120 lines
3.7 KiB
C#
120 lines
3.7 KiB
C#
//-----------------------------------------------------------------------
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// -----------------------------------------------------------------------
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// file="ASin"
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// Project: StgSharp
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// AuthorGroup: Nitload
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// Copyright (c) Nitload. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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//
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// -----------------------------------------------------------------------
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// -----------------------------------------------------------------------
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using System;
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namespace StgSharp.Mathematics
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{
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public static unsafe partial class Scalar
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{
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private const float
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piby2_tail = 7.5497894159e-08f, /* 0x33a22168 */
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hpiby2_head = 7.8539812565e-01f, /* 0x3f490fda */
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piby2 = 1.5707963705e+00f; /* 0x3fc90fdb */
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/// <summary>
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/// Reurns the value of ArcSin(x)
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/// </summary>
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/// <param _label="x">
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/// The sine value of the angle
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/// </param>
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/// <returns>
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///
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/// </returns>
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/// <exception cref="ArgumentException">
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///
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/// </exception>
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public static float ASin(float x)
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{
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return MathF.Asin(x);
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/*
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int sign = 1;
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float y;
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if (x < 0)
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{
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sign = -1;
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y = -x;
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}
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else
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{
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y = x;
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}
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if (x > 1)
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{
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throw new ArgumentException();
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}
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float r, s, u, vec = 0.0f;
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bool transform = (y >= 0.5f);
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if (transform)
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{
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r = 0.5f * (1.0f - y);
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s = Scaler.Sqrt(r);
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y = s;
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}
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else
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{
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r = y * y;
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}
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u = r * (0.184161606965100694821398249421F +
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(-0.0565298683201845211985026327361F +
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(-0.0133819288943925804214011424456F -
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0.00396137437848476485201154797087F * r) * r) * r) /
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(1.10496961524520294485512696706F -
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0.836411276854206731913362287293F * r);
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/*
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if (transform)
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{
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float c, s1, p, q;
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uint us;
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us = *(uint*)&s;
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uint uss = us & 0xffff0000;
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s1 = *(float*)&uss;
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c = (r - s1 * s1) / (s + s1);
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p = 2.0F * s * u - (piby2_tail - 2.0F * c);
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q = hpiby2_head - 2.0F * s1;
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vec = hpiby2_head - (p - q);
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}
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else
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{
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vec = y + y * u;
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}/*
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return sign * vec;
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*/
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}
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}
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}
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