Added rotation on the z axis

src/engine/math/Matrix4f.java

@@ -78,6 +78,21 @@ public class Matrix4f {
         return result;
     }
 
+    public static Matrix4f rotateZ(float angle){
+        Matrix4f result = identity();
+        float r = (float) Math.toRadians(angle);
+        float cos = (float) Math.cos(angle);
+        float sin = (float) Math.sin(angle);
+
+        result.elements[0 + 0 * 4] = cos;
+        result.elements[1 + 0 * 4] = -sin;
+
+        result.elements[0 + 1 * 4] = sin;
+        result.elements[2 + 1 * 4] = cos;
+
+        return result;
+    }
+
     public Matrix4f multiply(Matrix4f matrix){
         Matrix4f result = new Matrix4f();
         for (int y = 0; y< 4; y++){