lofivor/TODO.md

lofivor - build roadmap

survivor-like optimized for weak hardware. finding the performance ceiling first, then building the game.

phase 1: sandbox stress test

• create sandbox.zig (separate from existing game code)
• entity struct (x, y, vx, vy, color)
• flat array storage for entities
• spawn entities at random screen edges
• update loop: move toward center, respawn on arrival
• render: filled circles (4px radius, cyan)
• metrics overlay (entity count, frame time, update time, render time)
• controls: +/- 100, shift +/- 1000, space pause, r reset

phase 2: find the ceiling

• test on i5-6500T / HD 530 @ 1280x1024
• record entity count where 60fps breaks
• identify bottleneck (CPU update vs GPU render)
• document findings

findings (AMD Radeon test):

• 60fps breaks at ~5000 entities
• render-bound: update stays <1ms even at 30k entities, render time dominates
• individual drawCircle calls are the bottleneck

phase 3: optimization experiments

based on phase 2 results:

• batch rendering via texture blitting (10x improvement)
• if cpu-bound: SIMD, struct-of-arrays, multithreading (not needed)
• re-test after each change

findings:

• texture blitting: pre-render circle to texture, drawTexture() per entity
• baseline: 60fps @ ~5k entities
• optimized: 60fps @ ~50k entities, 30fps @ 100k entities
• see journal.txt for detailed benchmarks

phase 4: add collision

• spatial partitioning (grid or quadtree)
• projectile-to-enemy collision
• measure new ceiling with collision enabled

phase 5: game loop

• player entity (keyboard controlled)
• enemy spawning waves
• player attacks / projectiles
• enemy death on hit
• basic game feel

future

• different enemy types
• player upgrades
• actual game design (after we know the constraints)