gamecube rgba6 or rgb8

Discussion in 'Console Technology' started by 2008 IQ is unacceptable, Nov 12, 2008.

  1. 2008 IQ is unacceptable

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    what does metroid prime 1 run in? If it runs in rgb8, then how did they do such great transparent fx?

    Also, with rgb8, what allows transparencies?

    Finally, why does the gamecube version of re4 look so much better than the ps2 version (most notably in terms of color quality) if the gamecube version runs in 18 bit color + 6 bit alpha (or so I heard) while the ps2 version runs in 24 bit color + 8 bit alpha (I could be wrong, but I thought I read the ps2 always has runs in rgba8)?
     
  2. freezamite

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    I'm also interested in why de GC didn't support rgba8. It was a problem with the lack of memory, whith de small embebed buffer of the GPU (only 3 MB) or it was because de GPU didn't has the necessary logic to work with rgba8?
    I think that it has to be a problem with the 3MB buffer, because even my Voodoo 3fx can work with colors of 32 bits.

    But this even makes the thing more difficult to understand for me, because de first Xbox or the PS3 don't have a single MB of embebed memory on its GPU, and the buffers are allocated in the main memory, why is it impossible to do that on the GC? Because games like TP suffered a lot from 24 bit colors...
     
  3. Thowllly

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    Source alpha allows transparencies. Alpha blending (usually) has nothing to do with destination alpha. In fact, the destination alpha channel in 32bit screenmodes goes unused more often than not.
    I think the ps2 version looks worse because it uses 4bit CLUT textures. 4bit CLUT textures can work well for monochrome like textures , but it's a horrible format for realistic non monochrome textures. So to convert the textures from the GC version to 4bit CLUT they probably reduced the color variance in the textures to reduce conversion artifacts. Result: duller graphics.
    The backbuffer at least is usually 32bit, but it doesn't have to be.
     
  4. DeadlyNinja

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    24 bit? I thought it was 16 bit color that's causing the horrible image quality.
     
  5. freezamite

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    The color quality was horrible in that game, but I think that it was 24 bit colors.

    Anyone knows what is the problem that makes most (or all) the GC games had 24 bit colors?
    Has the Wii the same problem?
     
  6. ERP

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    Destination Alpha is for temporary storage rather than alpha blending and on GC it's also the only place you can do stencil like operations.
     
  7. freezamite

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    So it would be a problem of the limited GPU (even my Voodo 3fx can draw 32bit colors) and probably the wii have the same problem.
    Thanks.
     
  8. Squeak

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    The problem with PS2 RE4 is the lower texture resolution, not 4 bit textures or framebuffer.
    4bit CLUT (and 8 bit) is really a lot better format than its reputation. More often than not 16 colours is quite enough for textures. And for some textures, with rapid colour changes, it's even a better format than S3TC.
    There is also some useful stuff you can't do with S3TC. Most notably the palette changing tricks, which among other things allows for alternative compression schemes, animated textures and bump effects.
     
  9. Simon F

    Simon F Tea maker
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    But, in general it is worse.
     
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