mtxlib.cpp

游戏编程精华02－含有几十个游戏编程例子

  col[0] -= m[0];
  col[1] -= m[1];
  col[2] -= m[2];
  col[3] -= m[3];

  return *this;
}

// Multiply the matrix44 by another matrix44
matrix44 &matrix44::operator *= (const matrix44 &m) 
{
  matrix44 t;
  
  for (unsigned int r = 0; r < 4; r++) 
  {
    for (unsigned int c = 0; c < 4; c++) 
    {
      float f = 0;
          
      f += col[0][r] * m[c][0];
      f += col[1][r] * m[c][1];
      f += col[2][r] * m[c][2];
      f += col[3][r] * m[c][3];
          
      t[c][r] = f;
    }
  }
  
  *this = t;

  return *this;
}

// Multiply the matrix44 by a float
matrix44 &matrix44::operator *= (float f) 
{
  col[0] *= f;
  col[1] *= f;
  col[2] *= f;
  col[3] *= f;

  return *this;
}

// Are these two matrix44's equal?
bool operator == (const matrix44 &a, const matrix44 &b) 
{
  return ((a[0] == b[0]) && (a[1] == b[1]) &&
          (a[2] == b[2]) && (a[3] == b[3]));
}

// Are these two matrix44's not equal?
bool operator != (const matrix44 &a, const matrix44 &b) 
{
  return ((a[0] != b[0]) || (a[1] != b[1]) ||
          (a[2] != b[2]) || (a[3] != b[3]));
}

// Add two matrix44's
matrix44 operator + (const matrix44 &a, const matrix44 &b) 
{
  matrix44 ret(a);

  ret += b;

  return ret;
}

// Subtract one matrix44 from another
matrix44 operator - (const matrix44 &a, const matrix44 &b) 
{
  matrix44 ret(a);

  ret -= b;

  return ret;
}

// Multiply matrix44 by another matrix44
matrix44 operator * (const matrix44 &a, const matrix44 &b) 
{
  matrix44 ret(a);

  ret *= b;

  return ret;
}

// Multiply a vector3 by this matrix44
vector3 operator * (const matrix44 &m, const vector3 &v) 
{
  vector4 ret(v);

  ret = m * ret;

  return vector3(ret.x, ret.y, ret.z);
}

// Multiply a vector3 by this matrix44
vector3 operator * (const vector3 &v, const matrix44 &m) 
{
  vector4 ret(v);

  ret = ret * m;

  return vector3(ret.x, ret.y, ret.z);
}

// Multiply a vector4 by this matrix44
vector4 operator * (const matrix44 &m, const vector4 &v) 
{
  vector4 ret;

  ret.x = v.x * m[0][0] + v.y * m[1][0] + v.z * m[2][0] + v.w * m[3][0];
  ret.y = v.x * m[0][1] + v.y * m[1][1] + v.z * m[2][1] + v.w * m[3][1];
  ret.z = v.x * m[0][2] + v.y * m[1][2] + v.z * m[2][2] + v.w * m[3][2];
  ret.w = v.x * m[0][3] + v.y * m[1][3] + v.z * m[2][3] + v.w * m[3][3];

  return ret;
}

// Multiply a vector4 by this matrix44
vector4 operator * (const vector4 &v, const matrix44 &m) 
{
  vector4 ret;

  ret.x = DotProduct(m[0], v);
  ret.y = DotProduct(m[1], v);
  ret.z = DotProduct(m[2], v);
  ret.w = DotProduct(m[3], v);

  return ret;
}

// Multiply matrix44 by a float
matrix44 operator * (float f, const matrix44 &m) 
{
  matrix44 ret(m);

  ret *= f;

  return ret;
}

// Set matrix44 to the identity matrix
matrix44 &matrix44::identity() 
{
  for (unsigned int c = 0; c < 4; c++) 
  {
    for (unsigned int r = 0; r < 4; r++) 
    {
      if (c == r) 
        col[c][r] = 1.0F;
      else 
        col[c][r] = 0.0F;
    } 
  } 
  
  return *this;
}

// Transpose the matrix44
matrix44 &matrix44::transpose() 
{
  float t;
  
  for (unsigned int c = 0; c < 4; c++) 
  {
    for (unsigned int r = c + 1; r < 4; r++) 
    {
      t = col[c][r];
      col[c][r] = col[r][c];
      col[r][c] = t;
    } 
  } 
  
  return *this;
}

// Invert the matrix44
matrix44 &matrix44::invert() 
{
  matrix44 a(*this);
  matrix44 b(IdentityMatrix44());

  unsigned int r, c;
  unsigned int cc;
  unsigned int rowMax; // Points to max abs value row in this column
  unsigned int row;
  float tmp;

  // Go through columns
  for (c=0; c<4; c++) 
  {
      
    // Find the row with max value in this column
    rowMax = c;
    for (r=c+1; r<4; r++) 
    {
      if (fabs(a[c][r]) > fabs(a[c][rowMax])) 
      {
        rowMax = r;
      }
    }
      
    // If the max value here is 0, we can't invert.  Return identity.
    if (a[rowMax][c] == 0.0F) 
      return (identity());
      
    // Swap row "rowMax" with row "c"
    for (cc=0; cc<4; cc++) 
    {
      tmp = a[cc][c];
      a[cc][c] = a[cc][rowMax];
      a[cc][rowMax] = tmp;
      tmp = b[cc][c];
      b[cc][c] = b[cc][rowMax];
      b[cc][rowMax] = tmp;
    }
      
    // Now everything we do is on row "c".
    // Set the max cell to 1 by dividing the entire row by that value
    tmp = a[c][c];
    for (cc=0; cc<4; cc++) 
    {
      a[cc][c] /= tmp;
      b[cc][c] /= tmp;
    }
      
    // Now do the other rows, so that this column only has a 1 and 0's
    for (row = 0; row < 4; row++) 
    {
      if (row != c) 
      {
        tmp = a[c][row];
        for (cc=0; cc<4; cc++) 
        {
          a[cc][row] -= a[cc][c] * tmp;
          b[cc][row] -= b[cc][c] * tmp;
        }
      }
    }
      
  }

  *this = b;

  return *this;
}

// Return a matrix44 set to the identity matrix
matrix44 IdentityMatrix44() 
{
  matrix44 ret;

  return ret.identity();
}

// Return the transpose of the matrix44
matrix44 TransposeMatrix44(const matrix44 &m) 
{
  matrix44 ret(m);

  return ret.transpose();
}

// Return the inverted matrix44
matrix44 InvertMatrix44(const matrix44 &m) 
{
  matrix44 ret(m);

  return ret.invert();
}

// Return a 3D axis-rotation matrix44
// Pass in 'x', 'y', or 'z' for the axis.
matrix44 RotateRadMatrix44(char axis, float rad) 
{
  matrix44 ret;
  float sinA, cosA;

  sinA = (float)sin(rad);
  cosA = (float)cos(rad);

  switch(axis) 
  {
  case 'x':
  case 'X':
    ret[0][0] =  1.0F; ret[1][0] =  0.0F; ret[2][0] =  0.0F;
    ret[0][1] =  0.0F; ret[1][1] =  cosA; ret[2][1] = -sinA;
    ret[0][2] =  0.0F; ret[1][2] =  sinA; ret[2][2] =  cosA;
    break;
    
  case 'y':
  case 'Y':
    ret[0][0] =  cosA; ret[1][0] =  0.0F; ret[2][0] =  sinA;
    ret[0][1] =  0.0F; ret[1][1] =  1.0F; ret[2][1] =  0.0F;
    ret[0][2] = -sinA; ret[1][2] =  0.0F; ret[2][2] =  cosA;
    break;
    
  case 'z':
  case 'Z':
    ret[0][0] =  cosA; ret[1][0] = -sinA; ret[2][0] =  0.0F;
    ret[0][1] =  sinA; ret[1][1] =  cosA; ret[2][1] =  0.0F;
    ret[0][2] =  0.0F; ret[1][2] =  0.0F; ret[2][2] =  1.0F;
    break;
  }
  
  ret[0][3] = 0.0F; ret[1][3] = 0.0F; ret[2][3] = 0.0F;
  ret[3][0] = 0.0F;
  ret[3][1] = 0.0F;
  ret[3][2] = 0.0F;
  ret[3][3] = 1.0F;
  
  return ret;
}

// Return a 3D axis-rotation matrix44
// Pass in an arbitrary vector3 axis.
matrix44 RotateRadMatrix44(const vector3 &axis, float rad) 
{
  matrix44 ret;
  float sinA, cosA;
  float invCosA;
  vector3 nrm = axis;
  float x, y, z;
  float xSq, ySq, zSq;

  nrm.normalize();
  sinA = (float)sin(rad);
  cosA = (float)cos(rad);
  invCosA = 1.0F - cosA;

  x = nrm.x;
  y = nrm.y;
  z = nrm.z;

  xSq = x * x;
  ySq = y * y;
  zSq = z * z;

  ret[0][0] = (invCosA * xSq) + (cosA);
  ret[1][0] = (invCosA * x * y) - (sinA * z );
  ret[2][0] = (invCosA * x * z) + (sinA * y );
  ret[3][0] = 0.0F;
  
  ret[0][1] = (invCosA * x * y) + (sinA * z);
  ret[1][1] = (invCosA * ySq) + (cosA);
  ret[2][1] = (invCosA * y * z) - (sinA * x);
  ret[3][1] = 0.0F;

  ret[0][2] = (invCosA * x * z) - (sinA * y);
  ret[1][2] = (invCosA * y * z) + (sinA * x);
  ret[2][2] = (invCosA * zSq) + (cosA);
  ret[3][2] = 0.0F;

  ret[0][3] = 0.0F;
  ret[1][3] = 0.0F;
  ret[2][3] = 0.0F;
  ret[3][3] = 1.0F;

  return ret;
}

// Return a 3D translation matrix44
matrix44 TranslateMatrix44(float x, float y, float z) 
{
  matrix44 ret;

  ret.identity();
  ret[3][0] = x;
  ret[3][1] = y;
  ret[3][2] = z;

  return ret;
}

// Return a 3D/4D scale matrix44
matrix44 ScaleMatrix44(float x, float y, float z, float w) 
{
  matrix44 ret;

  ret.identity();
  ret[0][0] = x;
  ret[1][1] = y;
  ret[2][2] = z;
  ret[3][3] = w;

  return ret;
}

// Return a "lookat" matrix44 given the current camera position (vector3),
//   camera-up vector3, and camera-target vector3.
matrix44 LookAtMatrix44(const vector3 &camPos, const vector3 &camUp, 
                        const vector3 &target ) 
{
  matrix44 rot;
  matrix44 tran;

  vector3 look = (camPos - target);
  look.normalize();

  vector3 right = CrossProduct(camUp, look);
  right.normalize();

  vector3 up = CrossProduct(look, right);
  up.normalize();

  rot[0][0] = right.x;
  rot[1][0] = right.y;
  rot[2][0] = right.z;
  rot[3][0] = 0.0;

  rot[0][1] = up.x;
  rot[1][1] = up.y;
  rot[2][1] = up.z;
  rot[3][1] = 0.0;

  rot[0][2] = look.x;
  rot[1][2] = look.y;
  rot[2][2] = look.z;
  rot[3][2] = 0.0;

  rot[0][3] = 0.0F;
  rot[1][3] = 0.0F;
  rot[2][3] = 0.0F;
  rot[3][3] = 1.0F;

  tran = TranslateMatrix44(-camPos.x, -camPos.y, -camPos.z);

  return (rot * tran);
}

// Return a frustum matrix44 given the left, right, bottom, top,
//   near, and far values for the frustum boundaries.
matrix44 FrustumMatrix44(float l, float r, 
                         float b, float t, float n, float f) 
{
  matrix44 ret;
  float width = r-l;
  float height = t-b;
  float depth = f-n;

  ret[0][0] = (2*n) / width;
  ret[0][1] = 0.0F;
  ret[0][2] = 0.0F;
  ret[0][3] = 0.0F;

  ret[1][0] = 0.0F;
  ret[1][1] = (2*n) / height;
  ret[1][2] = 0.0F;
  ret[1][3] = 0.0F;

  ret[2][0] = (r + l) / width;
  ret[2][1] = (t + b) / height;
  ret[2][2] = -(f + n) / depth;
  ret[2][3] = -1.0F;

  ret[3][0] = 0.0F;
  ret[3][1] = 0.0F;
  ret[3][2] = -(2*f*n) / depth;
  ret[3][3] = 0.0F;

  return ret;
}

// Return a perspective matrix44 given the field-of-view in the Y
//   direction in degrees, the aspect ratio of Y/X, and near and
//   far plane distances.
matrix44 PerspectiveMatrix44(float fovY, float aspect, float n, float f) 
{
  matrix44 ret;
  float angle;
  float cot;

  angle = fovY / 2.0F;
  angle = DegToRad( angle );

  cot = (float) cos(angle) / (float) sin(angle);

  ret[0][0] = cot / aspect;
  ret[0][1] = 0.0F;
  ret[0][2] = 0.0F;
  ret[0][3] = 0.0F;

  ret[1][0] = 0.0F;
  ret[1][1] = cot;
  ret[1][2] = 0.0F;
  ret[1][3] = 0.0F;

  ret[2][0] = 0.0F;
  ret[2][1] = 0.0F;
  ret[2][2] = -(f + n) / (f - n);
  ret[2][3] = -1.0F;


  ret[3][0] = 0.0F;
  ret[3][1] = 0.0F;
  ret[3][2] = -(2*f*n) / (f - n);
  ret[3][3] = 0.0F;

  return ret;
}

// Return an orthographic matrix44 given the left, right, bottom, top,
//   near, and far values for the frustum boundaries.
matrix44 OrthoMatrix44(float l, float r, 
                       float b, float t, float n, float f) 
{
  matrix44 ret;
  float width = r-l;
  float height = t-b;
  float depth = f-n;
  
  ret[0][0] = 2.0F / width;
  ret[0][1] = 0.0F;
  ret[0][2] = 0.0F;
  ret[0][3] = 0.0F;

  ret[1][0] = 0.0F;
  ret[1][1] = 2.0F / height;
  ret[1][2] = 0.0F;
  ret[1][3] = 0.0F;

  ret[2][0] = 0.0F;
  ret[2][1] = 0.0F;
  ret[2][2] = -(2.0F) / depth;
  ret[2][3] = 0.0F;

  ret[3][0] = -(r + l) / width;
  ret[1][3] = -(t + b) / height;
  ret[3][2] = -(f + n) / depth;
  ret[3][3] = 1.0F;
  
  return ret;
}

// Return an orientation matrix using 3 basis normalized vectors
matrix44	OrthoNormalMatrix44(const vector3 &xdir, 
				const vector3 &ydir, const vector3 &zdir)
{
  matrix44 ret;
  
  ret[0] = (vector4)xdir;
  ret[1] = (vector4)ydir;
  ret[2] = (vector4)zdir;
  ret[3][3] = 1.0F;
  
  return ret;
}


////////////////////////////////////////////////////////////
// Debug functions
//

// Print a vector2 to a file
void vector2::fprint(FILE* file, char* str) const 
{
  fprintf(file, "%svector2: <%f, %f>\n", str, x, y);
}

// Print a vector3 to a file
void vector3::fprint(FILE* file, char* str) const 
{
  fprintf(file, "%svector3: <%f, %f, %f>\n", str, x, y, z);
}

// Print a vector4 to a file
void vector4::fprint(FILE* file, char* str) const 
{
  fprintf(file, "%svector4: <%f, %f, %f, %f>\n", str, x, y, z, w);
}

// Print a matrix33 to a file
void matrix33::fprint(FILE* file, char * str) const 
{
  fprintf(file, "%smatrix33:\n", str);
  vector3 row0(col[0][0], col[1][0], col[2][0]);
  row0.fprint(file, "\t");
  vector3 row1(col[0][1], col[1][1], col[2][1]);
  row1.fprint(file, "\t");
  vector3 row2(col[0][2], col[1][2], col[2][2]);
  row2.fprint(file, "\t");
}

// Print a matrix44 to a file
void matrix44::fprint(FILE* file, char* str) const 
{
  fprintf(file, "%smatrix44:\n", str);
  vector4 row0(col[0][0], col[1][0], col[2][0], col[3][0]);
  row0.fprint(file, "\t");
  vector4 row1(col[0][1], col[1][1], col[2][1], col[3][1]);
  row1.fprint(file, "\t");
  vector4 row2(col[0][2], col[1][2], col[2][2], col[3][2]);
  row2.fprint(file, "\t");
  vector4 row3(col[0][3], col[1][3], col[2][3], col[3][3]);
  row3.fprint(file, "\t");
}