God of War on PSP, recompiled to WebAssembly and running in the browser

A hobby project translates PSP MIPS executables ahead-of-time into C++, compiles them to WebAssembly, and links them with a small high-level emulation of the PSP OS and graphics so games run in the browser without a traditional emulator. God of War: Chains of Olympus and Ghost of Sparta boot, run menus, cutscenes and combat at around 55-60 FPS in Chrome and Firefox, support up to 4× the PSP's native 480×272 resolution, and play audio (ATRAC3+ decoded via FFmpeg, ADPCM voices via a reimplemented synthesizer). Movie playback is currently skipped, no game data is included, and users must supply decrypted game executables (tools or PPSSPP can dump these).

The core work is PSPRecomp-driven static recompilation, a small HLE kernel that implements threads, file I/O and streaming disc data over HTTP range requests, and a GE decoder that emits WebGL2 draw calls with framebuffers mapped to VRAM. Key engineering fixes delivered playable speed: batching swaps to vblank, using performance.now only when profiling, per-draw small index buffers to avoid Firefox GPU validation stalls, minimizing stencil/alpha full-screen copies, and running the GE on a worker with OffscreenCanvas so frame cost is the busier thread. Ghost of Sparta required PGD/KIRK DRM decryption and a lighting fix. Building a page requires git, CMake, Ninja, a C++20 toolchain, Emscripten, a PSP decrypter, and cross-origin-isolated hosting headers for SharedArrayBuffer.