A working side-scrolling game runs on a $0.09 CH32V003 RISC-V chip using Rust, hitting 25-30 FPS after switching from floats to fixed-point math.
Key Takeaways
CH32V003 costs $0.09 in bulk: 48MHz, 32-bit RISC-V, 2KiB RAM, 16KiB flash – comparable footprint to ATmega328P but faster core.
No hardware FPU on RV32EC means software-emulated f32 ops caused 1 FPS; replacing with the fixed crate’s fixed-point integers recovered 30+ FPS.
RAM budget of 128 bytes for the display buffer was viable because SSD1306 OLED is persistent – pixels hold between updates, acting as a free framebuffer.
Map encoded as [u64; 218] with 4-bit tile nibbles in ROM; bounding-box culling per 8-pixel strip keeps physics checks fast without heap allocation.
Cross-platform dev strategy: build game logic against a minifb desktop simulator on Mac, then swap only the rendering layer for the chip target.
Hacker News Comment Review
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