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 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]
| | | |
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 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
GLINVALIDOPERATION is generated if glMultMatrix is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GLMATRIXMODE
glGet with argument GLMODELVIEWMATRIX
glGet with argument GLPROJECTIONMATRIX
glGet with argument GLTEXTUREMATRIX
SEE ALSO
glLoadIdentity, glLoadMatrix, glMatrixMode, glPushMatrix
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