MythLayer

# MythLayer

**A battlemap effects overlay for table-mounted displays.**

One HTML file. No install. No accounts. No internet. No tracking. No subscription.

MythLayer is a fullscreen DM overlay designed for physical tabletop play. Run a looping video battlemap on a TV, projector, or table-mounted display, then use MythLayer to place spell effects, area templates, measurements, scene tints, objects, and dice rolls directly over the map.

Your minis stay on the table. 

Your terrain stays physical. 

The magic goes on top.

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## What MythLayer Does

MythLayer runs on top of a video battlemap and gives the DM a fast, right-click radial menu for placing:

- Animated spell effects

- 5e area templates

- Distance measurements

- Scene lighting tints

- Grid overlays

- Spell circles and object markers

- Procedural dice rolls

It is built for DMs who want the visual punch of a VTT without turning the whole table into a remote-play setup.

Open the file. Pick your map video. Launch the overlay. Right-click anywhere. Run the encounter.

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## Who It’s For

MythLayer is made for:

- DMs running games at a physical table with a TV or projector

- 5e, 5e 2024, and d20-style games

- Groups that use minis and real terrain

- DMs who already use animated battlemap videos

- Tables that want spell areas, fire, lightning, darkness, and terrain effects without a full VTT

- Anyone who wants a lightweight offline tool with no subscription

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## Core Features

### Animated Effects

Paint area effects onto the map using square, circle, or freehand placement.

Current effects include:

- Fire

- Poison

- Lightning

- Ice

- Daylight

- Darkness

- Magical Darkness

- Rough Terrain

Effects can be placed freely or snapped to the 5 ft grid.

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### 5e Measurement Tools

Built-in measurement tools for common tabletop area types:

- Distance

- Line

- Cone

- Cube

- Sphere

- Cylinder

- Emanation / Radius

Distance measurement supports multi-point paths, similar to map navigation tools. Click, click, click, then press Enter to finalize.

Measurements include live foot readouts, optional grid snapping, and customizable colors.

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### Locked Spell Templates

MythLayer includes quick-place animated spell templates with baked-in 5e dimensions.

Current spells include:

**Damage**

- Fireball

- Burning Hands

- Cone of Cold

- Lightning Bolt

- Shatter

**Control**

- Web

- Faerie Fire

- Hypnotic Pattern

**Aura**

- Spirit Guardians

- Pass Without Trace

**Zone**

- Flame Strike

- Cloudkill

The spell knows its size. Click, place, done.

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### Quick Template Sizes

The Templates menu includes common locked sizes for fast placement:

- 20 ft sphere

- 15 ft radius

- 30 ft radius

- 15 ft cone

- 60 ft cone

- 100 × 5 ft line

- 60 × 5 ft line

- 20 ft cube

- 30 ft cube

- 10 ft radius / 40 ft height cylinder

- 20 ft radius / 40 ft height cylinder

- 10 ft wall

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### Scene Objects

Place animated markers and magical objects directly onto the map.

Current objects include:

- Spell Circle

- Flame marker

The spell circle features rotating rune-glyphs, a counter-rotating star pattern, a fixed hexagram center, and a pulsing magical halo.

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### Scene Controls

Quick scene tools include:

- Day tint

- Night tint

- Normal lighting

- Clear Measurements

- Clear All

Locked items survive the clear command.

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### Procedural Dice Roller

MythLayer includes a built-in dice roller with no third-party widgets.

Roll:

- d4

- d6

- d8

- d10

- d12

- d20

- d100

Features include:

- Click-to-build dice pools

- Animated dice physics

- Spin and settle effects

- Optional procedural dice audio

- Result banner with individual rolls and total

- Roll history for the last 50 rolls

- History persists after page reload

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### Calibration

Click two points on your map, enter the known distance in feet, and MythLayer calculates the scale.

Once calibrated, all future measurements, spell templates, and effects use real tabletop feet.

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### Grid Support

MythLayer includes a 1×1 ft grid overlay with 5 ft cells.

Grid features:

- Toggle on/off

- Opacity controls

- Color controls

- Snap-to-grid placement

- Persistent settings

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### Persistent Settings

Your preferences are saved locally in your browser.

Current settings include:

- Animation intensity: Low / Medium / High

- Cursor size: Small / Medium / Large

- Labels: On / Off

- Snap: On / Off

- Multi-placement mode: On / Off

- Sound: On / Off

Set it once and MythLayer remembers it for future sessions.

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### Quality-of-Life Tools

- Right-click radial menu

- Hover descriptions for every tool

- Toast notifications for state changes

- Fullscreen toggle

- HUD readout for current tool, scale, grid, and snap status

- Lock individual placements

- Clear non-locked placements only

- Mouse wheel size adjustment for armed tools

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## Keyboard Shortcuts

| Key | Action |

|---|---|

| F / F11 | Toggle fullscreen |

| C | Clear non-locked placements |

| 1–7 | Quick-arm effects |

| Enter | Finalize distance measurement |

| Esc | Cancel current tool / close radial |

| Right-click | Open radial menu / cancel current tool |

| Mouse wheel | Adjust size while placing tools |

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## Why MythLayer Is Different

Foundry, Roll20, Owlbear Rodeo, and other VTTs are powerful tools. MythLayer is not trying to replace them.

MythLayer is built for a different use case:

A single shared screen. 

A physical table. 

Real minis. 

A DM who wants effects fast.

There are no accounts, servers, asset stores, subscriptions, installs, or required modules.

The entire tool is one lightweight HTML file. You can save it, move it, back it up, modify it, or run it offline.

It does one job: 

**paint useful tabletop effects over your battlemap video.**

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## System Requirements

**Browser**

- Chrome 100+

- Edge 100+

**Operating System**

- Windows

- macOS

- Linux

- ChromeOS

**Hardware**

- Laptop, desktop, mini-PC, or compatible device connected to a TV/projector

**Map Source**

- MP4

- WebM

- MOV

Firefox and Safari are not currently supported because they do not support the multi-display tools MythLayer uses to launch the overlay onto a selected screen.

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## Quick Start

1. Download `mythlayer_V0_25.1.html`

2. Open it in Chrome or Edge

3. Choose a battlemap video

4. Click **Detect Displays**

5. Grant display permission

6. Select your TV or projector

7. Click **Launch**

8. Right-click the overlay and choose **Calibrate**

9. Click two points a known distance apart

10. Enter the distance in feet

11. Start placing effects, measuring spells, and rolling dice

That’s it.

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## Current Status

**Alpha v0.25.1**

MythLayer is stable, table-tested, and actively being developed.

The radial menu, calibration system, measurement tools, spell templates, dice roller, and core overlay workflow are currently functional.

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## Planned Updates

Future updates may include:

- **Visual Effects Upgrade**

- Improved fire, poison, ice, and other core spell visuals

- More animated spell effects

- More environmental map effects and animated scene objects

- **Expanded Sound System**

- Toggleable FX sounds for placed effects, such as crackling fire, poison bubbling, lightning arcs, explosions, and magical pulses

- “On-use” sound triggers for moments like doors slamming, twigs snapping, water splashing, creatures growling, vaults opening, or painful groans

- A dedicated sound radial menu that can be preloaded before a session for fast access during play

- Session music controls for combat, exploration, taverns, boss fights, and scene transitions

- Possible support for external audio sources such as Spotify, YouTube Music, or local media players

- **Creatures and NPCs**

- Ability to place digital monsters, NPCs, hazards, or animated creatures directly onto the map

- Optional creature interaction states, such as idle, triggered, attacking, or revealed

- **Weather and Atmosphere**

- Map-wide or area-based weather effects

- Light rain, heavy rain, wind, snowstorms, sandstorms, tornadoes, fog, ashfall, magical storms, and similar overlays

- **Item and Object Placement**

- Placeable treasure, debris, obstacles, crystals, acid pools, lava pools, obelisks, traps, mimics, and other scene objects

- Optional animated or triggered versions of certain objects

- **Touch Frame / Interactive Table Support**

- Compatibility with touch frames or interactive displays

- Proximity-based triggers, such as a mimic activating when a miniature moves near it

- Triggered events like floor collapses, bats bursting from darkness, traps activating, or creatures scurrying across the map

- **Fog of War**

- Hide and reveal portions of the map during exploration

- Support for manual reveal tools and possible area-based reveal controls

- **Encounter Management Tools**

- Initiative tracker

- Token HP overlays

- Inline spell descriptions

- Advantage and disadvantage dice modes

- **Customization Tools**

- Fully customizable radial menus

- Custom radial layouts for different sessions, scenes, or campaigns

- Duplicate / copy placement tools

- Customization manager for saved presets and preferred layouts  

Updates will continue to ship as single HTML files. Older versions will keep working without forced upgrades or server dependencies.

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## Credits

Designed and built by **MJ**.

The single-file design, offline functionality, and DM-console workflow were core design goals from the beginning.

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## Feedback

If you find a bug, want a feature, or want to share your table setup, leave a comment on the itch.io page.

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**MythLayer. The map is the map. The minis are the minis. The magic goes here.**