OpenGL.GL.EXT.texture_buffer_object

OpenGL extension EXT.texture_buffer_object

This module customises the behaviour of the OpenGL.raw.GL.EXT.texture_buffer_object to provide a more Python-friendly API

Overview (from the spec)

This extension provides a new texture type, called a buffer texture. Buffer textures are one-dimensional arrays of texels whose storage comes from an attached buffer object. When a buffer object is bound to a buffer texture, a format is specified, and the data in the buffer object is treated as an array of texels of the specified format.

The use of a buffer object to provide storage allows the texture data to be specified in a number of different ways: via buffer object loads (BufferData), direct CPU writes (MapBuffer), framebuffer readbacks (EXT_pixel_buffer_object extension). A buffer object can also be loaded by transform feedback (NV_transform_feedback extension), which captures selected transformed attributes of vertices processed by the GL. Several of these mechanisms do not require an extra data copy, which would be required when using conventional TexImage-like entry points.

Buffer textures do not support mipmapping, texture lookups with normalized floating-point texture coordinates, and texture filtering of any sort, and may not be used in fixed-function fragment processing. They can be accessed via single texel fetch operations in programmable shaders. For assembly shaders (NV_gpu_program4), the TXF instruction is used. For GLSL (EXT_gpu_shader4), a new sampler type and texel fetch function are used.

Buffer textures can be substantially larger than equivalent one-dimensional textures; the maximum texture size supported for buffer textures in the initial implementation of this extension is 2^27 texels, versus 2^13 (8192) texels for otherwise equivalent one-dimensional textures. When a buffer object is attached to a buffer texture, a size is not specified; rather, the number of texels in the texture is taken by dividing the size of the buffer object by the size of each texel.

The official definition of this extension is available here: http://www.opengl.org/registry/specs/EXT/texture_buffer_object.txt