextureblitter.cpp
+++ b/src/gui/opengl/qopengltextureblitter.cpp
@@ -210,6 +210,7 @@ void QOpenGLTextureBlitterPrivate::blit(GLuint texture,
         if (textureMatrixUniformState != IdentityFlipped) {
             QMatrix3x3 flipped;
             flipped(1,1) = -1;
+            flipped(1,2) = 1;
             program->setUniformValue(textureTransformUniformPos, flipped);
             textureMatrixUniformState = IdentityFlipped;
         }
@@ -375,8 +376,8 @@ QMatrix3x3 QOpenGLTextureBlitter::sourceTransform(const QRectF &subTexture,
     qreal y_translate = topLeft.y() / textureSize.height();
 
     if (origin == OriginTopLeft) {
-        y_translate += (y_translate * 2) + y_scale;
-        y_scale = y_scale - 1;
+        y_scale = -y_scale;
+        y_translate = 1 - y_translate;
     }
 
     QMatrix3x3 matrix;
diff --git a/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp b/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp
index 503e326f386..8f51f511c98 100644
--- a/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp
+++ b/tests/manual/qopengltextureblitter/qopengltextureblitwindow.cpp
@@ -81,6 +81,7 @@ void QOpenGLTextureBlitWindow::render()
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     QOpenGLTexture texture(m_image);
+    texture.setWrapMode(QOpenGLTexture::ClampToEdge);
     texture.create();
 
     QOpenGLTexture texture_mirrored(m_image_mirrord);