code: func ClearBufferSubData(target uint32, internalformat uint32, offset int, size int, format uint32, xtype uint32, data unsafe.Pointer) {
  	syscall.Syscall9(gpClearBufferSubData, 7, uintptr(target), uintptr(internalformat), uintptr(offset), uintptr(size), uintptr(format), uintptr(xtype), uintptr(data), 0, 0)
  }
docs: // fill all or part of buffer object's data store with a fixed value