Is image polygon clipping possible directly on OpenCL? Or is OpenGL interoperability necessary for this?
If this is possible directly on OpenCL, I think this problem could be reduced to the filling of concave polygons changing the alpha channel; in fact I would like using a (native) kernel having as parameters the image (image2d_t) and the polygon (uint2 array).
No, polygon clipping is not directly available in OpenCL.
You could use OpenCL/OpenGL interop, or write a parallel scan-conversion function in OpenCL.