/*
* Copyright (C) 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.android.apps.santatracker.doodles.tilt;
import android.graphics.Canvas;
import com.google.android.apps.santatracker.doodles.shared.Actor;
import com.google.android.apps.santatracker.doodles.shared.Vector2D;
import com.google.android.apps.santatracker.doodles.shared.physics.Polygon;
import org.json.JSONException;
import org.json.JSONObject;
/**
* An actor which represents an object in the world which causes some reaction when it is collided
* with.
*/
public class CollisionActor extends Actor implements Touchable {
public static final String TYPE = "collision";
protected static final String POLYGON_KEY = "polygon";
// These measurements are in "world units", which are really just arbitrary units where one world
// unit == one pixel at the default camera zoom level.
public static final float DEFAULT_WIDTH = 200;
public static final float DEFAULT_HEIGHT = 200;
public Polygon collisionBody;
protected int selectedIndex = -1;
protected int midpointIndex = -1;
public CollisionActor(Polygon collisionBody) {
super(Vector2D.get(collisionBody.min.x, collisionBody.min.y), Vector2D.get());
this.collisionBody = collisionBody;
restitution = 0.7f;
inverseMass = Actor.INFINITE_MASS; // Give collision actors infinite mass.
zIndex = 10;
}
@Override
public void update(float deltaMs) {
positionBeforeFrame.set(position);
float deltaX = velocity.x * deltaMs / 1000.0f;
float deltaY = velocity.y * deltaMs / 1000.0f;
collisionBody.move(deltaX, deltaY);
position.set(collisionBody.min);
}
@Override
public boolean canHandleTouchAt(Vector2D worldCoords, float cameraScale) {
return collisionBody.getSelectedIndex(worldCoords, cameraScale) >= 0
|| collisionBody.getMidpointIndex(worldCoords, cameraScale) >= 0;
}
@Override
public void startTouchAt(Vector2D worldCoords, float cameraScale) {
selectedIndex = collisionBody.getSelectedIndex(worldCoords, cameraScale);
midpointIndex = collisionBody.getMidpointIndex(worldCoords, cameraScale);
}
@Override
public boolean handleMoveEvent(Vector2D delta) {
if (selectedIndex >= 0) {
Vector2D positionDelta = Vector2D.get(delta).scale(-1);
collisionBody.moveVertex(selectedIndex, positionDelta);
positionDelta.release();
return true;
}
return false;
}
@Override
public boolean handleLongPress() {
if (selectedIndex >= 0) {
if (canRemoveCollisionVertex()) {
// If we can, just remove the vertex.
collisionBody.removeVertexAt(selectedIndex);
return true;
}
} else if (midpointIndex >= 0) {
// Long press on a midpoint, add a vertex to the selected obstacle's polygon.
collisionBody.addVertexAfter(midpointIndex);
return true;
}
return false;
}
@Override
public String getType() {
return CollisionActor.TYPE;
}
@Override
public JSONObject toJSON() throws JSONException {
JSONObject json = new JSONObject();
json.put(TYPE_KEY, getType());
json.put(POLYGON_KEY, collisionBody.toJSON());
return json;
}
/**
* Resolve a collision with another physics actor.
*
* @param other The actor being collided with.
* @param deltaMs The length of the collision frame.
* @return true if resolving the collision moves the other actor, false otherwise.
*/
public boolean resolveCollision(Actor other, float deltaMs) {
return false;
}
public void draw(Canvas canvas) {
collisionBody.draw(canvas);
}
public boolean canRemoveCollisionVertex() {
return collisionBody.vertices.size() > 3;
}
public static CollisionActor fromJSON(JSONObject json) throws JSONException {
return new CollisionActor(Polygon.fromJSON(json.getJSONArray(POLYGON_KEY)));
}
}