Optimize text rendering, particle draw state, and scene loop hot paths

[Copilot]

This change targets the highest-frequency rendering and scene-management paths without changing public behavior. It removes repeated work in text drawing, particle rendering, and scene update/draw loops, while keeping cache invalidation aligned with existing SDL resource ownership.

• Text rendering

  • Cache rendered text textures by (renderer, font, text, color) instead of recreating a surface/texture on every draw.
  • Add explicit text-cache clearing so cached textures are released before renderer/font teardown.
  • Preserve the existing draw::text(...) API.

• Text measurement / UI layout

  • Cache get_text_size(font, text) results to avoid repeating SDL_ttf layout work for stable UI strings.
  • Reuse this cache across existing callers such as buttons and other UI text paths.
  • Clear measurement cache when font caches are unloaded.

• Particle rendering

  • Remove per-particle alpha reset churn for textured particles.
  • Only update texture alpha when the interpolated alpha actually changes, then restore default alpha once after the emitter draw pass.

• Scene update/draw

  • Stop compacting dead objects every frame; only run cleanup after something is actually marked dead.
  • Stop sorting scene objects unconditionally every frame; sort only when insertion/order changes or current ordering is no longer valid.
  • Reserve capacity before batched object insertion to avoid avoidable vector growth during scene creation bursts.

• Frame loop overhead

  • Reuse a single now() timestamp in managed scene loops instead of reading the clock multiple times per frame.

Example of the main rendering-path change:

TextCacheKey cache_key { r, font, text, pack_color(color) };
auto cached_text = text_cache.find(cache_key);
if (cached_text == text_cache.end()) {
    SDL_Surface* textSurface = TTF_RenderText_Blended(font.get(), text.c_str(), 0, sdlColor);
    SDL_Texture* textTexture = SDL_CreateTextureFromSurface(r, textSurface);
    cached_text = text_cache.emplace(cache_key, TextCacheEntry {
        make_cached_texture(textTexture),
        textSurface->w,
        textSurface->h,
    }).first;
}

SDL_RenderTexture(r, cached_text->second.texture.get(), nullptr, &dest);

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud