It’s gl_FragCoord.z
. It think it makes sense to linearize this value and the value from the depth map if you are going to compare them. You can do this by including the packing
chunk into your shader and then do this:
#include <packing>
float getLinearDepth( fragCoordZ ) {
float viewZ = perspectiveDepthToViewZ( fragCoordZ, cameraNear, cameraFar );
return viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );
}
The following example uses this code: three.js webgl - Depth Texture
As you can see, you need to pass in cameraNear
and cameraFar
as uniforms to the shader.