### Class

# CoglMatrixStack

#### Description [src]

```
final class Cogl.MatrixStack : GObject.Object
{
/* No available fields */
}
```

Efficiently tracking many related transformations.

Tracks your current position within a hierarchy and lets you build up a graph of transformations as you traverse through a hierarchy such as a scenegraph.

A `CoglMatrixStack`

always maintains a reference to a single
transformation at any point in time, representing the
transformation at the current position in the hierarchy. You can
get a reference to the current transformation by calling cogl_matrix_stack_get_entry().

When a `CoglMatrixStack`

is first created with
`cogl_matrix_stack_new()`

then it is conceptually positioned at the
root of your hierarchy and the current transformation simply
represents an identity transformation.

As you traverse your object hierarchy (your scenegraph) then you
should call `cogl_matrix_stack_push()`

whenever you move down one
level and call `cogl_matrix_stack_pop()`

whenever you move back up
one level towards the root.

At any time you can apply a set of operations, such as “rotate”,
“scale”, “translate” on top of the current transformation of a
`CoglMatrixStack`

using functions such as
cogl_matrix_stack_rotate(), `cogl_matrix_stack_scale()`

and
cogl_matrix_stack_translate(). These operations will derive a new
current transformation and will never affect a transformation
that you have referenced using cogl_matrix_stack_get_entry().

Internally applying operations to a `CoglMatrixStack`

builds up a
graph of `CoglMatrixEntry`

structures which each represent a single
immutable transform.

#### Constructors

###### cogl_matrix_stack_new

Allocates a new `CoglMatrixStack`

that can be used to build up
transformations relating to objects in a scenegraph like hierarchy.
(See the description of `CoglMatrixStack`

and `CoglMatrixEntry`

for
more details of what a matrix stack is best suited for).

#### Instance methods

###### cogl_matrix_stack_frustum

Replaces the current matrix with a perspective matrix for a given viewing frustum defined by 4 side clip planes that all cross through the origin and 2 near and far clip planes.

###### cogl_matrix_stack_get

Resolves the current `stack`

transform into a #graphene_matrix_t by
combining the operations that have been applied to build up the
current transform.

###### cogl_matrix_stack_get_entry

Gets a reference to the current transform represented by a
`CoglMatrixEntry`

pointer.

###### cogl_matrix_stack_pop

Restores the previous transform that was last saved by calling cogl_matrix_stack_push().

###### cogl_matrix_stack_push

Saves the current transform and starts a new transform that derives from the current transform.

###### cogl_matrix_stack_rotate

Multiplies the current matrix by one that rotates the around the
axis-vector specified by `x`

, `y`

and `z`

. The rotation follows the
right-hand thumb rule so for example rotating by 10 degrees about
the axis-vector (0, 0, 1) causes a small counter-clockwise rotation.

###### cogl_matrix_stack_rotate_euler

Multiplies the current matrix by one that rotates according to the
rotation described by `euler`

.

###### cogl_matrix_stack_scale

Multiplies the current matrix by one that scales the x, y and z axes by the given values.

###### cogl_matrix_stack_set

Replaces the current `stack`

matrix value with the value of `matrix`

.
This effectively discards any other operations that were applied
since the last time `cogl_matrix_stack_push()`

was called or since
the stack was initialized.

###### cogl_matrix_stack_translate

Multiplies the current matrix by one that translates along all three axes according to the given values.

#### Signals

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.