many things

core/src/mindustry/entities/bullet/BulletType.java

@@ -24,7 +24,7 @@ public abstract class BulletType extends Content{
     public float hitSize = 4;
     public float drawSize = 40f;
     public float drag = 0f;
-    public boolean pierce;
+    public boolean pierce, pierceBuilding;
     public Effect hitEffect, despawnEffect;
 
     /** Effect created when shooting. */
@@ -69,6 +69,8 @@ public abstract class BulletType extends Content{
     public boolean scaleVelocity;
     /** Whether this bullet can be hit by point defense. */
     public boolean hittable = true;
+    /** Whether this bullet can be reflected. */
+    public boolean reflectable = false;
 
     //additional effects
 
@@ -131,10 +133,14 @@ public abstract class BulletType extends Content{
         return true;
     }
 
-    public void hitTile(Bullet b, Building tile){
+    public void hitTile(Bullet b, Building tile, float initialHealth){
         hit(b);
     }
 
+    public void hitEntity(Bullet b, Hitboxc other, float initialHealth){
+
+    }
+
     public void hit(Bullet b){
         hit(b, b.x, b.y);
     }

core/src/mindustry/entities/bullet/HealBulletType.java

@@ -43,7 +43,7 @@ public class HealBulletType extends BulletType{
     }
 
     @Override
-    public void hitTile(Bullet b, Building tile){
+    public void hitTile(Bullet b, Building tile, float initialHealth){
         super.hit(b);
 
         if(tile.team == b.team && !(tile.block instanceof ConstructBlock)){

core/src/mindustry/entities/bullet/RailBulletType.java

@@ -0,0 +1,52 @@
+package mindustry.entities.bullet;
+
+import mindustry.content.*;
+import mindustry.entities.*;
+import mindustry.gen.*;
+
+public class RailBulletType extends BulletType{
+    public Effect pierceEffect = Fx.hitBulletSmall, updateEffect = Fx.none;
+    /** Multiplier of damage decreased per health pierced. */
+    public float pierceDamageFactor = 1f;
+
+    public RailBulletType(){
+        pierceBuilding = true;
+        pierce = true;
+        reflectable = false;
+        hitEffect = Fx.none;
+        despawnEffect = Fx.none;
+    }
+
+    void handle(Bullet b, Posc pos, float initialHealth){
+        float sub = initialHealth*pierceDamageFactor;
+
+        if(sub >= b.damage){
+            //cause a despawn
+            b.remove();
+        }
+
+        //subtract health from each consecutive pierce
+        b.damage -= Math.min(b.damage, sub);
+
+        if(b.damage > 0){
+            pierceEffect.at(pos.getX(), pos.getY(), b.rotation());
+        }
+
+        hitEffect.at(pos.getX(), pos.getY());
+    }
+
+    @Override
+    public void update(Bullet b){
+        updateEffect.at(b.x, b.y, b.rotation());
+    }
+
+    @Override
+    public void hitEntity(Bullet b, Hitboxc entity, float initialHealth){
+        handle(b, entity, initialHealth);
+    }
+
+    @Override
+    public void hitTile(Bullet b, Building tile, float initialHealth){
+        handle(b, tile, initialHealth);
+    }
+}