qt-everywhere-src-5.15.1/qtquick3d/src/runtimerender/res/effectlib/shadowMappingFragment.glsllib

#include "depthpass.glsllib"
float FragmentParaboloidDepth( vec4 inWorldPos, mat4 inMVP, vec2 inCameraProperties )
{
    if (inWorldPos.w < 0.0)
       discard;
    vec4 projVec = inMVP * vec4( inWorldPos.xyz, 1.0 );
    projVec /= projVec.w;
    projVec.z = depthValueToLinearDistance( 1.0 - projVec.z, inCameraProperties );
    return (projVec.z - inCameraProperties.x) / (inCameraProperties.y - inCameraProperties.x);
}