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