diff --git a/src/mathematics/mathematics_functions.cpp b/src/mathematics/mathematics_functions.cpp
index 54aa0878..1e13a0f1 100644
--- a/src/mathematics/mathematics_functions.cpp
+++ b/src/mathematics/mathematics_functions.cpp
@@ -47,7 +47,7 @@ void reactphysics3d::computeBarycentricCoordinatesInTriangle(const Vector3& a, c
     decimal denom = d00 * d11 - d01 * d01;
     v = (d11 * d20 - d01 * d21) / denom;
     w = (d00 * d21 - d01 * d20) / denom;
-    u = decimal(1.0) - u - w;
+    u = decimal(1.0) - v - w;
 }
 
 // Clamp a vector such that it is no longer than a given maximum length
diff --git a/test/tests/mathematics/TestMathematicsFunctions.h b/test/tests/mathematics/TestMathematicsFunctions.h
index f7cb56e5..1939efc2 100644
--- a/test/tests/mathematics/TestMathematicsFunctions.h
+++ b/test/tests/mathematics/TestMathematicsFunctions.h
@@ -107,19 +107,23 @@ class TestMathematicsFunctions : public Test {
             Vector3 a(0, 0, 0);
             Vector3 b(5, 0, 0);
             Vector3 c(0, 0, 5);
+            Vector3 testPoint(4, 0, 1);
             decimal u,v,w;
             computeBarycentricCoordinatesInTriangle(a, b, c, a, u, v, w);
-            test(approxEqual(u, 1.0, 0.0001));
-            test(approxEqual(v, 0.0, 0.0001));
-            test(approxEqual(w, 0.0, 0.0001));
+            test(approxEqual(u, 1.0, 0.000001));
+            test(approxEqual(v, 0.0, 0.000001));
+            test(approxEqual(w, 0.0, 0.000001));
             computeBarycentricCoordinatesInTriangle(a, b, c, b, u, v, w);
-            test(approxEqual(u, 0.0, 0.0001));
-            test(approxEqual(v, 1.0, 0.0001));
-            test(approxEqual(w, 0.0, 0.0001));
+            test(approxEqual(u, 0.0, 0.000001));
+            test(approxEqual(v, 1.0, 0.000001));
+            test(approxEqual(w, 0.0, 0.000001));
             computeBarycentricCoordinatesInTriangle(a, b, c, c, u, v, w);
-            test(approxEqual(u, 0.0, 0.0001));
-            test(approxEqual(v, 0.0, 0.0001));
-            test(approxEqual(w, 1.0, 0.0001));
+            test(approxEqual(u, 0.0, 0.000001));
+            test(approxEqual(v, 0.0, 0.000001));
+            test(approxEqual(w, 1.0, 0.000001));
+
+            computeBarycentricCoordinatesInTriangle(a, b, c, testPoint, u, v, w);
+            test(approxEqual(u + v + w, 1.0, 0.000001));
         }
 
  };