104 lines
3.0 KiB
JavaScript
104 lines
3.0 KiB
JavaScript
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const g = 9.8 / (144 * 144);
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let res = 20/10;
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class Pendulum {
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constructor(xoffset, yoffset, scale) {
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this.x1 = 0;
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this.y1 = 0;
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this.x2 = 0;
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this.y2 = 0;
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this.m1 = 2;
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this.m2 = 2;
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this.a1 = Math.PI / 2 + random(-Math.PI, Math.PI) / 16 + Math.PI/4;
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this.a2 = Math.PI + random(-Math.PI, Math.PI) / 16;
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this.r1 = 2;
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this.r2 = 2;
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this.a1_v = 0;
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this.a2_v = 0;
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this.a1_a = 0;
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this.a2_a = 0;
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this.xoffset = xoffset;
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this.yoffset = yoffset;
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this.scale = scale;
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this.poslog = [];
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this.fc = 0;
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this.setPos();
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}
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update() {
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this.a1_v += this.a1_a;
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this.a2_v += this.a2_a;
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this.a1 += this.a1_v;
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this.a2 += this.a2_v;
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this.updateA();
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this.setPos();
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if ((this.fc % res === 0) && (this.fc > 144*3)) {
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this.logPos();
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}
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}
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show() {
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this.fc++;
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push();
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translate(this.xoffset, this.yoffset);
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strokeWeight(20 * this.scale);
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point(0, 0);
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strokeWeight(40 * this.scale);
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point(this.x1, this.y1);
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point(this.x2, this.y2);
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strokeWeight(8 * this.scale);
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line(0, 0, this.x1, this.y1);
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line(this.x1, this.y1, this.x2, this.y2);
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pop();
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this.showTrail();
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}
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setPos() {
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this.x1 = sin(this.a1) * this.r1 * 100 * this.scale;
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this.y1 = cos(this.a1) * this.r1 * 100 * this.scale;
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this.x2 = this.x1 + sin(this.a2) * this.r2 * 100 * this.scale;
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this.y2 = this.y1 + cos(this.a2) * this.r2 * 100 * this.scale;
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}
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updateA() {
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let d = 2 * this.m1 + this.m2 - this.m2 * cos(2 * this.a1 - 2 * this.a2);
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let num1 = -g * (2 * this.m1 + this.m2) * sin(this.a1);
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let num2 = -this.m2 * g * sin(this.a1 - 2 * this.a2);
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let num3 = -2 * sin(this.a1 - this.a2) * this.m2;
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let num4 = this.a2_v * this.a2_v * this.r2 + this.a1_v * this.a1_v * this.r1 * cos(this.a1 - this.a2);
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this.a1_a = (num1 + num2 + num3 * num4) / (this.r1 * d);
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num1 = 2 * sin(this.a1 - this.a2);
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num2 = this.a1_v * this.a1_v * this.r1 * (this.m1 + this.m2);
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num3 = g * (this.m1 + this.m2) * cos(this.a1);
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num4 = this.a2_v * this.a2_v * this.r2 * this.m2 * cos(this.a1 - this.a2);
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this.a2_a = (num1 * (num2 + num3 + num4)) / (this.r2 * d);
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}
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logPos() {
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if(this.poslog.length<144/res*10)
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this.poslog.push(createVector(this.x2, this.y2));
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else{
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this.poslog.shift();
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this.poslog.push(createVector(this.x2, this.y2));
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}
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}
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showTrail() {
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push();
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translate(this.xoffset, this.yoffset);
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strokeWeight(2 * this.scale);
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stroke(33);
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noFill();
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beginShape();
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for (let i = 0; i < this.poslog.length; i++) {
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vertex(this.poslog[i].x, this.poslog[i].y);
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}
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endShape();
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pop();
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}
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}
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