HTML5 + CANVAS rotacja koła fortuny

Question

Witam,

Potrzebuje pomocy, nie wiem jak napisać funkcje która obraca koło na konkretne pole koła fortuny. Przykładowo spin(0), obraca koło na pozycje 0 (kolor złoty). Szukałem dużo informacji na ten temat lecz podczas próby obrotu przez obliczony radian, obrót jest błędny.

<button onclick="spins(0)">SPIN</button>
<canvas id="canvas" width="500" height="500"></canvas>

var startAngle = 0
var arc = Math.PI / (54 / 2);
var spinTimeout = null;

var spinArcStart = 10;
var spinTime = 0;
var spinTimeTotal = 0;

var ctx;

function drawRouletteWheel() {
    var canvas = document.getElementById("canvas");
    if (canvas.getContext) {
        var outsideRadius = 200;
        var insideRadius = 100;
        var textRadius = 152;

        ctx = canvas.getContext("2d");
        ctx.clearRect(0, 0, 500, 500);


        ctx.strokeStyle = "transparent";
        ctx.lineWidth = 3;

        ctx.font = 'bold 15px Questrial, sans-serif';

        for (var i = 0; i < 54; i++) {
            var angle = startAngle + i * arc;
            if (i === 0)
                ctx.fillStyle = 'yellow';
            else if (i % 2 === 0)
                ctx.fillStyle = 'black';
            else if (i === 1 || i === 53 || i === 9 || i === 11 || i === 19 || i === 21 || i === 33 || i === 35 || i === 43 || i === 45)
                ctx.fillStyle = 'green';
            else
                ctx.fillStyle = 'red';

            ctx.beginPath();
            ctx.arc(250, 250, outsideRadius, angle, angle + arc, false);
            ctx.arc(250, 250, insideRadius, angle + arc, angle, true);
            ctx.stroke();
            ctx.fill();

            ctx.save();
            ctx.fillStyle = "#ffffff";
            ctx.translate(250 + Math.cos(angle + arc / 2) * textRadius,
                250 + Math.sin(angle + arc / 2) * textRadius);
            ctx.rotate(angle + arc / 2 + Math.PI / 2);
            var text = i;
            ctx.fillText(text, -ctx.measureText(text).width / 2, 0);
            ctx.restore();
        }

        //Arrow
        ctx.fillStyle = "black";
        ctx.beginPath();
        ctx.moveTo(250 - 4, 250 - (outsideRadius + 5));
        ctx.lineTo(250 + 4, 250 - (outsideRadius + 5));
        ctx.lineTo(250 + 4, 250 - (outsideRadius - 5));
        ctx.lineTo(250 + 9, 250 - (outsideRadius - 5));
        ctx.lineTo(250 + 0, 250 - (outsideRadius - 13));
        ctx.lineTo(250 - 9, 250 - (outsideRadius - 5));
        ctx.lineTo(250 - 4, 250 - (outsideRadius - 5));
        ctx.lineTo(250 - 4, 250 - (outsideRadius + 5));
        ctx.fill();
    }
}

function spins(num) {
    //radianone = (1 / 54 * 360) * Math.PI / 180;
    rad = Math.PI * 4 + num; // (360 * Math.PI / 180) - radianone * (num + 0.5);
    spinAngleStart = rad - startAngle;
    spinTime = 0;
    spinTimeTotal = 360;
    rotateWheel();
}

// PREVIOUS CODE

function spin() {
    spinAngleStart = Math.random() * 10 + 10;
    spinTime = 0;
    spinTimeTotal = Math.random() * 3 + 4 * 2000;
    rotateWheel();
}

function rotateWheel() {
    spinTime += 20;
    if (spinTime >= spinTimeTotal) {
        stopRotateWheel();
        return;
    }
    var spinAngle = spinAngleStart - easeOut(spinTime, 0, spinAngleStart, spinTimeTotal);
    startAngle += (spinAngle * Math.PI / 180);
    drawRouletteWheel();
    spinTimeout = setTimeout('rotateWheel()', 20);
}

function stopRotateWheel() {
    clearTimeout(spinTimeout);
    var degrees = startAngle * 180 / Math.PI + 90;
    var arcd = arc * 180 / Math.PI;
    var index = Math.floor((360 - degrees % 360) / arcd);
    ctx.save();
    ctx.font = 'bold 30px Helvetica, Arial';
    var text = i
    ctx.fillText(text, 250 - ctx.measureText(text).width / 2, 250 + 10);
    ctx.restore();
}

function easeOut(t, b, c, d) {
    var ts = (t /= d) * t;
    var tc = ts * t;
    return b + c * (tc + -3 * ts + 3 * t);
}

drawRouletteWheel();

Pozdrawiam, liczę na pomoc z waszej strony! :)

Answer 1

bump! naprawde potrzebuje pomocy