40 lines
1.6 KiB
Markdown
40 lines
1.6 KiB
Markdown
# GB-GameOfLife
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An implementation of Conway's Game of Life for the GameBoy.
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Press START to pause and enter edit mode.
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In edit mode:
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- use the d-pad to move the cursor
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- press A to toggle a cell's state
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- press B to trigger one step of the automata
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- press SELECT to clear all the cells
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Press START again to resume animation of the automata.
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# Project's Backstory
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I started this as my first real programming written entirely in assembly.
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I thought the gameboy was a good fit for that, with its not too complex
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instruction set. I chose Conway's Game of Life because it's quite a
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classic of CS exercises and I thought it would be simple enough to do.
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Boy, I was wrong.
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I know the gameboy is far from fast enough to update all pixels on
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screen in between each frame. Who would have thought it would also
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not be fast enough to just update its 20x18 tiles? That's only 360
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bytes! In the v-blank, the time between two frames are rendered by
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the Picture Processing Unit or PPU, and where you have access to
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Video RAM, there's barely enough time to write to a quarter of the
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tilemap. And that's without reading from it!
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But there's hope: first, the gameboy has enough video ram to hold
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two tilemaps, so we can double buffer. Second, the v-blank is not
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the only time where you can write to Video RAM, you can also write
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in between the PPU rendering lines! That requires synchronising code
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with rendering but it should be doable.
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The first working version I got looked like this:
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