MirBSD manpage: glMultMatrix(3), glMultMatrixd(3), glMultMatrixf(3)


GLMULTMATRIX(3G)    UNIX Programmer's Manual     GLMULTMATRIX(3G)

NAME

     glMultMatrixd, glMultMatrixf - multiply the current matrix
     with the specified matrix

C SPECIFICATION

     void glMultMatrixd( const GLdouble *m )
     void glMultMatrixf( const GLfloat *m )

PARAMETERS

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

DESCRIPTION

     glMultMatrix 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 glMatrixMode). 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[1]
               |c[2]  c[4]
               |c[3]  c[5]
                      c[6]  c[8]
                      c[7]  c[9]
                            c[10]  c[12] |
                            c[11]  c[13] |     |
                                   c[14] |     |
                                   c[15] |  x  |v[0] |
                                         |     |v[1] |
                                         |     |v[2] |
                                               |v[3] |
                                                     |
                                                     |

     Calling glMultMatrix 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[1]
     |c[2]  c[4]
     |c[3]  c[5]
            c[6]  c[8]
            c[7]  c[9]
                  c[10]  c[12] |
                  c[11]  c[13] |     |
                         c[14] |     |
                         c[15] |  x  |m[0]
                               |     |m[1]
                               |     |m[2]  m[4]
                                     |m[3]  m[5]
                                            m[6]  m[8]
                                            m[7]  m[9]
                                                  m[10]  m[12] |
                                                  m[11]  m[13] |     |
                                                         m[14] |     |
                                                         m[15] |  x  |v[0] |
                                                               |     |v[1] |
                                                               |     |v[2] |
                                                                     |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 sin-
     gle or double precision, the GL may store or operate on

MirBSD #10-current     Printed 2021-12-07                       1

GLMULTMATRIX(3G)    UNIX Programmer's Manual     GLMULTMATRIX(3G)

     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 glMultMatrix 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 glMultMatrix is exe-
     cuted between the execution of glBegin and the corresponding
     execution of glEnd.

ASSOCIATED GETS

     glGet with argument GL_MATRIX_MODE
     glGet with argument GL_COLOR_MATRIX
     glGet with argument GL_MODELVIEW_MATRIX
     glGet with argument GL_PROJECTION_MATRIX
     glGet with argument GL_TEXTURE_MATRIX

SEE ALSO

     glLoadIdentity(3G), glLoadMatrix(3G), glMatrixMode(3G),
     glPushMatrix(3G)

MirBSD #10-current     Printed 2021-12-07                       2

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