diff --git a/common/mathlib.cc b/common/mathlib.cc
index 89d5efd7..e91c92ed 100644
--- a/common/mathlib.cc
+++ b/common/mathlib.cc
@@ -558,6 +558,11 @@ GLM_TriangleArea(const qvec3f &v0, const qvec3f &v1, const qvec3f &v2)
     return 0.5f * qv::length(qv::cross(v2 - v0, v1 - v0));
 }
 
+qvec4f GLM_MakePlane(const qvec3f &normal, const qvec3f &point)
+{
+    return qvec4f(normal[0], normal[1], normal[2], qv::dot(point, normal));
+}
+
 float GLM_DistAbovePlane(const qvec4f &plane, const qvec3f &point)
 {
     return qv::dot(qvec3f(plane), point) - plane[3];
diff --git a/include/common/mathlib.hh b/include/common/mathlib.hh
index ededf084..b2cfdcb6 100644
--- a/include/common/mathlib.hh
+++ b/include/common/mathlib.hh
@@ -322,6 +322,7 @@ bool GLM_EdgePlanes_PointInside(const std::vector<qvec4f> &edgeplanes, const qve
 float GLM_EdgePlanes_PointInsideDist(const std::vector<qvec4f> &edgeplanes, const qvec3f &point);
 qvec3f GLM_TriangleCentroid(const qvec3f &v0, const qvec3f &v1, const qvec3f &v2);
 float GLM_TriangleArea(const qvec3f &v0, const qvec3f &v1, const qvec3f &v2);
+qvec4f GLM_MakePlane(const qvec3f &normal, const qvec3f &point);
 float GLM_DistAbovePlane(const qvec4f &plane, const qvec3f &point);
 qvec3f GLM_ProjectPointOntoPlane(const qvec4f &plane, const qvec3f &point);
 float GLM_PolyArea(const std::vector<qvec3f> &points);
diff --git a/light/test_light.cc b/light/test_light.cc
index 4fa97560..5a2d4da6 100644
--- a/light/test_light.cc
+++ b/light/test_light.cc
@@ -282,6 +282,11 @@ TEST(mathlib, RotateFromUpToSurfaceNormal) {
     }
 }
 
+TEST(mathlib, MakePlane) {
+    EXPECT_EQ(qvec4f(0, 0, 1, 10), GLM_MakePlane(qvec3f(0,0,1), qvec3f(0,0,10)));
+    EXPECT_EQ(qvec4f(0, 0, 1, 10), GLM_MakePlane(qvec3f(0,0,1), qvec3f(100,100,10)));
+}
+
 TEST(mathlib, DistAbovePlane) {
     qvec4f plane(0, 0, 1, 10);
     qvec3f point(100, 100, 100);