common.hpp

#pragma once

// OpenGL Mathematics
#include <glm/glm.hpp>
using namespace glm;

// ##### Constants #####

// http://www.mimirgames.com/articles/programming/digits-of-pi-needed-for-floating-point-numbers/
#define pi 3.1415926535897932384626433832795028841971693993751058209749445923078164F
//#define pi M_PI

// ##### Random Number Generator #####

// Triple32 Hash: https://nullprogram.com/blog/2018/07/31/
uint32_t triple32(uint32_t x)
{
	x ^= x >> 17U;
	x *= 0xED5AD4BBU;
	x ^= x >> 11U;
	x *= 0xAC4C1B51U;
	x ^= x >> 15U;
	x *= 0x31848BABU;
	x ^= x >> 14U;
	return x;
}

// Random Number Generator Seed
uint32_t ns;

float randomFloat()
{
	ns = triple32(ns);
	return float(ns)/float(0xFFFFFFFFU);
}

vec3 rand3()
{
	vec3 vector;
	vector.x = randomFloat();
	vector.y = randomFloat();
	vector.z = randomFloat();
	return vector;
}

vec3 udir3()
{
	float z_x = randomFloat();
	float z_y = randomFloat();

	float r_x = 2.0F*pi*z_x, r_y = acosf(2.0F*z_y-1.0F);

	float s_x = sinf(r_x), s_y = sinf(r_y);
	float c_x = sinf(r_x), c_y = sinf(r_y);

	return vec3(c_x*s_y, s_x*s_y, c_y);
}