Rendering¶

The renderer draws the registry in two passes every frame: a world pass inside the active camera, then a screen pass in window pixels for HUD elements. Entities tagged ScreenSpace are drawn in the screen pass; everything else in the world pass.

Within each pass, layered systems (sprites, shapes, text) draw first, sorted by Position::z, then by system registration order, then by entity id. Non-layered systems then run their Render / RenderScreen in registration order.

Sprites¶

SpriteComponent names an asset and places it relative to the entity:

Engine::SpriteComponent sprite;
sprite.assetPath = "assets/player.png";
sprite.offsetX = -12.8f;
sprite.offsetY = -14.0f;
sprite.scaleX = 4.0f;
sprite.scaleY = 4.0f;
sprite.flipX = false;
sprite.flipY = false;

The sprite's top-left corner is drawn at (Position.x + offsetX, Position.y + offsetY). Positions are top-left corners everywhere in the engine, which is why the offset is what centres a padded sprite on its collider. SpriteSystem reads Rotation from the same entity and applies scaleX/scaleY when drawing.

Flipping is visual only: flipX/flipY mirror the drawing about the sprite's own centre. Component.flipX(entity) (Lua) also mirrors the whole child subtree about the entity's centre, so a rig turns around in one call.

Shapes¶

ShapeComponent supports rectangles, circles, regular polygons, and lines:

Engine::ShapeComponent body;
body.type = Engine::ShapeType::RECTANGLE;
body.width = 48.0f;
body.height = 32.0f;
body.color = SKYBLUE;
body.filled = true;

For polygons, set sides and radius. For lines, set endOffset and thickness.

Text¶

TextPlugin registers Text and TextSystem. Attach text with:

Engine::TextPlugin::AttachToEntity(registry, entity, "Score: 0", 24.0f);

Custom fonts, colours, and spacing are set directly on the Text component. If font.texture.id == 0 (no custom font loaded), the system falls back to Raylib's built-in font. Entities without a Position are skipped safely.

Camera¶

A camera is a normal entity with a CameraComponent and a Position. The active camera is the one with primary = true and the lowest entity id. CameraSystem handles follow, bounds, zoom, rotation, and shake.

Engine::CameraComponent cam;
cam.followTarget = player;
cam.followSpeed = 5.0f;       // 0 snaps instantly
cam.clampToBounds = true;
cam.bounds = {0.0f, 0.0f, levelWidth, levelHeight};
cam.zoom = 2.0f;
cam.shakeTrauma = 1.0f;       // shake strength is magnitude * trauma^2

Shake is visual only and never moves the camera's Position. The clamp ignores rotation.

HUD elements use the ScreenSpace tag and are drawn in window pixels. Convert between screen and world coordinates with CameraSystem::ScreenToWorld and WorldToScreen.

Virtual resolution¶

VirtualResolution is a fixed-size game canvas scaled and centred into the OS window with letterboxing or pillarboxing. The mouse can be mapped back into canvas space. Set virtualWidth/virtualHeight in ApplicationConfig; 0 means match the window.

Virtual canvas and editor¶

The editor's Scene view renders the registry with the same systems and camera, at the project's virtual resolution, so what you see is what the game draws. The editor camera is separate and can be panned and zoomed without affecting the game camera.

See Camera in the old guides and Engine → Assets.