Sprites

spectrum provides a SpriteAtlas class for managing and drawing sprites from a single image file. These are used with Display and Drawable.

Loading an Atlas

The simplest way to create an atlas is from a grid of evenly sized cells:

-- Load a 16×16 grid-based sprite sheet
local atlas = spectrum.SpriteAtlas.fromGrid("tiles_16x16.png", 16, 16)

If your grid represents ASCII-like glyphs (from codepoint 0 upward), use the helper:

local asciiAtlas = spectrum.SpriteAtlas.fromASCIIGrid("display/tiles_16x16.png", 16, 16)

This maps each quad to a UTF-8 character, allowing you to directly index by characters in Display.

Integration with Display

SpriteAtlas.fromASCIIGrid() is designed for codepages:

love.graphics.setDefaultFilter("nearest", "nearest")

local atlas = spectrum.SpriteAtlas.fromASCIIGrid("display/tiles_16x16.png", 16, 16)
local display = spectrum.Display(81, 41, atlas, prism.Vector2(16, 16))

Each display cell corresponds directly to a UTF-8 character mapped in the atlas.

Naming Sprites

SpriteAtlas.fromGrid() allows custom sprite names:

local names = { "floor", "wall", "water", "tree" }
local atlas = spectrum.SpriteAtlas.fromGrid("terrain.png", 16, 16, names)

You can then look up quads by those names:

local quad = atlas:getQuadByName("tree")

Using SpriteAtlas with Drawable

To draw something from a spritesheet, a Drawable must reference a sprite defined in the SpriteAtlas. This is done by setting sprite.index on the Drawable (or on the Sprite passed into it). The index can be:

• a number, selecting a quad by its grid position, or

• a string, selecting a quad by the name assigned when creating the atlas (e.g. via SpriteAtlas.fromGrid() with custom names or SpriteAtlas.fromAtlased()).

When Display draws a Drawable, it resolves this value automatically:

• numeric index → spriteAtlas:getQuadByIndex(index)

• string index → spriteAtlas:getQuadByName(name)

To use a named sprite, provide the matching name:

prism.components.Drawable{index = "player", color = prism.Color4.WHITE} -- named
prism.components.Drawable{index = "@", color = prism.Color4.WHITE} -- ASCII

Or use a numeric index directly:

prism.components.Drawable{index = 42, color = prism.Color4.WHITE}