Code Design

Minimap is composed of a few components.

1. UI element to represent map on screen.
2. Bounds (world space of the minimap).
3. Scale (number of pixels per world unit).
4. Background texture.
5. Moving Icons.

Minimap Implementations

The interface IMinimap represents the main responsibilities of a minimap. An important member of the IMinimap is the GetWorldBounds() function which returns a IMinimapShape. The minimap shape determines the space that the minimap takes up in real world space and is used in the minimap's function GetMinimapPosition(Vector3) which converts from world space to minimap space. World space is a Vector3 while minimap space is a Vector2 relative to the bottom right corner of the map.

Minimap Coordinate Space

Since this is designed with a 3D game in mind, we somehow have to convert the 3D space of points to the 2D space of the minimap. In order to do this conversion we need to have a way to represent objects in the minimap space.

To get around this problem, I created the IMinimapShape interface to handle this behavior. This is useful for both the minimap itself as well as objects or icons that may be added to the minimap. The MinimapSquare is a concrete implementation of this minimap shape as a simple square and has the code to be able to get the shape of an object from 3D space to a 3D plane as a configurable square.

Implementations

There are two implementations of the IMinimap :

• CenteredMinimap - A Centered minimap that will move and or rotate with a selected minimap icon from a tag. Also supports scaling the map to be larger or smaller.
• SimpleStaticMinimap - This is a simple minimap that will draw the background and objects on the minimap

Both of these implementations are based on the abstract class AbstractMinimap which has all the base functions for how the minimap should work including setting up the background and managing icons.

Minimap Layers

The AbstractMinimap configures the minimap to fit within its current RectTransform and will create a background texture within a supplied mask. The mask contains the minimap image within that area of the screen and can be any shape.

Minimap Layout

The minimap is organized into a few different sections. The minimap itself has a background texture drawn within the mask. The BackgroundTexture has many IMinimapElement drawn on top of it. In addition, multiple IMinimapIcon are created as GameObject on top of the minimap and moved independently.

The organization is basically

• IMinimapElement - Drawn on the background and never moves
• IMinimapIcon - Move on top of the minimap along with the game.

erDiagram
    Minimap {
        int pixelsPerUnit
        MinimapShape bounds
        Sprite mask
    }
    BackgroundTexture {
        Texture2D background
    }
    BackgroundElement {
        Texture2D texture
        Vector2 position
    }
    BackgroundIcon {
        Sprite sprite
        Vector2 position
    }

    Minimap ||--|{ BackgroundTexture : "Has One"
    BackgroundTexture ||--o{ BackgroundElement : "Drawn On"
    Minimap ||--o{ BackgroundIcon : "Moved On"

Minimap Components

The following is a description of the code for minimap components.

Background Texture

The BackgroundTexture is a class which supports creating a large texture and drawing elements on top of the background texture.

Minimap Elements

Background elements implement the IMinimapElement interface. There are two implementations of the IMinimapElement

• BoxMinimapElement - Box minimap that will draw a solid box on the background at a given position, rotation, and size.
• SpriteMinimapElement - Sprite minimap element that will draw a given texture on the background at a given position, rotation, and size.

Both of these are derived from the AbstractMinimapElement class which contains useful functions for drawing the element at the position relative to the world space.

The static class TextureUtils has useful functions for managing sprites and textures in Unity.

Minimap Icon

Minimap icons implement the @nickmaltbie.MinimapTools.Icon.IMinimapElement interface. There are two implementation of the @nickmaltbie.MinimapTools.Icon.IMinimapElement

• FixedSizeSpriteIcon - Icon that will always have the same pixel size on the minimap no matter the zoom level.
• @nickmaltbie.MinimapTools.Icon.RelativeSizeIcon - Icon that will scale with the map to maintain a consist size with its world size with the PixelsPerUnit So if an element was 1x1 units and the pixel scale was 30 pixels per unit, it would scale the icon to be 30x30 pixels.

These are derived from the @nickmaltbie.MinimapTools.Icon.AbstractSizeIcon class which contains useful functions for managing a sprite and creating a GameObject icon as a child of the minimap.