shooting works

src/main/java/core/Master.java

@@ -3,6 +3,7 @@ package core;
 import objects.DebugPos;
 import objects.ships.BattleShip;
 import objects.GameObject;
+import objects.ships.Turret;
 import objects.world.Grid;
 
 import javax.swing.*;
@@ -38,9 +39,9 @@ public class Master extends JPanel {
 
         BattleShip battleShip = new BattleShip(Color.DARK_GRAY);
         BattleShip bs = new BattleShip(70, 10, 5, 80, Color.GREEN);
-        /*for (int i = 0; i < 10; i++) {
+        for (int i = 0; i < 10; i++) {
             bs.addTurret(new Turret(bs, 25, 10 * i + 1, 50, i % 5));
-        }*/
+        }
         objects.add(bs);
         objects.add(battleShip);
     }

src/main/java/core/Vector2D.java

@@ -1,5 +1,6 @@
 package core;
 
+
 /**
  * A 2-dimensional Vector that can be used to store position or velocity
  */
@@ -45,7 +46,7 @@ public class Vector2D {
     }
 
     /**
-     * Mulitply this vector with a simple scalar, modifies this object
+     * Multiply this vector with a simple scalar, modifies this object
      *
      * @param a The scalar
      * @return this after the multiplication
@@ -111,6 +112,9 @@ public class Vector2D {
 
     /**
      * Rotate a point around another point
+     *
+     * This method can now be trusted
+     *
      * @param center The center of the rotation
      * @param value The point to be rotated, absolut to the center
      * @param rotation The rotation angle in radians
@@ -121,12 +125,18 @@ public class Vector2D {
 
         Vector2D dif = Vector2D.subtract(value, center);
 
-        double rotatedX = Math.cos(rotation * rotationDirection) * dif.x;
+        rotation = rotationDirection * rotation;
-        double rotatedY = Math.sin(rotation * rotationDirection) * dif.x;
+
+        double rotatedX = dif.x * Math.cos(rotation) - dif.y * Math.sin(rotation);
+        double rotatedY = dif.x * Math.sin(rotation) + dif.y * Math.cos(rotation);
 
         return new Vector2D(rotatedX + center.x, rotatedY + center.y);
     }
 
+    /**
+     * Copy this object
+     * @return A copy of this object
+     */
     public Vector2D copy(){
         return new Vector2D(x, y);
     }

src/main/java/objects/DebugPos.java

@@ -17,7 +17,7 @@ public class DebugPos extends GameObject {
     @Override
     public void draw(Graphics2D g2d, int w, Master master) {
         g2d.setPaint(Color.green);
-        g2d.drawOval((int) (position.x + size.x / 2), (int) (position.y + size.y / 2), (int) size.x, (int) size.y);
+        g2d.drawOval((int) (position.x - size.x / 2), (int) (position.y - size.y / 2), (int) size.x, (int) size.y);
     }
 
     @Override

src/main/java/objects/ships/BattleShip.java

@@ -17,9 +17,9 @@ public class BattleShip extends GameObject {
     public BattleShip(Color mainColor) {
         super(20, 20, 5, 40);
         turrets = new ArrayList<>();
-        turrets.add(new Turret(this, 25, 25, 50, 1));
+        turrets.add(new Turret(this, 25, 25, 50, 3));
-        //turrets.add(new Turret(this, 25, 10, 50, 2));
+        turrets.add(new Turret(this, 25, 10, 50, 2));
-        //turrets.add(new Turret(this, 25, 70, 50, 2));
+        turrets.add(new Turret(this, 25, 70, 50, 2));
         this.mainColor = mainColor;
     }
 

src/main/java/objects/ships/Turret.java

@@ -92,9 +92,7 @@ public class Turret extends GameObject {
                 lastShot = System.currentTimeMillis();
 
                 Vector2D shellVel = new Vector2D(xCenterAbs - msLoc.x, yCenterAbs - msLoc.y).normalized().negative().multiply(SHELL_SPEED);
-                Vector2D pos = Vector2D.rotateAround(new Vector2D(xCenterAbs, yCenterAbs), new Vector2D(barrelX, frontPosY), rotation, Vector2D.CLOCKWISE);
+                Vector2D pos = Vector2D.rotateAround(new Vector2D(xCenterAbs, yCenterAbs), new Vector2D(barrelX, frontPosY), rotation, Vector2D.COUNTERCLOCKWISE);
-
-                master.debugPos(pos);
 
                 master.create(new Shell(pos, new Vector2D(10, 10), shellVel));
             }

src/test/java/core/Vector2DTest.java

@@ -41,20 +41,33 @@ class Vector2DTest {
     }
 
     @Test
-    void rotateAroundTest(){
+    void rotateAroundTestSimple(){
         Vector2D cent = new Vector2D(0, 0);
         Vector2D a = new Vector2D(1, 0);
-        Vector2D exceptedA = new Vector2D(6.123233995736766E-17 ,-1); //floating point precision probably
+        Vector2D excepted = new Vector2D(0 ,-1); //floating point precision probably
-
-        Vector2D centB = new Vector2D(1, 1);
-        Vector2D b = new Vector2D(2, 1);
-        Vector2D exceptedB = new Vector2D(1 ,2);
-
-
         Vector2D rotated = Vector2D.rotateAround(cent, a, Math.toRadians(90), Vector2D.CLOCKWISE);
-        Vector2D rotatedb = Vector2D.rotateAround(centB, b, Math.toRadians(90), Vector2D.COUNTERCLOCKWISE);
+        assertEquals(round(excepted), round(rotated));
+    }
 
-        assertEquals(exceptedA, rotated);
+    @Test
-        assertEquals(exceptedB, rotatedb);
+    void rotateAroundTestMovedCenter(){
+        Vector2D cent = new Vector2D(1, 1);
+        Vector2D a = new Vector2D(2, 1);
+        Vector2D excepted = new Vector2D(1 ,2);
+        Vector2D rotated = Vector2D.rotateAround(cent, a, Math.toRadians(90), Vector2D.COUNTERCLOCKWISE);
+        assertEquals(round(excepted), round(rotated));
+    }
+
+    @Test
+    void rotateAroundTestExact(){
+        Vector2D cent = new Vector2D();
+        Vector2D a = new Vector2D(5, 6);
+        Vector2D rotated = Vector2D.rotateAround(cent, a, Math.toRadians(120), Vector2D.COUNTERCLOCKWISE);
+        Vector2D expected = new Vector2D(-7.6962, 1.3301);
+        assertEquals(round(expected), round(rotated));
+    }
+
+    public static Vector2D round(Vector2D a){
+        return new Vector2D(Math.round(a.x*10000d)/10000d, Math.round(a.y*10000d)/10000d);
     }
 }