unravel-ui-rmlui

name	unravel-ui-rmlui
description	Works on UnravelEngine in-game UI using RmlUi: HTML/CSS documents, ui_document component, world-space UI, and UI debugger. Use for game UI screens, RML/RCSS assets, UI rendering, or UI input handling.
disable-model-invocation	true

Unravel UI (RmlUi)

Start here

Purpose	Path
UI system	engine/engine/ui/ecs/systems/ui_system.h
UI document component	engine/engine/ui/ecs/components/ui_document_component.h
RmlUi backend	engine/engine/ui/rmlui/
Meta	engine/engine/meta/ecs/components/ui_document_component.hpp
Game panel debugger	game_panel.cpp — UI Debugger menu toggle
Templates	engine_data/data/ (UI templates if present)

Architecture

• RmlUi renders HTML+CSS to game viewport
• ui_document_component attaches .rml document to entity
• ui_system processes OS events, updates documents, renders layer stack
• Backend interfaces: RmlUi_Backend_Engine, RmlUi_RenderInterface, RmlUi_FileInterface, RmlUi_SystemInterface

Document assets

UI documents are assets — follow unravel-assets for import/meta. RML + RCSS file pairs.

World-space UI

Documents can render in world space (3D positioned UI). Transform linkage via entity transform_component.

UI debugger

Toggle in game panel menu bar:

• ui_system::is_debugger_enabled()
• Highlights element bounds for debugging layout

Input

ui_system connects to on_os_event with priority 100. Coordinate mapping via input::zone for window-relative coords.

Verification checklist

• Document loads and displays
• CSS styles apply correctly
• Input events reach focused elements
• World-space UI follows entity transform
• UI debugger shows correct bounds
• Play mode only behavior where appropriate
• No conflict with ImGui editor overlay

Common mistakes

• Confusing editor ImGui with in-game RmlUi
• Missing RCSS companion file
• OS events not forwarded to ui_system
• Document asset path/protocol incorrect