chore: sync from fn-registry agent

2026-05-11 16:28:43 +02:00
commit bed33856e7
3 changed files with 424 additions and 0 deletions
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+---
+name: engine_smoke
+lang: cpp
+domain: gamedev
+description: "Smoke test del stack gamedev: SDL3 + sokol_gfx + Dear ImGui. Valida que el stack compila y corre en PC (Linux/Windows desktop GL) y WASM (WebGL2 via emscripten) antes de invertir tiempo en runtime real (issue 0072a)."
+tags: [imgui, sdl3, sokol, gamedev, smoke, wasm]
+uses_functions: []
+uses_types: []
+framework: "imgui"
+entry_point: "main.cpp"
+dir_path: "cpp/apps/engine_smoke"
+repo_url: ""
+e2e_checks:
+  - id: build_pc
+    cmd: "cmake --build build --target engine_smoke -j"
+    timeout_s: 300
+  - id: smoke_self
+    cmd: "timeout 5 ./build/cpp/apps/engine_smoke/engine_smoke || test $? = 124"
+    timeout_s: 10
+    severity: warning  # requires display in CI; warning, not critical
+  - id: build_wasm
+    cmd: "bash bash/functions/pipelines/build_wasm_cpp_app.sh engine_smoke"
+    timeout_s: 600
+    severity: warning  # requires emsdk
+  - id: wasm_size_budget
+    cmd: "test -f build/wasm/engine_smoke/engine_smoke.wasm.gz && test $(stat -c%s build/wasm/engine_smoke/engine_smoke.wasm.gz) -lt 1572864"
+    severity: warning
+---
+
+# engine_smoke
+
+Primer experimento del stack gamedev (issue [0072a](../../../dev/issues/0072a-gamedev-smoke-sdl3-sokol-imgui.md)).
+
+## Que hace
+
+1. Abre ventana SDL3 1280x720 con context OpenGL.
+2. Inicializa `sokol_gfx` sobre ese context (GL 3.3 desktop, GLES3 en WASM).
+3. Pinta un fullscreen triangle con un fragment shader animado (gradient time-based).
+4. Pinta sobre eso un panel ImGui con FPS, tamaño de ventana y boton Quit.
+
+Sin `fn_framework`, sin `add_imgui_app()`. CMakeLists standalone para evitar contaminar el shell desktop hasta validar el stack.
+
+## Build PC (Linux)
+
+Desde la raiz del fn_registry:
+
+```bash
+cmake -S cpp -B build -DCMAKE_BUILD_TYPE=Release
+cmake --build build --target engine_smoke -j
+./build/cpp/apps/engine_smoke/engine_smoke
+```
+
+## Build WASM
+
+Requiere `emsdk` instalado y activado en el shell. Ver `cpp/vendor/sokol.VENDORING.md` y `bash/functions/pipelines/build_wasm_cpp_app.sh`.
+
+```bash
+bash bash/functions/pipelines/build_wasm_cpp_app.sh engine_smoke
+# Sirve build/wasm/engine_smoke/engine_smoke.html en navegador
+```
+
+Budget objetivo: gzip ≤ 1.5 MB.
+
+## Stack vendoreado
+
+- `cpp/vendor/sdl3/` — SDL3 release-3.4.8
+- `cpp/vendor/sokol/` — sokol_gfx single-header pinned commit
+- `cpp/vendor/imgui/` — ImGui 1.92.7 con backends `imgui_impl_sdl3` + `imgui_impl_opengl3`
+
+## Notas de implementacion
+
+- Fullscreen tri via `gl_VertexID` (3 vertices, no VBO). Cubre todo el viewport sin atributos.
+- Uniform `u_time` actualizado por frame.
+- Backend ImGui = `imgui_impl_opengl3` (oficial, 0 LoC custom). Compatible WebGL2 emscripten.
+- `SOKOL_GLCORE` desktop / `SOKOL_GLES3` web — selccion compile-time.
+- `setup_gfx` se llama UNA VEZ tras crear el GL context. `sg_setup` toma `sglue_environment()` que lee el contexto activo.
+
+## No-objetivos (smoke)
+
+- No texturas reales (eso entra en 0072b).
+- No audio.
+- No input game-style.
+- No fn_framework integration.
+- No mobile (Android/iOS son issues 0072g/h).