urho3d/Engine/Math/MathDefs.h

//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// 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
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#ifndef MATH_MATHDEFS_H
#define MATH_MATHDEFS_H

#include <cstdlib>
#include <cmath>

#ifndef M_PI
static const float M_PI = 3.141592653589793238462643f;
#endif

static const int M_MIN_INT = 0x80000000;
static const int M_MAX_INT = 0x7fffffff;
static const unsigned M_MIN_UNSIGNED = 0x00000000;
static const unsigned M_MAX_UNSIGNED = 0xffffffff;

static const float M_EPSILON = 0.0000001f;
static const float M_MIN_NEARCLIP = 0.01f;
static const float M_MAX_FOV = 160.0f;
static const float M_LARGE_VALUE = 100000000.0f;
static const float M_INFINITY = (float)HUGE_VAL;
static const float M_DEGTORAD = (float)M_PI / 180.0f;
static const float M_RADTODEG = 1.0f / M_DEGTORAD;

//! Intersection test result
enum Intersection
{
    OUTSIDE,
    INTERSECTS,
    INSIDE
};

//! Linear interpolation between two float values
inline float lerp(float lhs, float rhs, float t)
{
    return lhs * (1.0f - t) + rhs * t;
}

//! Return a random float between 0.0 (inclusive) and 1.0 (exclusive)
inline float random()
{
    return (rand() & 32767) / 32768.0f;
}

//! Return a random float between 0.0 and range, inclusive
inline float random(float range)
{
    return (rand() & 32767) * range / 32767.0f;
}

//! Return a random integer between 0 and range, inclusive
inline int random(int range)
{
    return ((rand() & 32767) * range + 16384) / 32767;
}

//! Return the smaller of two floats
inline float min(float lhs, float rhs)
{
    return lhs < rhs ? lhs : rhs;
}

//! Return the larger of two floats
inline float max(float lhs, float rhs)
{
    return lhs > rhs ? lhs : rhs;
}

//! Clamp a float to a range
inline float clamp(float value, float min, float max)
{
    if (value < min)
        return min;
    if (value > max)
        return max;
    return value;
}

//! Return the smaller of two integers
inline int min(int lhs, int rhs)
{
    return lhs < rhs ? lhs : rhs;
}

//! Return the larger of two integers
inline int max(int lhs, int rhs)
{
    return lhs > rhs ? lhs : rhs;
}

//! Clamp an integer to a range
inline int clamp(int value, int min, int max)
{
    if (value < min)
        return min;
    if (value > max)
        return max;
    return value;
}

//! Check whether an unsigned integer is a power of two
inline bool isPowerOfTwo(unsigned value)
{
    if (!value)
        return true;
    while (!(value & 1))
        value >>= 1;
    return value == 1;
}

#endif // MATH_MATHDEFS_H