Extend functionality of LOVE 11.0 Transform object

transform_hack.lua

-- Script that monkeypatch LOVE Transform
-- to add 3D support
local love = require("love")
local t = love.math.newTransform()
local t2 = love.math.newTransform()
local transformMt = getmetatable(t)

local function applyDump(ts, ...)
	t2:reset()
	t2:apply(ts)
	return "row", t:setMatrix(...):apply(t2):getMatrix()
end

function transformMt:translate3D(x, y, z)
	return self:setMatrix(applyDump(self,
		1, 0, 0, x,
		0, 1, 0, y,
		0, 0, 1, z,
		0, 0, 0, 1
	))
end

function transformMt:scale3D(x, y, z)
	x, y, z = x or 1, y or x or 1, z or x or 1
	return self:setMatrix(applyDump(self,
		x, 0, 0, 0,
		0, y, 0, 0,
		0, 0, z, 0,
		0, 0, 0, 1
	))
end

function transformMt:quaternionRotate(rot, x, y, z)
	local len = math.sqrt(x*x + y*y + z*z)
	if len == 0 then return end

	x, y, z = x/len, y/len, z/len
	local c, s = math.cos(rot), math.sin(rot)
	return self:setMatrix(applyDump(self,
		x*x*(1-c)+c,   y*x*(1-c)+z*s, x*z*(1-c)-y*s, 0,
		x*y*(1-c)-z*s, y*y*(1-c)+c,   y*z*(1-c)+x*s, 0,
		x*z*(1-c)+y*s, y*z*(1-c)-x*s, z*z*(1-c)+c,   0,
		0,             0,             0,             1
	))
end

function transformMt:rotateX(rot)
	local c, s = math.cos(rot), math.sin(rot)
	return self:setMatrix(applyDump(self,
		1, 0, 0, 0,
		0, c,-s, 0,
		0, s, c, 0,
		0, 0, 0, 1
	))
end

function transformMt:rotateY(rot)
	local c, s = math.cos(rot), math.sin(rot)
	return self:setMatrix(applyDump(self,
		c,  0, s, 0,
		0,  1, 0, 0,
		-s, 0, c, 0,
		0,  0, 0, 1
	))
end

transformMt.rotateZ = transformMt.rotate

function transformMt:transpose()
	return self:setMatrix("column", self:getMatrix())
end

return true