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
elements of a 4x4 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[4] c[8] c[12] ) (v[0] )
| | | |
|c[1] c[5] c[9] c[13] | |v[1] |
|c[2] c[6] c[10] c[14] | x |v[2] |
| | | |
(c[3] c[7] c[11] c[15] ) (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[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] |
|c[2] c[6] c[10] c[14] | x |m[2] m[6] m[10] m[14] | x |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 4x4 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
executed between the execution of glBegin and the
corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_MATRIX_MODE
glGet with argument GL_MODELVIEW_MATRIX
glGet with argument GL_PROJECTION_MATRIX
glGet with argument GL_TEXTURE_MATRIX
SEE ALSO
glLoadIdentity, glLoadMatrix, glMatrixMode, glPushMatrix