[HN Gopher] Nvidia emulation journey, part 1: RIVA 128/NV3 archi...
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       Nvidia emulation journey, part 1: RIVA 128/NV3 architecture history
       and overview
        
       Author : davikr
       Score  : 32 points
       Date   : 2025-02-27 20:51 UTC (2 hours ago)
        
 (HTM) web link (86box.net)
 (TXT) w3m dump (86box.net)
        
       | bilegeek wrote:
       | Amazing that they're able to make progress with such little
       | public documentation.
        
       | Sjonny wrote:
       | > 5.0 came out late during development of the chip, which turned
       | out to be mostly compliant, with the exception of some blending
       | modes such as additive blending which Jensen Huang later claimed
       | was due to Microsoft not giving them the specification in time.
       | 
       | Not sure if this is the same thing I had, but on my Riva128 the
       | alpha blending wasn't properly implemented. I distinctly recall
       | playing Unreal Tournament and when I fired the rocket launcher
       | there were big black squared with a smoke texture on them slowly
       | rotating :D couldn't see where I was shooting :D
        
         | pavlov wrote:
         | Yes, that would be an artifact of missing additive blending.
         | 
         | It simply means that each newly rendered polygon's RGB values
         | are added together with the pixel values already in the frame
         | buffer. It's good for lighting effects (although not a very
         | realistic simulation of light's behavior unless your frame
         | buffer is linear light rather than gamma corrected, but that
         | effectively requires floating point RGB which wasn't available
         | on gaming cards until 2003).
        
           | starfrost013 wrote:
           | Iirc, Riva 128 only supports 8 of the 32 D3D5 blend modes, or
           | something. Usually in the case of GPUs that don't support all
           | blending modes the Direct3D HAL will attempt to compensate by
           | using a different blending mode, or just give up and render
           | opaque pixels. The results are usually pretty ugly. Riva 128
           | is one of the better ones for the era in this regard.
        
           | msk-lywenn wrote:
           | [delayed]
        
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       (page generated 2025-02-27 23:00 UTC)