Image/texture implementation code
This module provides the Pan-OpenGL operations required to support OpenGL image handling. Most of this code is simply boilerplate code that sets OpenGL parameters such that normal Pythonic assumptions about data-ordering are met to allow easier interaction with other projects (such as PIL or Numpy).
Generally speaking, there are 3 pieces of information which control how an image is processed in the system:
this is the pixel format, such as GL_RGB/GL_RED/GL_ABGR_EXT
tuple of dimensions for the image, (width,height,depth) order
the storage data-type for the image, normally GL_UNSIGNED_BYTE when working in Python, but all of the standard OpenGL types for images can be used if you happen to have your data in some exotic format.
OpenGL.UNSIGNED_BYTE_IMAGES_AS_STRING -- if this global value is set, then read of unsigned byte images using glReadPixels and glGetTexImage produces a string instead of the default array format.
Attributes of Note:
used to lookup how many units of a given storage type are required to store a unit in a given format
maps Image storage types to their array data-type constants, i.e. maps GL_UNSIGNED_SHORT_4_4_4_4 to GL_UNSIGNED_SHORT so that we can use the standard array types for manipulating image arrays.
commands required to set up default array-transfer operations for an array of the specified rank.
New image formats and types will need to be registered here to be supported, this means that extension modules which add image types/formats need to alter the tables described above!
XXX Should be an API to handle that instead of direct modification.