init

libraries/sti/utils.lua

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+-- Some utility functions that shouldn't be exposed.
+local utils = {}
+
+-- https://github.com/stevedonovan/Penlight/blob/master/lua/pl/path.lua#L286
+function utils.format_path(path)
+	local np_gen1,np_gen2  = '[^SEP]+SEP%.%.SEP?','SEP+%.?SEP'
+	local np_pat1, np_pat2 = np_gen1:gsub('SEP','/'), np_gen2:gsub('SEP','/')
+	local k
+
+	repeat -- /./ -> /
+		path,k = path:gsub(np_pat2,'/',1)
+	until k == 0
+
+	repeat -- A/../ -> (empty)
+		path,k = path:gsub(np_pat1,'',1)
+	until k == 0
+
+	if path == '' then path = '.' end
+
+	return path
+end
+
+-- Compensation for scale/rotation shift
+function utils.compensate(tile, tileX, tileY, tileW, tileH)
+	local compx = 0
+	local compy = 0
+
+	if tile.sx < 0 then compx = tileW end
+	if tile.sy < 0 then compy = tileH end
+
+	if tile.r > 0 then
+		tileX = tileX + tileH - compy
+		tileY = tileY + tileH + compx - tileW
+	elseif tile.r < 0 then
+		tileX = tileX + compy
+		tileY = tileY - compx + tileH
+	else
+		tileX = tileX + compx
+		tileY = tileY + compy
+	end
+
+	return tileX, tileY
+end
+
+-- Cache images in main STI module
+function utils.cache_image(sti, path, image)
+	image = image or love.graphics.newImage(path)
+	image:setFilter("nearest", "nearest")
+	sti.cache[path] = image
+end
+
+-- We just don't know.
+function utils.get_tiles(imageW, tileW, margin, spacing)
+	imageW  = imageW - margin
+	local n = 0
+
+	while imageW >= tileW do
+		imageW = imageW - tileW
+		if n ~= 0 then imageW = imageW - spacing end
+		if imageW >= 0 then n  = n + 1 end
+	end
+
+	return n
+end
+
+-- Decompress tile layer data
+function utils.get_decompressed_data(data)
+	local ffi     = require "ffi"
+	local d       = {}
+	local decoded = ffi.cast("uint32_t*", data)
+
+	for i = 0, data:len() / ffi.sizeof("uint32_t") do
+		table.insert(d, tonumber(decoded[i]))
+	end
+
+	return d
+end
+
+-- Convert a Tiled ellipse object to a LOVE polygon
+function utils.convert_ellipse_to_polygon(x, y, w, h, max_segments)
+	local ceil = math.ceil
+	local cos  = math.cos
+	local sin  = math.sin
+
+	local function calc_segments(segments)
+		local function vdist(a, b)
+			local c = {
+				x = a.x - b.x,
+				y = a.y - b.y,
+			}
+
+			return c.x * c.x + c.y * c.y
+		end
+
+		segments = segments or 64
+		local vertices = {}
+
+		local v = { 1, 2, ceil(segments/4-1), ceil(segments/4) }
+
+		local m
+		if love and love.physics then
+			m = love.physics.getMeter()
+		else
+			m = 32
+		end
+
+		for _, i in ipairs(v) do
+			local angle = (i / segments) * math.pi * 2
+			local px    = x + w / 2 + cos(angle) * w / 2
+			local py    = y + h / 2 + sin(angle) * h / 2
+
+			table.insert(vertices, { x = px / m, y = py / m })
+		end
+
+		local dist1 = vdist(vertices[1], vertices[2])
+		local dist2 = vdist(vertices[3], vertices[4])
+
+		-- Box2D threshold
+		if dist1 < 0.0025 or dist2 < 0.0025 then
+			return calc_segments(segments-2)
+		end
+
+		return segments
+	end
+
+	local segments = calc_segments(max_segments)
+	local vertices = {}
+
+	table.insert(vertices, { x = x + w / 2, y = y + h / 2 })
+
+	for i = 0, segments do
+		local angle = (i / segments) * math.pi * 2
+		local px    = x + w / 2 + cos(angle) * w / 2
+		local py    = y + h / 2 + sin(angle) * h / 2
+
+		table.insert(vertices, { x = px, y = py })
+	end
+
+	return vertices
+end
+
+function utils.rotate_vertex(map, vertex, x, y, cos, sin, oy)
+	if map.orientation == "isometric" then
+		x, y               = utils.convert_isometric_to_screen(map, x, y)
+		vertex.x, vertex.y = utils.convert_isometric_to_screen(map, vertex.x, vertex.y)
+	end
+
+	vertex.x = vertex.x - x
+	vertex.y = vertex.y - y
+
+	return
+		x + cos * vertex.x - sin * vertex.y,
+		y + sin * vertex.x + cos * vertex.y - (oy or 0)
+end
+
+--- Project isometric position to cartesian position
+function utils.convert_isometric_to_screen(map, x, y)
+	local mapW    = map.width
+	local tileW   = map.tilewidth
+	local tileH   = map.tileheight
+	local tileX   = x / tileH
+	local tileY   = y / tileH
+	local offsetX = mapW * tileW / 2
+
+	return
+		(tileX - tileY) * tileW / 2 + offsetX,
+		(tileX + tileY) * tileH / 2
+end
+
+function utils.hex_to_color(hex)
+	if hex:sub(1, 1) == "#" then
+		hex = hex:sub(2)
+	end
+
+	return {
+		r = tonumber(hex:sub(1, 2), 16) / 255,
+		g = tonumber(hex:sub(3, 4), 16) / 255,
+		b = tonumber(hex:sub(5, 6), 16) / 255
+	}
+end
+
+function utils.pixel_function(_, _, r, g, b, a)
+	local mask = utils._TC
+
+	if r == mask.r and
+		g == mask.g and
+		b == mask.b then
+		return r, g, b, 0
+	end
+
+	return r, g, b, a
+end
+
+function utils.fix_transparent_color(tileset, path)
+	local image_data = love.image.newImageData(path)
+	tileset.image = love.graphics.newImage(image_data)
+
+	if tileset.transparentcolor then
+		utils._TC = utils.hex_to_color(tileset.transparentcolor)
+
+		image_data:mapPixel(utils.pixel_function)
+		tileset.image = love.graphics.newImage(image_data)
+	end
+end
+
+function utils.deepCopy(t)
+	local copy = {}
+	for k,v in pairs(t) do
+		if type(v) == "table" then
+			v = utils.deepCopy(v)
+		end
+		copy[k] = v
+	end
+	return copy
+end
+
+return utils