MMAR Grid

A lightweight, extensible, grid-first framework for Unity. MMAR Grid lets you:

• Generate and manage 2D grid worlds (X/Z plane) with integer precision
• Place and drag GridObjects that align/snap to the grid
• Query and convert between world and grid coordinates (Vector3 ⇄ Vector2Int)
• Build gameplay extensions on top: pathfinding, movement, explosions, etc.

This project already includes production-ready extensions:

• GridPathfinding (A*)
• GridMovementController (character controller)
• ExplosionManager (grid-aligned explosions with cardinal/diagonal options)

Contents

• Core (Base)
  • GridManager: grid definition, coordinate conversion, placement helpers
  • GridGroundObject: one per tile; holds an optional GridObject
  • GridObject: base class for placeable things (bombs, crates, players...)
• Extensions
  • GridPathfinding: A* search over the grid
  • GridMovementController: Bomberman-style 4/8-way tile movement with dash
  • ExplosionManager: tile-by-tile explosion visualisation and blocking

Install

You can use any one of the following three methods:

• Download and import from Asset Store.
• Unity Package Manager → Add package by Git URL https://github.com/mmar58/MMAR-Grid.git
• Clone the repo anywhere on your machine, and use Install package from disk from Package Manager.
• Copy the repo in your unity project

Core Concepts

GridManager

The heart of the system. Responsibilities:

• Holds grid size width × height and gridStartPoint
• Owns groundGridObjects: Dictionary<Vector2Int, GridGroundObject>
• Converts coordinates:
  • Vector2Int WorldToGrid(Vector3 world) → clamps into bounds
  • Vector3 GridToWorld(Vector2Int grid)
  • bool IsValidGridPosition(Vector2Int pos)
• Placement helpers:
  • PlaceObjectFromPrefab(GridObject prefab, Vector2Int pos)
  • AddGridObject(GridObject prefab) for drag-and-drop authoring

Each cell has a GridGroundObject that may hold one GridObject via onGridObject.

GridObject

Base class for anything that lives on the grid.

• Tracks gridPosition and y-offset on placement
• Snaps itself to the nearest valid tile on start (PlaceToNearestGrid())
• Provides drag UX via MouseInputManager integration

GridGroundObject

• Holds a reference to the onGridObject
• Surfaces mouse hover events through GridManager UnityEvents

Pathfinding (Extensions/GridPathfinding.cs)

A* pathfinding over the MMAR grid.

• 4-way movement (cardinals) with Manhattan heuristic
• Coroutine mode with partial updates and debug drawing
• Synchronous mode for one-off queries
• Utility methods: direct line checks, walkables in range

Important notes:

• Ensure GridManager is assigned/available before calling FindPath
• Keep walkability fresh:
  • Either call UpdateNodeWalkability(pos, walkable) when tiles change
  • Or query IsPositionWalkable(pos) dynamically when expanding neighbors
• For large maps, consider replacing the open set with a binary heap for speed
• If you need 8-way movement, extend GetNeighbors() with diagonals and switch to an octile heuristic

Character Movement (Extensions/GridMovementController.cs)

Plug-and-play player controller built on the grid.

• 4/8-way inputs (Unity Input System) with optional diagonal corner-cut protection
• Smooth per-tile motion (MoveTowards) with input buffering
• Optional dash across N tiles with easing
• Smooth look-at rotation toward movement/dash direction
• Helpers:
  • CurrentGridPosition
  • GetFacingDirection() and GetFrontGridPosition()
  • IsFrontPositionClear()

Wire it by adding PlayerInput and binding a "Move" (Vector2) and "Dash" action.

Explosions (Extensions/ExplosionManager.cs)

Tile-aligned explosions that respect blocking.

• Cardinal rays plus optional diagonals
• Stops on blocking objects; includes destructibles on impact
• Spawns an effect prefab per affected tile, with optional ring spread

Usage:

// From a Bomb, when exploding:
ExplosionManager.Instance.TriggerExplosion(centerGrid, range, allowDiagonal);
// Bomb object can then destroy itself

To integrate damage, iterate affected tiles and apply to any GridObject (or a custom interface).

Quick Start

1. Add a GridManager to a scene

• Set width/height and gridStartPoint
• Assign Grid Ground Object in Game Objects prefab of GridManager
• Assign gridGroundParent and gridObjectParent (optional)
• Generate tiles via the button or call GenerateGridGround()

2. Spawn/place objects

• Derive your items from GridObject
• Call PlaceObjectFromPrefab(prefab, pos) or drag in editor

3. Add Extensions as needed

• Pathfinding: add GridPathfinding and call FindPath(startWorld, endWorld) or FindPathAsync
• Movement: add GridMovementController + PlayerInput
• Explosions: add ExplosionManager and assign the effect prefab