obstacle.js

class Obstacle {
	constructor(vertices, velocity) {
      	// array of polygon's x- and y-coordinates (edges)
    	this.vertices = vertices;
      
      	// min. and max. x/y coordinates that create a rectangle
      	this.minValues = createVector();
      	this.maxValues = createVector();
    }
  
  	show() {
      	fill(153, 112, 178);
        stroke(123, 91, 142);
      	strokeWeight(4);
      
    	beginShape();
    
      	for (let i = 0; i < this.vertices.length; i++) {
        	vertex(this.vertices[i].x, this.vertices[i].y);
        }
      
      	// connect last vertex with first one
      	vertex(this.vertices[0].x, this.vertices[0].y);
      
      	endShape();
    }
  
  	update() {
    	for (let i = 0; i < this.vertices.length; i++) {
        	this.vertices[i].x -= gTerrain.velocity;
        }
      
      	let minX = null;
      	let maxX = null;
      	let minY = null;
      	let maxY = null;
      
      	// retrieve min. and max. values of polygon
      	for (let i = 0; i < this.vertices.length; i++) {
        	minX = this.vertices[i].x < minX || minX == null ? this.vertices[i].x : minX;
          	maxX = this.vertices[i].x > maxX || maxX == null ? this.vertices[i].x : maxX;
          	minY = this.vertices[i].y < minY || minY == null ? this.vertices[i].y : minY;
            maxY = this.vertices[i].y > maxY || maxY == null ? this.vertices[i].y : maxY;
        }
      
      	this.minValues.x = minX;
      	this.minValues.y = minY;
      	this.maxValues.x = maxX;
      	this.maxValues.y = maxY;
    }
  
  	offscreen() {
      	// max. x-value of polygon
    	let maxX = 0;
      
      	for (let i = 0; i < this.vertices.length; i++) {
        	maxX = this.vertices[i].x > maxX ? this.vertices[i].x : maxX;
        }
      
      	// if max. x-value less than or equal to 0, whole polygon is offscreen
      	return maxX <= 0;
    }
  
  	collidesPoint(posX, posY) {
      	// checks if point inside min-max rectangle (not really precise)
    	if (posX > this.minValues.x && posX < this.maxValues.x && posY > this.minValues.y && posY < this.maxValues.y) {
        	return true;
        }
    }
}