WebGL WEBGL_compressed_texture_etc1 Extension Proposed Specification

DO NOT IMPLEMENT!!!

Name

WEBGL_compressed_texture_etc1

Contact

WebGL working group (public_webgl 'at' khronos.org)

Contributors

Members of the WebGL working group

Version

Last modified date: February 23, 2012
Revision: 1

Number

WebGL extension #XYZ

Dependencies

Written against the WebGL API 1.0 specification.

Overview

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

When this extension is enabled:

• Compression format COMPRESSED_RGB_ETC1_WEBGL may be passed to the compressedTexImage2D and compressedTexSubImage2D entry points. 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 length of the ArrayBufferView, pixels, passed to either compressedTexImage2D or compressedTexSubImage2D 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.

IDL

interface WEBGL_compressed_texture_etc1 {
    /* Compressed Texture Format */
    const GLenum COMPRESSED_RGB_ETC1_WEBGL = 0x8D64; 
};
  

Revision History

Revision 1, 2012/02/23

• Initial revision.