Read stencil buffer post processing

I need to create a visual effect which I think is best done by reading the stencil buffer from a postprocessing shader.
I know you can create a RenderTargetTexture with createDepthStencilTexture, but can I also get just the stencil?
Also, how do you check the stencil part of the texture in GLSL? All the examples I can find are just using the depth.

I’m not sure reading the stencil is supported in WebGL.

There is an extension in OpenGL ( and it is supported out of the box in OpenGL 4+ but I can’t see it supported in WebGL (WebGLRenderingContext.texParameter[fi]() - Web APIs | MDN): the GL_DEPTH_STENCIL_TEXTURE_MODE value is not supported by texParameter().

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It is not supported as far as I am aware.

Thanks guys. For now I just used a color render pass instead with a custom material.

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