trigonometry.hh

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/*
 
MIT License
 
Copyright (c) 2023 PCSX-Redux authors
 
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*/
 
#pragma once
 
#include <EASTL/array.h>
#include <stdint.h>
 
#include "psyqo/fixed-point.hh"
 
namespace psyqo {
 
namespace TrigInternals {
 
void generateTable(eastl::array<int32_t, 512>& table, unsigned precisionBits);
 
}
 
typedef FixedPoint<10> Angle;
 
namespace trig_literals {
 
consteval Angle operator""_pi(long double angle) { return angle; }
 
}  // namespace trig_literals
 
template <unsigned precisionBits = 12>
class Trig {
  public:
    Trig() { TrigInternals::generateTable(table, precisionBits); }
 
    constexpr FixedPoint<precisionBits> cos(Angle a) const {
        using namespace trig_literals;
        uint32_t t = a.value;
 
        t %= (2.0_pi).value;
        a.value = t;
        int32_t r;
 
        if (a < 0.5_pi) {
            r = table[t];
        } else if (a < 1.0_pi) {
            r = -table[(1.0_pi).value - 1 - t];
        } else if (a < 1.5_pi) {
            r = -table[t - (1.0_pi).value];
        } else {
            r = table[(2.0_pi).value - 1 - t];
        }
 
        FixedPoint<precisionBits> ret;
        ret.value = r;
        return ret;
    }
 
    constexpr FixedPoint<precisionBits> sin(Angle a) const {
        using namespace trig_literals;
        return cos(a - 0.5_pi);
    }
 
  private:
    eastl::array<int32_t, 512> table;
};
 
}  // namespace psyqo