The DevEditor is an in-game tuning UI for camera, scene, and rendering parameters. It was added as part of PR #335.
For the camera architecture itself, see camera-system.md.
Developers and modders. The DevEditor lets you live-tune camera FOV, far plane, fog, 2D culling trapezoids, terrain/object render distances, and a suite of debug visualisations - without rebuilding.
It is debug-only:
- Built only when
_EDITORis defined (see Build Configurations inREADME.md). - Requires the ImGui submodule (
git submodule update --init). - Not present in Release builds.
Two ways:
- Press F12 in-game.
- Start the client with
--editorto launch with the editor enabled (or toggle later with F12).
While the editor is closed, an Open Editor button sits in the top-right of the game window; Close Editor is on the right of the editor window's menu bar.
The editor opens in a window of its own, beside the game window where the
screen has room (else over its right side), and stays in front of the game.
Its Windows menu opens the tool windows: Item, Skill, Dev and Map Editor,
the Effect Browser and the console. They open as tabs docked in the editor
window, the console along the bottom. Drag a tab out to float a tool window
anywhere, over the game window too, or onto another window to dock it there;
Windows > Reset Layout docks them all back. The layout and the windows'
places are kept between sessions (imgui.ini in the game folder).
The editor window, and a tool window floating outside the game window, are ordinary windows of the system, with its title bar, buttons and window snapping. Closing the editor window closes the editor. A floating tool window keeps its tab under the title bar: drag the tab, not the title bar, to dock it again. Windows > Fullscreen switches the editor window to full screen and back; F11 does the same for whichever of the editor's windows has the keyboard (in the game window F11 stays the game's camera reset).
- Windows: minimize, maximize and close, and a taskbar button for each editor window. Dragging or resizing an editor window by its title bar or frame pauses the game until the mouse is released, as it does for the game window.
- Linux: editor builds run on X11 so that the editor's windows can leave
the game window, through XWayland on a Wayland desktop (the game may look
softer there on a scaled screen). The window manager draws the title bar and
decides the buttons, the snapping and whether an editor window gets its own
taskbar entry.
SDL_VIDEO_DRIVER=waylandruns on Wayland instead, with the editor inside the game window. - macOS: close, minimize and the green button (full screen, and tiling on macOS 15). The editor's windows float above the game while MU is the active app, and minimized ones are in the Dock and the Window menu. macOS may keep F11 for itself: the green button or Ctrl+Cmd+F switch full screen too.
With the game in full-screen mode, the editor's windows stay inside the game window instead.
The editor is rendered with ImGui and consumes input over the game
(see MuInputBlockerCore.cpp for the input-routing logic). Keys go to the
window that has the keyboard: while one of the editor's own windows has it,
the game gets none of them (F12 still closes the editor from there).
Switch between FreeFly and the active gameplay camera (Default / Orbital).
While FreeFly is active, the gameplay camera continues running in the
background (the "spectated camera" tracked by CameraManager) - toggling back
puts you exactly where the gameplay camera now is, not where you left off.
The standard in-game hotkeys still work with the editor open, while the game window has the keyboard:
- F9 cycles Default ↔ Orbital.
- F10 toggles the zoom lock. F10 is intercepted at the Win32 message
layer (
WM_SYSKEYDOWN) so it fires reliably even when an editor window over the game has keyboard focus. - F11 resets the active camera (zoom rung for Default, rotation + zoom for Orbital).
While FreeFly is active and spectating a gameplay camera, the cone wireframe is augmented with two ground lines: a red line where the bottom of the spectated view hits the terrain and a yellow line where the top hits it. They terminate at the cone's apex→corner edges, so they visualise the camera's actual visible extent on the ground.
Shows real-time camera position (world coords + tile coords) and pitch / yaw. Useful when placing fixed camera shots or noting positions for screenshots.
Tunes the login scene only. Defaults come from LoginSceneCameraDefaults
in src/source/CameraMove.h.
| Control | What it changes | When you'd use it |
|---|---|---|
| Offset X / Y / Z | Translates the camera in world units relative to the tour-path point. | Fixing clipping, framing the title art differently. |
| Pitch / Yaw | Rotates the login camera. Pitch is the engine convention (-90° = horizontal, more negative = tilted up). |
Lining up a screenshot or matching legacy framing. |
| Tour mode - pause / resume / restart | Halts or rewinds the login waypoint walk. | Holding the camera still on a specific frame to tune offsets, then resuming. |
| Render terrain distance | Hard cap on how far login terrain tiles render. | Login fly-throughs that show distant terrain that normally pops in. |
| Render object distance | Hard cap on object cull radius for the login scene. | Same as above for objects/decor. |
Live-overrides CameraConfig::ForMainSceneDefaultCamera(). All values reset
to the factory config on restart.
| Control | What it changes | When you'd use it |
|---|---|---|
| Far Plane (~0.5m to 20km) | Grows or shrinks the visible far clip - also drives 3D object cull range. | Checking how much the game can render before fog/cull cuts in; tuning visibility for screenshots. |
| Camera Offset X / Y / Z | Hero-relative. Shifts the camera's eye point relative to the hero anchor. | Repositioning the third-person rig (e.g. higher angle, off-shoulder). |
| 2D Culling Trapezoid Width - near / far multipliers | Scales the Default camera's view-space ground trapezoid (near and far half-widths). The trapezoid itself is now derived from the live GL projection (FOV/aspect), so 16:9 corners stay covered without the legacy 4:3 fudge. | Tightening to see culling pop, or widening to confirm tiles render - useful when chasing edge-case clipping at corners. |
| Fog override checkbox | Gates the next three controls. Off = camera config's fog wins. | Toggle while comparing current vs. tuned fog. |
| Fog On / Off | Enables/disables OpenGL fog. | Quick A/B for "is this fog or culling cutting things off?" |
| Fog Start / End (% of ViewFar) | Sets the fog density ramp as a fraction of the current far plane. | Pulling fog in to mask LOD pop, or pushing it out for cleaner long-range shots. |
Live-overrides CameraConfig::ForMainSceneOrbitalCamera(). The orbital
trapezoid is seeded from the camera's natural pyramid on first enable
so the first tweak doesn't snap.
| Control | What it changes | When you'd use it |
|---|---|---|
| 2D Culling Trapezoid - far distance / far width | Sets the far edge of the ground trapezoid (in world units). | Adjusting how far past the hero terrain stays loaded as the orbital camera pans. |
| 2D Culling Trapezoid - near distance / near width | Sets the near edge. | Catching pop-in close to the hero on heavy zoom-in. |
| Fog On / Off | Enables/disables fog for the orbital config. | Quick A/B as with the default camera. |
| Fog Start / End (% of ViewFar) | Fog density ramp. | Same as default - orbital uses a much wider FOV (90°), so fog feels different. |
| Control | What it changes | When you'd use it |
|---|---|---|
| Character Pick Boxes | Draws per-character pick volumes. | Debugging click-to-target or hover hit-testing. |
| Item Pick Boxes | Same for dropped items. | Debugging item pickup ranges. |
| Item Cull Sphere | Visualises the item cull radius around each dropped item. | Sanity-checking the Item Cull Radius slider's effect. |
| Item Cull Radius slider | Overrides DEFAULT_CULL_RADIUS_ITEM (400) for the active session. |
Tuning how close you need to be before items render. |
| Tile Grid | Overlays a debug grid on terrain tiles. | Checking tile boundaries when investigating LOD or terrain bugs. |
| Rendering: Terrain / Static Objects / Effects / Dropped Items / Weather / Item Labels | Cuts each pass out of the frame entirely. | Isolating which pass owns a visual artefact, or measuring per-pass cost via $glstats. |
Read-only diagnostics:
- Real-time window and OpenGL viewport dimensions.
- Screen-rate scale factors.
- Window mode (windowed / fullscreen).
- A warning if the viewport and window dimensions disagree.
- A Copy debug info to clipboard button - handy for bug reports.
A tool window of its own (Windows > Map Editor, not one of the DevEditor's
own tabs) that opens an in-client editor for a map's terrain textures, terrain height,
walkability attributes, and world objects, plus a top-down minimap capture -
saving back to the game's own on-disk formats. See
src/MuEditor/UI/MapEditor/MAP_EDITOR.md
for the full usage guide (tabs, save targets, and the client/server attribute
merge workflow).
DevEditor overrides are runtime-only. They live on the m_DefaultOverride
and m_OrbitalOverride member structs and are applied each frame
(ApplyDefaultOverrideToConfig() / ApplyOrbitalOverrideToConfig()).
Closing the client throws them away.
The only camera value that survives a restart is the orbital wheel-zoom radius - see Camera System §3.
If you want to keep a tuned set of values, copy them out of the DevEditor
and feed them into the relevant CameraConfig::For… factory in
src/source/Camera/CameraConfig.h.
src/MuEditor/
Core/
MuEditorCore.h / .cpp # editor lifecycle, F12 toggle wiring
MuInputBlockerCore.cpp # routes input to the editor when active
UI/
Common/MuEditorUI.h / .cpp # shared editor chrome
Console/
MuEditorConsoleUI.h / .cpp # debug console / logging output
DevEditor/
DevEditorUI.h # struct + interface
DevEditorUI.cpp # all panels, overrides, debug toggles
MapEditor/
MAP_EDITOR.md # usage guide for the Map Editor (§3.3 above)
MapEditorUI.h / .cpp # tab UI + edit-mode dispatch
Map*.h / .cpp # per-tab logic: texture/object/attribute/height
# save+load, minimap capture, thumbnails