50 lines
3.9 KiB
Markdown
50 lines
3.9 KiB
Markdown
---
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title: "Week 2: Projectiles, footprints, and a UI detour"
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description: "Second week on the Odin tower defense prototype: homing projectiles, multi-tile towers, render split, and learning to stick with Raylib for UI."
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date: 2026-06-19
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type: devlog
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series: tower-defense-prototype
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series_order: 3
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languages: ["odin"]
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tags: ["odin", "tower-defense", "devlog"]
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---
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Week two on the [Odin prototype](https://github.com/Codegirl-Games/tower-defense-prototype). Last week ended with instant-hit archers and a keyboard-driven HUD. This week the game started to look like a tower defense: arrows fly, towers occupy real space on the grid, and I got my first proper UI, after a brief and expensive detour through third-party UI libraries.
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## What I built
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**Projectiles.** Archers no longer subtract health on the frame they fire. Towers spawn homing projectiles from a second object pool (`[MAX_PROJECTILES]Projectile`), track the target enemy by slot index, and deal damage on impact. Same pattern as the enemy pool from week one: acquire slot, reset fields, mark inactive when done.
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**Render split.** `render_world` became a thin orchestrator: `render_map`, `render_enemies`, `render_towers`, `render_projectiles`. Each system owns its draw calls. Small refactor, big readability win as files grew.
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**Multi-tile towers.** Tower archetypes gained `footprint_w` and `footprint_h`. The archer is 1×2 tiles, taller than a single cell. Placement now checks whether the full rectangle fits on build tiles and does not overlap other towers. Rendering draws a gold rectangle sized to the footprint instead of a fixed 28×28 square.
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**Memory cleanup.** Added explicit `delete` calls for dynamic arrays (`path`, `towers`, `events`) when the game loop exits. Odin will not save you from leaking if you allocated with `append`.
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**Overlay bar.** Moved gold and base health out of scattered `DrawText` calls into `overlay.odin`, a top bar with consistent padding and colors. Wave count and combat hints stayed in `hud.odin` for now.
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**Control panel.** Bottom bar with clickable buttons: select Archer, start wave. `poll_controls_command` feeds into the existing command layer so UI clicks and keyboard shortcuts share one path. Added `utils.odin` with a reusable `draw_button` helper for centered labels.
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## What worked
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- Projectile pool mirrored the enemy pool: copy the pattern, ship faster
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- Footprint-based placement forced me to think in grid coordinates early; multi-tower-type layouts will need this anyway
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- Command layer absorbed UI input cleanly: buttons return `Command` values just like keyboard handlers
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- Rip-and-replace on Clay was painful but left me with a simpler codebase than I started with
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## What broke
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- **UI library detour.** Tried ImGui bindings, then [Clay](https://github.com/nicklockwood/clay) for two days. Gold moved to Clay, start-wave became a Clay button, then I deleted all of it and rewrote the overlay in pure Raylib. Lesson: for a small game HUD, immediate-mode Raylib is enough. Do not import a layout engine until you have a layout problem.
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- **Tower selection half-wired.** The Archer button sets `world.selected_tower`, but `execute_command` still hardcodes `.Archer` on placement. UI looks done; logic is not.
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- **Split HUD.** Gold and health live in `overlay.odin`, wave/enemy count in `hud.odin`, controls in `controls.odin`. Three files for one screen; next cleanup pass needed.
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- **Range bug (later fix).** A typo in the distance function made archer range longer than intended. Caught at the end of the week; fix landed June 26.
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## Repo snapshot
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June 13–19 added about 470 net lines across 18 files. New modules: `projectile.odin`, `overlay.odin`, `controls.odin`, `utils.odin`. Still one tower type, but the archer now shoots, occupies space, and has a shop button.
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Next: end screens, fullscreen, more tower types, and enemy variety.
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