Allow flipped shot patterns

core/src/mindustry/entities/pattern/ShootBarrel.java

@@ -6,6 +6,14 @@ public class ShootBarrel extends ShootPattern{
     /** offset of barrel to start on */
     public int barrelOffset = 0;
 
+    @Override
+    public void flip(){
+        barrels = barrels.clone();
+        for(int i = 0; i < barrels.length; i += 3){
+            barrels[i] *= -1;
+        }
+    }
+
     @Override
     public void shoot(int totalShots, BulletHandler handler){
         for(int i = 0; i < shots; i++){

core/src/mindustry/entities/pattern/ShootMulti.java

@@ -12,6 +12,18 @@ public class ShootMulti extends ShootPattern{
     public ShootMulti(){
     }
 
+    //deep copy needed for flips
+    @Override
+    public void flip(){
+        source = source.copy();
+        source.flip();
+        dest = dest.clone();
+        for(int i = 0; i < dest.length; i++){
+            dest[i] = dest[i].copy();
+            dest[i].flip();
+        }
+    }
+
     @Override
     public void shoot(int totalShots, BulletHandler handler){
         source.shoot(totalShots, (x, y, rotation, delay, move) -> {

core/src/mindustry/entities/pattern/ShootPattern.java

@@ -3,7 +3,7 @@ package mindustry.entities.pattern;
 import mindustry.entities.*;
 
 /** Handles different types of bullet patterns for shooting. */
-public class ShootPattern{
+public class ShootPattern implements Cloneable{
     /** amount of shots per "trigger pull" */
     public int shots = 1;
     /** delay in ticks before first shot */
@@ -18,6 +18,19 @@ public class ShootPattern{
         }
     }
 
+    /** Subclasses should override this to flip its sides. */
+    public void flip(){
+
+    }
+
+    public ShootPattern copy(){
+        try{
+            return (ShootPattern)clone();
+        }catch(CloneNotSupportedException absurd){
+            throw new RuntimeException("impending doom", absurd);
+        }
+    }
+
     public interface BulletHandler{
         /**
          * @param x x offset of bullet, should be transformed by weapon rotation