| '''OpenGL extension SGI.cushion |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GLX.SGI.cushion to provide a more |
| Python-friendly API |
| |
| Overview (from the spec) |
| |
| This extension is directed at constant frame-rate applications. Such |
| applications are written to ensure that a new image is generated every |
| N video frame periods, where N is itself a small constant integer. |
| If the application is unable to generate a frame within N video frame |
| periods, it is said to have dropped a frame. Dropping a frame is a |
| *bad thing*. |
| |
| Constant frame-rate applications make every effort to avoid dropping |
| frames. In particular, they monitor the utilization of graphics |
| resources during the rendering of the current frame in order to predict |
| the behavior of subsequent frames. If such prediction indicates that |
| a frame may be dropped, the rendering complexity of the frame is |
| reduced (e.g. by using models of lower geometric resolution) so as to |
| avoid the overload condition. |
| |
| Unfortunately, because exact prediction is not possible, and because |
| there is no elasticity in the buffering of images, it is necessary |
| for constant frame-rate applications to under utilize the graphics |
| hardware. This extension adds elasticity to the buffering of completed |
| images, in order to allow constant frame-rate applications to make full |
| use of the available graphics computation without dropping frames. |
| It further allows this elasticity to be controlled by the application in |
| order to minimize the introduction of latency that could otherwise |
| occur. |
| |
| Applications that will benefit from this extension include simulation, |
| walk-through, and multimedia playback. |
| |
| WARNING - Silicon Graphics has filed for patent protection for some |
| of the techniques described in this extension document. |
| |
| The official definition of this extension is available here: |
| http://www.opengl.org/registry/specs/SGI/cushion.txt |
| ''' |
| from OpenGL import platform, constant, arrays |
| from OpenGL import extensions, wrapper |
| import ctypes |
| from OpenGL.raw.GLX import _types, _glgets |
| from OpenGL.raw.GLX.SGI.cushion import * |
| from OpenGL.raw.GLX.SGI.cushion import _EXTENSION_NAME |
|
|
| def glInitCushionSGI(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
|
|
|
| |
