6 files changed, 105 insertions, 8 deletions

diff --git a/src/widgets/kernel/qopenglwidget.cpp b/src/widgets/kernel/qopenglwidget.cpp
index 147e0774e7..4d45782170 100644
--- a/src/widgets/kernel/qopenglwidget.cpp
+++ b/src/widgets/kernel/qopenglwidget.cpp
@@ -566,7 +566,8 @@ public:
           paintDevice(0),
           updateBehavior(QOpenGLWidget::NoPartialUpdate),
           requestedSamples(0),
-          inPaintGL(false)
+          inPaintGL(false),
+          textureFormat(0)
     {
         requestedFormat = QSurfaceFormat::defaultFormat();
     }
@@ -580,6 +581,7 @@ public:
     void recreateFbo();
 
     GLuint textureId() const Q_DECL_OVERRIDE;
+    QPlatformTextureList::Flags textureListFlags() Q_DECL_OVERRIDE;
 
     void initialize();
     void invokeUserPaint();
@@ -610,6 +612,7 @@ public:
     QOpenGLWidget::UpdateBehavior updateBehavior;
     int requestedSamples;
     bool inPaintGL;
+    GLenum textureFormat;
 };
 
 void QOpenGLWidgetPaintDevicePrivate::beginPaint()
@@ -654,6 +657,35 @@ GLuint QOpenGLWidgetPrivate::textureId() const
     return resolvedFbo ? resolvedFbo->texture() : (fbo ? fbo->texture() : 0);
 }
 
+#ifndef GL_SRGB
+#define GL_SRGB 0x8C40
+#endif
+#ifndef GL_SRGB8
+#define GL_SRGB8 0x8C41
+#endif
+#ifndef GL_SRGB_ALPHA
+#define GL_SRGB_ALPHA 0x8C42
+#endif
+#ifndef GL_SRGB8_ALPHA8
+#define GL_SRGB8_ALPHA8 0x8C43
+#endif
+
+QPlatformTextureList::Flags QOpenGLWidgetPrivate::textureListFlags()
+{
+    QPlatformTextureList::Flags flags = QWidgetPrivate::textureListFlags();
+    switch (textureFormat) {
+    case GL_SRGB:
+    case GL_SRGB8:
+    case GL_SRGB_ALPHA:
+    case GL_SRGB8_ALPHA8:
+        flags |= QPlatformTextureList::TextureIsSrgb;
+        break;
+    default:
+        break;
+    }
+    return flags;
+}
+
 void QOpenGLWidgetPrivate::reset()
 {
     Q_Q(QOpenGLWidget);
@@ -703,12 +735,16 @@ void QOpenGLWidgetPrivate::recreateFbo()
     QOpenGLFramebufferObjectFormat format;
     format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
     format.setSamples(samples);
+    if (textureFormat)
+        format.setInternalTextureFormat(textureFormat);
 
     const QSize deviceSize = q->size() * q->devicePixelRatioF();
     fbo = new QOpenGLFramebufferObject(deviceSize, format);
     if (samples > 0)
         resolvedFbo = new QOpenGLFramebufferObject(deviceSize);
 
+    textureFormat = fbo->format().internalTextureFormat();
+
     fbo->bind();
     context->functions()->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
@@ -767,7 +803,9 @@ void QOpenGLWidgetPrivate::initialize()
         return;
     }
 
-    // Propagate settings that make sense only for the tlw.
+    // Propagate settings that make sense only for the tlw. Note that this only
+    // makes sense for properties that get picked up even after the native
+    // window is created.
     QSurfaceFormat tlwFormat = tlw->windowHandle()->format();
     if (requestedFormat.swapInterval() != tlwFormat.swapInterval()) {
         // Most platforms will pick up the changed swap interval on the next
@@ -990,7 +1028,6 @@ QOpenGLWidget::UpdateBehavior QOpenGLWidget::updateBehavior() const
  */
 void QOpenGLWidget::setFormat(const QSurfaceFormat &format)
 {
-    Q_UNUSED(format);
     Q_D(QOpenGLWidget);
     if (Q_UNLIKELY(d->initialized)) {
         qWarning("QOpenGLWidget: Already initialized, setting the format has no effect");
@@ -1023,6 +1060,47 @@ QSurfaceFormat QOpenGLWidget::format() const
 }
 
 /*!
+    Sets a custom internal texture format.
+
+    When working with sRGB framebuffers, it will be necessary to specify a
+    format like \c{GL_SRGB8_ALPHA8}. This can be achieved by calling this
+    function.
+
+    \note This function has no effect if called after the widget has already
+    been shown and thus it performed initialization.
+
+    \note This function will typically have to be used in combination with a
+    QSurfaceFormat::setDefaultFormat() call that sets the color space to
+    QSurfaceFormat::sRGBColorSpace.
+
+    \since 5.10
+ */
+void QOpenGLWidget::setTextureFormat(GLenum texFormat)
+{
+    Q_D(QOpenGLWidget);
+    if (Q_UNLIKELY(d->initialized)) {
+        qWarning("QOpenGLWidget: Already initialized, setting the internal texture format has no effect");
+        return;
+    }
+
+    d->textureFormat = texFormat;
+}
+
+/*!
+    \return the active internal texture format if the widget has already
+    initialized, the requested format if one was set but the widget has not yet
+    been made visible, or 0 if setTextureFormat() was not called and the widget
+    has not yet been made visible.
+
+    \since 5.10
+ */
+GLenum QOpenGLWidget::textureFormat() const
+{
+    Q_D(const QOpenGLWidget);
+    return d->textureFormat;
+}
+
+/*!
   \return \e true if the widget and OpenGL resources, like the context, have
   been successfully initialized. Note that the return value is always false
   until the widget is shown.
diff --git a/src/widgets/kernel/qopenglwidget.h b/src/widgets/kernel/qopenglwidget.h
index b60d79bedb..c0a6e41522 100644
--- a/src/widgets/kernel/qopenglwidget.h
+++ b/src/widgets/kernel/qopenglwidget.h
@@ -72,6 +72,9 @@ public:
     void setFormat(const QSurfaceFormat &format);
     QSurfaceFormat format() const;
 
+    GLenum textureFormat() const;
+    void setTextureFormat(GLenum texFormat);
+
     bool isValid() const;
 
     void makeCurrent();
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 70bc407587..8a642940cd 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -67,7 +67,6 @@
 # include <private/qmainwindowlayout_p.h>
 #endif
 #include <qpa/qplatformwindow.h>
-#include <qpa/qplatformbackingstore.h>
 #include "private/qwidgetwindow_p.h"
 #include "qpainter.h"
 #include "qtooltip.h"
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index 68e063c25a..858328e618 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -69,6 +69,7 @@
 #include "QtWidgets/qgraphicsscene.h"
 #include "QtWidgets/qgraphicsview.h"
 #include <private/qgesture_p.h>
+#include <qpa/qplatformbackingstore.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -81,7 +82,6 @@ class QWidgetBackingStore;
 class QGraphicsProxyWidget;
 class QWidgetItemV2;
 class QOpenGLContext;
-class QPlatformTextureList;
 
 class QStyle;
 
@@ -630,6 +630,12 @@ public:
 
 #ifndef QT_NO_OPENGL
     virtual GLuint textureId() const { return 0; }
+    virtual QPlatformTextureList::Flags textureListFlags() {
+        Q_Q(QWidget);
+        return q->testAttribute(Qt::WA_AlwaysStackOnTop)
+            ? QPlatformTextureList::StacksOnTop
+            : QPlatformTextureList::Flags(0);
+    }
     virtual QImage grabFramebuffer() { return QImage(); }
     virtual void beginBackingStorePainting() { }
     virtual void endBackingStorePainting() { }
diff --git a/src/widgets/kernel/qwidgetbackingstore.cpp b/src/widgets/kernel/qwidgetbackingstore.cpp
index 781ad9600d..4421218d1d 100644
--- a/src/widgets/kernel/qwidgetbackingstore.cpp
+++ b/src/widgets/kernel/qwidgetbackingstore.cpp
@@ -945,9 +945,7 @@ static void findTextureWidgetsRecursively(QWidget *tlw, QWidget *widget, QPlatfo
 {
     QWidgetPrivate *wd = QWidgetPrivate::get(widget);
     if (wd->renderToTexture) {
-        QPlatformTextureList::Flags flags = 0;
-        if (widget->testAttribute(Qt::WA_AlwaysStackOnTop))
-            flags |= QPlatformTextureList::StacksOnTop;
+        QPlatformTextureList::Flags flags = wd->textureListFlags();
         const QRect rect(widget->mapTo(tlw, QPoint()), widget->size());
         widgetTextures->appendTexture(widget, wd->textureId(), rect, wd->clipRect(), flags);
     }
diff --git a/src/widgets/kernel/qwindowcontainer.cpp b/src/widgets/kernel/qwindowcontainer.cpp
index 7ae63e54b3..a17c69c5ce 100644
--- a/src/widgets/kernel/qwindowcontainer.cpp
+++ b/src/widgets/kernel/qwindowcontainer.cpp
@@ -337,6 +337,19 @@ bool QWindowContainer::event(QEvent *e)
         e->accept();
         return true;
 #endif
+
+    case QEvent::Paint:
+    {
+        static bool needsPunch = !QGuiApplicationPrivate::platformIntegration()->hasCapability(
+            QPlatformIntegration::TopStackedNativeChildWindows);
+        if (needsPunch) {
+            QPainter p(this);
+            p.setCompositionMode(QPainter::CompositionMode_Source);
+            p.fillRect(rect(), Qt::transparent);
+        }
+        break;
+    }
+
     default:
         break;
     }