diff --git a/src/api/l_vectors.c b/src/api/l_vectors.c
index cca25f3a..1e8ae2cd 100644
--- a/src/api/l_vectors.c
+++ b/src/api/l_vectors.c
@@ -1436,12 +1436,10 @@ static int l_lovrMat4Unpack(lua_State* L) {
     }
     return 16;
   } else {
-    float angle, ax, ay, az;
-    float position[4], orientation[4], scale[4];
+    float position[4], scale[4], angle, ax, ay, az;
     mat4_getPosition(m, position);
     mat4_getScale(m, scale);
-    mat4_getOrientation(m, orientation);
-    quat_getAngleAxis(orientation, &angle, &ax, &ay, &az); // TODO mat4_getAngleAxis (see math.lua)
+    mat4_getAngleAxis(m, &angle, &ax, &ay, &az);
     lua_pushnumber(L, position[0]);
     lua_pushnumber(L, position[1]);
     lua_pushnumber(L, position[2]);
diff --git a/src/core/maf.h b/src/core/maf.h
index 5d89b67b..223d0ff0 100644
--- a/src/core/maf.h
+++ b/src/core/maf.h
@@ -558,6 +558,22 @@ MAF void mat4_getOrientation(mat4 m, quat orientation) {
   quat_fromMat4(orientation, m);
 }
 
+MAF void mat4_getAngleAxis(mat4 m, float* angle, float* ax, float* ay, float* az) {
+  float sx = vec3_length(m + 0);
+  float sy = vec3_length(m + 4);
+  float sz = vec3_length(m + 8);
+  float diagonal[4] = { m[0], m[5], m[10] };
+  float axis[4] = { m[6] - m[9], m[8] - m[2], m[1] - m[4] };
+  diagonal[0] /= sx;
+  diagonal[1] /= sy;
+  diagonal[2] /= sz;
+  vec3_normalize(axis);
+  *angle = acosf((diagonal[0] + diagonal[1] + diagonal[2] - 1.f) / 2.f);
+  *ax = axis[0];
+  *ay = axis[1];
+  *az = axis[2];
+}
+
 MAF void mat4_getScale(mat4 m, vec3 scale) {
   vec3_set(scale, vec3_length(m + 0), vec3_length(m + 4), vec3_length(m + 8));
 }