Description [src]

struct CoglMatrixEntry {
  /* No available fields */

Represents a single immutable transformation that was retrieved from a CoglMatrixStack using cogl_matrix_stack_get_entry().

Internally a CoglMatrixEntry represents a single matrix operation (such as “rotate”, “scale”, “translate”) which is applied to the transform of a single parent entry.

Using the CoglMatrixStack api effectively builds up a graph of these immutable CoglMatrixEntry structures whereby operations that can be shared between multiple transformations will result in shared CoglMatrixEntry nodes in the graph.

When a CoglMatrixStack is first created it references one CoglMatrixEntry that represents a single “load identity” operation. This serves as the root entry and all operations that are then applied to the stack will extend the graph starting from this root “load identity” entry.

Given the typical usage model for a CoglMatrixStack and the way the entries are built up while traversing a scenegraph then in most cases where an application is interested in comparing two transformations for equality then it is enough to simply compare two CoglMatrixEntry pointers directly. Technically this can lead to false negatives that could be identified with a deeper comparison but often these false negatives are unlikely and don’t matter anyway so this enables extremely cheap comparisons.

CoglMatrixEntrys are reference counted using cogl_matrix_entry_ref() and cogl_matrix_entry_unref() not with g_object_ref() and g_object_unref().

Instance methods


Determines if the only difference between two transforms is a translation and if so returns what the x, y, and z components of the translation are.


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


Determines whether entry is known to represent an identity transform.


Takes a reference on the given entry to ensure the entry stays alive and remains valid. When you are finished with the entry then you should call cogl_matrix_entry_unref().


Releases a reference on entry either taken by calling cogl_matrix_entry_unref() or to release the reference given when calling cogl_matrix_stack_get_entry().