Gl.MultMatrixf (gb.opengl)

Multiply the current matrix with the specified matrix.

Parameters

m

Points to 16 consecutive values that are used as the elements of a $4\times 4$ column-major matrix.

Description

Gl.MultMatrix 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 Gl.MatrixMode). It is either the projection matrix, modelview matrix, or the texture matrix.

Examples

If the current matrix is $\mathit{C}$ and the coordinates to be transformed are , then the current transformation is $\mathit{C}\times \mathit{v}$, or

$\left(\begin{array}{cccc}\mathit{c}\left.[/0\right]& \mathit{c}\left.[/4\right]& \mathit{c}\left.[/8\right]& \mathit{c}\left.[/12\right]\\ \mathit{c}\left.[/1\right]& \mathit{c}\left.[/5\right]& \mathit{c}\left.[/9\right]& \mathit{c}\left.[/13\right]\\ \mathit{c}\left.[/2\right]& \mathit{c}\left.[/6\right]& \mathit{c}\left.[/10\right]& \mathit{c}\left.[/14\right]\\ \mathit{c}\left.[/3\right]& \mathit{c}\left.[/7\right]& \mathit{c}\left.[/11\right]& \mathit{c}\left.[/15\right]\end{array}\right)\times \left(\begin{array}{c}\mathit{v}\left.[/0\right]\\ \mathit{v}\left.[/1\right]\\ \mathit{v}\left.[/2\right]\\ \mathit{v}\left.[/3\right]\end{array}\right)$

Calling Gl.MultMatrix with an argument of replaces the current transformation with $\left(\mathit{C}\times \mathit{M}\right)\times \mathit{v}$, or

$\left(\begin{array}{cccc}\mathit{c}\left.[/0\right]& \mathit{c}\left.[/4\right]& \mathit{c}\left.[/8\right]& \mathit{c}\left.[/12\right]\\ \mathit{c}\left.[/1\right]& \mathit{c}\left.[/5\right]& \mathit{c}\left.[/9\right]& \mathit{c}\left.[/13\right]\\ \mathit{c}\left.[/2\right]& \mathit{c}\left.[/6\right]& \mathit{c}\left.[/10\right]& \mathit{c}\left.[/14\right]\\ \mathit{c}\left.[/3\right]& \mathit{c}\left.[/7\right]& \mathit{c}\left.[/11\right]& \mathit{c}\left.[/15\right]\end{array}\right)\times \left(\begin{array}{cccc}\mathit{m}\left.[/0\right]& \mathit{m}\left.[/4\right]& \mathit{m}\left.[/8\right]& \mathit{m}\left.[/12\right]\\ \mathit{m}\left.[/1\right]& \mathit{m}\left.[/5\right]& \mathit{m}\left.[/9\right]& \mathit{m}\left.[/13\right]\\ \mathit{m}\left.[/2\right]& \mathit{m}\left.[/6\right]& \mathit{m}\left.[/10\right]& \mathit{m}\left.[/14\right]\\ \mathit{m}\left.[/3\right]& \mathit{m}\left.[/7\right]& \mathit{m}\left.[/11\right]& \mathit{m}\left.[/15\right]\end{array}\right)\times \left(\begin{array}{c}\mathit{v}\left.[/0\right]\\ \mathit{v}\left.[/1\right]\\ \mathit{v}\left.[/2\right]\\ \mathit{v}\left.[/3\right]\end{array}\right)$

Where $\mathit{v}$ is represented as a $4\times 1$ 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, $4\times 4$ 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 Gl.MultMatrix 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 Gl.MultMatrix is executed between the execution of Gl.Begin and the corresponding execution of Gl.End.

Associated Gets

Gl.Get with argument Gl.MATRIX_MODE

Gl.Get with argument Gl.COLOR_MATRIX

Gl.Get with argument Gl.MODELVIEW_MATRIX

Gl.Get with argument Gl.PROJECTION_MATRIX

Gl.Get with argument Gl.TEXTURE_MATRIX

See also

See original documentation on OpenGL website