Native bindings to the ARB_texture_rectangle extension.

OpenGL texturing is limited to images with power-of-two dimensions and an optional 1-texel border. The ARB_texture_rectangle extension adds a new texture target that supports 2D textures without requiring power-of-two dimensions.

Non-power-of-two sized (NPOTS) textures are useful for storing video images that do not have power-of-two sized (POTS). Re-sampling artifacts are avoided and less texture memory may be required by using non-power-of-two sized textures. Non-power-of-two sized textures are also useful for shadow maps and window-space texturing.

However, non-power-of-two sized textures have limitations that do not apply to power-of-two sized textures. NPOTS textures may not use mipmap filtering; POTS textures support both mipmapped and non-mipmapped filtering. NPOTS textures support only the CLAMP, CLAMP_TO_EDGE, and CLAMP_TO_BORDER wrap modes; POTS textures support CLAMP_TO_EDGE, REPEAT, CLAMP, MIRRORED_REPEAT, and CLAMP_TO_BORDER (and GL_MIRROR_CLAMP_ATI and GL_MIRROR_CLAMP_TO_EDGE_ATI if ATI_texture_mirror_once is supported). NPOTS textures do not support an optional 1-texel border; POTS textures do support an optional 1-texel border.

NPOTS textures are accessed by dimension-dependent (aka non-normalized) texture coordinates. So instead of thinking of the texture image lying in a [0..1]x[0..1] range, the NPOTS texture image lies in a [0..w]x[0..h] range.

This extension adds a new texture target and related state (proxy, binding, max texture size).