我一直在使用用户Andrew Thompson提供的以下示例 - ＆gt; Collision detection with complex shapes
我试图在方法'draw'中的程序（下面的代码）中实现这个，但由于某种原因，将方块的颜色更改为“Red”的语句永远不会被评估为true，我无法理解为什么;我已经尝试了几乎所有的东西，但缺乏安德鲁的进一步帮助我似乎无法正确实现这个代码的进展，以便当三角形的三角形接触广场时，方块将颜色变为红色。
非常感谢任何和所有帮助（下面的代码）：
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.geom.*;
import static java.lang.Math.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
import javax.swing.Timer;
public class Boids extends JPanel {
Flock flock;
Flock flock2;
final int w, h;
public Boids() {
w = 1200;
h = 600;
setPreferredSize(new Dimension(w, h));
setBackground(Color.black);
spawnFlock();
new Timer(17, (ActionEvent e) -> {
if (flock.hasLeftTheBuilding(w))
spawnFlock();
repaint();
}).start();
}
public void spawnFlock() {
Random rand = new Random();
int n = rand.nextInt(599) + 1;
flock = Flock.spawn(100, h - n, 20);
}
@Override
public void paintComponent(Graphics gg) {
super.paintComponent(gg);
Graphics2D g = (Graphics2D) gg;
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
flock.run(g, w, h);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setTitle("Simulator v0.6");
f.setResizable(false);
f.add(new Boids(), BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
});
}
}
class Boid {
static final Random r = new Random();
static final Vec migrate = new Vec(0.02, 0);
static final int size = 3;
final double maxForce, maxSpeed;
Vec location, velocity, acceleration;
private boolean included = true;
Boid(double x, double y) {
acceleration = new Vec();
velocity = new Vec(r.nextInt(3) + 1, r.nextInt(3) - 1);
location = new Vec(x, y);
maxSpeed = 3.0;
maxForce = 0.05;
}
void update() {
velocity.add(acceleration);
velocity.limit(maxSpeed);
location.add(velocity);
acceleration.mult(0);
}
void applyForce(Vec force) {
acceleration.add(force);
}
Vec seek(Vec target) {
Vec steer = Vec.sub(target, location);
steer.normalize();
steer.mult(maxSpeed);
steer.sub(velocity);
steer.limit(maxForce);
return steer;
}
void flock(Graphics2D g, List<Boid> boids) {
view(g, boids);
Vec rule1 = separation(boids);
Vec rule2 = alignment(boids);
Vec rule3 = cohesion(boids);
rule1.mult(2.5);
rule2.mult(1.5);
rule3.mult(1.3);
applyForce(rule1);
applyForce(rule2);
applyForce(rule3);
applyForce(migrate);
}
public boolean doAreasCollide(Area area1, Area area2) {
boolean collide = false;
Area collide1 = new Area(area1);
collide1.subtract(area2);
if (!collide1.equals(area1)) {
collide = true;
}
Area collide2 = new Area(area2);
collide2.subtract(area1);
if (!collide2.equals(area2)) {
collide = true;
}
return collide;
}
void view(Graphics2D g, List<Boid> boids) {
double sightDistance = 100;
double peripheryAngle = PI * 0.85;
for (Boid b : boids) {
b.included = false;
if (b == this)
continue;
double d = Vec.dist(location, b.location);
if (d <= 0 || d > sightDistance)
continue;
Vec lineOfSight = Vec.sub(b.location, location);
double angle = Vec.angleBetween(lineOfSight, velocity);
if (angle < peripheryAngle)
b.included = true;
}
}
Vec separation(List<Boid> boids) {
double desiredSeparation = 25;
Vec steer = new Vec(0, 0);
int count = 0;
for (Boid b : boids) {
if (!b.included)
continue;
double d = Vec.dist(location, b.location);
if ((d > 0) && (d < desiredSeparation)) {
Vec diff = Vec.sub(location, b.location);
diff.normalize();
diff.div(d); // weight by distance
steer.add(diff);
count++;
}
}
if (count > 0) {
steer.div(count);
}
if (steer.mag() > 0) {
steer.normalize();
steer.mult(maxSpeed);
steer.sub(velocity);
steer.limit(maxForce);
return steer;
}
return new Vec(0, 0);
}
Vec alignment(List<Boid> boids) {
double preferredDist = 50;
Vec steer = new Vec(0, 0);
int count = 0;
for (Boid b : boids) {
if (!b.included)
continue;
double d = Vec.dist(location, b.location);
if ((d > 0) && (d < preferredDist)) {
steer.add(b.velocity);
count++;
}
}
if (count > 0) {
steer.div(count);
steer.normalize();
steer.mult(maxSpeed);
steer.sub(velocity);
steer.limit(maxForce);
}
return steer;
}
Vec cohesion(List<Boid> boids) {
double preferredDist = 50;
Vec target = new Vec(0, 0);
int count = 0;
for (Boid b : boids) {
if (!b.included)
continue;
double d = Vec.dist(location, b.location);
if ((d > 0) && (d < preferredDist)) {
target.add(b.location);
count++;
}
}
if (count > 0) {
target.div(count);
return seek(target);
}
return target;
}
void draw(Graphics2D g) {
AffineTransform save = g.getTransform();
int[] xTriangle = {33,36,34};
int[] yTriangle = {30,30,20};
Area triangle = new Area(new Polygon(xTriangle, yTriangle, 3));
g.translate(location.x, location.y);
g.rotate(velocity.heading() + PI / 2);
g.setColor(Color.green);
// g.fill(shape);
g.setColor(Color.green);
g.draw(triangle);
g.fill(triangle);
g.setTransform(save);
Area square = new Area(new Rectangle(600,250,200,200));
g.draw(square);
if (doAreasCollide(square, triangle)) {
g.setColor(Color.RED);
System.out.println("Collision");
} else {
g.setColor(Color.GREEN);
System.out.println("noCollision");
}
g.fill(square);
}
public void run(Graphics2D g, List<Boid> boids, int w, int h) {
flock(g, boids);
update();
draw(g);
}
}
class Flock {
List<Boid> boids;
Flock() {
boids = new ArrayList<>();
}
void run(Graphics2D g, int w, int h) {
for (Boid b : boids) {
b.run(g, boids, w, h);
}
}
boolean hasLeftTheBuilding(int w) {
int count = 0;
for (Boid b : boids) {
if (b.location.x + Boid.size > w)
count++;
}
return boids.size() == count;
}
void addBoid(Boid b) {
boids.add(b);
}
static Flock spawn(double w, double h, int numBoids) {
Flock flock = new Flock();
for (int i = 0; i < numBoids; i++)
flock.addBoid(new Boid(w, h));
return flock;
}
}
class Vec {
double x, y;
Vec() {
}
Vec(double x, double y) {
this.x = x;
this.y = y;
}
void add(Vec v) {
x += v.x;
y += v.y;
}
void sub(Vec v) {
x -= v.x;
y -= v.y;
}
void div(double val) {
x /= val;
y /= val;
}
void mult(double val) {
x *= val;
y *= val;
}
double mag() {
return sqrt(pow(x, 2) + pow(y, 2));
}
double dot(Vec v) {
return x * v.x + y * v.y;
}
void normalize() {
double mag = mag();
if (mag != 0) {
x /= mag;
y /= mag;
}
}
void limit(double lim) {
double mag = mag();
if (mag != 0 && mag > lim) {
x *= lim / mag;
y *= lim / mag;
}
}
double heading() {
return atan2(y, x);
}
static Vec sub(Vec v, Vec v2) {
return new Vec(v.x - v2.x, v.y - v2.y);
}
static double dist(Vec v, Vec v2) {
return sqrt(pow(v.x - v2.x, 2) + pow(v.y - v2.y, 2));
}
static double angleBetween(Vec v, Vec v2) {
return acos(v.dot(v2) / (v.mag() * v2.mag()));
}
}