fglMultMatrix(3G)

NAME
     fglMultMatrixd, fglMultMatrixf - multiply the current matrix with the
     specified matrix


FORTRAN SPECIFICATION
     SUBROUTINE fglMultMatrixd( CHARACTER*8 m )
     SUBROUTINE fglMultMatrixf( CHARACTER*8 m )


PARAMETERS
     m  Points to 16 consecutive values that are used as the elements of a
        4 x 4 column-major matrix.

DESCRIPTION
     fglMultMatrix multiplies the current matrix with the one specified using
     m, and replaces the current matrix with the product.

     The current matrix is determined by the current matrix mode (see
     fglMatrixMode). It is either the projection matrix, modelview matrix, or
     the texture matrix.

EXAMPLES
     If the current matrix is C, and the coordinates to be transformed are,
     v = (v[0],v[1],v[2],v[3]).  Then the current transformation is C x v, or



                      (c[0]  c[4]  c[8]   c[12] )     (v[0] )

                      |                         |     |     |
                       c[1]  c[5]  c[9]   c[13]        v[1]
                      |                         |     |     |
                                                   x
                      |c[2]  c[6]  c[10]  c[14] |     |v[2] |

                      |                         |     |     |
                       c[3]  c[7]  c[11]   c[15]       v[3]
                      (                         )     (     )



     Calling fglMultMatrix with an argument of m = m[0],m[1],...,m[15]
     replaces the current transformation with (C x M) x v, or



      (c[0]  c[4]  c[8]   c[12] )     (m[0]  m[4]  m[8]   m[12] )     (v[0] )

      |                         |     |                         |     |     |
       c[1]  c[5]  c[9]   c[13]        m[1]  m[5]  m[9]   m[13]        v[1]
      |                         |     |                         |     |     |
                                   x                               x
      |c[2]  c[6]  c[10]  c[14] |     |m[2]  m[6]  m[10]  m[14] |     |v[2] |

      |                         |     |                         |     |     |
       c[3]  c[7]  c[11]   c[15]       m[3]  m[7]  m[11]   m[15]       v[3]
      (                         )     (                         )     (     )



     Where 'x' denotes matrix multiplication, and v is represented as a 4 x 1
     matrix.

NOTES
     While the elements of the matrix may be specified with single or double
     precision, the GL may store or operate on these values in less than
     single precision.
     In many computer languages 4 x 4 arrays are represented in row-major
     order. The transformations just described represent these matrices in
     column-major order.  The order of the multiplication is important. For
     example, if the current transformation is a rotation, and fglMultMatrix
     is called with a translation matrix, the translation is done directly on
     the coordinates to be transformed, while the rotation is done on the
     results of that translation.

ERRORS
     GL_INVALID_OPERATION is generated if fglMultMatrix is executed between
     the execution of fglBegin and the corresponding execution of fglEnd.

ASSOCIATED GETS
     fglGet with argument GL_MATRIX_MODE
     fglGet with argument GL_COLOR_MATRIX
     fglGet with argument GL_MODELVIEW_MATRIX
     fglGet with argument GL_PROJECTION_MATRIX
     fglGet with argument GL_TEXTURE_MATRIX


SEE ALSO
     fglLoadIdentity, fglLoadMatrix, fglMatrixMode, fglPushMatrix