Graphical Power of Sega CD

Discussion in 'Technical Discussion' started by Tralis, Sep 14, 2016.

  1. Tralis


    Toaster Extraordinaire Oldbie
    One of the biggest, most marketed advantages the SNES had over the Genesis was Mode 7 graphics. My understanding of the Sega CD is that it substantially beefs up the Genesis' processing power and allows hardware scaling and rotation but not more colors. How substantial is this? How does it stack up against the SNES?
    I understand the SNES could only rotate/scale the background layer with Mode 7. Could the Sega CD rotate/scale sprites too? How does it compare to SNES with extra chips?
  2. Dandaman


    Also known as Dandaman955 Tech Member
    The Sega CD has an ASIC that allows it to handle scaling and rotation. That's pretty much it as far as graphics are concerned: Everything else uses the Mega Drive's VDP. Same palette limit, same number of planes, etc.
  3. flamewing


    Emerald Hunter Tech Member
    Sonic Classic Heroes; Sonic 2 Special Stage Editor; Sonic 3&K Heroes (on hold)
    Just to hammer the point home: everything else uses the Mega Drive's VDP. This includes displaying the graphics that were scaled/rotated with the ASIC: you have to transfer the tiles generated by the ASIC, as well as the required plane maps, to the VDP. That is, you are limited by the VDP's bandwidth as well.
  4. Also considering the fact that such a thing, for a large-to-full screen operation, can take up a huge amount of VDP tile RAM space available. I still don't know why they didn't just do a 32x-style loopback mechanism and save everyone the grief of the way it was designed as it was.

    The Sega CD was always going to be very expensive, regardless. :psyduck: