我的碰撞检测实现不正常

Question

I've been trying to use some simple force implementations in p5.js, I have the concept in mind but I feel like I overlooked a simple error in my code. This is my code right now:

var x = 0;
var y = 0;
var grav = new p5.Vector(0, 13, 0);
var bounce = new p5.Vector(0, -13, 0);
var isbounce = false;
var ymax = 0;

function setup() {
    createCanvas(600, 400);
}

function draw() {
    console.log(ymax, isbounce);
    background(0);
    fill(255);
    ellipse(200, y, 50, 50);

    if (y < 376 && isbounce == false) {
        y += grav.y;
    }
    if (y >= 376) {
        isbounce = true;
    }
    if (isbounce == true) {
        y += bounce.y;
        if (y == ymax) {
            isbounce = false;
            ymax++;
        }
    }
}

JSfiddle

As you can see, the object does bounce twice, but then it completely floats off the screen. I can't explain this, I looked at the console and it confirmed that it only bounced twice (setting isbounce to true, false and true again). What I'm expecting is that isbounce will be set to true everytime the object hits the ground, and to false whenever its y value reaches ymax (which decreases everytime it bounces to stimulate energy loss). I thought this was a rather easy implementation of forces, but I'm puzzled as to why it doesn't work.

Answer 1

替换if (y == ymax) { by if (y <= ymax) {以确保它在屏幕顶部反弹。