init

libraries/sti/atlas.lua

@@ -0,0 +1,159 @@
+---- 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