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EXT_float_blend extension

The WebGL API's EXT_float_blend extension allows blending and draw buffers with 32-bit floating-point components.

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

Note: This extension is available to both, WebGL1 and WebGL2 contexts. However, to use it, you need to enable the use of 32-bit floating-point draw buffers by enabling the extension WEBGL_color_buffer_float (for WebGL1) or EXT_color_buffer_float (for WebGL2). Doing so automatically enables EXT_float_blend as well, if and only if EXT_float_blend is also supported. Support for EXT_color_buffer_float does not imply support for EXT_float_blend.

With this extension enabled, calling drawArrays() or drawElements() with blending enabled and a draw buffer with 32-bit floating-point components will no longer result in an INVALID_OPERATION error.

Usage notes

On devices that support the EXT_float_blend extension, it is automatically, implicitly, enabled when any one or more of EXT_color_buffer_float, OES_texture_float, or WEBGL_color_buffer_float are enabled. This ensures that content written before EXT_float_blend was exposed by WebGL will function as expected.

Examples

js

const gl = canvas.getContext("webgl2");

// enable necessary extensions
gl.getExtension("EXT_color_buffer_float");
gl.getExtension("EXT_float_blend");

const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);

// use floating point format
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA32F, 1, 1, 0, gl.RGBA, gl.FLOAT, null);

const fb = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
gl.framebufferTexture2D(
  gl.FRAMEBUFFER,
  gl.COLOR_ATTACHMENT0,
  gl.TEXTURE_2D,
  tex,
  0,
);

// enable blending
gl.enable(gl.BLEND);

gl.drawArrays(gl.POINTS, 0, 1);
// won't throw gl.INVALID_OPERATION with the extension enabled

Specifications

Specification
WebGL EXT_float_blend Extension Specification

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
EXT_float_blend 75 79 67 No 64 14.1 75
75Until Chrome 77, this extension was unavailable on several Android devices powered by GLES 3.2. See bug 964208.
 67 54 15–16 11.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/EXT_float_blend