kn_math.hpp

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/* vector3.hpp                                                            */
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#pragma once
 
#include "common.hpp"
 
namespace kn::math {
 
template <typename T>
concept number = std::integral<T> or std::floating_point<T>;
 
/** @brief Returns the absolute value of x.
 * @param x The value to return the absolute value of.
 * @return The absolute value of x.
 */
constexpr auto abs(number auto x) {
  return x < 0 ? -x : x;
}
 
/** @brief Returns the minimum of a and b.
 * @param a The first value to compare.
 * @param b The second value to compare.
 * @return The minimum of a and b.
 */
constexpr auto min(number auto a, number auto b) {
  return a < b ? a : b;
}
 
/** @brief Returns the maximum of a and b.
 * @param a The first value to compare.
 * @param b The second value to compare.
 * @return The maximum of a and b.
 */
constexpr auto max(number auto a, number auto b) {
  return a > b ? a : b;
}
 
/** @brief Returns the clamp of x between min and max.
 * @param x The value to clamp.
 * @param min The minimum value.
 * @param max The maximum value.
 * @return The clamped value of x.
 */
constexpr auto clamp(number auto x, number auto min, number auto max) {
  return x < min ? min : (x > max ? max : x);
}
 
/** @brief Returns the square of x.
 * @param x The value to square.
 * @return The square of x.
 */
constexpr auto pow2(number auto x) {
  return x * x;
}
 
/** @brief Returns the cube of x.
 * @param x The value to cube.
 * @return The cube of x.
 */
constexpr auto pow3(number auto x) {
  return x * x * x;
}
 
/** @brief Returns the value of x to the power of 4.
 * @param x The value to raise to the power of 4.
 * @return The value of x to the power of 4.
 */
constexpr auto pow4(number auto x) {
  return x * x * x * x;
}
 
/** @brief Returns the value of x to the power of 5.
 * @param x The value to raise to the power of 5.
 * @return The value of x to the power of 5.
 */
constexpr auto pow5(number auto x) {
  return x * x * x * x * x;
}
 
/** @brief Returns square root of x.
 * @param x The value to return the square root of.
 * @return The square root of x.
 */
auto sqrt(number auto x) {
  if constexpr (std::same_as<decltype(x), float>)
    return ::sqrtf(x);
  else
    return ::sqrt(static_cast<real_t>(x));
}
 
/** @brief Returns fast inverse square root of x.
 * Implements the Quake III algorithm.
 * @param x The value to return the inverse square root of.
 * @return The inverse square root of x.
 */
inline float rsqrt(float x) {
  return 1.0f / ::sqrtf(x);
}
 
/** @brief Returns the linear interpolation between a and b by t.
 * @param a The first value to interpolate.
 * @param b The second value to interpolate.
 * @param t The interpolation factor.
 * @return The linear interpolation between a and b by t.
 */
constexpr auto lerp(number auto a, number auto b, number auto t) {
  return a + t * (b - a);
}
}  // namespace kn::math