How can I activate or unactivate the direct rendering (hardware acceleration)?
The hardware acceleration of the display system is provided with the DRI module (“direct rendering infrastructure”) of the video card driver. The hardware acceleration could speed up the terrain preview rotation or translation, by accelerating the OpenGL calls. However, it doesn’t have any effect on the refresh speed of the height field. The preview mesh is recalculated after any change in the height field. This is the heaviest part of the processing, and it takes place before any call to the OpenGL library. Futhermore, the activation of the DRI module could produce these problems: • An abnormal memory usage. which seems to be related the the interaction between the video card driver, the X-Windows substem and the Linux kernel. It seemed generalized around 2005 (Geomorph 0.31), but it improved with driver, X-Windows or kernel updates. It can still be seen with new hardware and unmature drivers – for instance, on a 2008 laptop with an Intel X3100 graphic accelerator like the one used fo
