Merge pull request #4 from ismailbozk/master

Vector4, Matrix4 multiplication bug fix.
nicklockwood · Aug 1, 2015 · 4489ea8 · 4489ea8
2 parents 97619b7 + ac0f412
commit 4489ea8
Show file tree

Hide file tree

Showing 2 changed files with 37 additions and 1 deletion.
diff --git a/Tests/VectorMathTests/VectorMathTests.swift b/Tests/VectorMathTests/VectorMathTests.swift
@@ -123,6 +123,42 @@ class Matrix4Tests: XCTestCase {
 
         XCTAssertTrue(matrix ~= compare)
     }
+
+    func testRotationAndTranslation() {
+        let point = Vector4(0.0, -1.0, 0.0, 1.0);
+        let euclideanTransformation = Matrix4(0.0, 1.0, 0.0, 0.0,
+            -1.0, 0.0, 0.0, 0.0,
+            0.0, 0.0, 0.0, 0.0,
+            -1.0, 0.0, 0.0, 1.0);
+
+        let result = euclideanTransformation * point;
+        let expectedResult = Vector4(0.0, 0.0, 0.0, 1.0);
+
+        XCTAssertTrue(result ~= expectedResult);
+    }
+
+
+    func testTransformationMatrixMultiplication() {
+        let somePoint = Vector4(2.0, 2.0, 2.0, 1.0);
+        let zAxisTransformationMaxtrix90Positive = Matrix4(0.0, 1.0, 0.0, 0.0,
+            -1.0, 0.0, 0.0, 0.0,
+            0.0, 0.0, 0.0, 0.0,
+            0.0, 0.0, 0.0, 1.0);
+        let yAxisTransformationMaxtrix90Positive = Matrix4(0.0, 0.0, 1.0, 0.0,
+            0.0, 1.0, 0.0, 0.0,
+            -1.0, 0.0, 0.0, 0.0,
+            0.0, 0.0, 0.0, 1.0);
+        let xAxisTransformationMaxtrix90Positive = Matrix4(1.0, 0.0, 0.0, 0.0,
+            0.0, 0.0, -1.0, 0.0,
+            0.0, 1.0, 0.0, 0.0,
+            0.0, 0.0, 0.0, 1.0);
+
+        let resultPoint = (xAxisTransformationMaxtrix90Positive * (yAxisTransformationMaxtrix90Positive * (zAxisTransformationMaxtrix90Positive * somePoint)));
+
+        let comparePoint = (xAxisTransformationMaxtrix90Positive * yAxisTransformationMaxtrix90Positive * zAxisTransformationMaxtrix90Positive) * somePoint;
+
+        XCTAssertTrue(resultPoint ~= comparePoint);
+    }
 }
 
 class QuaternionTests: XCTestCase {

diff --git a/VectorMath/VectorMath.swift b/VectorMath/VectorMath.swift
@@ -527,7 +527,7 @@ func *(lhs: Vector4, rhs: Matrix4) -> Vector4 {
         lhs.x * rhs.m11 + lhs.y * rhs.m21 + lhs.z * rhs.m31 + lhs.w * rhs.m41,
         lhs.x * rhs.m12 + lhs.y * rhs.m22 + lhs.z * rhs.m32 + lhs.w * rhs.m42,
         lhs.x * rhs.m13 + lhs.y * rhs.m23 + lhs.z * rhs.m33 + lhs.w * rhs.m43,
-        lhs.x * rhs.m14 + lhs.y * rhs.m24 + lhs.z * rhs.m34 + lhs.w * rhs.m43
+        lhs.x * rhs.m14 + lhs.y * rhs.m24 + lhs.z * rhs.m34 + lhs.w * rhs.m44
     )
 }