render.py

def render(engine, scene):
    try:
        session = engine._session
        xoff, yoff = session["offset"]

        _htiles = {}  # highlighted tiles
        session["peak"] = 0  # memory peak usage

        def display_callback(x, y, width, height, buffer, data):
            _x = x - xoff
            _y = y - yoff

            if buffer:
                try:
                    result = _htiles.pop((_x, _y), None)
                    if result is None:
                        result = engine.begin_result(_x, _y, width, height)
                    _buffer = ctypes.cast(buffer, ctypes.POINTER(ctypes.c_uint16))
                    rect = numpy.ctypeslib.as_array(_buffer, shape=(width * height, 4))
                    # TODO: gamma correction. need??? kick is darker
                    # set 1/2.2 the driver_display node by default
                    #rect **= 2.2
                    result.layers[0].passes[0].rect = rect
                    engine.end_result(result)
                finally:
                    arnold.AiFree(buffer)
            else:
                result = engine.begin_result(_x, _y, width, height)
                # TODO: sometimes highlighted tiles become empty
                #engine.update_result(result)
                _htiles[(_x, _y)] = result

            if engine.test_break():
                arnold.AiRenderAbort()
                while _htiles:
                    (_x, _y), result = _htiles.popitem()
                    engine.end_result(result, True)

            mem = session["mem"] = arnold.AiMsgUtilGetUsedMemory() / 1048576  # 1024*1024
            peak = session["peak"] = max(session["peak"], mem)
            engine.update_memory_stats(mem, peak)

        # display callback must be a variable
        cb = arnold.AtDisplayCallBack(display_callback)
        arnold.AiNodeSetPtr(session['display'], "callback", cb)

        res = arnold.AiRender(arnold.AI_RENDER_MODE_CAMERA)
        if res != arnold.AI_SUCCESS:
            ipr = session.get("ipr")
            if ipr:
                options = arnold.AiUniverseGetOptions()
                for sl in range(*ipr):
                    arnold.AiNodeSetInt(options, "AA_samples", sl)
                    res = arnold.AiRender(arnold.AI_RENDER_MODE_CAMERA)
                    if res == arnold.AI_SUCCESS:
                        break
                    engine.update_stats("", "Mem: %.2fMb, SL: %d" % (session.get("mem", "NA"), sl))
        if res != arnold.AI_SUCCESS:
            engine.error_set("Render status: %d" % res)
    except:
        # cancel render on error
        engine.end_result(None, True)
    finally:
        del engine._session
        arnold.AiEnd()