WEBGL_compressed_texture_etc1 WebGL working group (public_webgl 'at' khronos.org) Members of the WebGL working group 24

This extension exposes the compressed texture format defined in the OES_compressed_ETC1_RGB8_texture OpenGL ES extension to WebGL.

Compression format COMPRESSED_RGB_ETC1_WEBGL may be passed to the compressedTexImage2D entry point. This format correspond to the format defined in the OES_compressed_ETC1_RGB8_texture OpenGL ES extension. Although the enum name is changed, the numeric value is the same. The correspondence is given by this table:

WebGL format enum	OpenGL format enum	Numeric value
COMPRESSED_RGB_ETC1_WEBGL	ETC1_RGB8_OES	0x8D64

Calling getParameter with the argument COMPRESSED_TEXTURE_FORMATS will include the format from this specification.

The following format-specific restrictions must be enforced:

COMPRESSED_RGB_ETC1_WEBGL

The byteLength of the ArrayBufferView, pixels, passed to compressedTexImage2D must be equal to the following number of bytes:

floor((width + 3) / 4) * floor((height + 3) / 4) * 8

If it is not, an INVALID_VALUE error is generated.

[NoInterfaceObject] interface WEBGL_compressed_texture_etc1 { /* Compressed Texture Format */ const GLenum COMPRESSED_RGB_ETC1_WEBGL = 0x8D64; }; Initial revision. Clarified that length of ArrayBufferView is actually byteLength. Moved to draft status. Assigned extension number 24 to WEBGL_compressed_texture_etc1 extension. Remove ability to use the format with compressedTexSubImage2D, as per the GLES extension spec. Moved to community approved after discussion on public_webgl list. Added NoInterfaceObject extended attribute.