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XXX - Not complete yet!!!
Name
S3_s3tc
Name Strings
GL_S3_s3tc
Contact
Unknown.
IP Status
There is significant IP associated with the S3TC format. In 1999 S3
told the OpenGL ARB that they would not license it for general use
in OpenGL. IHVs shipping this extension probably have executed
licenses directly with S3 or its successors (Sonic Blue, S3
Graphics).
The current ownership of the S3TC IP is unknown to the ARB. It is
known that when S3 exited the graphics hardware business, part of
their operations were sold to ATI and part were spun off to a joint
Taiwanese venture with Via Technologies, called S3 Graphics.
Status
Shipping in several vendor drivers.
Deprecated in favor of EXT_texture_compression_s3tc.
Version
Unknown
Number
276
Dependencies
OpenGL 1.1 is required.
The extension is not specified; only the new tokens are known.
Overview
This extension allows specifying texture data in compressed S3TC
format.
Issues
* Need a specification, at least at a functional level. No
detailed online documentation can be found in Google, only
enum values.
New Procedures and Functions
None.
New Tokens
Accepted by the ??? parameter of ??? (presumably by the <format>
argument of TexImage2D?):
RGB_S3TC 0x83A0
RGB4_S3TC 0x83A1
RGBA_S3TC 0x83A2
RGBA4_S3TC 0x83A3
RGBA_DXT5_S3TC 0x83A4
RGBA4_DXT5_S3TC 0x83A5
Additions to Chapter 2 of the OpenGL 1.2 Specification (OpenGL Operation)
Unknown.
Additions to Chapter 3 of the OpenGL 1.2.1 Specification (Rasterization)
Unknown. Probably only changes to accepted client texture formats
for 2D textures.
Additions to Chapter 4 of the OpenGL 1.2.1 Specification (Per-Fragment
Operations and the Frame Buffer)
Unknown.
Additions to Chapter 5 of the OpenGL 1.2.1 Specification (Special Functions)
Unknown.
Additions to Chapter 6 of the OpenGL 1.2 Specification (State and State
Requests)
Unknown.
Additions to Appendix A of the OpenGL 1.2.1 Specification (Invariance)
Unknown.
Additions to the GLX / WGL / AGL Specifications
None
GLX Protocol
Unknown. Passing compressed data would affect the computed data
size, so some enhancements to the existing TexImage2D protocol might
be needed.
Errors
Unknown.
New State
Unknown.
Revision History
* Revision 2, January 17, 2003 (Mark Kilgard) - Document
RGBA_DXT5_S3TC and RGBA4_DXT5_S3TC enumerants. Update status as
deprecated in favor of EXT_texture_compression_s3tc spec.
* Revision 1, December 18, 2002 (Jon Leech) - Minimal documentation on
the extension based on public header files.