Unigine::Curve2d Class

Header:

#include <UnigineCurve2d.h>

This class represents an interface enabling you to create and manage 2D curves. These curves are used, for example, to control behavior of various parameters of particle systems (how they change over time).

Methods:

Name	Description View: Sort by:
Curve2d	Constructor.
getHash	Returns a hash value calculated for the curve.
getNumKeys	Returns the current total number of key points in the curve .
setRepeatModeStart	Sets the mode for the beginning of the curve to be used for repeating the sequence defined by the key points of the curve (tiling curves).
getRepeatModeStart	Returns the current mode for the beginning of the curve used for repeating the sequence defined by the key points of the curve (tiling curves).
setRepeatModeEnd	Sets the mode for the end of the curve to be used for repeating the sequence defined by the key points of the curve (tiling curves).
getRepeatModeEnd	Returns the current mode for the end of the curve used for repeating the sequence defined by the key points of the curve (tiling curves).
clear	Clears the curve removing all key points and tangents.
copy	Copies all the data (all key points and tangents) from the specified source curve.
addKey	Adds a new key point with the specified coordinates to the curve.
removeKey	Removes the key point with the specified number from the curve.
moveKey	Moves the key point with the specified number to a new position (preserving the tangents).
sortKeys	Sorts all key points ov the curve by time (X axis) in the ascending order.
setKeyPoint	Sets new coordinates for the specified key point (tangents are unaffected).
setKeyLeftTangent	Sets new coordinates for the left tangent at the specified key point of the curve.
setKeyRightTangent	Sets new coordinates for the right tangent at the specified key point of the curve.
getKeyPoint	Returns the coordinates of the key point with the specified number.
getKeyLeftTangent	Returns the current coordinates for the left tangent at the specified key point of the curve.
getKeyRightTangent	Returns the current coordinates for the right tangent at the specified key point of the curve.
saveState	Saves data of the curve to a binary stream.
restoreState	Restores curve data from a binary stream.
save	Saves data of the curve to the specified instance of the Xml class.
load	Loads curve data from the specified instance of the Xml class.
addChangedCallback	Adds a callback function to be called on changing the curve.
removeChangedCallback	Removes the specified callback from the list of changed callbacks.
clearChangedCallbacks	Clears all added changed callbacks.
evaluate	Returns the evaluated value of the curve at the specified point in time.

Curve2d Class

Enums

REPEAT_MODE#

Mode to be used for repeating the sequence defined by the key points of the curve (tiling curves).

Name	Description
REPEAT_MODE_CLAMP = 0	The value of the start or the end key is retained. Use this option if you don't want any changes before or after the effect created by the curve.
REPEAT_MODE_LOOP = 1	The curve is tiled. The created effect is repeated cyclically. If the values of the first and the last key are different, the transition between the curves will be abrupt.
REPEAT_MODE_PING_PONG = 2	Every next curve section is a reflection of the previous curve section. The created effect is repeated in the forward-and-backward manner.
NUM_REPEAT_MODES = 3	Number of repeat modes.

Members

Curve2d ( ) #

Constructor. Creates a new 2d curve instance.

Curve2d ( const Ptr<Curve2d> & curve ) #

Constructor. Initializes the curve by copying the specified source curve.

Arguments

const Ptr<Curve2d> & curve - Source curve.

void clear ( ) #

Clears the curve removing all key points and tangents.

void copy ( const Ptr<Curve2d> & curve ) #

Copies all the data (all key points and tangents) from the specified source curve.

Arguments

const Ptr<Curve2d> & curve - Source curve.

int getHash ( ) const#

Returns a hash value calculated for the curve. This value is used for performance optimization and helps define if the curve really needs to be updated, or nothing has changed in its parameters (repeat mode, key points, and tangents are all the same).

Return value

Hash value calculated for the curve.

int getNumKeys ( ) const#

Returns the current total number of key points in the curve .

Return value

Total number of key points in the curve.

int addKey ( const Math::vec2 & point ) #

Adds a new key point with the specified coordinates to the curve. Upon completion on this operation the CHANGED callback is fired.

Arguments

const Math::vec2 & point - Coordinates of the new key point to be added.

Return value

Number of the added key point.

int addKey ( const Math::vec2 & point, const Math::vec2 & left_tangent, const Math::vec2 & right_tangent ) #

Adds a new key point with the specified coordinates and tangents to the curve. Upon completion on this operation the CHANGED callback is fired.

Arguments

const Math::vec2 & point - Coordinates of the new key point to be added.
const Math::vec2 & left_tangent - Coordinates of the left tangent at the key point.
const Math::vec2 & right_tangent - Coordinates of the right tangent at the key point.

Return value

Number of the added key point.

void removeKey ( int index ) #

Removes the key point with the specified number from the curve. Upon completion on this operation the CHANGED callback is fired.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.

int moveKey ( int index, const Math::vec2 & point ) #

Moves the key point with the specified number to a new position (preserving the tangents). Upon completion on this operation the CHANGED callback is fired. The index of key point will be updated automatically. This method can be used to implement dragging of keys on the curve. In case of moving multiple keys it is recommended to use the setKeyPoint() method to set new values for keys and then sort them all at once via the sortKeys() method to save performance.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.
const Math::vec2 & point

void sortKeys ( ) #

Sorts all key points ov the curve by time (X axis) in the ascending order. Upon completion on this operation the CHANGED callback is fired.

void setKeyPoint ( int index, const Math::vec2 & point ) #

Sets new coordinates for the specified key point (tangents are unaffected). Upon completion on this operation the CHANGED callback is fired. This method unlike the moveKey() does not update the index of the key point automatically. It can be used to implement dragging of multiple keys to set new values for them along with subsequent sorting all keys at once via the sortKeys() method to save performance.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.
const Math::vec2 & point - New coordinates to be set for the specified point.

void setKeyLeftTangent ( int index, const Math::vec2 & point ) #

Sets new coordinates for the left tangent at the specified key point of the curve. Upon completion on this operation the CHANGED callback is fired.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.
const Math::vec2 & point - New coordinates of the left tangent at the specified key point to be set.

void setKeyRightTangent ( int index, const Math::vec2 & point ) #

Sets new coordinates for the right tangent at the specified key point of the curve. Upon completion on this operation the CHANGED callback is fired.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.
const Math::vec2 & point - New coordinates of the right tangent at the specified key point to be set.

Math::vec2 getKeyPoint ( int index ) #

Returns the coordinates of the key point with the specified number.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.

Return value

Current coordinates of the specified key point.

Math::vec2 getKeyLeftTangent ( int index ) #

Returns the current coordinates for the left tangent at the specified key point of the curve.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.

Return value

Current coordinates of the left tangent at the specified key point.

Math::vec2 getKeyRightTangent ( int index ) #

Returns the current coordinates for the right tangent at the specified key point of the curve.

Arguments

int index - Key point number, in the range from 0 to the total number of key points in the curve.

Return value

Current coordinates of the right tangent at the specified key point.

int saveState ( const Ptr<Stream> & stream ) const#

Saves data of the curve to a binary stream.

Example using saveState() and restoreState() methods:

Source code (C++)

// initialize a node and set its state
Curve2dPtr curve = Curve2d::create();
curve->addKey(vec2(1, 0));
curve->addKey(vec2(2, 1));
curve->addKey(vec2(4, 3));

// save state
BlobPtr blob_state = Blob::create();
curve->saveState(blob_state);

// change state
curve->removeKey(1);

// restore state
blob_state->seekSet(0);				// returning the carriage to the start of the blob
curve->restoreState(blob_state);

Arguments

const Ptr<Stream> & stream - Stream to which the curve data will be saved.

Return value

true if the curve data is saved successfully; otherwise, false.

bool restoreState ( const Ptr<Stream> & stream ) #

Restores curve data from a binary stream.

Example using saveState() and restoreState() methods:

Source code (C++)

// initialize a node and set its state
Curve2dPtr curve = Curve2d::create();
curve->addKey(vec2(1, 0));
curve->addKey(vec2(2, 1));
curve->addKey(vec2(4, 3));

// save state
BlobPtr blob_state = Blob::create();
curve->saveState(blob_state);

// change state
curve->removeKey(1);

// restore state
blob_state->seekSet(0);				// returning the carriage to the start of the blob
curve->restoreState(blob_state);

Arguments

const Ptr<Stream> & stream - Stream in which the saved curve parameter data is stored.

Return value

true if the curve data is restored successfully; otherwise, false.

bool save ( const Ptr<Xml> & xml ) const#

Saves data of the curve to the specified instance of the Xml class.

Arguments

const Ptr<Xml> & xml - Xml class instance to which the curve data will be saved.

Return value

true if the curve data is successfully saved to the specified Xml class instance; otherwise, false.

bool load ( const Ptr<Xml> & xml ) #

Loads curve data from the specified instance of the Xml class.

Arguments

const Ptr<Xml> & xml - Xml class instance in which the curve data is stored.

Return value

true if the curve data is successfully loaded from the specified Xml class instance; otherwise, false.

void setRepeatModeStart ( Curve2d::REPEAT_MODE start ) #

Sets the mode for the beginning of the curve to be used for repeating the sequence defined by the key points of the curve (tiling curves).

Arguments

Curve2d::REPEAT_MODE start - Repeat mode for the beginning of the curve (defines behavior before the first key point), one of the REPEAT_MODE_* values.

Curve2d::REPEAT_MODE getRepeatModeStart ( ) const#

Returns the current mode for the beginning of the curve used for repeating the sequence defined by the key points of the curve (tiling curves).

Return value

Current repeat mode for the beginning of the curve (defines behavior before the first key point), one of the REPEAT_MODE_* values.

void setRepeatModeEnd ( Curve2d::REPEAT_MODE end ) #

Sets the mode for the end of the curve to be used for repeating the sequence defined by the key points of the curve (tiling curves).

Arguments

Curve2d::REPEAT_MODE end - Repeat mode for the end of the curve (defines behavior after the last key point), one of the REPEAT_MODE_* values.

Curve2d::REPEAT_MODE getRepeatModeEnd ( ) const#

Returns the current mode for the end of the curve used for repeating the sequence defined by the key points of the curve (tiling curves).

Return value

Current repeat mode for the end of the curve (defines behavior after the last key point), one of the REPEAT_MODE_* values.

void * addChangedCallback ( Unigine::CallbackBase * func ) #

Adds a callback function to be called on changing the curve. The signature of the changed callback function must be as follows:

Source code (C++)

void changed_callback_function_name();

You can set a callback function as follows:

Source code (C++)

addChangedCallback(MakeCallback(changed_callback_function_name));

Example: Setting a changed callback function for a curve:

Source code (C++)

class SomeClass {

	/*...*/
	
	// curve for which a changed callback function is to be set
	Unigine::Curve2d curve;
	
	/*...*/
};

/*...*/

// callback function
void SomeClass::on_change()
{
	// insert your code handling curve changing here
}

void SomeClass::registerCallback()
{
	// setting the on_change() function to handle curve changing
	curve->addChangedCallback(MakeCallback(this, &SomeClass::on_change));
}

Arguments

Unigine::CallbackBase * func - Callback pointer.

Return value

ID of the last added changed callback, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.

bool removeChangedCallback ( void * id ) #

Removes the specified callback from the list of changed callbacks.

Arguments

void * id - Changed callback ID obtained when adding it.

Return value

True if the changed callback with the given ID was removed successfully; otherwise false.

void clearChangedCallbacks ( ) #

Clears all added changed callbacks.

float evaluate ( float time ) const#

Returns the evaluated value of the curve at the specified point in time.

Arguments

float time - The time within the curve you want to evaluate (horizontal axis in the curve graph).

Return value

The value of the curve, at the specified point in time.

Last update: 13.12.2021

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