Irrlicht Engine

For the DOF, how do you control the focal depth? In the PostProcessManager, I tried playing with this a bit

DepthMaterial->setVertexShaderConstant("DistanceScale", 0.0006f);

but the results were not stunning. For larger values everything is blurred. A range of -0.0002 to 0.0002 seems fine for ...

There is some talk of a Depth of Field shader for IrrLicht. However, I haven't found any source whatsoever. I'd like to see someone's implementation of of a DOF shader for HLSL if one exists. If not, can someone show me how to create a stencil buffer onto which I can render the DOF.

Best would be a ...