include/cglib/definitions.h

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#ifndef _DEFINITIONS_H_
#define _DEFINITIONS_H_

#define WIN32_LEAN_AND_MEAN

#include <stdlib.h>
#include <math.h>
#include <float.h>
#include <limits.h>

#ifdef _WIN32
#define M_PI 3.14159265358979323846f
#endif

#define INV_PI 0.31830988618379067154f
#define INV_TWOPI 0.15915494309189533577f
#define INV_FOURPI 0.079577471545947673f

#define RAY_EPSILON 1e-4f
#define EPSILON 1e-5f

#ifndef INFINITY
#define INFINITY FLT_MAX
#endif

#define FOR(__i,__times) for(int __i=0;__i<__times;__i++)
#define FOR2(__i,__from,__to) for(int __i=__from;__i<=__to;__i++)
#define FOR3(__i,__from,__to) for(int __i=__from;__i<__to;__i++)

inline float lerp(float t, float v1, float v2) {
    return (1.f - t) * v1 + t * v2;
}

inline float clamp(float val, float low, float high) {
    if (val < low) return low;
    else if (val > high) return high;
    else return val;
}

inline int clamp(int val, int low, int high) {
    if (val < low) return low;
    else if (val > high) return high;
    else return val;
}

inline int mod(int a, int b) {
    int n = int(a/b);
    a -= n*b;
    if (a < 0)
        a += b;
    return a;
}

inline float radians(float deg) {
    return ((float)M_PI/180.f) * deg;
}

inline float degrees(float rad) {
    return (180.f/(float)M_PI) * rad;
}

inline float randf()
{
    return (float)rand() / RAND_MAX;
}

inline float random(float lower=0.0, float upper=1.0, int granularity=RAND_MAX-1)
{
    float width = (upper - lower) / granularity;
    return lower + width * (rand() % (granularity+1));
}

inline int ceilpow2(int x)
{
    if (x < 0) return 1;
    int ans = 1;
    while (ans < x)
        ans = ans << 1;
    return ans;
}

inline int divceil(int dividend, int divisor)
{
    if (dividend <= 0) return 0;
    return (dividend-1) / divisor + 1;
}

#endif /* _DEFINITIONS_H_ */

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