Copy Texture availability test None, since this feature is always available (GLAF will emulate it if
necessary). However, you can call glaf_IsCopyTextureNative(), that
will tell you whether the system really supports copy texture or if GLAF
is emulating it.
Copy Texture support rules
None.
Copy Texture functions glaf_CopyTexImage1D
Copy Texture definitions in 'gl2glaf.h' (optional) #define glCopyTexImage1D
glaf_CopyTexImage1D
Copy Texture side effects If GLAF needs to emulate the copy texture feature, and you're copying a 1D texture but you left 2D convolution enabled, the texture may not be copied. This problem may happen only with 1D textures. Convolution is correctly managed for 2D textures. The emulation mode will perform a glReadPixels() honoring the current state of the full pixel transfer pipeline (including imaging extensions), followed by a glTexImage() with a "disabled" pixel transfer pipeline. The complete state of the pixel transfer pipeline and pixel store modes will be restored to their previous value before returning. Just a very few 1.0 implementations lack copy texture, so this emulation
mode won't be used too often. Anyway, if you wish to avoid it, you can
guess if it's emulated or not with glaf_IsCopyTextureNative()
Copy SubTexture Availability Test GLboolean glaf_IsCopySubTextureSupported(void) Unlike Copy Texture, Copy SubTexture can't be emulated if the SubTexture
feature is not supported. This function returns GL_TRUE if the feature
is supported or GL_FALSE otherwise. Calling the functions of an
unsupported feature or using its enumerants may crash the application,
or generate OpenGL errors, or even undefined behaviour, so you should never
use a feature without testing its availability first.
Copy SubTexture support rules
None.
Copy SubTexture functions glaf_CopyTexSubImage1D
Copy SubTexture definitions in 'gl2glaf.h' (optional) #define glCopyTexSubImage1D
glaf_CopyTexSubImage1D
Copy SubTexture side effects If the Copy Texture feature is not natively supported but SubTexture
is, then Copy SubTexture will be emulated. In this case, the same notes
from 'Copy Texture side effects' above apply.
|
Copyright (C) 2001 César Blecua Udías