84 lines
2.2 KiB
Lua
84 lines
2.2 KiB
Lua
local Math = require "math"
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local Object = require "lib/classic"
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---@class Atlas
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---A spriteset laid out on a regular grid.
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local Atlas = Object:extend()
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---Creates a new atlas.
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---@param image_path string The path to the source image for the atlas.
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---@param sw integer The width of each sprite.
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---@param sh integer The height of each sprite.
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---@param ax integer? The anchor X coordinate of each sprite. Defaults to 0.
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---@param ay integer? The anchor Y coordinate of each sprite. Defaults to 0.
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function Atlas:new(image_path, sw, sh, ax, ay)
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local image = love.graphics.newImage(image_path)
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---The source image of the atlas.
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self.image = image
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---The width of each atlas's sprite.
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self.sw = sw
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---The height of each atlas's sprite.
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self.sh = sh
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---The anchor X coordinate of each sprite.
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self.ax = ax or 0
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---The anchor Y coordinate of each sprite.
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self.ay = ay or 0
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---The width of the atlas in texels.
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self.iw = image:getPixelWidth()
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---The height of the atlas in texels.
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self.ih = image:getPixelHeight()
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---The width of the atlas in sprites.
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self.w = Math.floor(self.iw / sw)
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---The height of the atlas in sprites.
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self.h = Math.floor(self.ih / sh)
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---The total number of sprites.
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self.num = self.w * self.h
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---A drawable mesh for each sprite.
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self.meshes = {}
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for row = 1, self.h do
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for col = 1, self.w do
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--UV texture coordinates
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local l = (col - 1) * sw / self.iw
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local t = (row - 1) * sh / self.ih
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local r = col * sw / self.iw
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local b = row * sh / self.ih
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--Vertex data
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local vertices = {
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{ 0, 0, l, t },
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{ sw, 0, r, t },
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{ 0, sh, l, b },
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{ sw, sh, r, b }
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}
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--Create and push the mesh
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local mesh = love.graphics.newMesh(vertices, "strip", "static")
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mesh:setTexture(self.image)
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self.meshes[#self.meshes + 1] = mesh
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end
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end
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end
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---Draws a sprite at a given location.
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---@param sprite integer The index of the sprite to draw.
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---@param x integer The X coordinate to draw at.
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---@param y integer The Y coordinate to draw at.
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function Atlas:draw(sprite, x, y)
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local mesh = self.meshes[sprite]
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love.graphics.draw(mesh, x - self.ax, y - self.ay)
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end
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return Atlas
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