OOFastArithmetic.h

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/*
 
OOFastArithmetic.h
 
Mathematical framework for Oolite.
 
Oolite
Copyright (C) 2004-2013 Giles C Williams and contributors
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
 
*/
 
 
#ifndef INCLUDED_OOMATHS_h
    #error Do not include OOFastArithmetic.h directly; include OOMaths.h.
#else
 
 
/* Clamp to range. */
OOINLINE float OOClamp_0_1_f(float value) INLINE_CONST_FUNC;
OOINLINE float OOClamp_n1_1_f(float value) INLINE_CONST_FUNC;
OOINLINE double OOClamp_0_1_d(double value) INLINE_CONST_FUNC;
OOINLINE float OOClamp_0_max_f(float value, float max) INLINE_CONST_FUNC;
OOINLINE double OOClamp_0_max_d(double value, double max) INLINE_CONST_FUNC;
 
/* Linear interpolation. */
OOINLINE float OOLerp(float v0, float v1, float fraction) INLINE_CONST_FUNC;
OOINLINE double OOLerpd(double v0, double v1, double fraction) INLINE_CONST_FUNC;
 
 
/* Round integer up to nearest power of 2. NOTE: these return 0 if the high bit of value is set. */
OOINLINE INLINE_CONST_FUNC uint32_t OORoundUpToPowerOf2_32(uint32_t value)
{
    return 0x80000000U >> (__builtin_clz(value - 1) - 1);
}
 
 
OOINLINE INLINE_CONST_FUNC uint64_t OORoundUpToPowerOf2_64(uint64_t value)
{
    return 0x8000000000000000ULL >> (__builtin_clzll(value - 1) - 1);
}
 
 
#if __OBJC__
#if OOLITE_64_BIT
OOINLINE INLINE_CONST_FUNC NSUInteger OORoundUpToPowerOf2_NS(NSUInteger value)
{
    return OORoundUpToPowerOf2_64(value);
}
#else
OOINLINE INLINE_CONST_FUNC NSUInteger OORoundUpToPowerOf2_NS(NSUInteger value)
{
    return OORoundUpToPowerOf2_32(value);
}
#endif
#endif
 
 
OOINLINE float OOClamp_0_1_f(float value)
{
    return fmax(0.0f, fmin(value, 1.0f));
}
 
OOINLINE float OOClamp_n1_1_f(float value)
{
    return fmax(-1.0f, fmin(value, 1.0f));
}
 
OOINLINE double OOClamp_0_1_d(double value)
{
    return fmax(0.0f, fmin(value, 1.0f));
}
 
OOINLINE float OOClamp_0_max_f(float value, float max)
{
    return fmax(0.0f, fmin(value, max));
}
 
OOINLINE double OOClamp_0_max_d(double value, double max)
{
    return fmax(0.0, fmin(value, max));
}
 
 
OOINLINE float OOLerp(float v0, float v1, float fraction)
{
    // Linear interpolation - equivalent to v0 * (1.0f - fraction) + v1 * fraction.
    return v0 + fraction * (v1 - v0);
}
 
OOINLINE double OOLerpd(double v0, double v1, double fraction)
{
    // Linear interpolation - equivalent to v0 * (1.0 - fraction) + v1 * fraction.
    return v0 + fraction * (v1 - v0);
}
 
 
 
#endif  /* INCLUDED_OOMATHS_h */