Viewports

Viewports are implemented as entities with ViewportComponent component. Those referenced in ViewportPanel are rendered to screen, otherwise they are rendered off-screen. There is always one focused ViewportPanel (identified by the context variable FocusedViewportPanel).

See components/Viewport.h and utils/viewport.h for utility functions related to viewport, viewport panels and cameras.

Entity visibility

Each ViewportComponent has visible_layers and hidden_layers that control which entities can be renderer in this viewport (see Layer component for details).

The default viewport shows only DefaultLayers::DefaultLayer

Multi viewport

Additional viewports can be created by calling

ui::Entity camera_entity = add_camera(ui::Registry &, ui::Camera camera);
// or use get_focused_camera_entity(ui::Registry &)  to reuse current camera

// Creates an offscreen viewport with the specified camera
ui::Entity viewport_entity = add_viewport(ui::Registry &, ui::Entity camera_entity)

// Creates a UI panel that shows the viewport
ui::Entity viewport_entity = add_viewport_panel(ui::Registry &, const std::string & name, ui::Entity viewport_entity);