Library Functions Manual

NAME¶

SoCalculator - General purpose calculator for floats and 3D float vectors.

SYNOPSIS¶

#include <Inventor/engines/SoCalculator.h>

Inherits SoEngine.

Public Member Functions¶

virtual SoType getTypeId (void) const
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
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)
static SoType getClassTypeId (void)
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

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 ) [protected], [virtual]¶

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) [protected], [virtual]¶

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.

Member Data Documentation¶