FFI'd color

modules/color.lua

@@ -7,7 +7,9 @@ local color    = {}
 local color_mt = {}
 
 local function new(r, g, b, a)
-	return setmetatable({ r, g, b, a }, color)
+	local c = { r, g, b, a }
+	c._c = c
+	return setmetatable(c, color)
 end
 
 -- HSV utilities (adapted from http://www.cs.rit.edu/~ncs/color/t_convert.html)
@@ -93,6 +95,16 @@ local function color_to_hsv(c)
 	return { h, s, v, a }
 end
 
+-- Do the check to see if JIT is enabled. If so use the optimized FFI structs.
+local status, ffi, the_type
+if type(jit) == "table" and jit.status() then
+    status, ffi = pcall(require, "ffi")
+    if status then
+        ffi.cdef "typedef struct { double _c[4]; } cpml_color;"
+        new = ffi.typeof("cpml_color")
+    end
+end
+
 function color.new(r, g, b, a)
 	-- number, number, number, number
 	if r and g and b and a then
@@ -254,11 +266,52 @@ function color.linear_to_gamma(r, g, b, a)
 	end
 end
 
+function color.is_color(a)
+	if type(a) == "cdata" then
+		return ffi.istype("cpml_color", a)
+	end
+
+	if type(a) ~= "table" then
+		return false
+	end
+
+	for i = 1, 4 do
+		if type(a[i]) ~= "number" then
+			return false
+		end
+	end
+
+	return true
+end
+
 function color.to_string(a)
 	return string.format("[ %3.0f, %3.0f, %3.0f, %3.0f ]", a[1], a[2], a[3], a[4])
 end
 
-color_mt.__index    = color
+function color_mt.__index(t, k)
+	if type(t) == "cdata" then
+		if type(k) == "number" then
+			return t._c[k-1]
+		end
+	elseif type(k) == "number" then
+		return t._c[k]
+	end
+
+	return rawget(color, k)
+end
+
+function color_mt.__newindex(t, k, v)
+	if type(t) == "cdata" then
+		if type(k) == "number" then
+			t._c[k-1] = v
+		end
+	elseif type(k) == "number" then
+		t._c[k] = v
+	end
+
+	rawset(color, k, v)
+end
+
 color_mt.__tostring = color.to_string
 
 function color_mt.__call(_, r, g, b, a)
@@ -283,4 +336,8 @@ function color_mt.__mul(a, b)
 	end
 end
 
+if status then
+	ffi.metatype(new, color_mt)
+end
+
 return setmetatable({}, color_mt)

modules/mat4.lua

@@ -79,8 +79,8 @@ function mat4.new(a)
 	return out
 end
 
-function mat4.identity()
-	return identity(new())
+function mat4.identity(a)
+	return identity(a or new())
 end
 
 function mat4.from_angle_axis(angle, axis)
@@ -399,16 +399,11 @@ function mat4.shear(out, a, yx, zx, xy, zy, xz, yz)
 	return out:mul(tmp, a)
 end
 
+local forward, side, new_up = vec3(), vec3(), vec3()
 function mat4.look_at(out, a, eye, center, up)
-	local forward = vec3():normalize(center - eye)
-
-	local side = vec3()
-		:cross(forward, up)
-		:normalize(side)
-
-	local new_up = vec3()
-		:cross(side, forward)
-		:normalize(new_up)
+	forward:normalize(center - eye)
+	side:cross(forward, up):normalize(side)
+	new_up:cross(side, forward):normalize(new_up)
 
 	identity(tmp)
 	tmp[1]  =  side.x
@@ -512,9 +507,9 @@ end
 
 function mat4.to_string(a)
 	local str = "[ "
-	for i=1, 16 do
+	for i = 1, 16 do
 		str = str .. string.format("%+0.3f", a[i])
-		if i < #a then
+		if i < 16 then
 			str = str .. ", "
 		end
 	end
@@ -641,7 +636,6 @@ function mat4.to_frustum(a, infinite)
 	return frustum
 end
 
---mat4_mt.__index    = mat4
 function mat4_mt.__index(t, k)
 	if type(t) == "cdata" then
 		if type(k) == "number" then

spec/mat4_spec.lua

@@ -212,6 +212,28 @@ describe("mat4:", function()
 		assert.is.equal(b[16], 4)
 	end)
 
+	it("tests shear", function()
+		local a = mat4()
+		local yx, zx, xy, zy, xz, yz = 1, 1, 1, -1, -1, -1
+		local b = mat4():shear(a, yx, zx, xy, zy, xz, yz)
+		assert.is.equal(b[1],   1)
+		assert.is.equal(b[2],   1)
+		assert.is.equal(b[3],   1)
+		assert.is.equal(b[4],   0)
+		assert.is.equal(b[5],   1)
+		assert.is.equal(b[6],   1)
+		assert.is.equal(b[7],  -1)
+		assert.is.equal(b[8],   0)
+		assert.is.equal(b[9],  -1)
+		assert.is.equal(b[10], -1)
+		assert.is.equal(b[11],  1)
+		assert.is.equal(b[12],  0)
+		assert.is.equal(b[13],  0)
+		assert.is.equal(b[14],  0)
+		assert.is.equal(b[15],  0)
+		assert.is.equal(b[16],  1)
+	end)
+
 	it("tests projections", function()
 		local a  = mat4()
 		local b  = mat4.from_perspective(45, 1, 0.1, 1000)
@@ -275,7 +297,6 @@ end)
 	from_ortho
 	from_perspective
 	from_hmd_perspective
-	shear
 	look_at
 	to_frustum
 --]]