141 lines
4.0 KiB
C++
141 lines
4.0 KiB
C++
#ifndef FASTMATH_H
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#define FASTMATH_H
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#include <cmath>
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#include <iostream>
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#include <stdint.h>
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#include <stdlib.h>
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#define SHIFT_AMOUNT 16
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#define HALF_SHIFT (SHIFT_AMOUNT / 2)
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#define SHIFT_MASK ((1 << SHIFT_AMOUNT) - 1)
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#define TO_FLOAT(x) \
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(((float)(x >> SHIFT_AMOUNT)) + \
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((double)(x & SHIFT_MASK) / (1 << SHIFT_AMOUNT)))
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#define TO_INT(x) ((int32_t)(x * (1 << SHIFT_AMOUNT)))
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#define MUL_F(a, b) (((a) >> HALF_SHIFT) * ((b) >> HALF_SHIFT))
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#define DIV_F(a, b) ((((a) << HALF_SHIFT) / (b)) << HALF_SHIFT)
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struct decimal {
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const int32_t i;
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decimal(float i) : i(TO_INT(i)) {}
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decimal(double i) : i(TO_INT(i)) {}
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decimal(int32_t i) : i(i) {}
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friend std::ostream &operator<<(std::ostream &os, const decimal &d) {
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return (os << TO_FLOAT(d.i));
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}
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friend decimal operator+(const decimal &d1, const decimal &d2) {
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return {d1.i + d2.i};
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}
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decimal &operator+=(const decimal &d) { return (*this) = {i + d.i}; }
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friend decimal operator-(const decimal &d1, const decimal &d2) {
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return {d1.i - d2.i};
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}
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friend decimal operator-(const decimal &d) { return {-d.i}; }
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friend decimal operator*(const decimal &d1, const decimal &d2) {
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return {MUL_F(d1.i, d2.i)};
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}
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friend decimal operator/(const decimal &d1, const decimal &d2) {
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return {DIV_F(d1.i, d2.i)};
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}
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friend bool operator<(const decimal &d1, const decimal &d2) {
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return d1.i < d2.i;
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}
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friend bool operator>(const decimal &d1, const decimal &d2) {
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return d1.i > d2.i;
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}
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friend bool operator==(const decimal &d1, const decimal &d2) {
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return d1.i == d2.i;
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}
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decimal &operator=(decimal const &in) {
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if (this != &in) {
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std::destroy_at(this);
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std::construct_at(this, in);
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}
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return *this;
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}
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decimal sqrt() { return {((int32_t)sqrtf(i)) << HALF_SHIFT}; }
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float to_float() { return TO_FLOAT(i); }
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};
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struct vec3 {
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const decimal x;
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const decimal y;
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const decimal z;
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vec3(float x, float y, float z)
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: x(decimal(x)), y(decimal(y)), z(decimal(z)) {}
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vec3(double x, double y, double z)
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: x(decimal(x)), y(decimal(y)), z(decimal(z)) {}
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vec3(int32_t x, int32_t y, int32_t z)
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: x(decimal(x)), y(decimal(y)), z(decimal(z)) {}
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vec3(decimal x, decimal y, decimal z) : x(x), y(y), z(z) {}
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friend vec3 operator+(const vec3 &v1, const vec3 &v2) {
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return vec3(v1.x + v2.x, v1.y + v2.y, v1.z + v2.z);
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}
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friend vec3 operator-(const vec3 &v1, const vec3 &v2) {
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return vec3(v1.x - v2.x, v1.y - v2.y, v1.z - v2.z);
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}
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vec3 operator-() { return vec3(-x, -y, -z); }
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friend vec3 operator*(const vec3 &v, const decimal &n) {
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int32_t f = n.i >> HALF_SHIFT;
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return vec3({(v.x.i >> HALF_SHIFT) * f}, {(v.y.i >> HALF_SHIFT) * f},
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{(v.z.i >> HALF_SHIFT) * f});
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}
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friend vec3 operator*(const decimal &n, const vec3 &v) { return v * n; }
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decimal operator*(const vec3 &v) { return v.x * x + v.y * y + v.z * z; }
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friend bool operator==(const vec3 &v1, const vec3 &v2) {
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return (v1.x == v2.x) & (v1.y == v2.y) & (v1.z == v2.z);
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}
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vec3 &operator=(vec3 const &in) {
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if (this != &in) {
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std::destroy_at(this);
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std::construct_at(this, in);
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}
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return *this;
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}
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friend std::ostream &operator<<(std::ostream &os, const vec3 &v) {
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return (os << "(" << v.x << ", " << v.y << ", " << v.z << ")"
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<< std::endl);
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}
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vec3 cross(const vec3 &v) {
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return vec3((y * v.z) - (z * v.y), (z * v.x) - (x * v.z),
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(x * v.y) - (y * v.x));
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}
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decimal len_sq() { return *this * *this; }
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decimal len() { return this->len_sq().sqrt(); }
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vec3 normalize() {
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decimal f = decimal(1.0) / this->len();
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return (*this * f);
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}
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};
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#endif
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