code: func ReadnPixels(x int32, y int32, width int32, height int32, format uint32, xtype uint32, bufSize int32, data unsafe.Pointer) {
  	C.glowReadnPixels(gpReadnPixels, (C.GLint)(x), (C.GLint)(y), (C.GLsizei)(width), (C.GLsizei)(height), (C.GLenum)(format), (C.GLenum)(xtype), (C.GLsizei)(bufSize), data)
  }
docs: // read a block of pixels from the frame buffer