Name

    EXT_bgra

Name Strings

    GL_EXT_bgra

Version

    Microsoft revision 1.0, May 19, 1997 (drewb)
    $Date: 2005/06/02 18:11:10 $ $Revision: 1.1 $

Number

    129

Dependencies

    None

Overview

    EXT_bgra extends the list of host-memory color formats.
    Specifically, it provides formats which match the memory layout of
    Windows DIBs so that applications can use the same data in both
    Windows API calls and OpenGL pixel API calls.

New Procedures and Functions

    None

New Tokens

    Accepted by the <format> parameter of DrawPixels, GetTexImage,
    ReadPixels, TexImage1D, and TexImage2D:

	BGR_EXT			0x80E0
	BGRA_EXT		0x80E1

Additions to Chapter 2 of the 1.1 Specification (OpenGL Operation)

    None

Additions to Chapter 3 of the 1.1 Specification (Rasterization)

    One entry is added to table 3.5 (DrawPixels and ReadPixels formats).
    The new table is:

	Name			Type		Elements		Target 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
	BGR_EXT			Component	B, G, R			Color
	BGRA_EXT		Component	B, G, R, A		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 1.1 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 <format> is one of RED,
    GREEN, BLUE, ALPHA, RGB, RGBA, BGR_EXT, BGRA_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 <format> is one of RED, GREEN, BLUE, ALPHA, RGB, RGBA,
    BGR_EXT, BGRA_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

Revision History

    Original draft, revision 0.9, October 13, 1995 (drewb)
	Created
    Minor revision, revision 1.0, May 19, 1997 (drewb)
	Removed Microsoft Confidential.
