線と線の交差判定 <script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/1.5.0/p5.js"></script> <div id="p5canvas"></div> <script> let lp1; //line 1 point 1 let lp2; //line 1 point 2 let lp3; //line 2 point 1 let lp4; //line 2 point 2 let lpm1;//line 3 point 1 mousexy let lpm2;//line 3 point 2 function setup() { let sqsize=50; createCanvas(400, 400).parent("p5canvas"); textSize(20); lp1=createVector(width / 2-sqsize, height / 2-sqsize); lp2=createVector(width / 2+sqsize, height / 2+sqsize); lp3=createVector(width / 2-sqsize, height / 2+sqsize); lp4=createVector(width / 2+sqsize, height / 2-sqsize); lpm1=createVector(width / 2-30, height / 2); lpm2=createVector(0,0); } function mousePressed() { lpm1.set(mouseX,mouseY); } function crosscheck( p1,p2,p3,p4) { let a1, a2; a1 = (p3.x * p2.y - p3.x * p1.y - p1.x * p2.y + p1.x * p1.y - p2.x * p3.y + p2.x * p1.y + p1.x * p3.y - p1.x * p1.y)* (p4.x * p2.y - ...