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How the heck did they get transparency during Shaft in Aku-Dracula X (Castlevania)?

Discussion in 'Saturn Dev' started by vexatious, Jun 24, 2013.

  1. vexatious

    vexatious New Member

    Don't know if this is an emulator glitch (used yabause in software mode) but when Shaft boss is confronted there is transparency on the floating half-circle textures. Shaft himself and the orb are also transparent but they're 2D sprites as opposed to the floating half-circles (most of the game seems to render 2D as textures through a 3D engine but I highly doubt shaft and the orb are rendered as 3D textures). If this is indeed not an emulator glitch then how the heck did they do that? There's no way to do transparency on 3D textures (look at Sonic R and Burning Rangers for example) and software is way too slow for transparent polygon textures on a MIPS SH2 cpu.

    Assuming there's no emulator glitch, the game engine seems to have both 3D and 2D abilities since some backgrounds have transparent clouds (purple clouds before clock tower where giant skull is are rendered with 2D transparency); while others don't (white 2D clouds in other parts use mesh tranparency and appear to use a 3D rendering technique instead which doesn't even look good). Also noticed some sprites are rendered with 2D transparency while the majority use 3D rendering with mesh-fake transparency that looks improper (alucards cape for example and the low RGB color on most sprites). It's like they forgot to change every object to a sprite and left most as 3D textures...

    Can someone confirm this? Preferrably on real hardware with screenshots. Would post some myself but I have to replay the game and use an emulator.

    Here's an image of Akumajou Dracula X using yabause in software video mode (1408x960 pixels). If this is an emulator glitch then so sorry for taking up space. Otherwise, you can clearly see smoke under alucard isn't transparent, the textured polygons rotating around the orb are transparent (and the orb itself), and shaft is transparent; this doesn't change during fight. Emulator glitch or some unknown way to get transparencies on 3D textures?

    Red ooze spill and glass containers transparent

    Some clouds are transparent (hard to see clouds but notice moon underneath them)

    Some clouds are'nt transparent (notice mesh transparent cloud over moon)

    Do we have access to the libraries used in this game? Pretty late game from saturn release date so must be a good library. Maybe we got better stuff?

    For the record, they really made a frankenstein of this game whether or not these are emulation faults (could someone confirm this?). Great game btw!
    David Gámiz Jiménez likes this.
  2. CyberWarriorX

    CyberWarriorX New Member

    Probably using VDP2 color calculation for the first two screenshots. Contrary to what some people think, the Saturn -did- support transparencies(VDP2 color calculation), but there's significant limitations on what you can do. The other two screenshots appear to be using VDP1's mesh transparency where basically ever other pixel in a checkerboard pattern to produce a transparent affect. If I recall correctly in Yabause's OpenGL renderer mesh transparencies are also drawn as regular transparencies. I'm guessing you're running using the software renderer.
    David Gámiz Jiménez likes this.
  3. Hello SScommunity!

    First of all, THANK YOU for this great point of meeting for our lovely machine! :)

    Sorry to resurrect such an old post but in the first screenshot, I have a question that gnaws at me.
    Perhaps the magic orb with rings that revolve around him, has multi layer transparency ??? This is possible?? In other games like Loaded(map, smoke and flare weapons effects) or Die Hard Trilogy(The car game: explosions or flare semaphore) I've also seen...

    EDIT: Add screenshots Loaded in share folder.

    It is a question to which I still have not found an answer... THANKS in advance! :)
    Last edited: Oct 9, 2016
  4. vbt

    vbt Staff Member

    welcome here ! just run yabause and check vdp1/vdp2 viewers. if you can't i can try to get the iso of the game
    edit : i've checked yout pictures, you have already tried with yabause:oops:
    Last edited: Oct 9, 2016
  5. Yes I did ;) I am making a post for my personal blog, I make a research the specs that not utilized in SS. And this is one difficult to found the reasons and the possible solutions. Right now, the only clues are this titles and this commentary(news.ycombinator.com/item?id=10965156) based in the Official SEGA SDK. I read the SDK docs, and with my actual knowledge be arrived to the same conclusion. VDP1 is capable to make transparency between sprites levels.
    But I want found someone specialist in Sega Saturn programmer or best, try to contact whit programmer of Loaded or Die Hard Trilogy, to resolve this doubts.

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