Name EXT_abgr Name Strings GL_EXT_abgr Version $Date: 1995/03/31 04:40:18 $ $Revision: 1.10 $ Number 1 Dependencies None Overview EXT_abgr extends the list of host-memory color formats. Specifically, it provides a reverse-order alternative to image format RGBA. The ABGR component order matches the cpack Iris GL format on big-endian machines. New Procedures and Functions None New Tokens Accepted by the parameter of DrawPixels, GetTexImage, ReadPixels, TexImage1D, and TexImage2D: ABGR_EXT 0x8000 Additions to Chapter 2 of the GL Specification (OpenGL Operation) None Additions to Chapter 3 of the GL Specification (Rasterization) One entry is added to table 3.5 (DrawPixels and ReadPixels formats). The new table is: Target Name Type Elements Buffer ---- ---- -------- ------ COLOR_INDEX Index Color Index Color STENCIL_INDEX Index Stencil value Stencil DEPTH_COMPONENT Component Depth value Depth RED Component R Color GREEN Component G Color BLUE Component B Color ALPHA Component A Color RGB Component R, G, B Color RGBA Component R, G, B, A Color LUMINANCE Component Luminance value Color LUMINANCE_ALPHA Component Luminance value, A Color ABGR_EXT Component A, B, G, R Color Table 3.5: DrawPixels and ReadPixels formats. The third column gives a description of and the number and order of elements in a group. Additions to Chapter 4 of the GL Specification (Per-Fragment Operations and the Framebuffer) The new format is added to the discussion of Obtaining Pixels from the Framebuffer. It should read " If the is one of RED, GREEN, BLUE, ALPHA, RGB, RGBA, ABGR_EXT, LUMINANCE, or LUMINANCE_ALPHA, and the GL is in color index mode, then the color index is obtained." The new format is added to the discussion of Index Lookup. It should read "If is one of RED, GREEN, BLUE, ALPHA, RGB, RGBA, ABGR_EXT, LUMINANCE, or LUMINANCE_ALPHA, then the index is used to reference 4 tables of color components: PIXEL_MAP_I_TO_R, PIXEL_MAP_I_TO_G, PIXEL_MAP_I_TO_B, and PIXEL_MAP_I_TO_A." Additions to Chapter 5 of the GL Specification (Special Functions) None Additions to Chapter 6 of the GL Specification (State and State Requests) None Additions to the GLX Specification None GLX Protocol One entry is added to tables 1 and 5 in the GLX Protocol Specification: format encoding ------ -------- GL_ABGR_EXT 0x8000 Table A.2 is also extended: format nelements ------ -------- GL_ABGR_EXT 4 Errors None New State None New Implementation Dependent State None