The Horizon Editor

Orientation

Editor Layout

The editor is a single window built from dockable panels around a central Scene viewport. Double-clicking assets opens additional full-size asset editor tabs (material graphs, widget designer, particle graphs …) alongside the Scene tab.

The footer bar holds Undo/Redo buttons on the left, the status text in the centre, and the current resolution and FPS on the right. Log output is written to HorizonEngine.log next to the executable (truncated each launch).

Starting point

Project Hub

The editor launches into the Project Hub: a list of known projects plus a New Project form. Creating a project asks for a template, a scripting language, a name and a directory.

Templates

Scripting language

The language is a whole-project choice, fixed at creation. It gates which gameplay-logic assets the Content Browser offers and which components appear:

Where you live

Scene Viewport

The Scene panel renders the world through the editor camera and carries an inline toolbar: a mode selector (View / Landscape), the gizmo buttons Move / Rotate / Scale, a gizmo-space combo (Local / World), a Screen ring toggle for the rotate gizmo, and the centred Play / Stop button.

Camera navigation

Gizmos

W / E / R switch between translate, rotate and scale (mirrored by the toolbar buttons). The space combo toggles manipulation in local or world axes; Screen ring adds the view-axis outer ring to the rotate gizmo. Gizmos are suppressed while flying, while Alt is held, and in Landscape mode. Every edit is undoable (Ctrl/Cmd+Z).

Static-mesh assets can be dragged from the Content Browser into the viewport to spawn an entity at the drop point.

Hierarchy

World Outliner

The Outliner shows the entity hierarchy of the active scene. Drag an entity onto another to reparent it. Right-click the background for Create Entity; right-click an entity for Create Child Entity, Rename, Save as Prefab and Delete.

The special Sky and Weather entities (added through the Environment window) appear here like any other entity — select them to edit the full sky and weather settings in the Details panel. The Sun and Moon are children of the Sky entity and are driven automatically.

Properties

Details Panel

The Details panel lists every component on the selected entity with full property editors, and ends with the Add Component button. Components you can add directly: Transform, Transform 2D, Mesh, Skeletal Mesh, Nav Mesh, Nav Agent, Material, Camera, Light, Rigid Body, Collider, Script (Lua/Python projects), Audio Source, Audio Listener, Particle System, LOD and Foliage.

Additional components appear with full editors when an entity carries them through other workflows — the Animator family (Animator, Animator Blend, Animator State Machine, Property Animator), Character Controller, Terrain, the in-world UI components, and the Environment/Weather editors on the Sky and Weather entities.

The complete component reference — every property of every component — lives on Scenes & Entities.

Assets

Content Browser

A folder tree on the left, an asset grid on the right. There are up to three roots:

• Content — your project's assets.
• Engine — built-in default assets (read-only).
• Source — the C++ class tree (C++ projects only).

Creating assets

Right-click the background (or an item's Create Asset submenu) to create an asset; a naming popup follows immediately. Always available:

Gameplay-logic assets depend on the project language: HorizonCode Class plus Player Controller / Player Character (HorizonCode projects), Script (Lua/Python projects), or C++ Class (C++ projects — writes a .h/.cpp pair under Source/).

Importing

Assets ▸ Import Asset… (or a folder's Import context item) dispatches by extension to the mesh, texture, audio, material and font importers. Audio import currently accepts WAV.

Deep dives

Asset Editor Tabs

Double-clicking an asset opens a dedicated editor tab next to the Scene tab. Material graphs, HorizonCode graphs, the Level Script, the Game Instance, particle graphs and animator state machines all share one node-graph canvas — learn it once (pan with the right mouse button, box-select with the left, zoom with the wheel) and every graph editor works the same way.

Terrain

Landscape Mode

Switch the viewport toolbar's mode selector to Landscape and the Quick Settings panel becomes the terrain tool.

Create Landscape

With no terrain in the scene the panel shows a creation form: Width (X), Depth (Z), Resolution (2–512), Height Scale, and procedural noise — Seed (0 = flat), Octaves, Frequency, Lacunarity, Gain — with a live grid preview. Creating adds a Terrain entity with a default terrain material. The seed noise is baked once into editable heights; from then on the terrain is a plain heightfield your brushes edit directly.

Sculpting

Six brush tools: Raise, Lower, Smooth, Flatten, Ramp, Roughen, with Radius (0.5–500 m), Falloff and Strength. Drag with the left mouse button in the viewport to sculpt — Flatten pulls toward the height under the drag-start point, Ramp blends between two dragged points. Reset Sculpting clears all edits. Strokes only regenerate the terrain chunks they touch, so sculpting stays fast on large terrains.

Terrain renders as a grid of chunk entities with automatic LOD meshes and skirt geometry — details under Rendering ▸ Performance. Scatter vegetation with the Foliage component.

Sky & weather

Environment Window

View ▸ Environment manages the two special scene entities:

• Sky — Add Sky / Remove Sky. The Sky entity carries the Environment component (atmosphere, day-night cycle, clouds, stars, fog …) and owns the Sun and Moon as child entities. Removing it leaves a flat background colour.
• Weather — Add Weather / Remove Weather. Requires a Sky to drive; carries the Weather component (presets, precipitation, auto-cycle).

The window only adds, removes and selects — the actual settings are edited in the Details panel. The full parameter reference is on Rendering & Environment.

Test it

Play Mode

The Play button in the Scene toolbar starts a play-in-editor session; Escape (or the Stop button) ends it. Entering play initialises physics, fires Play on Start audio, starts scripts and spawns HorizonCode player classes. While playing, physics steps at a fixed timestep, scripts receive onUpdate, collision events dispatch, widgets tick, and input actions fire.

The scene renders through the camera marked Main Camera (or the first camera found). On stop, the world is restored to its pre-play state and a Play Session Report window summarises the session. Animation, navigation and particle systems also run outside play mode so you can preview them while editing.

Measure

Performance Profiler

View ▸ Performance Profiler opens the engine's built-in profiler. Three tabs:

Setup

Preferences

Edit ▸ Preferences (Ctrl/Cmd + ,) holds machine-level settings:

• Renderer — graphics backend picker (OpenGL everywhere; Metal on macOS; Direct3D 11/12 on Windows; Vulkan where enabled), VSync, GPU weather particles.
• Post-processing — Bloom (threshold, intensity) and ambient occlusion (method SSAO / HBAO / GTAO, radius, intensity). See Post-Processing.
• C++ Toolchain — the status of CMake and a C++ compiler on this machine, with a Recheck button. A "C++ Toolchain Not Found" dialog also appears at startup when they're missing, offering automatic installation — the toolchain is needed for C++ projects and for compiling HorizonCode at export.

Reference

Menu Reference

On macOS the same commands live in the native menu bar (⌘N, ⌘O, ⌘S, ⇧⌘S, ⌘,, ⌃⌘F …), plus the standard app and window menus.

Muscle memory

Shortcut Reference

In play mode the default fly camera uses W A S D, E/Space up, Q/Ctrl down and Shift for 3× speed.