imagecore/utils/mathutils.h

/*
 * MIT License
 *
 * Copyright (c) 2017 Twitter
 *
 * 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.
 */

#pragma once

#include "imagecore/imagecore.h"
#include <climits>

inline float lerp(float a, float b, float v)
{
	return a + (b - a) * v;
}

inline float step(float a, float b, float v)
{
	return (v - a) / (b - a);
}

inline int max(int x, int y)
{
	return x > y ? x : y;
}

inline int min(int x, int y)
{
	return x < y ? x : y;
}

inline unsigned int max(unsigned int x, unsigned int y)
{
	return x > y ? x : y;
}

inline unsigned int min(unsigned int x, unsigned int y)
{
	return x < y ? x : y;
}

inline uint64_t max(uint64_t x, uint64_t y)
{
	return x > y ? x : y;
}

inline uint64_t min(uint64_t x, uint64_t y)
{
	return x < y ? x : y;
}

inline int clamp(int minv, int maxv, int a)
{
	return max(minv, min(a, maxv));
}

inline float saturate(float f)
{
	return fmaxf(0, fminf(1, f));
}

inline float clampf(float v, float min, float max)
{
	return fmaxf(min, fminf(v, max));
}

inline float npowf(float x, float e)
{
	return x >= 0.0f ? powf(x, e) : -powf(-x, e);
}

inline unsigned char luminance(unsigned char r, unsigned char b, unsigned char g)
{
	return (max(r, max(g, b)));
}

inline unsigned int align(unsigned int v, unsigned int a)
{
	if(a > 0) {
		unsigned int rem = v % a;
		if( rem != 0 ) {
			return v + (a - rem);
		}
	}
	return v;
}

inline void swap(unsigned int& a, unsigned int& b)
{
	unsigned int temp = a;
	a = b;
	b = temp;
}

inline unsigned int div2_round(unsigned int a)
{
	if(a == UINT_MAX) {
		return (a - 1) / 2 + 1;
	} else {
		return (a + 1) / 2;
	}
}