52 lines
2.2 KiB
Markdown
52 lines
2.2 KiB
Markdown
---
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name: game_loop
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kind: function
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lang: cpp
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domain: gamedev
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version: "0.1.0"
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purity: impure
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signature: "loop_run(SDL_Window*, const LoopCfg&) -> void"
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description: "Game loop fixed-timestep estilo Glenn Fiedler ('Fix Your Timestep'). Desacopla simulacion (on_fixed_update con dt fijo) de renderizado (on_render con factor de interpolacion). Acumulador con cap anti spiral-of-death. Branch automatico desktop (while loop bloqueante) vs __EMSCRIPTEN__ (emscripten_set_main_loop). Issue 0072b."
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tags: [gamedev, game-loop, sdl3, wasm, fixed-timestep]
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uses_functions: []
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uses_types: []
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returns: []
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returns_optional: false
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error_type: "error_go_core"
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imports: []
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example: |
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struct State { bool quit = false; float t = 0; };
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State st;
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fn::game::LoopCfg cfg;
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cfg.user = &st;
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cfg.on_fixed_update = [](void* u, float dt) {
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auto s = (State*)u;
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s->t += dt;
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};
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cfg.on_render = [](void* u, float interp) {
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// render with interp factor between [0, 1)
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};
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cfg.should_quit = [](void* u) { return ((State*)u)->quit; };
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fn::game::loop_run(window, cfg);
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tested: false
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tests: []
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test_file_path: ""
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file_path: "cpp/functions/gamedev/game_loop.cpp"
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params:
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- name: window
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desc: "SDL_Window activo (no usado actualmente; reservado para futuras integraciones swap/vsync)."
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- name: cfg
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desc: "LoopCfg con fixed_dt (default 1/60), max_steps_per_frame (cap), callbacks on_fixed_update/on_render/should_quit y user pointer."
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output: "Bloquea hasta should_quit==true (desktop). En WASM retorna inmediatamente y registra emscripten_set_main_loop."
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---
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# game_loop
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Loop canonico para apps gamedev del registry. Garantiza que la simulacion corra a `fixed_dt` constante (default 60 Hz) independientemente del framerate de render, y expone factor `interp` para que el renderer interpole posiciones entre estados de fisica.
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Detalles:
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- `frame_time` se cap a `fixed_dt * max_steps_per_frame` para evitar la espiral de la muerte cuando el debugger pausa.
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- En `__EMSCRIPTEN__` el estado del acumulador vive en variable static (`g_rt`) — solo un loop activo por modulo WASM.
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- `should_quit` se consulta antes de cada frame; en WASM dispara `emscripten_cancel_main_loop`.
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- `loop_run` retorna sin hacer nada si ambos callbacks son nulos.
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