scalar.h

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#pragma once
 
#include <cfloat>
#include <type_traits>
#include <valarray>
 
#include "impeller/geometry/constants.h"
 
namespace impeller {
 
using Scalar = float;
 
template <class T, class = std::enable_if_t<std::is_arithmetic_v<T>>>
constexpr T Absolute(const T& val) {
  return val >= T{} ? val : -val;
}
 
constexpr inline bool ScalarNearlyZero(Scalar x,
                                       Scalar tolerance = kEhCloseEnough) {
  return Absolute(x) <= tolerance;
}
 
constexpr inline bool ScalarNearlyEqual(Scalar x,
                                        Scalar y,
                                        Scalar tolerance = kEhCloseEnough) {
  return ScalarNearlyZero(x - y, tolerance);
}
 
struct Degrees;
 
struct Radians {
  Scalar radians = 0.0;
 
  constexpr Radians() = default;
 
  explicit constexpr Radians(Scalar p_radians) : radians(p_radians) {}
};
 
struct Degrees {
  Scalar degrees = 0.0;
 
  constexpr Degrees() = default;
 
  explicit constexpr Degrees(Scalar p_degrees) : degrees(p_degrees) {}
 
  constexpr operator Radians() const {
    return Radians{degrees * kPi / 180.0f};
  };
};
 
}  // namespace impeller