diff --git a/modules/intersect.lua b/modules/intersect.lua
index b982943..512d1f5 100644
--- a/modules/intersect.lua
+++ b/modules/intersect.lua
@@ -542,6 +542,59 @@ function intersect.sphere_sphere(a, b)
 	return intersect.circle_circle(a, b)
 end
 
+-- http://realtimecollisiondetection.net/blog/?p=103
+-- sphere.position is a vec3
+-- sphere.radius   is a number
+-- triangle[1]     is a vec3
+-- triangle[2]     is a vec3
+-- triangle[3]     is a vec3
+function intersect.sphere_trianlge(sphere, triangle)
+	local A  = triangle[1] - sphere.position
+	local B  = triangle[2] - sphere.position
+	local C  = triangle[3] - sphere.position
+
+	local rr = sphere.radius * sphere.radius
+	local V  = vec3():cross(B - A, C - A)
+
+	local d  = A:dot(V)
+	local e  = V:dot(V)
+	local aa = A:dot(A)
+	local ab = A:dot(B)
+	local ac = A:dot(C)
+	local bb = B:dot(B)
+	local bc = B:dot(C)
+	local cc = C:dot(C)
+
+	local AB = B - A
+	local BC = C - B
+	local CA = A - C
+
+	local d1 = ab - aa
+	local d2 = bc - bb
+	local d3 = ac - cc
+
+	local e1 = AB:dot(AB)
+	local e2 = BC:dot(BC)
+	local e3 = CA:dot(CA)
+
+	local Q1 = A * e1 - d1 * AB
+	local Q2 = B * e2 - d2 * BC
+	local Q3 = C * e3 - d3 * CA
+	local QC = C * e1 - Q1
+	local QA = A * e2 - Q2
+	local QB = B * e3 - Q3
+
+	local s1 = d * d > rr * e
+	local s2 = (aa > rr) and (ab > aa) and (ac > aa)
+	local s3 = (bb > rr) and (ab > bb) and (bc > bb)
+	local s4 = (cc > rr) and (ac > cc) and (bc > cc)
+	local s5 = (Q1:dot(Q1) > rr * e1 * e1) and (Q1:dot(QC) > 0)
+	local s6 = (Q2:dot(Q2) > rr * e2 * e2) and (Q2:dot(QA) > 0)
+	local s7 = (Q3:dot(Q3) > rr * e3 * e3) and (Q3:dot(QB) > 0)
+
+	return s1 or s2 or s3 or s4 or s5 or s6 or s7
+end
+
 -- sphere.position is a vec3
 -- sphere.radius   is a number
 -- frustum.left    is a plane { a, b, c, d }