vec: Add nan checking functions

Add:
* vec2.has_nan + test
* vec3.has_nan + test
* quat.has_nan
* mat4.has_nan
* utils.is_nan + test

modules/_private_utils.lua

@@ -9,4 +9,8 @@ function private.round(value, precision)
 	return value >= 0 and floor(value+0.5) or ceil(value-0.5)
 end
 
+function private.is_nan(a)
+	return a ~= a
+end
+
 return private

modules/mat4.lua

@@ -6,6 +6,7 @@ local vec2      = require(modules .. "vec2")
 local vec3      = require(modules .. "vec3")
 local quat      = require(modules .. "quat")
 local utils     = require(modules .. "utils")
+local private   = require(modules .. "_private_utils")
 local sqrt      = math.sqrt
 local cos       = math.cos
 local sin       = math.sin
@@ -650,6 +651,18 @@ function mat4.is_mat4(a)
 	return true
 end
 
+--- Return whether any component is NaN
+-- @tparam mat4 a Matrix to be tested
+-- @treturn boolean if any component is NaN
+function vec2.has_nan(a)
+	for i=1, 16 do
+		if private.is_nan(a[i]) then
+			return true
+		end
+	end
+	return false
+end
+
 --- Return a formatted string.
 -- @tparam mat4 a Matrix to be turned into a string
 -- @treturn string formatted

modules/quat.lua

@@ -4,6 +4,7 @@
 local modules       = (...):gsub('%.[^%.]+$', '') .. "."
 local constants     = require(modules .. "constants")
 local vec3          = require(modules .. "vec3")
+local private       = require(modules .. "_private_utils")
 local DOT_THRESHOLD = constants.DOT_THRESHOLD
 local DBL_EPSILON   = constants.DBL_EPSILON
 local acos          = math.acos
@@ -362,6 +363,16 @@ function quat.is_imaginary(a)
 	return a.w == 0
 end
 
+--- Return whether any component is NaN
+-- @tparam quat a Quaternion to be tested
+-- @treturn boolean if x,y,z, or w is NaN
+function quat.has_nan(a)
+	return private.is_nan(a.x) or
+		private.is_nan(a.y) or
+		private.is_nan(a.z) or
+		private.is_nan(a.w)
+end
+
 --- Convert a quaternion into an angle plus axis components.
 -- @tparam quat a Quaternion to convert
 -- @tparam identityAxis vec3 of axis to use on identity/degenerate quaternions (optional, default returns 0,0,0,1)

modules/utils.lua

@@ -128,6 +128,12 @@ function utils.is_pot(value)
 	return (frexp(value)) == 0.5
 end
 
+--- Check if a value is NaN
+-- Returns true if a number is not a valid number
+-- @param value
+-- @return boolean
+utils.is_nan = private.is_nan
+
 -- Originally from vec3
 function utils.project_on(a, b)
 	local s =

modules/vec2.lua

@@ -320,6 +320,14 @@ function vec2.is_zero(a)
 	return a.x == 0 and a.y == 0
 end
 
+--- Return whether either value is NaN
+-- @tparam vec2 a Vector to be tested
+-- @treturn boolean if x or y is nan
+function vec2.has_nan(a)
+	return private.is_nan(a.x) or
+		private.is_nan(a.y)
+end
+
 --- Convert point from cartesian to polar.
 -- @tparam vec2 a Vector to convert
 -- @treturn number radius

modules/vec3.lua

@@ -332,6 +332,15 @@ function vec3.is_zero(a)
 	return a.x == 0 and a.y == 0 and a.z == 0
 end
 
+--- Return whether any component is NaN
+-- @tparam vec3 a Vector to be tested
+-- @treturn boolean if x,y, or z are nan
+function vec3.has_nan(a)
+	return private.is_nan(a.x) or
+		private.is_nan(a.y) or
+		private.is_nan(a.z)
+end
+
 --- Return a formatted string.
 -- @tparam vec3 a Vector to be turned into a string
 -- @treturn string formatted

spec/utils_spec.lua

@@ -28,6 +28,11 @@ describe("utils:", function()
 		assert.is_true(tolerance(v, 0.39346934028737))
 	end)
 
+	it("checks a nan", function()
+		local a = 0/0
+		assert.is_true(utils.is_nan(a))
+	end)
+
 	it("rounds a number", function()
 		-- round up
 		local v = utils.round(1.3252525, 0.01)

spec/vec2_spec.lua

@@ -35,6 +35,11 @@ describe("vec2:", function()
 		assert.is.equal(5, a.y)
 	end)
 
+	it("creates a vector from nan", function()
+		local a = vec2(0/0)
+		assert.is_true(a:has_nan())
+	end)
+
 	it("clones a vector", function()
 		local a = vec2(3, 5)
 		local b = a:clone()

spec/vec3_spec.lua

@@ -40,6 +40,11 @@ describe("vec3:", function()
 		assert.is.equal(7, a.z)
 	end)
 
+	it("creates a vector from nan", function()
+		local a = vec3(0/0)
+		assert.is_true(a:has_nan())
+	end)
+
 	it("clones a vector", function()
 		local a = vec3(3, 5, 7)
 		local b = a:clone()