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love2d-tank/libs/sti/atlas.lua

188 lines
3.6 KiB

---- Texture atlas complement for the Simple Tiled Implementation
-- @copyright 2022
-- @author Eduardo Hernández coz.eduardo.hernandez@gmail.com
-- @license MIT/X11
local module = {}
--- Create a texture atlas
-- @param files Array with filenames
-- @param sort If "size" will sort by size, or if "id" will sort by id
-- @param ids Array with ids of each file
-- @param pow2 If true, will force a power of 2 size
function module.Atlas(files, sort, ids, pow2)
local function Node(x, y, w, h)
return { x = x, y = y, w = w, h = h }
end
local function nextpow2(n)
local res = 1
while res <= n do
res = res * 2
end
return res
end
local function loadImgs()
local images = {}
for i = 1, #files do
images[i] = {}
--images[i].name = files[i]
if ids then
images[i].id = ids[i]
end
images[i].img = love.graphics.newImage(files[i])
images[i].w = images[i].img:getWidth()
images[i].h = images[i].img:getHeight()
images[i].area = images[i].w * images[i].h
end
if sort == "size" or sort == "id" then
table.sort(images, function(a, b)
return (a.area > b.area)
end)
end
return images
end
--TODO: understand this func
local function add(root, id, w, h)
if root.left or root.right then
if root.left then
local node = add(root.left, id, w, h)
if node then
return node
end
end
if root.right then
local node = add(root.right, id, w, h)
if node then
return node
end
end
return nil
end
if w > root.w or h > root.h then
return nil
end
local _w, _h = root.w - w, root.h - h
if _w <= _h then
root.left = Node(root.x + w, root.y, _w, h)
root.right = Node(root.x, root.y + h, root.w, _h)
else
root.left = Node(root.x, root.y + h, w, _h)
root.right = Node(root.x + w, root.y, _w, root.h)
end
root.w = w
root.h = h
root.id = id
return root
end
local function unmap(root)
if not root then
return {}
end
local tree = {}
if root.id then
tree[root.id] = {}
tree[root.id].x, tree[root.id].y = root.x, root.y
end
local left = unmap(root.left)
local right = unmap(root.right)
for k, v in pairs(left) do
tree[k] = {}
tree[k].x, tree[k].y = v.x, v.y
end
for k, v in pairs(right) do
tree[k] = {}
tree[k].x, tree[k].y = v.x, v.y
end
return tree
end
local function bake()
local images = loadImgs()
local root = {}
local w, h = images[1].w, images[1].h
if pow2 then
if w % 1 == 0 then
w = nextpow2(w)
end
if h % 1 == 0 then
h = nextpow2(h)
end
end
repeat
local node
root = Node(0, 0, w, h)
for i = 1, #images do
node = add(root, i, images[i].w, images[i].h)
if not node then
break
end
end
if not node then
if h <= w then
if pow2 then
h = h * 2
else
h = h + 1
end
else
if pow2 then
w = w * 2
else
w = w + 1
end
end
else
break
end
until false
local limits = love.graphics.getSystemLimits()
if w > limits.texturesize or h > limits.texturesize then
return "Resulting texture is too large for this system"
end
local coords = unmap(root)
local map = love.graphics.newCanvas(w, h)
love.graphics.setCanvas(map)
-- love.graphics.clear()
for i = 1, #images do
love.graphics.draw(images[i].img, coords[i].x, coords[i].y)
if ids then
coords[i].id = images[i].id
end
end
love.graphics.setCanvas()
if sort == "ids" then
table.sort(coords, function(a, b)
return (a.id < b.id)
end)
end
return { image = map, coords = coords }
end
return bake()
end
return module