diff --git a/src/engine/math_util.c b/src/engine/math_util.c
index d4fbb2159..65a62c044 100644
--- a/src/engine/math_util.c
+++ b/src/engine/math_util.c
@@ -293,77 +293,67 @@ void mtxf_translate(Mat4 dest, Vec3f b) {
  * angle allows a bank rotation of the camera.
  */
 void mtxf_lookat(Mat4 mtx, Vec3f from, Vec3f to, s16 roll) {
-    register f32 invLength;
-    f32 dx;
-    f32 dz;
-    f32 xColY;
-    f32 yColY;
-    f32 zColY;
-    f32 xColZ;
-    f32 yColZ;
-    f32 zColZ;
-    f32 xColX;
-    f32 yColX;
-    f32 zColX;
+    Vec3f forward, right, up;
+    f32 sinRoll, cosRoll;
+    f32 dx, dz, xzDist;
+    f32 invLength;
+
+    forward[0] = from[0] - to[0];
+    forward[1] = from[1] - to[1];
+    forward[2] = from[2] - to[2];
+    invLength = 1.0f / sqrtf(forward[0] * forward[0] + forward[1] * forward[1] + forward[2] * forward[2]);
+    forward[0] *= invLength;
+    forward[1] *= invLength;
+    forward[2] *= invLength;
 
     dx = to[0] - from[0];
     dz = to[2] - from[2];
+    xzDist = dx * dx + dz * dz;
+    if (xzDist != 0.0f) {
+        invLength = -1.0f / sqrtf(xzDist);
+        dx *= invLength;
+        dz *= invLength;
+    } else {
+        dx = dz = 0.0f;
+    }
+	
+    sinRoll = sins(roll);
+    cosRoll = coss(roll);
 
-    invLength = -1.0 / sqrtf(dx * dx + dz * dz);
-    dx *= invLength;
-    dz *= invLength;
+    up[0] = sinRoll * dz;
+    up[1] = cosRoll;
+    up[2] = -sinRoll * dx;
 
-    yColY = coss(roll);
-    xColY = sins(roll) * dz;
-    zColY = -sins(roll) * dx;
+    right[0] = up[1] * forward[2] - up[2] * forward[1];
+    right[1] = up[2] * forward[0] - up[0] * forward[2];
+    right[2] = up[0] * forward[1] - up[1] * forward[0];
 
-    xColZ = to[0] - from[0];
-    yColZ = to[1] - from[1];
-    zColZ = to[2] - from[2];
+    invLength = 1.0f / sqrtf(right[0] * right[0] + right[1] * right[1] + right[2] * right[2]);
+    right[0] *= invLength;
+    right[1] *= invLength;
+    right[2] *= invLength;
 
-    invLength = -1.0 / sqrtf(xColZ * xColZ + yColZ * yColZ + zColZ * zColZ);
-    xColZ *= invLength;
-    yColZ *= invLength;
-    zColZ *= invLength;
+    up[0] = forward[1] * right[2] - forward[2] * right[1];
+    up[1] = forward[2] * right[0] - forward[0] * right[2];
+    up[2] = forward[0] * right[1] - forward[1] * right[0];
+	
+    mtx[0][0] = right[0];
+    mtx[1][0] = right[1];
+    mtx[2][0] = right[2];
+    mtx[3][0] = -(from[0] * right[0] + from[1] * right[1] + from[2] * right[2]);
 
-    xColX = yColY * zColZ - zColY * yColZ;
-    yColX = zColY * xColZ - xColY * zColZ;
-    zColX = xColY * yColZ - yColY * xColZ;
+    mtx[0][1] = up[0];
+    mtx[1][1] = up[1];
+    mtx[2][1] = up[2];
+    mtx[3][1] = -(from[0] * up[0] + from[1] * up[1] + from[2] * up[2]);
 
-    invLength = 1.0 / sqrtf(xColX * xColX + yColX * yColX + zColX * zColX);
+    mtx[0][2] = forward[0];
+    mtx[1][2] = forward[1];
+    mtx[2][2] = forward[2];
+    mtx[3][2] = -(from[0] * forward[0] + from[1] * forward[1] + from[2] * forward[2]);
 
-    xColX *= invLength;
-    yColX *= invLength;
-    zColX *= invLength;
-
-    xColY = yColZ * zColX - zColZ * yColX;
-    yColY = zColZ * xColX - xColZ * zColX;
-    zColY = xColZ * yColX - yColZ * xColX;
-
-    invLength = 1.0 / sqrtf(xColY * xColY + yColY * yColY + zColY * zColY);
-    xColY *= invLength;
-    yColY *= invLength;
-    zColY *= invLength;
-
-    mtx[0][0] = xColX;
-    mtx[1][0] = yColX;
-    mtx[2][0] = zColX;
-    mtx[3][0] = -(from[0] * xColX + from[1] * yColX + from[2] * zColX);
-
-    mtx[0][1] = xColY;
-    mtx[1][1] = yColY;
-    mtx[2][1] = zColY;
-    mtx[3][1] = -(from[0] * xColY + from[1] * yColY + from[2] * zColY);
-
-    mtx[0][2] = xColZ;
-    mtx[1][2] = yColZ;
-    mtx[2][2] = zColZ;
-    mtx[3][2] = -(from[0] * xColZ + from[1] * yColZ + from[2] * zColZ);
-
-    mtx[0][3] = 0;
-    mtx[1][3] = 0;
-    mtx[2][3] = 0;
-    mtx[3][3] = 1;
+    mtx[0][3] = mtx[1][3] = mtx[2][3] = 0.0f;
+    mtx[3][3] = 1.0f;
 }
 
 /**