WEBGL compressed texture pvrtc

The WEBGL_compressed_texture_pvrtc extension is part of the WebGL API and exposes four PVRTC compressed texture formats.

Compressed textures reduce the amount of memory needed to store a texture on the GPU, allowing for higher resolution textures or more of the same resolution textures.

WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.

Constants

The compressed texture formats are exposed by four constants and can be used in two functions: compressedTexImage2D() (where the height and width parameters must be powers of 2) and compressedTexSubImage2D() (where the the height and width parameters must equal the current values of the existing texture and the xoffset and yoffset parameters must be 0).

ext.COMPRESSED_RGB_PVRTC_4BPPV1_IMG

RGB compression in 4-bit mode. One block for each 4×4 pixels.

ext.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG

RGBA compression in 4-bit mode. One block for each 4×4 pixels.

ext.COMPRESSED_RGB_PVRTC_2BPPV1_IMG

RGB compression in 2-bit mode. One block for each 8×4 pixels.

ext.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG

RGBA compression in 2-bit mode. One block for each 8×4 pixels.

Examples

var ext = gl.getExtension('WEBGL_compressed_texture_pvrtc');

var texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);

gl.compressedTexImage2D(gl.TEXTURE_2D, 0, ext.COMPRESSED_RGB_PVRTC_4BPPV1_IMG, 512, 512, 0, textureData); 

Specifications

Specification	Status	Comment
WEBGL_compressed_texture_pvrtc The definition of 'WEBGL_compressed_texture_pvrtc' in that specification.	Draft	Initial definition.

Browser compatibility

See also

• PVRTC Texture Compression – Wikipedia
• WebGLRenderingContext.getExtension()
• WebGLRenderingContext.compressedTexImage2D()
• WebGLRenderingContext.compressedTexSubImage2D()
• WebGLRenderingContext.getParameter()