140 lines
2.4 KiB
C#
140 lines
2.4 KiB
C#
#region License
|
|
|
|
/* MoonWorks - Game Development Framework
|
|
* Copyright 2021 Evan Hemsley
|
|
*/
|
|
|
|
/* Derived from code by Ethan Lee (Copyright 2009-2021).
|
|
* Released under the Microsoft Public License.
|
|
* See fna.LICENSE for details.
|
|
|
|
* Derived from code by the Mono.Xna Team (Copyright 2006).
|
|
* Released under the MIT License. See monoxna.LICENSE for details.
|
|
*/
|
|
|
|
#endregion
|
|
|
|
#region Using Statements
|
|
using System;
|
|
using System.Runtime.InteropServices;
|
|
#endregion
|
|
|
|
namespace MoonWorks.Graphics
|
|
{
|
|
internal static class HalfTypeHelper
|
|
{
|
|
#region Private Struct uif
|
|
|
|
[StructLayout(LayoutKind.Explicit)]
|
|
private struct uif
|
|
{
|
|
[FieldOffset(0)]
|
|
public float f;
|
|
[FieldOffset(0)]
|
|
public int i;
|
|
[FieldOffset(0)]
|
|
public uint u;
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region Internal Static Methods
|
|
|
|
internal static ushort Convert(float f)
|
|
{
|
|
uif uif = new uif();
|
|
uif.f = f;
|
|
return Convert(uif.i);
|
|
}
|
|
|
|
internal static ushort Convert(int i)
|
|
{
|
|
int s = (i >> 16) & 0x00008000;
|
|
int e = ((i >> 23) & 0x000000ff) - (127 - 15);
|
|
int m = i & 0x007fffff;
|
|
|
|
if (e <= 0)
|
|
{
|
|
if (e < -10)
|
|
{
|
|
return (ushort) s;
|
|
}
|
|
|
|
m = m | 0x00800000;
|
|
|
|
int t = 14 - e;
|
|
int a = (1 << (t - 1)) - 1;
|
|
int b = (m >> t) & 1;
|
|
|
|
m = (m + a + b) >> t;
|
|
|
|
return (ushort) (s | m);
|
|
}
|
|
else if (e == 0xff - (127 - 15))
|
|
{
|
|
if (m == 0)
|
|
{
|
|
return (ushort) (s | 0x7c00);
|
|
}
|
|
else
|
|
{
|
|
m >>= 13;
|
|
return (ushort) (s | 0x7c00 | m | ((m == 0) ? 1 : 0));
|
|
}
|
|
}
|
|
else
|
|
{
|
|
m = m + 0x00000fff + ((m >> 13) & 1);
|
|
|
|
if ((m & 0x00800000) != 0)
|
|
{
|
|
m = 0;
|
|
e += 1;
|
|
}
|
|
|
|
if (e > 30)
|
|
{
|
|
return (ushort) (s | 0x7c00);
|
|
}
|
|
|
|
return (ushort) (s | (e << 10) | (m >> 13));
|
|
}
|
|
}
|
|
|
|
internal static float Convert(ushort value)
|
|
{
|
|
uint rst;
|
|
uint mantissa = (uint) (value & 1023);
|
|
uint exp = 0xfffffff2;
|
|
|
|
if ((value & -33792) == 0)
|
|
{
|
|
if (mantissa != 0)
|
|
{
|
|
while ((mantissa & 1024) == 0)
|
|
{
|
|
exp--;
|
|
mantissa = mantissa << 1;
|
|
}
|
|
mantissa &= 0xfffffbff;
|
|
rst = ((uint) ((((uint) value & 0x8000) << 16) | ((exp + 127) << 23))) | (mantissa << 13);
|
|
}
|
|
else
|
|
{
|
|
rst = (uint) ((value & 0x8000) << 16);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
rst = (uint) (((((uint) value & 0x8000) << 16) | ((((((uint) value >> 10) & 0x1f) - 15) + 127) << 23)) | (mantissa << 13));
|
|
}
|
|
|
|
uif uif = new uif();
|
|
uif.u = rst;
|
|
return uif.f;
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
}
|