SPIGOT-5553, #1336: Add EntityKnockbackEvent

By: Jishuna <joshl5324@gmail.com>

paper-server/nms-patches/net/minecraft/world/level/Explosion.patch

@@ -96,7 +96,22 @@
                          }
  
                          double d12 = (1.0D - d7) * (double) getSeenPercent(vec3d, entity);
-@@ -287,9 +337,63 @@
+@@ -247,6 +297,14 @@
+                         d10 *= d13;
+                         Vec3D vec3d1 = new Vec3D(d8, d9, d10);
+ 
++                        // CraftBukkit start - Call EntityKnockbackEvent
++                        if (entity instanceof EntityLiving) {
++                            Vec3D result = entity.getDeltaMovement().add(vec3d1);
++                            org.bukkit.event.entity.EntityKnockbackEvent event = CraftEventFactory.callEntityKnockbackEvent((org.bukkit.craftbukkit.entity.CraftLivingEntity) entity.getBukkitEntity(), source, org.bukkit.event.entity.EntityKnockbackEvent.KnockbackCause.EXPLOSION, d13, vec3d1, result.x, result.y, result.z);
++
++                            vec3d1 = (event.isCancelled()) ? Vec3D.ZERO : new Vec3D(event.getFinalKnockback().getX(), event.getFinalKnockback().getY(), event.getFinalKnockback().getZ());
++                        }
++                        // CraftBukkit end
+                         entity.setDeltaMovement(entity.getDeltaMovement().add(vec3d1));
+                         if (entity instanceof EntityHuman) {
+                             EntityHuman entityhuman = (EntityHuman) entity;
+@@ -287,9 +345,63 @@
  
              SystemUtils.shuffle(this.toBlow, this.level.random);
              ObjectListIterator objectlistiterator = this.toBlow.iterator();
@@ -160,7 +175,7 @@
  
                  this.level.getBlockState(blockposition).onExplosionHit(this.level, blockposition, this, (itemstack, blockposition1) -> {
                      addOrAppendStack(list, itemstack, blockposition1);
-@@ -314,7 +418,11 @@
+@@ -314,7 +426,11 @@
                  BlockPosition blockposition1 = (BlockPosition) objectlistiterator1.next();
  
                  if (this.random.nextInt(3) == 0 && this.level.getBlockState(blockposition1).isAir() && this.level.getBlockState(blockposition1.below()).isSolidRender(this.level, blockposition1.below())) {
@@ -173,7 +188,7 @@
                  }
              }
          }
-@@ -322,6 +430,7 @@
+@@ -322,6 +438,7 @@
      }
  
      private static void addOrAppendStack(List<Pair<ItemStack, BlockPosition>> list, ItemStack itemstack, BlockPosition blockposition) {