General purpose calculator for floats and 3D float vectors.The SoCalculator uses the values from the input fields (which are either single floating point values or vectors) as variables in the free-form engine expressions and places the results on the output fields. More...

#include <Inventor/engines/SoCalculator.h>

Inheritance diagram for SoCalculator:

Public Member Functions
virtual SoType	getTypeId (void) const
	Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting. More...

virtual const SoFieldData *	getFieldData (void) const

virtual const SoEngineOutputData *	getOutputData (void) const

	SoCalculator (void)

Public Member Functions inherited from SoEngine
void	evaluateWrapper (void)

virtual int	getOutputs (SoEngineOutputList &l) const

SoEngineOutput *	getOutput (const SbName &outputname) const

SbBool	getOutputName (const SoEngineOutput *output, SbName &outputname) const

SbBool	isNotifying (void) const

virtual void	notify (SoNotList *nl)

SoEngine *	copy (void) const

virtual SoFieldContainer *	copyThroughConnection (void) const

SbBool	shouldCopy (void) const

virtual void	writeInstance (SoOutput *out)

Public Member Functions inherited from SoFieldContainer
void	setToDefaults (void)

SbBool	hasDefaultValues (void) const

SbBool	fieldsAreEqual (const SoFieldContainer *container) const

void	copyFieldValues (const SoFieldContainer *container, SbBool copyconnections=FALSE)

SbBool	set (const char *const fielddata)

void	get (SbString &fielddata)

virtual int	getFields (SoFieldList &l) const

virtual int	getAllFields (SoFieldList &l) const

virtual SoField *	getField (const SbName &name) const

virtual SoField *	getEventIn (const SbName &name) const

virtual SoField *	getEventOut (const SbName &name) const

SbBool	getFieldName (const SoField *const field, SbName &name) const

SbBool	enableNotify (const SbBool flag)

SbBool	isNotifyEnabled (void) const

SbBool	set (const char fielddata, SoInput input)

void	get (SbString &fielddata, SoOutput *out)

virtual SbBool	validateNewFieldValue (SoField field, void newval)

virtual void	addWriteReference (SoOutput *out, SbBool isfromfield=FALSE)

SbBool	getIsBuiltIn (void) const

virtual void	copyContents (const SoFieldContainer *from, SbBool copyconnections)

virtual void	getFieldsMemorySize (size_t &managed, size_t &unmanaged) const

void	setUserData (void *userdata) const

void *	getUserData (void) const

Public Member Functions inherited from SoBase
void	ref (void) const

void	unref (void) const

void	unrefNoDelete (void) const

int32_t	getRefCount (void) const

void	touch (void)

SbBool	isOfType (SoType type) const
	Returns `TRUE` if the type of this object is either of the same type or inherited from type. More...

virtual SbName	getName (void) const

virtual void	setName (const SbName &newname)

virtual void	startNotify (void)

void	addAuditor (void *const auditor, const SoNotRec::Type type)

void	removeAuditor (void *const auditor, const SoNotRec::Type type)

const SoAuditorList &	getAuditors (void) const

SbBool	shouldWrite (void)

void	assertAlive (void) const

Static Public Member Functions
static SoType	getClassTypeId (void)

static void *	createInstance (void)

static void	initClass (void)

Static Public Member Functions inherited from SoEngine
static void	initClass (void)

static void	initClasses (void)

static SoType	getClassTypeId (void)

static SoEngine *	getByName (const SbName &name)

static int	getByName (const SbName &name, SoEngineList &el)

Static Public Member Functions inherited from SoFieldContainer
static void	initClass (void)

static SoType	getClassTypeId (void)

static void	cleanupClass (void)

static void	initCopyDict (void)

static void	addCopy (const SoFieldContainer orig, const SoFieldContainer copy)

static SoFieldContainer *	checkCopy (const SoFieldContainer *orig)

static SoFieldContainer *	findCopy (const SoFieldContainer *orig, const SbBool copyconnections)

static void	copyDone (void)

Static Public Member Functions inherited from SoBase
static void	initClass (void)
	Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.

static SoType	getClassTypeId (void)
	This static method returns the SoType object associated with objects of this class.

static void	addName (SoBase const base, const char const name)

static void	removeName (SoBase const base, const char const name)

static void	incrementCurrentWriteCounter (void)

static void	decrementCurrentWriteCounter (void)

static SoBase *	getNamedBase (const SbName &name, SoType type)

static int	getNamedBases (const SbName &name, SoBaseList &baselist, SoType type)

static SbBool	read (SoInput input, SoBase &base, SoType expectedtype)

static void	setInstancePrefix (const SbString &c)

static void	setTraceRefs (SbBool trace)

static SbBool	getTraceRefs (void)

static SbBool	connectRoute (SoInput *input, const SbName &fromnodename, const SbName &fromfieldname, const SbName &tonodename, const SbName &tofieldname)

static SbBool	readRoute (SoInput *input)

Public Attributes
SoMFFloat	a

SoMFFloat	b

SoMFFloat	c

SoMFFloat	d

SoMFFloat	e

SoMFFloat	f

SoMFFloat	g

SoMFFloat	h

SoMFVec3f	A

SoMFVec3f	B

SoMFVec3f	C

SoMFVec3f	D

SoMFVec3f	E

SoMFVec3f	F

SoMFVec3f	G

SoMFVec3f	H

SoMFString	expression

SoEngineOutput	oa

SoEngineOutput	ob

SoEngineOutput	oc

SoEngineOutput	od

SoEngineOutput	oA

SoEngineOutput	oB

SoEngineOutput	oC

SoEngineOutput	oD

Protected Member Functions
virtual	~SoCalculator (void)

virtual void	inputChanged (SoField *which)

Protected Member Functions inherited from SoEngine
	SoEngine (void)

virtual	~SoEngine (void)

virtual SbBool	readInstance (SoInput *in, unsigned short flags)

void	writeOutputTypes (SoOutput *out)

Protected Member Functions inherited from SoFieldContainer
	SoFieldContainer (void)

virtual	~SoFieldContainer ()

Protected Member Functions inherited from SoBase
	SoBase (void)

virtual	~SoBase ()

SbBool	hasMultipleWriteRefs (void) const

SbBool	writeHeader (SoOutput *out, SbBool isgroup, SbBool isengine) const

void	writeFooter (SoOutput *out) const

virtual const char *	getFileFormatName (void) const

virtual SoNotRec	createNotRec (void)

Static Protected Member Functions
static const SoFieldData **	getInputDataPtr (void)

static const SoEngineOutputData **	getOutputDataPtr (void)

Static Protected Member Functions inherited from SoEngine
static const SoFieldData **	getInputDataPtr (void)

static const SoEngineOutputData **	getOutputDataPtr (void)

Static Protected Member Functions inherited from SoBase
static uint32_t	getCurrentWriteCounter (void)

static void	staticDataLock (void)

static void	staticDataUnlock (void)

Additional Inherited Members
Protected Types inherited from SoBase
enum	BaseFlags { IS_ENGINE = 0x01, IS_GROUP = 0x02 }

Protected Attributes inherited from SoFieldContainer
SbBool	isBuiltIn

Detailed Description

General purpose calculator for floats and 3D float vectors.

The SoCalculator uses the values from the input fields (which are either single floating point values or vectors) as variables in the free-form engine expressions and places the results on the output fields.

The engine has sixteen input fields; eight scalar inputs (a, b, c, d, e, f g, and h), and eight vector inputs (A, B, C, D, E, F, G, and H).

There are eight output fields; four scalar outputs (oa, ob, oc, and od), and four vector outputs (oA, oB, oC, and oD).

The expression syntax is quite similar to C/C++, with a very limited set of keywords and functions.

An example:

oa = a * (0.5 + b) / c

Will multiply the value in a with the value in b plus 0.5, divide that result with c, and place the result in oa. Since this is an engine, the expression will only be evaluated when someone attempts to read the value in oa, not every time an input in changed.

All inputs are multi-fields, and if there are several values in an input, the expression will be evaluated once for every input field value, and the output will create as many values as there are input field values.

If there is more than one input field, and the input fields do not have the same number of values, the engine will create as many output values as the input field with the biggest number of values. When the index get out of bounds for some other input field, the last field value will be used.

Vector expressions are similar to scalar expression. An example:

oA = A + vec3f(1.0, 0.0, 0.0) * B

Will take the vector in A, add the value in B multiplied with (1,0,0), and place the result in oA.

In addition to regular arithmetics, the SoCalculator syntax also includes some functions.

Scalar functions:

cos(x) - cosine function (x in radians)
sin(x) - sinus function
tan(x) - tangent function
acos(x) - arc cosine function
asin(x) - arc sinus function
atan(x) - arc tangent function
atan2(y, x) - arc tangent function of two variables (y, x).
cosh(x) - hyperbolic cosine function
sinh(x) - hyperbolic sinus function
tanh(x) - hyperbolic tangent function
sqrt(x) - square root function
pow(x,y) - x raised to the power of y
exp(x) - e to the power of x
log(x) - natural logarithm of x
log10() - base-10 logarithm of x
ceil(x) - rounds x upwards to the nearest integer
floor(x) - rounds x downwards to the nearest integer
fabs(x) - absolute value
fmod(x, y) - remainder of dividing x by y
rand(x) - pseudo-random value between 0 and 1

Vector functions:

cross(x, y) - cross product of x and y
dot(x,y) - dot product of x and y (returns scalar value)
length(x) - length of x (returns scalar value)
normalize(x) - returns normalized version of x
x[y] - access components in x (y should be a scalar value in the range [0,2])

There are also some named constants that can be used:

MAXFLOAT
MINFLOAT
M_E
M_LOG2E
M_LOG10E
M_LN2
M_PI
M_SQRT2 - sqrt(2)
M_SQRT1_2 - sqrt(1/2)

The only control flow available is the ? operator. An example:

oa = (a > b) ? (a * 0.5) : (b * c)

(The parentheses are not necessary, they're there just to make the example easier to read)

In addition to the standard comparators (<, >, <=, >=, ==, !=), you can also use && (AND) and || (OR) to combine expression, and the unary ! (NOT) operator.

One final thing worth mentioning is the temporary variables. There exists sixteen temporary variables that can be used in expressions. ta, tb, tc, td, te, tf, tg, and th are scalar variables, and tA, tB, tC, tD, tE, tF, tG, and tH are vector variables. They are usually used when you have more than one expression that should be evaluated in order.

An example with three expressions:

ta = a * b; tb = c + d; tc = e - f
tA = vec3f(ta, tb, tc) + A
oA = tA * B

The example just shows how temporary variables can be used to make your expressions easier to read. Please note that it's possible to have several statements in one expression. You just separate them with semicolons.

Here is a simple example of how an SoCalculator engine may be used in an .iv file:

DEF mycamera PerspectiveCamera {
  orientation 1 0 0 1.57
}
DEF headlight DirectionalLight {
  intensity 0.8
  direction 0 0 1
}
Separator {
  # Render a cube not affected by lighting
  LightModel { model BASE_COLOR }
  BaseColor { rgb = Calculator {
                      a = USE headlight . intensity
                      expression [ "oA = vec3f( a, a, a)" ]
                    } . oA }
  Cube {}
}

In the example, the color of the Cube is a function of the intensity of the DirectionalLight, even though the Cube is rendered without lighting because of the BASE_COLOR LightModel.

Constructor & Destructor Documentation

SoCalculator::SoCalculator ( void )

Constructor.

SoCalculator::~SoCalculator ( void )

protectedvirtual

Destructor.

Member Function Documentation

SoType SoCalculator::getTypeId ( void ) const

virtual

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting.

Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Implements SoBase.

const SoFieldData * SoCalculator::getFieldData ( void ) const

virtual

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoFieldContainer.

const SoEngineOutputData * SoCalculator::getOutputData ( void ) const

virtual

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Implements SoEngine.

void SoCalculator::inputChanged ( SoField * which )

protectedvirtual

Called when an input is changed. The default method does nothing, but subclasses may override this method to do The Right Thing when a specific field is changed.

Reimplemented from SoEngine.