![]() ![]() In this case, QGLFramebufferObject should be used instead. Note: OpenGL ES 2.X does not support PBuffers, so QGLPixelBuffer will not work. Once a QGraphicsView has been initialized as above, regular widgets can be added to the canvas using QGraphicsProxyWidget if the application requires them. It is also recommended that the window be shown full-screen because that usually has the best performance on current OpenGL ES implementations. It is recommended that the QGraphicsView::FullViewportUpdate flag be set because the default double-buffered behavior of QGLWidget does not support partial updates. setViewportUpdateMode(QGraphicsView::FullViewportUpdate) setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff) setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff) However, any application that uses QGraphicsView can set a QGLWidget as the viewport and obtain access to the OpenGL paint engine that way: QGraphicsView view(&scene) Note: The OpenGL paint engine is not currently supported in regular widgets. These issues will be addressed in future versions of Qt. Using OpenGL ES to accelerate regular widgets as well as compositing top-level windows with OpenGL ES are not currently supported. The current implementation only supports OpenGL ES and 2D painting within a QGLWidget. To use OpenGL-enabled widgets in a Qt for Embedded application, all that is required is to subclass QGLWidget and draw into instances of the subclass with standard OpenGL functions. It can also overlay controls and decorations onto 3D scenes drawn using OpenGL. This specialized paint engine can be used to improve 2D rendering performance on appropriate hardware. To translate QPainter operations into OpenGL ES calls (there are actually two subclasses, one for OpenGL/ES 1.1 and another for OpenGL/ES 2.0), Qt uses a subclass of QPaintEngine. However, Qt for Embedded can be adapted to a wide range of OpenGL versions. Qt provides a plugin that integrates both OpenGL ES versions 1.x and 2.x with Qt for Embedded. The QtOpenGL module offers classes that make it easy to draw 3D graphics in GUI applications using OpenGL ES. Instead of using the pre-defined functions, the programmer writes small shader programs telling the hardware in detail how to render each object. Instead of using function transformation and a fragment pipeline, 2.x uses the OpenGL ES Shading Language (GLSL ES). OpenGL 2.x has a significantly shorter graphics pipeline than 1.x. OpenGL ES 1.x limits processing to a pre-defined set of fixed options for drawing and lighting objects. It is worth noting that there is a significant difference between the two, and that they are not compatible with each other. OpenGL ES version 1.x is designed for fixed function hardware, while its successor OpenGL ES version 2.x is designed for programmable hardware. Because it is designed for use with embedded systems, it has a smaller, more constrained API. OpenGL ES is a subset of the OpenGL standard. It provides a powerful, low-level interface between software and acceleration hardware, and it is operating system and window system independent. OpenGL is an industry standard API for 2D/3D graphics. ![]()
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