32x Doom ‘Resurrection’ 3.0 lands with MIP mapping and Sega CD PCM speed boost support

Victor Luchitz has just published 32x Doom ‘Resurrection’ v3.0.  I imagine some may have thought the game couldn’t improve anymore at this point and they’d be very much in the wrong!:  https://twitter.com/vluchitz/status/1693004325595775146

I won’t cover every single new change in this post, but I will cover the biggest Sega 32x boundary pushers!

First up we have the inclusion of Doom’s staple melting screen effect which is used during scene transitions.  The effect wasn’t present in many of the early console ports and was initially believed unfeasible on the 32x due to its RAM and VRAM limitations.  Luckily Vic overcame these by making use of the Sega Genesis’s RAM and VRAM, which is normally used to display tiles on the Genesis, as temporary storage that the 32x could use to assist in processing the effect. The Genesis 68000 CPU is also used extensively during the effect.

Second, we have the reintroduction of the Cyberdemon and Spider MasterMind bosses.  Due to limited cart space and RAM, it was believed these bosses would never see the light of day in the 32x version of Doom but thanks to some serious optimization and the introduction of the Sega Mapper for bank switching support (more space!), version 3.0 reintroduces both the monsters and their respective maps.

Next up we have the introduction of Mipmapping for walls and flats.  Distant walls and floors exhibit less texturing aliasing.  Since distant mipmaps are smaller in size they cache better which creates a minor performance boast in highest detail mode.  This was achieved through major optimizations to sprites and textures that removed a lot of redundant data from ROM and the introduction of the Sega Mapper that created more free space for textures.

Finally, a new sound driver has been added that enables use of the Sega CD hardware to offload sound mixing from the 32X. I wrote about this driver in my previous post here!  The driver frees up the 32xs SH2 processors giving the game an additional performance boost.  It highlights how the Sega CD has some benefit for both Sega Genesis and 32x cart games when it comes to sound.

When the game is used in the CD32X configuration it uses all 5 CPUs and most of the specialized chips with the exception of Sega CD ASIC:

  • The 32x SH2s handle gameplay and graphics.
  • The Genesis Z80 handles the Yamaha FM chip’s music playback.
  • The Genesis 68000 CPU handles coordination between the various CPUs, decompresses VGM streams, controller input and networking.
  • The Sega CD 68000 CPU handles ADPCM decompression, CDA playback and instructs the PCM chip of the Sega CD.

All in all, 3.0 might not seem a big deal on the surface but it packs so many things we never saw in retail releases and gives both the PlayStation and Saturn (particularly Saturn!) versions of the game a run for their money.

I’m blown away by every new update this game gets!

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