Using WebGL extensions
WebGL, like its sister APIs (OpenGL and OpenGL ES), supports extensions. A complete list of extensions is available in the khronos webgl extension registry.
Note: In WebGL, unlike in other GL APIs, extensions are only available if explicitly requested.
Canonical extension names, vendor prefixes and preferences
Extensions may be supported by browser vendors before being officially ratified (but only when they are in draft stage). In that case, their name can be prefixed by the vendor prefix (MOZ_
, WEBKIT_
, etc.) or the extension is only available once a browser preference has been toggled.
If you wish to work with the bleeding edge of extensions, and want to keep working on upon ratification (assuming, of course, that the extension doesn't change in incompatible ways), that you query the canonical extension name as well as the vendor extension name. For instance:
js
const ext =
gl.getExtension("OES_vertex_array_object") ||
gl.getExtension("MOZ_OES_vertex_array_object") ||
gl.getExtension("WEBKIT_OES_vertex_array_object");
Note that, vendor prefix have been discouraged thus most browser implement experimental extensions behind a feature flag rather than vendor prefix.
The feature flags are:
webgl.enable-draft-extensions
in Firefoxchrome://flags/#enable-webgl-draft-extensions
in Chromium based browsers (Chrome, Opera).
Naming conventions
WebGL extensions are prefixed with "ANGLE", "OES", "EXT" or "WEBGL". These prefixes reflect origin and intent:
ANGLE_
: Extensions that are written by the ANGLE library authors.OES_
andKHR_
: Extensions that mirror functionality from OpenGL ES (OES) or OpenGL API extensions approved by the respective architecture review boards (Khronos).OVR_
: Extensions that optimize for virtual reality.EXT_
: Extensions that mirror other OpenGL ES or OpenGL API extensions.WEBGL_
: Extensions that are WebGL-specific and intended to be compatible with multiple web browsers. It should also be used for extensions which originated with the OpenGL ES or OpenGL APIs, but whose behavior has been significantly altered.
Querying available extensions
The WebGL context supports querying what extensions are available.
js
const available_extensions = gl.getSupportedExtensions();
The WebGLRenderingContext.getSupportedExtensions()
method returns an array of strings, one for each supported extension.
Extension list
The current extensions are:
ANGLE_instanced_arrays
EXT_blend_minmax
EXT_color_buffer_float
EXT_color_buffer_half_float
EXT_disjoint_timer_query
EXT_float_blend
ExperimentalEXT_frag_depth
EXT_shader_texture_lod
EXT_sRGB
EXT_texture_compression_bptc
EXT_texture_compression_rgtc
EXT_texture_filter_anisotropic
EXT_texture_norm16
KHR_parallel_shader_compile
OES_draw_buffers_indexed
OES_element_index_uint
OES_fbo_render_mipmap
OES_standard_derivatives
OES_texture_float
OES_texture_float_linear
OES_texture_half_float
OES_texture_half_float_linear
OES_vertex_array_object
OVR_multiview2
WEBGL_color_buffer_float
WEBGL_compressed_texture_astc
WEBGL_compressed_texture_etc
WEBGL_compressed_texture_etc1
WEBGL_compressed_texture_pvrtc
WEBGL_compressed_texture_s3tc
WEBGL_compressed_texture_s3tc_srgb
WEBGL_debug_renderer_info
WEBGL_debug_shaders
WEBGL_depth_texture
WEBGL_draw_buffers
WEBGL_lose_context
WEBGL_multi_draw
Enabling an extension
Before an extension can be used it has to be enabled using WebGLRenderingContext.getExtension()
. For example:
js
const float_texture_ext = gl.getExtension("OES_texture_float");
The return value is null
if the extension is not supported, or an extension object otherwise.
Extension objects
If an extension defines specific symbols or functions that are not available in the core specification of WebGL, they will be available on the extension object returned by the call to gl.getExtension()
.