GA/GA_ElementWrangler.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by:
 *      Side Effects Software Inc
 *      123 Front Street West, Suite 1401
 *      Toronto, Ontario
 *      Canada   M5J 2M2
 *      416-504-9876
 *
 * NAME:        GA_ElementWrangler.h ( GA Library, C++)
 *
 * COMMENTS:    A utility class to abstract common preamble from GA_GBElement
 *              methods to a higher level.
 */

#ifndef __GA_ElementWrangler__
#define __GA_ElementWrangler__

#include <UT/UT_NonCopyable.h>
#include "GA_API.h"
#include "GA_AttributeRefMap.h"

/// @brief A utility class to amortize overhead from GA_GBElement attribute
/// handling methods.
///
/// The GA_ElementWrangler class provides a simplified interface for common
/// attribute operations as elements are added or removed.
///
/// This class is not thread-safe, so each thread should have its own copy,
/// and any attributes added after its instantiation will not be processed.

class GA_API GA_ElementWrangler
{
public:
    void         copyAttributeValues(GA_Offset dest, GA_Offset src)
                 { 
                     myMap.copyValue(myOwner, dest, myOwner, src);
                 }
    void         scaleAttributeValues(GA_Offset dest, fpreal scale)
                 {
                     myMap.multiply(myOwner, dest, scale);
                 }
    void         addAttributeValues(GA_Offset dest, GA_Offset src,
                                    fpreal scale=1)
                 {
                     myMap.addValue(myOwner, dest, myOwner, src, scale);
                 }
    void         lerpAttributeValues(GA_Offset dest, GA_Offset src0,
                                     GA_Offset src1, fpreal bias)
                 {
                     myMap.lerpValue(myOwner, dest, myOwner, src0, src1, bias);
                 }

    bool         isValid(GA_Detail &dest) const
                 {
                     return myMap.getDestDetail() == &dest &&
                            myMap.getSourceDetail() == &dest;
                 }
    bool         isValid(GA_Detail &dest, const GA_Detail &src) const
                 {
                     return myMap.getDestDetail() == &dest &&
                            myMap.getSourceDetail() == &src;
                 }
protected:
    GA_ElementWrangler(GA_AttributeOwner owner, GA_Detail &dest,
                       const GA_Attribute *exclude = 0);
    GA_ElementWrangler(GA_AttributeOwner owner, GA_Detail &dest,
                       const GA_Detail &src, const GA_Attribute *exclude = 0);
    /// Protected destructor as we don't support polymorphic destruction.
    ~GA_ElementWrangler() {}

    GA_AttributeRefMap                  &getMap() { return myMap; }
private:
    GA_AttributeOwner                    myOwner;
    GA_AttributeRefMap                   myMap;
};

/// By default, operations on "P" are performed as with any other attribute.
/// However, it's possible to turn on the homogeneous flag which will ensure
/// that operations are done using homogeneous coordinates.
class GA_API GA_PointWrangler : public GA_ElementWrangler
{
public:
    enum IncludeP { EXCLUDE_P, INCLUDE_P };

     /// The GA_PointWrangler::IncludeP argument passed to the constructor
     /// determines whether the base class operations include "P".
     GA_PointWrangler(GA_Detail &dest, IncludeP p);
     GA_PointWrangler(GA_Detail &dest, const GA_Detail &src, IncludeP p);

    ~GA_PointWrangler()
     {
         delete myAlternateMap;
     }

    bool         includesP() const { return myBaseIncludeP == INCLUDE_P; }

    using GA_ElementWrangler::copyAttributeValues;
    using GA_ElementWrangler::scaleAttributeValues;
    using GA_ElementWrangler::addAttributeValues;
    using GA_ElementWrangler::lerpAttributeValues;

    void         copyAttributeValues(GA_Offset dest, GA_Offset src,
                                     IncludeP copy_p)
                 { 
                     if (copy_p == myBaseIncludeP)
                         copyAttributeValues(dest, src);
                     else
                     {
                         initAlternateHandle();
                         myAlternateMap->copyValue(
                                 GA_ATTRIB_POINT, dest,
                                 GA_ATTRIB_POINT, src);
                     }
                 }
    void         scaleAttributeValues(GA_Offset dest, fpreal scale,
                                      IncludeP scale_p)
                 {
                     if (scale_p == myBaseIncludeP)
                         scaleAttributeValues(dest, scale);
                     else
                     {
                         initAlternateHandle();
                         myAlternateMap->multiply(
                                 GA_ATTRIB_POINT, dest, scale);
                     }
                 }
    void         addAttributeValues(GA_Offset dest, GA_Offset src,
                                    fpreal scale, IncludeP add_p)
                 {
                     if (add_p == myBaseIncludeP)
                         addAttributeValues(dest, src, scale);
                     else
                     {
                         initAlternateHandle();
                         myAlternateMap->addValue(
                                 GA_ATTRIB_POINT, dest,
                                 GA_ATTRIB_POINT, src, scale);
                     }
                 }
    void         lerpAttributeValues(GA_Offset dest, GA_Offset src0,
                                     GA_Offset src1, fpreal bias,
                                     IncludeP lerp_p)
                 {
                     if (lerp_p == myBaseIncludeP)
                         lerpAttributeValues(dest, src0, src1, bias);
                     else
                     {
                         initAlternateHandle();
                         myAlternateMap->lerpValue(
                                 GA_ATTRIB_POINT, dest,
                                 GA_ATTRIB_POINT, src0, src1, bias);
                     }
                 }
private:
    void         initAlternateHandle()
                 {
                     if (!myAlternateMap)
                         allocAlternateHandle();
                 }
    void         allocAlternateHandle();

    // We keep track of whether the base class handle includes "P" since we
    // may need to allocate an alternate handle when an operation requests
    // the opposite behavior.
    IncludeP                             myBaseIncludeP;
    GA_AttributeRefMap                  *myAlternateMap;
};

class GA_API GA_VertexWrangler : public GA_ElementWrangler
{
public:
    GA_VertexWrangler(GA_Detail &dest)
        : GA_ElementWrangler(GA_ATTRIB_VERTEX, dest) {}
    GA_VertexWrangler(GA_Detail &dest, const GA_Detail &src)
        : GA_ElementWrangler(GA_ATTRIB_VERTEX, dest, src) {}
private:
};

class GA_API GA_PrimitiveWrangler : public GA_ElementWrangler
{
public:
    GA_PrimitiveWrangler(GA_Detail &dest)
        : GA_ElementWrangler(GA_ATTRIB_PRIMITIVE, dest) {}
    GA_PrimitiveWrangler(GA_Detail &dest, const GA_Detail &src)
        : GA_ElementWrangler(GA_ATTRIB_PRIMITIVE, dest, src) {}
private:
};

class GA_API GA_ElementWranglerCache : private UT_NonCopyable
{
public:
     GA_ElementWranglerCache(GA_Detail &dest,
                             GA_PointWrangler::IncludeP include_p)
        : myDestGdp(&dest), mySrcGdp(&dest), myPrimitiveWrangler(0),
          myVertexWrangler(0), myPointWrangler(0), myIncludeP(include_p) {}
     GA_ElementWranglerCache(GA_Detail &dest, const GA_Detail &src,
                             GA_PointWrangler::IncludeP include_p)
        : myDestGdp(&dest), mySrcGdp(&src), myPrimitiveWrangler(0),
          myVertexWrangler(0), myPointWrangler(0), myIncludeP(include_p) {}
    ~GA_ElementWranglerCache()
    {
        if (myPrimitiveWrangler)
            delete myPrimitiveWrangler;
        if (myVertexWrangler)
            delete myVertexWrangler;
        if (myPointWrangler)
            delete myPointWrangler;
    }

    void                         clear()
    {
        if (myPrimitiveWrangler)
        {
            delete myPrimitiveWrangler;
            myPrimitiveWrangler = 0;
        }
        if (myVertexWrangler)
        {
            delete myVertexWrangler;
            myVertexWrangler = 0;
        }
        if (myPointWrangler)
        {
            delete myPointWrangler;
            myPointWrangler = 0;
        }
    }

    void                         reset(GA_Detail &dest)
                                 {
                                     myDestGdp = &dest;
                                     mySrcGdp = &dest;
                                     clear();
                                 }
    void                         reset(GA_Detail &dest, const GA_Detail &src)
                                 {
                                     myDestGdp = &dest;
                                     mySrcGdp = &src;
                                     clear();
                                 }
    bool                         isValid(const GA_Detail &dest) const
                                 {
                                     return myDestGdp == &dest &&
                                            mySrcGdp == &dest;
                                 }
    bool                         isValid(const GA_Detail &dest,
                                         const GA_Detail &src) const
                                 {
                                     return myDestGdp == &dest &&
                                            mySrcGdp == &src;
                                 }

    GA_PrimitiveWrangler        &getPrimitive()
    {
        if (!myPrimitiveWrangler)
            myPrimitiveWrangler = new GA_PrimitiveWrangler(*myDestGdp,
                                                           *mySrcGdp);
        return *myPrimitiveWrangler;
    }
    GA_VertexWrangler           &getVertex()
    {
        if (!myVertexWrangler)
            myVertexWrangler = new GA_VertexWrangler(*myDestGdp,
                                                     *mySrcGdp);
        return *myVertexWrangler;
    }
    GA_PointWrangler            &getPoint()
    {
        if (!myPointWrangler)
            myPointWrangler = new GA_PointWrangler(*myDestGdp, *mySrcGdp,
                                                   myIncludeP);
        return *myPointWrangler;
    }

private:
    GA_Detail                   *myDestGdp;
    const GA_Detail             *mySrcGdp;
    GA_PrimitiveWrangler        *myPrimitiveWrangler;
    GA_VertexWrangler           *myVertexWrangler;
    GA_PointWrangler            *myPointWrangler;
    GA_PointWrangler::IncludeP   myIncludeP;
};

#endif

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