flecs_tests/CLAUDE.md

CLAUDE.md

Project: Cartograph

A browser-based world map creation tool (like Wonderdraft/Inkarnate). C99 compiled to WebAssembly via Emscripten.

Stack

• Graphics: Sokol (WebGPU backend, SOKOL_WGPU) — lib/sokol/
• UI: Dear ImGui via cimgui — lib/imgui/
• Math: cglm (types are C arrays: vec2 = float[2], mat4 = float[4][4] column-major) — lib/cglm/
• Shaders: WGSL in src/shaders/, compiled to C headers via xxd -i into src/generated/

Build

• make (release) / make debug — outputs app.html
• All includes go through src/api.h which defines SOKOL_IMPL, SOKOL_WGPU, and pulls in every library header
• Include paths: lib/sokol, lib/imgui, lib/imgui/imgui, lib/util, lib/cglm/include

Key files

• src/main.c — entry point, sokol init, render loop, input (zoom/pan/drag)
• src/api.h — central include hub, backend defines
• src/sprite.h — sprite batching, texture manager, file import stubs
• src/util.h — vector_t (dynamic array) and mem_pool_t (free-list pool), both stripe-based
• src/rand.h — xorshift32 PRNG

Conventions

• No malloc/free directly — use ALLOC/FREE macros (wired to smemtrack in main.c)
• Assert is encouraged for invariant checks
• Data structures use stripe-based allocation (byte stride per element, not sizeof)

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Tradeoff: These guidelines bias toward caution over speed. For trivial tasks, use judgment.

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

• State your assumptions explicitly. If uncertain, ask.
• If multiple interpretations exist, present them - don't pick silently.
• If a simpler approach exists, say so. Push back when warranted.
• If something is unclear, stop. Name what's confusing. Ask.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

• No features beyond what was asked.
• No abstractions for single-use code.
• No "flexibility" or "configurability" that wasn't requested.
• No error handling for impossible scenarios.
• If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:

• Don't "improve" adjacent code, comments, or formatting.
• Don't refactor things that aren't broken.
• Match existing style, even if you'd do it differently.
• If you notice unrelated dead code, mention it - don't delete it.

When your changes create orphans:

• Remove imports/variables/functions that YOUR changes made unused.
• Don't remove pre-existing dead code unless asked.

The test: Every changed line should trace directly to the user's request.

4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:

• "Add validation" → "Write tests for invalid inputs, then make them pass"
• "Fix the bug" → "Write a test that reproduces it, then make it pass"
• "Refactor X" → "Ensure tests pass before and after"

For multi-step tasks, state a brief plan:

1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

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These guidelines are working if: fewer unnecessary changes in diffs, fewer rewrites due to overcomplication, and clarifying questions come before implementation rather than after mistakes.