so I made this way to detect and react to squares moving and touching other squares. It uses Pythagorean theorem to make a third parameter so you don't get two true if statements when squares touch. I recently have been attempting to use this method on a square to a rectangle, and cannot seem to get it working. I have drawn lines to help visualize what the code is doing. Anybody have any suggestions on how to get this collision working properly?
const canvas = document.getElementById('canvas');
const context = canvas.getContext('2d');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
let gravity = 1.5;
let friction = 0.9;
//CHARACTER:
class Player {
constructor(x, y, w, h, vx, vy, c, j) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.vx = vx;
this.vy = vy;
this.color = c;
this.jumping = j;
}
draw() {
context.fillStyle = this.color;
context.fillRect(this.x, this.y, this.w, this.h);
}
canvasCollision() {
if (this.x <= 0) this.x = 0;
if (this.y <= 0) this.y = 0;
if (this.x + this.w >= canvas.width) this.x = canvas.width - this.w;
if (this.y + this.h >= canvas.height) {this.y = canvas.height - this.h; this.vy = 0; this.jumping = false};
}
update() {
this.draw();
this.vy += gravity;
this.x += this.vx;
this.y += this.vy;
this.vx *= friction;
this.vy *= friction;
this.canvasCollision() //must be after other updates
}
}
let player1 = new Player(75, canvas.height/2 + 75, 75, 75, 0, 0, '#8DAA9D', false);
function controlPlayer1(obj) {
//this order matters. If update is before jump then obj won't jump when on top of other block.
if (controller1.up1 && !obj.jumping) { obj.vy -= 25; obj.jumping = true };
if (controller1.left1) { obj.vx -= 0.5 };
if (controller1.right1) { obj.vx += 0.5 };
obj.update();
}
//MOVEMENT:
class Controller {
constructor() {
this.left1 = false;
this.up1 = false;
this.right1 = false;
this.down1 = false;
let controller1 = (e) => {
if (e.code === 'KeyD') { this.right1 = e.type === 'keydown' }
if (e.code === 'KeyA') { this.left1 = e.type === 'keydown' }
if (e.code === 'KeyW') { this.up1 = e.type === 'keydown' }
if (e.code === 'KeyS') { this.down1 = e.type === 'keydown' }
}
window.addEventListener('keydown', controller1);
window.addEventListener('keyup', controller1);
}
}
let controller1 = new Controller();
//PLATFORM
class Platform {
constructor(x, y, w, h, yv, c) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.yv = yv;
this.color = c;
}
draw(){
context.fillStyle = this.color;
context.fillRect(this.x, this.y, this.w, this.h);
}
update(){
this.draw();
this.y += this.yv;
this.yv *= 0.9;// friction
}
}
let platform1 = new Platform(canvas.width/2, canvas.height - 150, 100, 30, 0, '#202020');
let platform2 = new Platform (canvas.width/4, canvas.height/2, 75, 75, 0, '#202020');
//COLLISION DETECTION
function platformDetection(obj, obj2){
//center point of each side of obj1
let objLeft = {x: obj.x, y: obj.y + obj.h/2};
let objTop = {x: obj.x + obj.w/2, y: obj.y};
let objRight = {x: obj.x + obj.w, y: obj.y + obj.h/2};
let objBottom = {x: obj.x + obj.w/2, y: obj.y + obj.h};
//center point of each side a obj2
let obj2Left = {x: obj2.x, y: obj2.y + obj2.h/2};
let obj2Top = {x: obj2.x + obj2.w/2, y: obj2.y};
let obj2Right = {x: obj2.x + obj2.w, y: obj2.y + obj2.h/2};
let obj2Bottom = {x: obj2.x + obj2.w/2, y: obj2.y + obj2.h};
//distance between obj1 and obj2 opposing sides
let rightDistX = objRight.x - obj2Left.x;
let rightDistY = objRight.y - obj2Left.y;
let leftDistX = objLeft.x - obj2Right.x;
let leftDistY = objLeft.y - obj2Right.y;
let topDistX = objTop.x - obj2Bottom.x;
let topDistY = objTop.y - obj2Bottom.y;
let bottomDistX = objBottom.x - obj2Top.x;
let bottomDistY = objBottom.y - obj2Top.y;
//pythagorean theorem for distance. dRight is from the right side of obj1 to the left of obj2. the rest follow suit.
let dRight = Math.sqrt(rightDistX*rightDistX + rightDistY*rightDistY);
let dLeft = Math.sqrt(leftDistX*leftDistX + leftDistY*leftDistY);
let dTop = Math.sqrt(topDistX*topDistX + topDistY*topDistY);
let dBottom = Math.sqrt(bottomDistX*bottomDistX + bottomDistY*bottomDistY);
//Math.min return the smallest value thus variable minimum will be which ever sides are closest together
let minimum = Math.min(dRight, dLeft, dBottom, dTop);
let val = 0;
//compare minimum to pythagorean theorem and set val based on which ever side is closest
if (dTop == minimum) {
val = 1;
//the context stuff can be deleted. It's just here for visual. The if statements can be one line each.
context.lineWidth = 2;
context.strokeStyle = 'blue';
context.beginPath();
context.moveTo(objTop.x, objTop.y);
context.lineTo(obj2Bottom.x, obj2Bottom.y);
context.stroke();
}
else if (dRight == minimum) {
val = 2;
context.strokeStyle = 'orange';
context.beginPath();
context.moveTo(objRight.x, objRight.y);
context.lineTo(obj2Left.x, obj2Left.y);
context.stroke();
}
else if (dBottom == minimum) {
val = 3;
context.strokeStyle = 'green';
context.beginPath();
context.moveTo(objBottom.x, objBottom.y);
context.lineTo(obj2Top.x, obj2Top.y);
context.stroke();
}
else if (dLeft == minimum) {
val = 4;
context.strokeStyle = 'pink';
context.beginPath();
context.moveTo(objLeft.x, objLeft.y);
context.lineTo(obj2Right.x, obj2Right.y);
context.stroke();
}
//pass the objects and val
platformAction(obj, obj2, val);
}
//ACTION
function platformAction(obj, obj2, val){
//player1 top to player2 bottom
if (obj.y <= obj2.y + obj2.h && obj2.y + obj2.h >= obj.y && val == 1) {
obj2.y = obj.y - obj2.h;
obj.y = obj2.y + obj2.h;
obj2.vy = 0;
obj2.jumping = false;
obj.jumping = true;
}
//player1 right to player2 left
if (obj.x + obj.w >= obj2.x && obj2.x <= obj.x + obj.w && val == 2) {
obj2.x = obj.x + obj.w;
obj.x = obj2.x - obj.w - 1;
obj2.vx = 0;
}
//player1 bottom to player2 top
if (obj.y + obj.h >= obj2.y && obj2.y <= obj.y + obj.h && val == 3) {
obj.y = obj2.y - obj.h;
obj2.y = obj.y + obj.h;
obj.vy = 0;
obj.jumping = false;
obj2.jumping = true;
}
//player1 left to player2 right
if (obj.x <= obj2.x + obj2.w && obj2.x + obj2.w >= obj.x && val == 4) {
obj2.x = obj.x - obj2.w;
obj.x = obj2.x + obj2.w + 1;
obj.vx = 0;
obj2.vx = 0;
}
}
function initObj(obj){
obj.update();
}
function loop() {
context.clearRect(0, 0, canvas.width, canvas.height);
context.fillStyle = 'grey';
context.fillRect(0, 0, canvas.width, canvas.height);
//PLATFORM
initObj(platform1);
initObj(platform2);
//PLATFORM DETECTION
platformDetection(player1, platform1);
platformDetection(player1, platform2);
//PLAYER
controlPlayer1(player1);
requestAnimationFrame(loop)
}
loop();<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=device-dpi">
<title>Tone.io</title>
<style>
body {
height:100vh;
width:100vh;
margin: 0;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<script src = "Js/Tone.js" type = "text/javascript"></script>
</body>
</html>
obj.vx = 0; obj2.vx = 0;in theval==4conditional in yourplatformActionfunction. – Finsteraarhorn