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07ab79db64
`std::abs(x - y)` where x and y are unsigned integers fails to compile with an "call of overloaded 'abs(unsigned int)' is ambiguous" error on GCC, and even if it did compile, that expression still wouldn't give the correct result since `x - y` is unsigned.
171 lines
3.6 KiB
C++
171 lines
3.6 KiB
C++
// Copyright 2008 Dolphin Emulator Project
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// Licensed under GPLv2+
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// Refer to the license.txt file included.
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#pragma once
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#include <algorithm>
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#include <cmath>
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#include <type_traits>
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#include <vector>
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#include "Common/CommonTypes.h"
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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namespace MathUtil
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{
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constexpr double TAU = 6.2831853071795865;
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constexpr double PI = TAU / 2;
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constexpr double GRAVITY_ACCELERATION = 9.80665;
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template <typename T>
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constexpr auto Sign(const T& val) -> decltype((T{} < val) - (val < T{}))
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{
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return (T{} < val) - (val < T{});
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}
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template <typename T, typename F>
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constexpr auto Lerp(const T& x, const T& y, const F& a) -> decltype(x + (y - x) * a)
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{
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return x + (y - x) * a;
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}
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template <typename T>
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constexpr bool IsPow2(T imm)
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{
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return imm > 0 && (imm & (imm - 1)) == 0;
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}
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constexpr u32 NextPowerOf2(u32 value)
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{
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--value;
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value |= value >> 1;
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value |= value >> 2;
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value |= value >> 4;
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value |= value >> 8;
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value |= value >> 16;
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++value;
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return value;
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}
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template <class T>
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struct Rectangle
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{
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T left{};
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T top{};
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T right{};
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T bottom{};
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constexpr Rectangle() = default;
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constexpr Rectangle(T theLeft, T theTop, T theRight, T theBottom)
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: left(theLeft), top(theTop), right(theRight), bottom(theBottom)
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{
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}
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constexpr bool operator==(const Rectangle& r) const
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{
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return left == r.left && top == r.top && right == r.right && bottom == r.bottom;
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}
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constexpr T GetWidth() const { return GetDistance(left, right); }
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constexpr T GetHeight() const { return GetDistance(top, bottom); }
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// If the rectangle is in a coordinate system with a lower-left origin, use
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// this Clamp.
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void ClampLL(T x1, T y1, T x2, T y2)
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{
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left = std::clamp(left, x1, x2);
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right = std::clamp(right, x1, x2);
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top = std::clamp(top, y2, y1);
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bottom = std::clamp(bottom, y2, y1);
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}
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// If the rectangle is in a coordinate system with an upper-left origin,
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// use this Clamp.
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void ClampUL(T x1, T y1, T x2, T y2)
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{
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left = std::clamp(left, x1, x2);
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right = std::clamp(right, x1, x2);
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top = std::clamp(top, y1, y2);
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bottom = std::clamp(bottom, y1, y2);
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}
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private:
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constexpr T GetDistance(T a, T b) const
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{
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if constexpr (std::is_unsigned<T>())
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return b > a ? b - a : a - b;
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else
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return std::abs(b - a);
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}
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};
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template <typename T>
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class RunningMean
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{
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public:
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constexpr void Clear() { *this = {}; }
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constexpr void Push(T x) { m_mean = m_mean + (x - m_mean) / ++m_count; }
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constexpr size_t Count() const { return m_count; }
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constexpr T Mean() const { return m_mean; }
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private:
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size_t m_count = 0;
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T m_mean{};
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};
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template <typename T>
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class RunningVariance
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{
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public:
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constexpr void Clear() { *this = {}; }
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constexpr void Push(T x)
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{
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const auto old_mean = m_running_mean.Mean();
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m_running_mean.Push(x);
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m_variance += (x - old_mean) * (x - m_running_mean.Mean());
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}
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constexpr size_t Count() const { return m_running_mean.Count(); }
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constexpr T Mean() const { return m_running_mean.Mean(); }
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constexpr T Variance() const { return m_variance / (Count() - 1); }
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constexpr T StandardDeviation() const { return std::sqrt(Variance()); }
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private:
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RunningMean<T> m_running_mean;
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T m_variance{};
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};
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} // namespace MathUtil
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float MathFloatVectorSum(const std::vector<float>&);
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// Rounds down. 0 -> undefined
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inline int IntLog2(u64 val)
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{
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#if defined(__GNUC__)
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return 63 - __builtin_clzll(val);
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#elif defined(_MSC_VER)
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unsigned long result = ULONG_MAX;
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_BitScanReverse64(&result, val);
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return result;
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#else
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int result = -1;
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while (val != 0)
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{
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val >>= 1;
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++result;
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}
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return result;
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#endif
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}
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