Using gl_FragDepth in WebGL

Question

I am writing a 3D application in webgl, and need to provide my own depth data that is contained within a texture, my current code does this:

VS:

    varying vec2 vUv;

    void main() {
        vUv = uv;
    }

FS:

    uniform sampler2D depthTex;

    varying vec2 vUv;

    void main() {
        gl_FragDepth = texture2D(depthTex, vUv).r;
    }

however gl_FragDepth is disabled in opengl-es (and therefor webgl) is there anyway to somehow enable it, or any way to provide my own depth data that doesnt involve heavy manipulation of render targets?

Take a look at this: http://stackoverflow.com/questions/24101017/webgl-alternative-to-writing-to-gl-fragdepth — Dragan Okanovic, Jul 01 '14 at 07:53

score 5 · Answer 1 · answered Jul 10 '14 at 17:48

The EXT_frag_depth extension enables the use of gl_FragDepthEXT. You can check if your browser supports it here. At the moment it's only supported in Firefox.

The extension can be loaded using

gl.getExtension("EXT_frag_depth");

And you can check if it is available programatically using

gl.getSupportedExtensions().indexOf("EXT_frag_depth") >= 0

Robert Monfera · Answer 2 · 2022-03-30T15:04:04.263

1

WebGL2 supports gl_FragDepth as core functionality, and the previously mentioned EXT_frag_depth extension is therefore no longer available for WebGL2.

edited Mar 30 '22 at 15:04

answered Jan 03 '22 at 18:57

Robert Monfera

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Using gl_FragDepth in WebGL

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