hello, can anybody tell me how to use alt_up_video_dma_draw function in quartus 2018

thanks dlim for your tip, but can you be more specific as I did not find in which ip core i can find how to use alt_video_dma_draw function as it is a bit different in quartus 18.1 version. To be more precise I am reading an .hex image initialised in an on chip memory in nios2, but the data I am getting is different from the data contained in the .hex file. I am investigating this function that draw pixels in vga screen which is not displaying the right image.

I am quit happy to provide you with more details about the quartus project i am using if you need them. thanks