Support Alpha8 and Grayscale8 natively in the OpenGL paint engine

Adds special shaders for the Alpha8 and Grayscale8 formats so that
they do not need to rely on the support of GL_ALPHA and GL_LUMINANCE
that has been removed from core in recent OpenGL versions.

Change-Id: Ie370379b458abf2a50e252bc5099aefc1b11fb1d
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/tests/auto/gui/qopengl/tst_qopengl.cpp b/tests/auto/gui/qopengl/tst_qopengl.cpp
index 89ad66c1e8..a8834563a1 100644
--- a/tests/auto/gui/qopengl/tst_qopengl.cpp
+++ b/tests/auto/gui/qopengl/tst_qopengl.cpp
@@ -98,6 +98,8 @@ private slots:
     void textureblitterPartTargetRectTransform();
     void defaultSurfaceFormat();
 
+    void imageFormatPainting();
+
 #ifdef USE_GLX
     void glxContextWrap();
 #endif
@@ -718,6 +720,68 @@ void tst_QOpenGL::fboHandleNulledAfterContextDestroyed()
     QCOMPARE(fbo->handle(), 0U);
 }
 
+void tst_QOpenGL::imageFormatPainting()
+{
+    QScopedPointer<QSurface> surface(createSurface(QSurface::Window));
+
+    QOpenGLContext ctx;
+    QVERIFY(ctx.create());
+
+    QVERIFY(ctx.makeCurrent(surface.data()));
+
+    if (!QOpenGLFramebufferObject::hasOpenGLFramebufferObjects())
+        QSKIP("QOpenGLFramebufferObject not supported on this platform");
+
+    QOpenGLFramebufferObjectFormat fboFormat;
+    fboFormat.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
+
+    const QSize size(128, 128);
+    QOpenGLFramebufferObject fbo(size, fboFormat);
+
+    if (fbo.attachment() != QOpenGLFramebufferObject::CombinedDepthStencil)
+        QSKIP("FBOs missing combined depth~stencil support");
+
+    QVERIFY(fbo.bind());
+
+    QImage alpha(128, 128, QImage::Format_Alpha8);
+    alpha.fill(127);
+
+    QPainter fboPainter;
+    QOpenGLPaintDevice device(fbo.width(), fbo.height());
+
+    QVERIFY(fboPainter.begin(&device));
+    fboPainter.fillRect(0, 0, 128, 128, qRgb(255, 0, 255));
+    fboPainter.setCompositionMode(QPainter::CompositionMode_DestinationIn);
+    fboPainter.drawImage(0, 0, alpha);
+    fboPainter.end();
+
+    QImage fb = fbo.toImage();
+    QCOMPARE(fb.pixel(0, 0), qRgba(127, 0, 127, 127));
+
+    QImage grayscale(128, 128, QImage::Format_Grayscale8);
+    grayscale.fill(128);
+
+    QVERIFY(fboPainter.begin(&device));
+    fboPainter.setCompositionMode(QPainter::CompositionMode_Plus);
+    fboPainter.drawImage(0, 0, grayscale);
+    fboPainter.end();
+
+    fb = fbo.toImage();
+    QCOMPARE(fb.pixel(0, 0), qRgb(255, 128, 255));
+
+    QImage argb(128, 128, QImage::Format_ARGB32);
+    argb.fill(qRgba(255, 255, 255, 128));
+
+    QVERIFY(fboPainter.begin(&device));
+    fboPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
+    fboPainter.drawImage(0, 0, argb);
+    fboPainter.end();
+
+    fb = fbo.toImage();
+    QCOMPARE(fb.pixel(0, 0), qRgb(255, 192, 255));
+
+}
+
 void tst_QOpenGL::openGLPaintDevice_data()
 {
     QTest::addColumn<int>("surfaceClass");