WEBGL_compressed_texture_pvrtc extension

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

TheWEBGL_compressed_texture_pvrtc extension is part of theWebGL API and exposes fourPVRTC 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 theWebGLRenderingContext.getExtension() method. For more information, see alsoUsing Extensions in theWebGL tutorial.

Note:PVRTC is typically only available on mobile devices with PowerVR chipsets.It is used in all generations of the iPhone, iPod Touch and iPad and supported on certain Android devices that use a PowerVR GPU.

This extension is available to both,WebGL1 andWebGL2 contexts.

Note:On iOS devices, this extension is namedWEBKIT_WEBGL_compressed_texture_pvrtc.

Constants

The compressed texture formats are exposed by four constants and can be used in two functions:compressedTexImage2D() (where theheight andwidth parameters must be powers of 2) andcompressedTexSubImage2D() (where the height and width parameters must equal the current values of the existing texture and thexoffset andyoffset 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

const ext = gl.getExtension("WEBGL_compressed_texture_pvrtc");const 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,);