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创建一个ArrayList
粒子,但不要在 中添加任何粒子setup()
:
ArrayList<Particle> paticles = new ArrayList<Particle>();
void setup() {
size(400, 400);
colorMode(HSB);
stroke(255);
}
连续添加颗粒draw()
。该函数millis()
用于获取自程序启动以来的时间:
void draw() {
int num = 100;
int interval = 100; // 0.5 seconds
int time = millis(); // milliseconds since starting the program
if (paticles.size() < num && paticles.size()*interval+5000 < time) {
paticles.add(new Particle(new PVector(random(width), random(height)), 100, 150));
}
background(0);
for (int i = 0; i < paticles.size(); i ++) {
Particle p = paticles.get(i);
p.update(paticles, i);
}
}
请注意,该类Particle必须进行调整,因为它必须使用ArrayList可变长度的数组而不是固定长度的数组进行操作:
class Particle {
PVector pos;
PVector vel;
float r, mr;
float spd = 0.1;
float max = 2;
Particle(PVector pos, float r, float mr) {
this.pos = pos;
this.r = r;
this.mr = mr;
vel = new PVector(random(-1, 1), random(-1, 1));
}
void update(ArrayList<Particle> paticles, int i) {
float h = map(mouseX, 0, width, 0, 255);
pos.add(vel);
if (pos.x < -10) pos.x = width;
if (pos.x > width + 10) pos.x = 0;
if (pos.y < -10) pos.y = height;
if (pos.y > height + 10) pos.y = 0;
vel.x = constrain(vel.x + random(-spd, spd), -max, max);
vel.y = constrain(vel.y + random(-spd, spd), -max, max);
for (int j = i + 1; j < paticles.size(); j ++) {
Particle pj = paticles.get(j);
float ang = atan2(pos.y - pj.pos.y, pos.x - pj.pos.x);
float dist = pos.dist(pj.pos);
if (dist < r) {
stroke(h, 255, map(dist, 0, r, 255, 0));
strokeWeight(map(dist, 0, r, 3, 0));
line(pos.x, pos.y, pj.pos.x, pj.pos.y);
float force = map(dist, 0, r, 4, 0);
vel.x += force * cos(ang);
vel.y += force * sin(ang);
}
}
float ang = atan2(pos.y - mouseY, pos.x - mouseX);
float dist = pos.dist(new PVector(mouseX, mouseY));
if (dist < r) {
stroke(0, 0, map(dist, 0, r, 255, 0));
strokeWeight(map(dist, 0, r, 3, 0));
line(pos.x, pos.y, mouseX, mouseY);
float force = map(dist, 0, r, 30, 0);
vel.x += force * cos(ang);
vel.y += force * sin(ang);
}
noStroke();
fill(h, 255, 255);
ellipse(pos.x, pos.y, 5, 5);
}
}
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