5621a7c501
While we will cover the entire surface with our textured quads, the clear is still necessary in order to make top-levels with TranslucentBackground render correctly: We don't want to blend transparent areas with undefined content that is in the surface's framebuffer. Blending is problematic for alpha values. We now prevent the blended alpha from being written out. This ensures that in examples like qquickviewcomparison, where the backingstore image contains an alpha of 0.5 while the QQuickWidget texture 1.0, the result is still an alpha value of 1.0 in the final image. Writing out an alpha of 0.5 would break on systems where windows get an alpha buffer by default. hellogl2 can now take a --transparent parameter which makes the QOpenGLWidget being cleared to transparent in order to verify it works in combination with Qt::WA_TranslucentBackground. The swapped red and blue problem is also corrected. RGBA8888 does not need swizzling. The only format that needs this is RGB32. Task-number: QTBUG-40716 Change-Id: I54a9fd3a91a1b59575b38cdb908835315514e40f Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Qt provides support for integration with OpenGL implementations on all platforms, giving developers the opportunity to display hardware accelerated 3D graphics alongside a more conventional user interface. These examples demonstrate the basic techniques used to take advantage of OpenGL in Qt applications. Documentation for these examples can be found via the Examples link in the main Qt documentation.