@luma.gl/webgl2-polyfill

@luma.gl/webgl2-polyfill

This module installs a partial set of polyfills for WebGL1 contexts, making them more API compatible with WebGL2.

• It adds WebGL2 methods to the WebGL1 context, and simply forwards the calls to WebGL1 extensions.
• It also overrides some getParameter type calls returning default values when WebGL2 constants are used.

This way applications can use the WebGL2 API even when using WebGL1 with extensions. While you will still have to check that the extensions you need are available, using the WebGL2 API removes multiple code paths from your application and prepares your code base for WebGL2.

Usage

yarn add @luma.gl/webgl2-polyfill

import polyfillContext from '@luma.gl/webgl2-polyfill';

const gl = canvas.getContext('webgl');
polyfillContext(gl);
// New methods are now available on the context

Functions

polyfillContext(gl : WebGLRenderingContext) : WebGLRenderingContext

Installs WebGL2 polyfills on the supplied context.

Returns: the supplied context, with additional methods added (unless it was already a WebGL2RenderingContext in which case those methods were already present).

Note: Can be called multiple times and will only install the polyfills once.

Polyfill List

After polyfillContext has been called on a WebGLRenderingContext, the following WebGL2RenderingContext methods will be available on the context:

Polyfilled Method	Uses Extension	Fallback if no extension
gl.createVertexArray()	OES_vertex_array_object	throws error
gl.deleteVertexArray()		ignored
gl.bindVertexArray()		ignored
gl.isVertexArray()		ignored

Polyfilled Method	Uses Extension	Fallback if no extension
gl.vertexAttribDivisor()	ANGLE_instanced_arrays	throws error
gl.drawElementsInstanced()		ignored
gl.drawArraysInstanced()		ignored

Polyfilled Method	Uses Extension	Fallback if no extension
gl.drawBuffers()	WEBGL_draw_buffers	throws error

Polyfilled Method	Uses Extension	Fallback if no extension
gl.createQuery()	EXT_disjoint_timer_query	throws error
gl.deleteQuery()		ignored
gl.beginQuery()		ignored
gl.endQuery()		ignored
gl.getQuery()		ignored
gl.getQueryParameter()		ignored

Remarks

• This module was originally created as a helper for luma.gl, but is designed to be independently usable in other projects. It has no dependencies and makes no assumptions about other modules being available.

Changelog

7.4.0-alpha.2

• DevicePixelRatio: Cache canvas size to avoid expensive setting on each frame (#1269)
• WebGL Features: add caching (#1270)