# 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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