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var pos; var targetPos; var mousePos; function setup() { createCanvas(1000, 600); fill(0); pos = createVector(0, 0); targetPos = createVector(0, 0); mousePos = createVector(width/2, height/2); } function draw() { background(255); targetPos.set(mousePos); targetPos.sub(pos); // find the vector between mouse position and ellipse position targetPos.mult(0.2); // each step in the animation will move this percentage of the distance to the target position pos.add(targetPos); ellipse(pos.x, pos.y, 60, 60); } function mousePressed() { mousePos.set(mouseX, mouseY); } |
Exercise
- Add an additional ellipse that follows the mouse at a slower rate than the first ellipse.
- Modify the code so that the ellipse always follows the mouse position.
- Replace with the ellipse with another shape (like a triangle or even a car) , and keep it pointed towards the mouse.
Exercise Solution Using Arrays
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var pos = []; var targetPos = []; var mousePos = []; var arrayLength = 5; function setup() { createCanvas(1000, 600); fill(0); for (var i = 0; i< arrayLength; i++) { pos[i] = createVector(0, 0); targetPos[i] = createVector(0, 0); } mousePos = createVector(width/2, height/2); } function draw() { mousePos.set(mouseX, mouseY); background(255); for (var i = 0; i < pos.length; i++) { targetPos[i].set(mousePos); targetPos[i].sub(pos[i]); // find the vector between mouse position and ellipse position targetPos[i].mult((i*0.02) + 0.05); // each step in the animation will move this percentage of the distance to the target position pos[i].add(targetPos[i]); fill(125,255,23); ellipse(pos[i].x, pos[i].y, 60, 60); } } |
Exercise Solution Using Arrays and Classes
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let shape = []; var arrayLength = 60; function setup() { createCanvas(1000, 600); fill(0); for (var i= 0; i < arrayLength; i++) { shape[i] = new myShape((i*0.02) + 0.02); } } function draw() { background(255); for (var i= 0; i < shape.length; i++) { shape[i].update(); } } class myShape { constructor(_speed) { this.pos = createVector(0,0); this.targetPos = createVector(0,0); this.mousePos = createVector(width/2, height/2); this.speed = _speed; } update() { this.mousePos.set(mouseX, mouseY); this.targetPos.set(this.mousePos); this.targetPos.sub(this.pos); // find the vector between mouse position and ellipse position this.targetPos.mult(this.speed); // each step in the animation will move this percentage of the distance to the target position this.pos.add(this.targetPos); pushMatrix(); translate(this.pos.x, this.pos.y); rotate(calcAngle(this.pos, this.mousePos)); triangle(0,0,-5,20,5,20); popMatrix(); } calcAngle(p1, p2) { return -atan2(p1.x - p2.x,p1.y - p2.y); } } |
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