Example #1
0
        public static XMVector HsvToRgb(XMVector hsv)
        {
            XMVector h = XMVector.SplatX(hsv);
            XMVector s = XMVector.SplatY(hsv);
            XMVector v = XMVector.SplatY(hsv);

            XMVector h6 = XMVector.Multiply(h, XMGlobalConstants.Six);
            XMVector i  = h6.Floor();
            XMVector f  = XMVector.Subtract(h6, i);

            // p = v* (1-s)
            XMVector p = XMVector.Multiply(v, XMVector.Subtract(XMGlobalConstants.One, s));

            // q = v*(1-f*s)
            XMVector q = XMVector.Multiply(v, XMVector.Subtract(XMGlobalConstants.One, XMVector.Multiply(f, s)));

            // t = v*(1 - (1-f)*s)
            XMVector t = XMVector.Multiply(v, XMVector.Subtract(XMGlobalConstants.One, XMVector.Multiply(XMVector.Subtract(XMGlobalConstants.One, f), s)));

            int ii = (int)XMVector.Mod(i, XMGlobalConstants.Six).X;

            XMVector rgb;

            switch (ii)
            {
            case 0:
                // rgb = vtp
                XMVector vt = XMVector.Select(t, v, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(p, vt, XMGlobalConstants.Select1100);
                break;

            case 1:
                // rgb = qvp
                XMVector qv = XMVector.Select(v, q, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(p, qv, XMGlobalConstants.Select1100);
                break;

            case 2:
                // rgb = pvt
                XMVector pv = XMVector.Select(v, p, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(t, pv, XMGlobalConstants.Select1100);
                break;

            case 3:
                // rgb = pqv
                XMVector pq = XMVector.Select(q, p, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(v, pq, XMGlobalConstants.Select1100);
                break;

            case 4:
                // rgb = tpv
                XMVector tp = XMVector.Select(p, t, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(v, tp, XMGlobalConstants.Select1100);
                break;

            default:
                // rgb = vpq
                XMVector vp = XMVector.Select(p, v, XMGlobalConstants.Select1000);
                rgb = XMVector.Select(q, vp, XMGlobalConstants.Select1100);
                break;
            }

            return(XMVector.Select(hsv, rgb, XMGlobalConstants.Select1110));
        }