Fix vec3 test failures, add unit vectors.

modules/vec3.lua

@@ -43,18 +43,25 @@ if hasffi and jitenabled then
 	ffi.cdef "struct cpml_vec3 { double x, y, z; };"
 	new = ffi.typeof("struct cpml_vec3")
 	function isvector(v)
-		return ffi.istype(new, v)
+		return ffi.istype(new, v) or type(v.x and v.y and v.z) == "number"
 	end
 else
 	function new(x,y,z)
+		-- allow construction via vec3(a, b, c), vec3 { a, b, c } or vec3 { x = a, y = b, z = c }
+		if type(x) == "table" then
+			return setmetatable({x=x.x or x[1] or 0, y=x.y or x[2] or 0, z=x.z or x[3] or 0}, vector)
+		end
 		return setmetatable({x = x or 0, y = y or 0, z = z or 0}, vector)
 	end
 	function isvector(v)
-		return getmetatable(v) == vector
+		return getmetatable(v) == vector or type(v.x and v.y and v.z) == "number"
 	end
 end
 
 local zero = new(0,0,0)
+local unit_x = new(1,0,0)
+local unit_y = new(0,1,0)
+local unit_z = new(0,0,1)
 
 function vector:clone()
 	return new(self.x, self.y, self.z)
@@ -246,5 +253,15 @@ if hasffi and jitenabled then
 end
 
 -- the module
-return setmetatable({new = new, isvector = isvector, zero = zero},
-{__call = function(_, ...) return new(...) end})
+return setmetatable(
+	{
+		new      = new,
+		isvector = isvector,
+		zero     = zero,
+		unit_x   = unit_x,
+		unit_y   = unit_y,
+		unit_z   = unit_z
+	}, {
+		__call = function(_, ...) return new(...) end
+	}
+)

spec/vec3_spec.lua

@@ -37,10 +37,28 @@ describe("vec3:", function()
 		assert.is_false(vec3(3,3,3) >= vec3(5,5,5))
 	end)
 
-	it("testing misc operators", function()
-		-- tostring
-		assert.has_no.errors(function() return tostring(vec3(1,1,1)) end)
+	it("testing new", function()
+		local v = vec3()
+		assert.is_true(v.x == 0)
+		assert.is_true(v.y == 0)
+		assert.is_true(v.z == 0)
 
+		v = vec3{1, 2, 3}
+		assert.is_true(v.x == 1)
+		assert.is_true(v.y == 2)
+		assert.is_true(v.z == 3)
+
+		v = vec3(4, 5, 6)
+		assert.is_true(v.x == 4)
+		assert.is_true(v.y == 5)
+		assert.is_true(v.z == 6)
+	end)
+
+	it("testing tostring", function()
+		assert.has_no.errors(function() return tostring(vec3(1,1,1)) end)
+	end)
+
+	it("testing isvector", function()
 		assert.is_true(vec3.isvector(vec3()))
 		assert.is_true(vec3.isvector(vec3{1,1}))
 		assert.is_true(vec3.isvector{x=1, y=2, z=3})
@@ -60,7 +78,7 @@ describe("vec3:", function()
 	end)
 
 	it("testing cross", function()
-		assert.is.equal(vec3(1,0,0):cross(vec3(0,1,0)), vec3(0,0,1))
+		assert.is.equal(vec3.unit_x:cross(vec3.unit_y), vec3.unit_z)
 	end)
 
 	it("testing len and normalize", function()
@@ -73,8 +91,11 @@ describe("vec3:", function()
 		assert.is.equal(vec3(2,0,2):len2(), 8)
 	end)
 
+	it("testing lerp", function()
+		assert.is.equal(vec3(0, 0, 0):lerp(vec3(1, 1, 1), 0.5), vec3(0.5, 0.5, 0.5))
+	end)
+
 	describe("vec3 pending tests", function()
-		pending "lerp"
 		pending "trim"
 		pending "angle_to"
 		pending "angle_between"