From 2e5e21102ea5b1a7f5b3c77126f891b657eb8434 Mon Sep 17 00:00:00 2001
From: pacien
Date: Sat, 3 Feb 2018 15:51:18 +0100
Subject: Implement explosion blast handling

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 .../fr/umlv/java/wallj/block/GarbageBlock.java     | 32 ++++++++++++++++++++++
 .../java/fr/umlv/java/wallj/block/JBoxBlock.java   | 10 ++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/src/main/java/fr/umlv/java/wallj/block/GarbageBlock.java b/src/main/java/fr/umlv/java/wallj/block/GarbageBlock.java
index a8635ec..9338888 100644
--- a/src/main/java/fr/umlv/java/wallj/block/GarbageBlock.java
+++ b/src/main/java/fr/umlv/java/wallj/block/GarbageBlock.java
@@ -3,13 +3,18 @@ package fr.umlv.java.wallj.block;
 import fr.umlv.java.wallj.board.TileVec2;
 import fr.umlv.java.wallj.context.Context;
 import fr.umlv.java.wallj.context.GraphicsContext;
+import fr.umlv.java.wallj.event.BombExplosionEvent;
 import fr.umlv.java.wallj.event.Event;
+import fr.umlv.java.wallj.event.Events;
 import org.jbox2d.common.Vec2;
 import org.jbox2d.dynamics.BodyType;
+import org.jbox2d.dynamics.Fixture;
+import org.jbox2d.dynamics.World;
 
 import java.awt.*;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * A garbage block.
@@ -18,6 +23,8 @@ import java.util.List;
  */
 public class GarbageBlock extends JBoxBlock {
   private static final Color COLOR = new Color(102, 51, 0);
+  private static final int STOP_RAYCAST = 0;
+  private static final float EXPLOSION_RANGE = 20f * TileVec2.TILE_DIM;
 
   GarbageBlock(Vec2 pos) {
     super(BlockType.GARBAGE, BodyType.DYNAMIC, SolidDef.circleShape(), pos);
@@ -25,11 +32,36 @@ public class GarbageBlock extends JBoxBlock {
 
   @Override
   public List<Event> update(Context context) {
+    handleExplosionBlasts(context.getEvents(), context.getGame().getCurrentStage().getWorld());
     paint(context.getGraphicsContext());
     return Collections.emptyList();
   }
 
+  private void handleExplosionBlasts(List<Event> events, World world) {
+    Events.filter(events, BombExplosionEvent.class).forEach(explosion -> {
+      Vec2 source = explosion.getSource().toVec2();
+      world.raycast((fixture, point, normal, fraction) -> {
+        if (isSelf(fixture)) getBody().applyForceToCenter(computeBlastForce(source));
+        return STOP_RAYCAST;
+      }, source, getPos());
+    });
+  }
+
   private void paint(GraphicsContext graphicsContext) {
     graphicsContext.paintCircle(COLOR, getPos(), TileVec2.TILE_DIM);
   }
+
+  private boolean isSelf(Fixture fixture) {
+    for (Fixture self = getBody().getFixtureList(); self != null; self = self.getNext())
+      if (Objects.equals(fixture, self))
+        return true;
+
+    return false;
+  }
+
+  private Vec2 computeBlastForce(Vec2 source) {
+    Vec2 diff = getPos().sub(source);
+    float dist = diff.normalize();
+    return diff.mul(EXPLOSION_RANGE / dist);
+  }
 }
diff --git a/src/main/java/fr/umlv/java/wallj/block/JBoxBlock.java b/src/main/java/fr/umlv/java/wallj/block/JBoxBlock.java
index f0f2834..e01f4b0 100644
--- a/src/main/java/fr/umlv/java/wallj/block/JBoxBlock.java
+++ b/src/main/java/fr/umlv/java/wallj/block/JBoxBlock.java
@@ -20,6 +20,13 @@ public abstract class JBoxBlock extends Block {
     fixtureDef = SolidDef.fixtureDefOf(Objects.requireNonNull(bodyShape));
   }
 
+  /**
+   * @return the JBox2D body
+   */
+  public Body getBody() {
+    return body;
+  }
+
   @Override
   public Vec2 getPos() {
     if (body == null) throw new IllegalStateException("Uninitialised block.");
@@ -30,8 +37,9 @@ public abstract class JBoxBlock extends Block {
   public void link(World world) {
     if (body != null) throw new IllegalStateException("Block is already linked.");
     body = world.createBody(bodyDef);
-    body.createFixture(fixtureDef);
     body.setUserData(this);
+    Fixture fixture = body.createFixture(fixtureDef);
+    fixture.setUserData(body);
   }
 
   @Override
-- 
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