overview of OpenGL

mixing of OpenGL and Xlib

mixing of OpenGL and Xlib

The OpenGL implementation conforms to the specification definition for mixing of Xlib and OpenGL rendering to the same drawable. The following points should be considered when mixing Xlib and OpenGL:

•OpenGL and Xlib renderers are implemented through separate pipelines and control streams, thus, rendering synchronization must be performed as necessary by the user’s application via the GLX glXWaitX() and glXWaitGL() function calls.

•Xlib rendering does not affect the Z-buffer, so rendering in X and then OpenGL would result in the OpenGL rendering replacing the Xlib rendering. This is true if the last OpenGL rendering to the Z-buffer at that location resulted in the depth test passing.

Note that mixing Xlib rendering with OpenGL rendering as well as with VMD, when using alpha buffers, can produce unexpected side effects and should be avoided.

Chapter 1

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