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RayCast example
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‎examples/box2d_EdgeShapes/box2d_EdgeShapes.java‎

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/**
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*
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* LiquidFunProcessing | Copyright 2017 Thomas Diewald - www.thomasdiewald.com
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*
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* https://github.com/diwi/LiquidFunProcessing.git
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*
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* Box2d / LiquidFun Library for Processing.
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* MIT License: https://opensource.org/licenses/MIT
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*
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*/
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package box2d_EdgeShapes;
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import com.thomasdiewald.liquidfun.java.DwWorld;
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import org.jbox2d.callbacks.RayCastCallback;
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import org.jbox2d.collision.shapes.CircleShape;
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import org.jbox2d.collision.shapes.EdgeShape;
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import org.jbox2d.collision.shapes.PolygonShape;
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import org.jbox2d.common.Color3f;
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import org.jbox2d.common.MathUtils;
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import org.jbox2d.common.Vec2;
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import org.jbox2d.dynamics.Body;
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import org.jbox2d.dynamics.BodyDef;
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import org.jbox2d.dynamics.BodyType;
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import org.jbox2d.dynamics.Fixture;
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import org.jbox2d.dynamics.FixtureDef;
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import processing.core.*;
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import processing.opengl.PGraphics2D;
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public class box2d_EdgeShapes extends PApplet {
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// Example to demonstrate how to use the RayCastCallback
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int viewport_w = 1280;
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int viewport_h = 720;
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int viewport_x = 230;
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int viewport_y = 0;
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boolean UPDATE_PHYSICS = true;
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boolean USE_DEBUG_DRAW = false;
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DwWorld world;
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public void settings(){
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size(viewport_w, viewport_h, P2D);
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smooth(8);
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}
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public void setup(){
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surface.setLocation(viewport_x, viewport_y);
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reset();
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frameRate(120);
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}
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public void release(){
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if(world != null) world.release(); world = null;
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}
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public void reset(){
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// release old resources
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release();
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world = new DwWorld(this, 25);
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world.transform.setCamera(0, 10, 25);
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// create scene: rigid bodies, particles, etc ...
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initScene();
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}
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int id = 0;
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public void draw(){
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// create a new body every second
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if((frameCount%120) == 0){
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Create(id++%5);
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}
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if(UPDATE_PHYSICS){
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world.update();
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}
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PGraphics2D canvas = (PGraphics2D) this.g;
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canvas.background(32);
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canvas.pushMatrix();
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world.applyTransform(canvas);
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world.drawBulletSpawnTrack(canvas);
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if(USE_DEBUG_DRAW){
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world.displayDebugDraw(canvas);
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// DwDebugDraw.display(canvas, world);
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} else {
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world.display(canvas);
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}
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step();
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canvas.popMatrix();
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// info
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int num_bodies = world.getBodyCount();
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int num_particles = world.getParticleCount();
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String txt_fps = String.format(getClass().getName()+ " [bodies: %d] [particles: %d] [fps %6.2f]", num_bodies, num_particles, frameRate);
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surface.setTitle(txt_fps);
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}
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//////////////////////////////////////////////////////////////////////////////
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// User Interaction
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//////////////////////////////////////////////////////////////////////////////
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public void keyReleased(){
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if(key == 't') UPDATE_PHYSICS = !UPDATE_PHYSICS;
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if(key == 'r') reset();
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if(key == 'f') USE_DEBUG_DRAW = !USE_DEBUG_DRAW;
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if(key >= '1' && key <= '5') Create(key-'1');
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}
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//////////////////////////////////////////////////////////////////////////////
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// Scene Setup
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//////////////////////////////////////////////////////////////////////////////
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int e_maxBodies = 256;
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int m_bodyIndex;
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Body m_bodies[] = new Body[e_maxBodies];
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PolygonShape m_polygons[] = new PolygonShape[4];
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CircleShape m_circle;
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float m_angle;
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// https://github.com/jbox2d/jbox2d/blob/master/jbox2d-testbed/src/main/java/org/jbox2d/testbed/tests/EdgeShapes.java
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public void initScene() {
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for (int i = 0; i < m_bodies.length; i++) {
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m_bodies[i] = null;
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}
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// Ground body
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{
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BodyDef bd = new BodyDef();
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Body ground = world.createBody(bd);
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float x1 = -20.0f;
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float y1 = 2.0f * MathUtils.cos(x1 / 10.0f * MathUtils.PI);
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for (int i = 0; i < 80; ++i) {
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float x2 = x1 + 0.5f;
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float y2 = 2.0f * MathUtils.cos(x2 / 10.0f * MathUtils.PI);
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EdgeShape shape = new EdgeShape();
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shape.set(new Vec2(x1, y1), new Vec2(x2, y2));
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ground.createFixture(shape, 0.0f);
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x1 = x2;
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y1 = y2;
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}
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world.bodies.add(ground, false, color(0), true, color(255,255,0), 1f);
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}
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{
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Vec2 vertices[] = new Vec2[3];
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vertices[0] = new Vec2(-0.5f, 0.0f);
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vertices[1] = new Vec2(0.5f, 0.0f);
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vertices[2] = new Vec2(0.0f, 1.5f);
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m_polygons[0] = new PolygonShape();
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m_polygons[0].set(vertices, 3);
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}
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{
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Vec2 vertices[] = new Vec2[3];
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vertices[0] = new Vec2(-0.1f, 0.0f);
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vertices[1] = new Vec2(0.1f, 0.0f);
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vertices[2] = new Vec2(0.0f, 1.5f);
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m_polygons[1] = new PolygonShape();
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m_polygons[1].set(vertices, 3);
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}
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{
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float w = 1.0f;
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float b = w / (2.0f + MathUtils.sqrt(2.0f));
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float s = MathUtils.sqrt(2.0f) * b;
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Vec2 vertices[] = new Vec2[8];
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vertices[0] = new Vec2(0.5f * s, 0.0f);
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vertices[1] = new Vec2(0.5f * w, b);
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vertices[2] = new Vec2(0.5f * w, b + s);
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vertices[3] = new Vec2(0.5f * s, w);
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vertices[4] = new Vec2(-0.5f * s, w);
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vertices[5] = new Vec2(-0.5f * w, b + s);
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vertices[6] = new Vec2(-0.5f * w, b);
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vertices[7] = new Vec2(-0.5f * s, 0.0f);
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m_polygons[2] = new PolygonShape();
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m_polygons[2].set(vertices, 8);
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}
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{
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m_polygons[3] = new PolygonShape();
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m_polygons[3].setAsBox(0.5f, 0.5f);
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}
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{
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m_circle = new CircleShape();
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m_circle.m_radius = 0.5f;
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}
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m_bodyIndex = 0;
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m_angle = 0.0f;
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}
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void Create(int index) {
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if (m_bodies[m_bodyIndex] != null) {
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world.destroyBody(m_bodies[m_bodyIndex]);
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m_bodies[m_bodyIndex] = null;
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}
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BodyDef bd = new BodyDef();
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float x = MathUtils.randomFloat(-10.0f, 10.0f);
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float y = MathUtils.randomFloat(10.0f, 20.0f);
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bd.position.set(x, y);
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bd.angle = MathUtils.randomFloat(-MathUtils.PI, MathUtils.PI);
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bd.type = BodyType.DYNAMIC;
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if (index == 4) {
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bd.angularDamping = 0.02f;
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}
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m_bodies[m_bodyIndex] = world.createBody(bd);
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if (index < 4) {
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FixtureDef fd = new FixtureDef();
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fd.shape = m_polygons[index];
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fd.friction = 0.3f;
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fd.density = 20.0f;
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m_bodies[m_bodyIndex].createFixture(fd);
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} else {
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FixtureDef fd = new FixtureDef();
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fd.shape = m_circle;
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fd.friction = 0.3f;
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fd.density = 20.0f;
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m_bodies[m_bodyIndex].createFixture(fd);
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}
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world.bodies.add(m_bodies[m_bodyIndex], true, color(255,0,0), true, color(0), 1f);
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m_bodyIndex = (m_bodyIndex + 1) % e_maxBodies;
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}
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EdgeShapesCallback callback = new EdgeShapesCallback();
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public void step(){
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m_angle += 0.25f * PI / 180.0f;
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float radius = 25.0f;
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Vec2 point1 = new Vec2(0.0f, 10.0f);
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Vec2 p1p2 = new Vec2(radius * cos(m_angle), -radius * abs(sin(m_angle)));
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Vec2 point2 = point1.add(p1p2);
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callback.m_fixture = null;
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world.raycast(callback, point1, point2);
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if (callback.m_fixture != null) {
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world.debug_draw.drawPoint(callback.m_point, 5.0f/world.transform.screen_scale, new Color3f(0.4f, 0.9f, 0.4f));
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world.debug_draw.drawSegment(point1, callback.m_point, new Color3f(0.8f, 0.8f, 0.8f));
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Vec2 head = callback.m_normal.mul(.5f).addLocal(callback.m_point);
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world.debug_draw.drawSegment(callback.m_point, head, new Color3f(0.9f, 0.9f, 0.4f));
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} else {
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world.debug_draw.drawSegment(point1, point2, new Color3f(0.8f, 0.8f, 0.8f));
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}
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}
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static class EdgeShapesCallback implements RayCastCallback {
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Fixture m_fixture = null;
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Vec2 m_point;
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Vec2 m_normal;
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public float reportFixture(Fixture fixture, final Vec2 point, final Vec2 normal, float fraction) {
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m_fixture = fixture;
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m_point = point;
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m_normal = normal;
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return fraction;
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}
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}
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public static void main(String args[]) {
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PApplet.main(new String[] { box2d_EdgeShapes.class.getName() });
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}
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}

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