common/vecmat.h

   1 #ifndef COMMON_VECMAT_H
   2 #define COMMON_VECMAT_H
   3
   4 #include <algorithm>
   5 #include <array>
   6 #include <cmath>
   7 #include <cstddef>
   8 #include <limits>
   9
  10 #include "alspan.h"
  11
  12
  13 namespace alu {
  14
  15 class Vector {
  16     alignas(16) std::array<float,4> mVals{};
  17
  18 public:
  19     constexpr Vector() noexcept = default;
  20     constexpr Vector(const Vector&) noexcept = default;
  21     constexpr Vector(Vector&&) noexcept = default;
  22     constexpr explicit Vector(float a, float b, float c, float d) noexcept : mVals{{a,b,c,d}} { }
  23
  24     constexpr auto operator=(const Vector&) noexcept -> Vector& = default;
  25     constexpr auto operator=(Vector&&) noexcept -> Vector& = default;
  26
  27     [[nodiscard]] constexpr
  28     auto operator[](std::size_t idx) noexcept -> float& { return mVals[idx]; }
  29     [[nodiscard]] constexpr
  30     auto operator[](std::size_t idx) const noexcept -> const float& { return mVals[idx]; }
  31
  32     constexpr auto operator+=(const Vector &rhs) noexcept -> Vector&
  33     {
  34         mVals[0] += rhs.mVals[0];
  35         mVals[1] += rhs.mVals[1];
  36         mVals[2] += rhs.mVals[2];
  37         mVals[3] += rhs.mVals[3];
  38         return *this;
  39     }
  40
  41     [[nodiscard]] constexpr
  42     auto operator-(const Vector &rhs) const noexcept -> Vector
  43     {
  44         return Vector{mVals[0] - rhs.mVals[0], mVals[1] - rhs.mVals[1],
  45             mVals[2] - rhs.mVals[2], mVals[3] - rhs.mVals[3]};
  46     }
  47
  48     constexpr auto normalize() -> float
  49     {
  50         const auto length_sqr = float{mVals[0]*mVals[0] + mVals[1]*mVals[1] + mVals[2]*mVals[2]};
  51         if(length_sqr > std::numeric_limits<float>::epsilon())
  52         {
  53             const auto length = std::sqrt(length_sqr);
  54             auto inv_length = float{1.0f / length};
  55             mVals[0] *= inv_length;
  56             mVals[1] *= inv_length;
  57             mVals[2] *= inv_length;
  58             return length;
  59         }
  60         mVals[0] = mVals[1] = mVals[2] = 0.0f;
  61         return 0.0f;
  62     }
  63
  64     [[nodiscard]] constexpr auto cross_product(const Vector &rhs) const noexcept -> Vector
  65     {
  66         return Vector{
  67             mVals[1]*rhs.mVals[2] - mVals[2]*rhs.mVals[1],
  68             mVals[2]*rhs.mVals[0] - mVals[0]*rhs.mVals[2],
  69             mVals[0]*rhs.mVals[1] - mVals[1]*rhs.mVals[0],
  70             0.0f};
  71     }
  72
  73     [[nodiscard]] constexpr auto dot_product(const Vector &rhs) const noexcept -> float
  74     { return mVals[0]*rhs.mVals[0] + mVals[1]*rhs.mVals[1] + mVals[2]*rhs.mVals[2]; }
  75 };
  76
  77 class Matrix {
  78     alignas(16) std::array<float,16> mVals{};
  79
  80 public:
  81     constexpr Matrix() noexcept = default;
  82     constexpr Matrix(const Matrix&) noexcept = default;
  83     constexpr Matrix(Matrix&&) noexcept = default;
  84     constexpr explicit Matrix(
  85         float aa, float ab, float ac, float ad,
  86         float ba, float bb, float bc, float bd,
  87         float ca, float cb, float cc, float cd,
  88         float da, float db, float dc, float dd) noexcept
  89         : mVals{{aa,ab,ac,ad, ba,bb,bc,bd, ca,cb,cc,cd, da,db,dc,dd}}
  90     { }
  91
  92     constexpr auto operator=(const Matrix&) noexcept -> Matrix& = default;
  93     constexpr auto operator=(Matrix&&) noexcept -> Matrix& = default;
  94
  95     [[nodiscard]] constexpr auto operator[](std::size_t idx) noexcept
  96     { return al::span<float,4>{&mVals[idx*4], 4}; }
  97     [[nodiscard]] constexpr auto operator[](std::size_t idx) const noexcept
  98     { return al::span<const float,4>{&mVals[idx*4], 4}; }
  99
 100     [[nodiscard]] static constexpr auto Identity() noexcept -> Matrix
 101     {
 102         return Matrix{
 103             1.0f, 0.0f, 0.0f, 0.0f,
 104             0.0f, 1.0f, 0.0f, 0.0f,
 105             0.0f, 0.0f, 1.0f, 0.0f,
 106             0.0f, 0.0f, 0.0f, 1.0f};
 107     }
 108
 109     [[nodiscard]] friend constexpr
 110     auto operator*(const Matrix &mtx, const Vector &vec) noexcept -> Vector
 111     {
 112         return Vector{
 113             vec[0]*mtx[0][0] + vec[1]*mtx[1][0] + vec[2]*mtx[2][0] + vec[3]*mtx[3][0],
 114             vec[0]*mtx[0][1] + vec[1]*mtx[1][1] + vec[2]*mtx[2][1] + vec[3]*mtx[3][1],
 115             vec[0]*mtx[0][2] + vec[1]*mtx[1][2] + vec[2]*mtx[2][2] + vec[3]*mtx[3][2],
 116             vec[0]*mtx[0][3] + vec[1]*mtx[1][3] + vec[2]*mtx[2][3] + vec[3]*mtx[3][3]};
 117     }
 118 };
 119
 120 } // namespace alu
 121
 122 #endif /* COMMON_VECMAT_H */