forked from Qortal/Brooklyn
107 lines
3.0 KiB
Plaintext
107 lines
3.0 KiB
Plaintext
Name
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MESA_bgra
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Name Strings
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GL_MESA_bgra
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Contact
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Gert Wollny (gert.wollny 'at' collabora.com)
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Notice
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Copyright (c) 2021 Collabora LTD
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Copyright (c) 2009-2013 The Khronos Group Inc. Copyright terms at
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http://www.khronos.org/registry/speccopyright.html
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Version
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Version 1, 2021/04/30.
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Based on EXT_bgra version 1, modified 1997/05/19.
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Number
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TBD
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Dependencies
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OpenGL ES 2.0 is required.
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Written based on the wording of the OpenGL ES 3.2 specification.
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There are interactions with the extensions EXT_clear_texture.
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Overview
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MESA_bgra extends the list of combinations host-memory color formats
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with internal formats to include BGRA and BGR as acceptable formats
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with RGB8/SRGB8 and RGBA/sRGB8_ALPHA8 as internal formats respectively.
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This feature is of interest in virtualized environments, where the host
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supports OpenGL ES only, and the virtualized guest is supposed to support
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a subset of OpenGL including textures created with the format BGRA.
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IP Status
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Open-source; freely implementable.
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Issues
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None.
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New Procedures and Functions
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None
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New Tokens
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Accepted by the <format> parameter of TexImage2D and TexSubImage2D:
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GL_BGR_EXT 0x80E0
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GL_BGRA_EXT 0x80E1
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Additions to Chapter 8 of the GLES 3.2 Specification (Textures and Samplers)
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Add to table 8.2 (Pixels data formats, valid combinations of format,
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type, and unsized internalformat).
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Format Type External Internal Format
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Bytes
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per Pixel
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-------------------------------------------------------------
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BGRA UNSIGNED_BYTE 4 RGBA
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BGR UNSIGNED_BYTE 3 RGB
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Add to table 8.5 (Pixels data formats).
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Format Name Elements Meaning and Order Target Buffer
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-------------------------------------------------------------
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BGR_EXT B, G, R Color
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BGRA_EXT B, G, R, A Color
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Add to table 8.9 (Effective internal format correspondig to
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external format).
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Format Type Effective
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Internal format
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-------------------------------------------------------------
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BGRA_EXT UNSIGNED_BYTE RGBA8
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BGR_EXT UNSIGNED_BYTE RGB8
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Interactions with EXT_clear_texture
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When EXT_clear_texture is supported the accepted formats for
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ClearTextureEXT and ClearSubTextureEXT are extended to include
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the entries added above.
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Revision History
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Original draft, revision 1.0, May 4, 2021 (Gert Wollny)
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rewrite EXT_bgra against OpenGL ES 3.2 instead of OpenGL 1,0.
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Revision 1.1 (May 5. 2021): Add the new tokens, and fix
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Clear*Texture function names.
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