dolphin/Source/Core/Common/MathUtil.cpp

// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <cmath>
#include <cstring>
#include <limits>
#include <numeric>

#include "Common/CommonTypes.h"
#include "Common/MathUtil.h"

inline void MatrixMul(int n, const float* a, const float* b, float* result)
{
  for (int i = 0; i < n; ++i)
  {
    for (int j = 0; j < n; ++j)
    {
      float temp = 0;
      for (int k = 0; k < n; ++k)
      {
        temp += a[i * n + k] * b[k * n + j];
      }
      result[i * n + j] = temp;
    }
  }
}

// Calculate sum of a float list
float MathFloatVectorSum(const std::vector<float>& Vec)
{
  return std::accumulate(Vec.begin(), Vec.end(), 0.0f);
}

void Matrix33::LoadIdentity(Matrix33& mtx)
{
  memset(mtx.data, 0, sizeof(mtx.data));
  mtx.data[0] = 1.0f;
  mtx.data[4] = 1.0f;
  mtx.data[8] = 1.0f;
}

void Matrix33::RotateX(Matrix33& mtx, float rad)
{
  float s = sin(rad);
  float c = cos(rad);
  memset(mtx.data, 0, sizeof(mtx.data));
  mtx.data[0] = 1;
  mtx.data[4] = c;
  mtx.data[5] = -s;
  mtx.data[7] = s;
  mtx.data[8] = c;
}
void Matrix33::RotateY(Matrix33& mtx, float rad)
{
  float s = sin(rad);
  float c = cos(rad);
  memset(mtx.data, 0, sizeof(mtx.data));
  mtx.data[0] = c;
  mtx.data[2] = s;
  mtx.data[4] = 1;
  mtx.data[6] = -s;
  mtx.data[8] = c;
}

void Matrix33::Multiply(const Matrix33& a, const Matrix33& b, Matrix33& result)
{
  MatrixMul(3, a.data, b.data, result.data);
}

void Matrix33::Multiply(const Matrix33& a, const float vec[3], float result[3])
{
  for (int i = 0; i < 3; ++i)
  {
    result[i] = 0;

    for (int k = 0; k < 3; ++k)
    {
      result[i] += a.data[i * 3 + k] * vec[k];
    }
  }
}

void Matrix44::LoadIdentity(Matrix44& mtx)
{
  memset(mtx.data, 0, sizeof(mtx.data));
  mtx.data[0] = 1.0f;
  mtx.data[5] = 1.0f;
  mtx.data[10] = 1.0f;
  mtx.data[15] = 1.0f;
}

void Matrix44::LoadMatrix33(Matrix44& mtx, const Matrix33& m33)
{
  for (int i = 0; i < 3; ++i)
  {
    for (int j = 0; j < 3; ++j)
    {
      mtx.data[i * 4 + j] = m33.data[i * 3 + j];
    }
  }

  for (int i = 0; i < 3; ++i)
  {
    mtx.data[i * 4 + 3] = 0;
    mtx.data[i + 12] = 0;
  }
  mtx.data[15] = 1.0f;
}

void Matrix44::Set(Matrix44& mtx, const float mtxArray[16])
{
  for (int i = 0; i < 16; ++i)
  {
    mtx.data[i] = mtxArray[i];
  }
}

void Matrix44::Translate(Matrix44& mtx, const float vec[3])
{
  LoadIdentity(mtx);
  mtx.data[3] = vec[0];
  mtx.data[7] = vec[1];
  mtx.data[11] = vec[2];
}

void Matrix44::Shear(Matrix44& mtx, const float a, const float b)
{
  LoadIdentity(mtx);
  mtx.data[2] = a;
  mtx.data[6] = b;
}

void Matrix44::Multiply(const Matrix44& a, const Matrix44& b, Matrix44& result)
{
  MatrixMul(4, a.data, b.data, result.data);
}