window.onload = function() { startNew(); document.getElementById("new").addEventListener("click",startNew); } function startNew() { var A = {x: 0, y: 0}; var B = {x: 0, y: 0}; var C = {x: 0, y: 0}; var S = {x: 0, y: 0}; var E = {x: 0, y: 0}; var cnv = document.getElementById("ocean"); var ctx = cnv.getContext('2d'); var o = document.getElementById("txtout"); var c = document.getElementById("cinfo"); var report = ""; var oceanWidth = ctx.canvas.width; var oceanHeight = ctx.canvas.height; //create ocean ctx.clearRect(0,0,oceanWidth,oceanHeight); ctx.strokeStyle = "black"; // create triangle do { [A.x, A.y, B.x, B.y, C.x, C.y] = generate_triangle(oceanWidth, oceanHeight); } while(Math.abs(((A.x-C.x)*(B.y-C.y)-(A.y-C.y)*(B.x-C.x))/2)/(oceanWidth*oceanHeight)<0.3); //create course do { [S.x, S.y] = generate_point(oceanWidth, oceanHeight); } while(chkPoint(S.x, S.y, A.x, A.y, B.x, B.y, C.x, C.y) > 0); [E.x, E.y] = generate_point(oceanWidth, oceanHeight); report = "Course info, from point: " + S.x + ", " + S.y + " to point: " + E.x + ", " + E.y; c.innerHTML = report; report = ""; //draw triangle ctx.beginPath(); ctx.moveTo(A.x, A.y); ctx.fillText("A", A.x, A.y); ctx.lineTo(B.x,B.y); ctx.fillText("B", B.x, B.y); ctx.lineTo(C.x, C.y); ctx.fillText("C",C.x, C.y); ctx.closePath(); ctx.stroke(); //draw course ctx.strokeStyle = "green"; ctx.beginPath(); ctx.moveTo(S.x, S.y); ctx.fillText("S", S.x, S.y); ctx.lineTo(E.x, E.y); ctx.fillText("E", E.x, E.y); ctx.stroke(); //ship Movement var courseLength = Math.sqrt(Math.pow((S.x - E.x),2) + Math.pow((S.y - E.y),2)); var deltaX, deltaY; var stepX, stepY, stepNum; var enterFlag = false, leaveFlag = false, crashFlag = false; var X = S.x, Y = S.y; var riskFact = Math.ceil(0.01 * courseLength); deltaX = E.x - S.x; deltaY = E.y - S.y; if(Math.abs(deltaX) > Math.abs(deltaY)) { stepX = deltaX/Math.abs(deltaX); stepY = deltaY/Math.abs(deltaX); stepNum = Math.abs(deltaX); } else { stepX = deltaX/Math.abs(deltaY); stepY = deltaY/Math.abs(deltaY); stepNum = Math.abs(deltaY); } for(i = 0; i < stepNum; i++) { X += stepX; Y += stepY; if(chkPoint(X, Y, A.x, A.y, B.x, B.y, C.x, C.y) === 1) { //ship enter Bermuda triangle, increasing risk enterFlag = true; crashFlag = rndDisappear(courseLength,riskFact++); } if(enterFlag && (chkPoint(X, Y, A.x, A.y, B.x, B.y, C.x, C.y) === 0)) leaveFlag = true; //ship cross Bermuda triangle if (crashFlag||leaveFlag) break; } //disappear at end point in triangle if((!crashFlag)&&(!leaveFlag)&&enterFlag) { crashFlag = true; X=E.x; Y=E.y } if(crashFlag) { ctx.strokeStyle = "red"; ctx.beginPath(); ctx.arc(Math.round(X),Math.round(Y),5,0,2*Math.PI); ctx.stroke(); report = "Ship disappeared in Bermuda Triangle at point with coordinates: " + Math.round(X) + ", " + Math.round(Y); o.innerHTML = report; } if(!enterFlag) { report = "Ship does not enter Bermuda Triangle"; o.innerHTML = report; } if(leaveFlag) { report = "Ship successfully cross Bermuda Triangle"; o.innerHTML = report; } } function generate_triangle(width, height) { var AX, AY, BX, BY, CX, CY; [AX, AY] = generate_point(width, height); [BX, BY] = generate_point(width, height); [CX, CY] = generate_point(width, height); return [AX, AY, BX, BY, CX, CY]; } function generate_point(width, height) { var X, Y; X = Math.round(Math.random() * width); Y = Math.round(Math.random() * height); return [X, Y]; } function chkPoint(X, Y, AX, AY, BX, BY, CX, CY) { // return 0 if point is out of the triangle // return 1 if point is in the triangle // return 2 if point lies on the side of the triangle var r1 = (AX - X) * (BY - AY) - (BX - AX) * (AY - Y); var r2 = (BX - X) * (CY - BY) - (CX - BX) * (BY - Y); var r3 = (CX - X) * (AY - CY) - (AX - CX) * (CY - Y); if (((r1 < 0)&&(r2 < 0)&&(r3 < 0))||((r1 > 0)&&(r2 > 0)&&(r3 > 0))) return 1; if ((r1 === 0) || (r2 === 0) || (r3 === 0)) return 2; if ((r1 * r2 * r3 ) < 0) return 0; if (((r1 > 0)&&(r2 < 0) && (r3 < 0))||((r1 < 0)&&(r2 < 0)&& (r3 > 0))||((r1 < 0)&&(r2 > 0)&&(r3 < 0))) return 0; } function rndDisappear(path, riskFactor) { return (Math.round(path*Math.random()) < riskFactor); }

bermuda triangle