# TransformState¶

class TransformState

Indicates a coordinate-system transform on vertices. TransformStates are the primary means for storing transformations on the scene graph.

Transforms may be specified in one of two ways: componentwise, with a pos- hpr-scale, or with an arbitrary transform matrix. If you specify a transform componentwise, it will remember its original components.

TransformState objects are managed very much like RenderState objects. They are immutable and reference-counted automatically.

You should not attempt to create or modify a TransformState object directly. Instead, call one of the make() functions to create one for you. And instead of modifying a TransformState object, create a new one.

Inheritance diagram

void cache_ref(void) const

Overrides this method to update PStats appropriately.

bool cache_unref(void) const

Overrides this method to update PStats appropriately.

static int clear_cache(void)

Empties the cache of composed TransformStates. This makes every TransformState forget what results when it is composed with other TransformStates.

This will eliminate any TransformState objects that have been allocated but have no references outside of the internal TransformState map. It will not eliminate TransformState objects that are still in use.

Nowadays, this method should not be necessary, as reference-count cycles in the composition cache should be automatically detected and broken.

The return value is the number of TransformStates freed by this operation.

int compare_to(TransformState const &other) const
int compare_to(TransformState const &other, bool uniquify_matrix) const

Provides an arbitrary ordering among all unique TransformStates, so we can store the essentially different ones in a big set and throw away the rest.

Note that if this returns 0, it doesn’t necessarily imply that operator == returns true; it uses a very slightly different comparison threshold.

Provides an arbitrary ordering among all unique TransformStates, so we can store the essentially different ones in a big set and throw away the rest.

Note that if this returns 0, it doesn’t necessarily imply that operator == returns true; it uses a very slightly different comparison threshold.

If uniquify_matrix is true, then matrix-defined TransformStates are also uniqified. If uniquify_matrix is false, then only component-defined TransformStates are uniquified, which is less expensive.

bool components_given(void) const

Returns true if the transform was specified componentwise, or false if it was specified with a general 4x4 matrix. If this is true, the components returned by get_pos() and get_scale() will be exactly those that were set; otherwise, these functions will return computed values. If this is true, the rotation may have been set either with a hpr trio or with a quaternion; hpr_given() or quat_given() can resolve the difference.

ConstPointerTo<TransformState> compose(TransformState const *other) const

Returns a new TransformState object that represents the composition of this state with the other state.

The result of this operation is cached, and will be retained as long as both this TransformState object and the other TransformState object continue to exist. Should one of them destruct, the cached entry will be removed, and its pointer will be allowed to destruct as well.

static int garbage_collect(void)

Performs a garbage-collection cycle. This must be called periodically if garbage-collect-states is true to ensure that TransformStates get cleaned up appropriately. It does no harm to call it even if this variable is not true, but there is probably no advantage in that case.

static TypeHandle get_class_type(void)
PyObject *get_composition_cache(void) const
std::size_t get_composition_cache_num_entries(void) const

Returns the number of entries in the composition cache for this TransformState. This is the number of other TransformStates whose composition with this one has been cached. This number is not useful for any practical reason other than performance analysis.

TransformState const *get_composition_cache_result(std::size_t n) const

Returns the result TransformState of the nth element in the composition cache. Returns NULL if there doesn’t happen to be an entry in the nth element.

In general, a->compose(a->get_composition_cache_source(n)) == a->get_composition_cache_result(n).

This has no practical value other than for examining the cache for performance analysis.

std::size_t get_composition_cache_size(void) const

Returns the number of slots in the composition cache for this TransformState. You may use this as an upper bound when walking through all of the composition cache results via get_composition_cache_source() or result().

This has no practical value other than for examining the cache for performance analysis.

TransformState const *get_composition_cache_source(std::size_t n) const

Returns the source TransformState of the nth element in the composition cache. Returns NULL if there doesn’t happen to be an entry in the nth element. See get_composition_cache_result().

This has no practical value other than for examining the cache for performance analysis.

int get_geom_rendering(int geom_rendering) const

Returns the union of the Geom::GeomRendering bits that will be required once this TransformState is applied to a geom which includes the indicated geom_rendering bits. The RenderState’s get_geom_rendering() should already have been applied.

std::size_t get_hash(void) const

Returns a suitable hash value for phash_map.

LVecBase3 const &get_hpr(void) const

Returns the rotation component of the transform as a trio of Euler angles. It is an error to call this if has_components() returned false.

ConstPointerTo<TransformState> get_inverse(void) const

Returns the inverse of this transform. If you are going to immediately compose this result with another TransformState, it is faster to do it in one operation with invert_compose().

PyObject *get_invert_composition_cache(void) const
std::size_t get_invert_composition_cache_num_entries(void) const

Returns the number of entries in the invert_composition cache for this TransformState. This is similar to the composition cache, but it records cache entries for the invert_compose() operation. See get_composition_cache_num_entries().

TransformState const *get_invert_composition_cache_result(std::size_t n) const

Returns the result TransformState of the nth element in the invert composition cache. Returns NULL if there doesn’t happen to be an entry in the nth element.

In general, a->invert_compose(a->get_invert_composition_cache_source(n)) == a->get_invert_composition_cache_result(n).

This has no practical value other than for examining the cache for performance analysis.

std::size_t get_invert_composition_cache_size(void) const

Returns the number of slots in the composition cache for this TransformState. You may use this as an upper bound when walking through all of the composition cache results via get_invert_composition_cache_source() or result().

This has no practical value other than for examining the cache for performance analysis.

TransformState const *get_invert_composition_cache_source(std::size_t n) const

Returns the source TransformState of the nth element in the invert composition cache. Returns NULL if there doesn’t happen to be an entry in the nth element. See get_invert_composition_cache_result().

This has no practical value other than for examining the cache for performance analysis.

LMatrix4 const &get_mat(void) const

Returns the matrix that describes the transform.

LMatrix3 get_mat3(void) const

Returns the 3x3 matrix that describes the 2-d transform. It is an error to call this if is_2d() returned false.

LQuaternion const &get_norm_quat(void) const

Returns the rotation component of the transform as a quaternion. Unlike the result of get_quat(), the return value of this method is guaranteed to be normalized. It is an error to call this if has_components() returned false.

static int get_num_states(void)

Returns the total number of unique TransformState objects allocated in the world. This will go up and down during normal operations.

static int get_num_unused_states(void)

Returns the total number of TransformState objects that have been allocated but have no references outside of the internal TransformState cache.

A nonzero return value is not necessarily indicative of leaked references; it is normal for two TransformState objects, both of which have references held outside the cache, to have the result of their composition stored within the cache. This result will be retained within the cache until one of the base TransformStates is released.

Use list_cycles() to get an idea of the number of actual “leaked” TransformState objects.

LPoint3 const &get_pos(void) const

Returns the pos component of the transform. It is an error to call this if has_pos() returned false.

LVecBase2 get_pos2d(void) const

Returns the pos component of the 2-d transform. It is an error to call this if has_pos() or is_2d() returned false.

LQuaternion const &get_quat(void) const

Returns the rotation component of the transform as a quaternion. The return value will be normalized if a normalized quaternion was given to the constructor (or if the quaternion was computed implicitly); it will be non- normalized if a non-normalized quaternion was given to the constructor. See also get_norm_quat().

It is an error to call this if has_components() returned false.

PN_stdfloat get_rotate2d(void) const

Returns the rotation component of the 2-d transform as an angle in degrees clockwise about the origin. It is an error to call this if has_components() or is_2d() returned false.

LVecBase3 const &get_scale(void) const

Returns the scale component of the transform. It is an error to call this if has_components() returned false.

LVecBase2 get_scale2d(void) const

Returns the scale component of the 2-d transform. It is an error to call this if has_components() or is_2d() returned false.

LVecBase3 const &get_shear(void) const

Returns the shear component of the transform. It is an error to call this if has_components() returned false.

PN_stdfloat get_shear2d(void) const

Returns the shear component of the 2-d transform. It is an error to call this if has_components() or is_2d() returned false.

static PyObject *get_states(void)
PN_stdfloat get_uniform_scale(void) const

Returns the scale component of the transform, as a single number. It is an error to call this if has_uniform_scale() returned false.

ConstPointerTo<TransformState> get_unique(void) const

Returns the pointer to the unique TransformState in the cache that is equivalent to this one. This may be the same pointer as this object, or it may be a different pointer; but it will be an equivalent object, and it will be a shared pointer. This may be called from time to time to improve cache benefits.

static PyObject *get_unused_states(void)
bool has_components(void) const

Returns true if the transform can be described by separate pos, hpr, and scale components. Most transforms we use in everyday life can be so described, but some kinds of transforms (for instance, those involving a skew) cannot.

This is not related to whether the transform was originally described componentwise. Even a transform that was constructed with a 4x4 may return true here if the matrix is a simple affine matrix with no skew.

If this returns true, you may safely call get_hpr() and get_scale() to retrieve the components. (You may always safely call get_pos() whether this returns true or false.)

bool has_hpr(void) const

Returns true if the transform’s rotation component can be extracted out separately and described as a set of Euler angles. This is generally true only when has_components() is true.

bool has_identity_scale(void) const

Returns true if the scale is uniform 1.0, or false if the scale has some real value.

bool has_mat(void) const

Returns true if the transform can be described as a matrix. This is generally always true, unless is_invalid() is true.

bool has_nonzero_shear(void) const

Returns true if the shear component is non-zero, false if it is zero or if the matrix cannot be decomposed.

bool has_pos(void) const

Returns true if the transform’s pos component can be extracted out separately. This is generally always true, unless the transform is invalid (i.e. is_invalid() returns true).

bool has_quat(void) const

Returns true if the transform’s rotation component can be extracted out separately and described as a quaternion. This is generally true only when has_components() is true.

bool has_scale(void) const

Returns true if the transform’s scale component can be extracted out separately. This is generally true only when has_components() is true.

bool has_shear(void) const

Returns true if the transform’s shear component can be extracted out separately. This is generally true only when has_components() is true.

bool has_uniform_scale(void) const

Returns true if the scale is uniform across all three axes (and therefore can be expressed as a single number), or false if the transform has a different scale in different dimensions.

bool hpr_given(void) const

Returns true if the rotation was specified via a trio of Euler angles, false otherwise. If this is true, get_hpr() will be exactly as set; otherwise, it will return a computed value.

ConstPointerTo<TransformState> invert_compose(TransformState const *other) const

Returns a new TransformState object that represents the composition of this state’s inverse with the other state.

This is similar to compose(), but is particularly useful for computing the relative state of a node as viewed from some other node.

bool is_2d(void) const

Returns true if the transform has been constructed entirely using the 2-d transform operations, e.g. make_pos2d(), and therefore operates strictly in two-dimensional space on X and Y only.

bool is_identity(void) const

Returns true if the transform represents the identity matrix, false otherwise.

bool is_invalid(void) const

Returns true if the transform represents an invalid matrix, for instance the result of inverting a singular matrix, or false if the transform is valid.

bool is_singular(void) const

Returns true if the transform represents a singular transform (that is, it has a zero scale, and it cannot be inverted), or false otherwise.

static void list_cycles(std::ostream &out)

Detects all of the reference-count cycles in the cache and reports them to standard output.

These cycles may be inadvertently created when state compositions cycle back to a starting point. Nowadays, these cycles should be automatically detected and broken, so this method should never list any cycles unless there is a bug in that detection logic.

The cycles listed here are not leaks in the strictest sense of the word, since they can be reclaimed by a call to clear_cache(); but they will not be reclaimed automatically.

static void list_states(std::ostream &out)

Lists all of the TransformStates in the cache to the output stream, one per line. This can be quite a lot of output if the cache is large, so be prepared.

ConstPointerTo<TransformState> make_hpr(LVecBase3 const &hpr)

Makes a new TransformState with the specified components.

static ConstPointerTo<TransformState> make_identity(void)

Constructs an identity transform.

static ConstPointerTo<TransformState> make_invalid(void)

Constructs an invalid transform; for instance, the result of inverting a singular matrix.

static ConstPointerTo<TransformState> make_mat(LMatrix4 const &mat)

Makes a new TransformState with the specified transformation matrix.

static ConstPointerTo<TransformState> make_mat3(LMatrix3 const &mat)

Makes a new two-dimensional TransformState with the specified 3x3 transformation matrix.

ConstPointerTo<TransformState> make_pos(LVecBase3 const &pos)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_pos2d(LVecBase2 const &pos)

Makes a new 2-d TransformState with the specified components.

ConstPointerTo<TransformState> make_pos_hpr(LVecBase3 const &pos, LVecBase3 const &hpr)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_pos_hpr_scale(LVecBase3 const &pos, LVecBase3 const &hpr, LVecBase3 const &scale)

Makes a new TransformState with the specified components.

static ConstPointerTo<TransformState> make_pos_hpr_scale_shear(LVecBase3 const &pos, LVecBase3 const &hpr, LVecBase3 const &scale, LVecBase3 const &shear)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_pos_quat_scale(LVecBase3 const &pos, LQuaternion const &quat, LVecBase3 const &scale)

Makes a new TransformState with the specified components.

static ConstPointerTo<TransformState> make_pos_quat_scale_shear(LVecBase3 const &pos, LQuaternion const &quat, LVecBase3 const &scale, LVecBase3 const &shear)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_pos_rotate2d(LVecBase2 const &pos, PN_stdfloat rotate)

Makes a new 2-d TransformState with the specified components.

ConstPointerTo<TransformState> make_pos_rotate_scale2d(LVecBase2 const &pos, PN_stdfloat rotate, LVecBase2 const &scale)

Makes a new 2-d TransformState with the specified components.

static ConstPointerTo<TransformState> make_pos_rotate_scale_shear2d(LVecBase2 const &pos, PN_stdfloat rotate, LVecBase2 const &scale, PN_stdfloat shear)

Makes a new two-dimensional TransformState with the specified components.

ConstPointerTo<TransformState> make_quat(LQuaternion const &quat)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_rotate2d(PN_stdfloat rotate)

Makes a new 2-d TransformState with the specified components.

ConstPointerTo<TransformState> make_scale(PN_stdfloat scale)
ConstPointerTo<TransformState> make_scale(LVecBase3 const &scale)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_scale2d(PN_stdfloat scale)
ConstPointerTo<TransformState> make_scale2d(LVecBase2 const &scale)

Makes a new 2-d TransformState with the specified components.

ConstPointerTo<TransformState> make_shear(LVecBase3 const &shear)

Makes a new TransformState with the specified components.

ConstPointerTo<TransformState> make_shear2d(PN_stdfloat shear)

Makes a new 2-d TransformState with the specified components.

void node_ref(void) const

Overrides this method to update PStats appropriately.

bool node_unref(void) const

Overrides this method to update PStats appropriately.

void output(std::ostream &out) const
bool quat_given(void) const

Returns true if the rotation was specified via a quaternion, false otherwise. If this is true, get_quat() will be exactly as set; otherwise, it will return a computed value.

ConstPointerTo<TransformState> set_hpr(LVecBase3 const &hpr) const

Returns a new TransformState object that represents the original TransformState with its rotation component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_pos(LVecBase3 const &pos) const

Returns a new TransformState object that represents the original TransformState with its pos component replaced with the indicated value.

ConstPointerTo<TransformState> set_pos2d(LVecBase2 const &pos) const

Returns a new TransformState object that represents the original 2-d TransformState with its pos component replaced with the indicated value.

ConstPointerTo<TransformState> set_quat(LQuaternion const &quat) const

Returns a new TransformState object that represents the original TransformState with its rotation component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_rotate2d(PN_stdfloat rotate) const

Returns a new TransformState object that represents the original 2-d TransformState with its rotation component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_scale(LVecBase3 const &scale) const

Returns a new TransformState object that represents the original TransformState with its scale component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_scale2d(LVecBase2 const &scale) const

Returns a new TransformState object that represents the original 2-d TransformState with its scale component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_shear(LVecBase3 const &shear) const

Returns a new TransformState object that represents the original TransformState with its shear component replaced with the indicated value, if possible.

ConstPointerTo<TransformState> set_shear2d(PN_stdfloat shear) const

Returns a new TransformState object that represents the original 2-d TransformState with its shear component replaced with the indicated value, if possible.

bool validate_composition_cache(void) const

Returns true if the composition cache and invert composition cache for this particular TransformState are self-consistent and valid, false otherwise.

static bool validate_states(void)

Ensures that the cache is still stored in sorted order, and that none of the cache elements have been inadvertently deleted. Returns true if so, false if there is a problem (which implies someone has modified one of the supposedly-const TransformState objects).

void write(std::ostream &out, int indent_level) const
void write_composition_cache(std::ostream &out, int indent_level) const

Writes a brief description of the composition cache and invert composition cache to the indicated ostream. This is not useful except for performance analysis, to examine the cache structure.