glMultMatrix(3G) OpenGL Reference 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 elements 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[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 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]
| | | | | |
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.
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glMultMatrix(3G) OpenGL Reference glMultMatrix(3G)
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 executed 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, glLoadMatrix, glMatrixMode, glPushMatrix
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