VTuber in Sonic 1

Created by ProjectFM

Title screen with Sonime's neutral expression

VTuber in Sonic 1 is a hack of Sonic 1 which adds the character of Sonime, who will react to your gameplay with animations in voice clips. The goal was to emulate the experience of watching a VTuber play the game within the limitations of Sega Genesis console. This hack was based on a mock-up by Kilo.

Labyrinth Zone with Sonime looking shocked

Labyrinth Zone and Scrap Brain Zone Act 3 offered a unique issue in that the Sonic and Sonime share colors, but Sonic has to change color underwater. The solution I came up with was to use the system's shadow and highlight mode. It halves the colors of everything with low priority while keeping everything high priority untouched. A benefit of using this mode is that it's possible to create areas under the water surface in which the colors are unmodified. I used this opportunity to implement an opproximation of a cut feature from Sonic 1 in which Sonic can gain air from air pockets rather than bubbles.

Known Bugs:

  • Standing on a platform for a couple seconds caused Sonime to repeat a voice clip every frame instead of once.
  • There's nothing in place to keep Sonime from interrupting herself.
  • The background of the air pockets is composed of sprites, resulting in it not warping with the rest of the foreground and sometimes tearing.

Sonic getting hit in Star Light Zone with Sonime wincing

Downloads:
v2ber (Oct 2021)
v1ber (Jan 2021)

Credits:

  • ProjectFM - Programming, Animation, Art Adjustments, Sound Design
  • Kilo - Character Art, Original Concept
  • DeltaWooloo - v2 Help (Programming, Finding Samples)

+ resources by:

  • Hivebrain - 2005 Sonic 1 Disassembly
  • Inugami Kerone - Voice Samples
  • MainMemory - SonLVL and SonPLN
  • MarkeyJester - Dual PCM - FlexEd and LZ Optimized Deformation Code
  • Mercury - Dynamic Special Stage Walls system
  • jman2050 - Port the REV01 Background Effects
  • snkenjoi - Flex 2
  • Super Egg - How to Optimize Shield Art Loading in Sonic 1
  • plus various other small fixes which I haven't been keeping track of

Related Pages
SHC 2021 Page (v2)
SSRG Page (v1)