CVEX_Transform.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.
 *
 * NAME:        CVEX_Transform.h (CVEX Library, C++)
 *
 * COMMENTS:
 */

#ifndef __CVEX_Transform__
#define __CVEX_Transform__

#include "CVEX_API.h"
#include <VEX/VEX_PodTypes.h>
#include <UT/UT_Array.h>
#include <UT/UT_IntArray.h>
#include <UT/UT_Matrix4.h>
#include <UT/UT_NonCopyable.h>
#include <UT/UT_OpCaller.h>
#include <UT/UT_SharedPtr.h>

class VEX_TransformContext;
class UT_OpCaller;
class UT_StringHolder;
class cvex_TransformData;
template <VEX_Precision PREC> class CVEX_ContextT;

/// Each VEX shader can have a transform bound to it.  This transform is used
/// by the ptransform(), ntransform(), etc. functions to look up "world" or
/// "object" space.
///
/// Variables in the shader are defined to be in "current" space.  The CVEX
/// context allows you to specify various transforms from the current space to
/// another space.  The other spaces are defined by the built-in VEX spaces:
///     - "space:world": Transform current space to "world" space
///     - "space:camera": Transform current to "camera" space
///     - "space:object": Transform current to "object" space
///     - "space:light":  Transform current to "light" space
///
/// It's also possible to specify a "lookup" helper class which can be used to
/// look up user defined spaces.
class CVEX_API CVEX_Transform
{
public:
     CVEX_Transform();
    ~CVEX_Transform();

    UT_NON_COPYABLE(CVEX_Transform)

    /// Resets the transform so it can be re-used by different
    /// contexts.
    void clear();

    /// Class that passes information about context of transform lookup
    /// The @c cwd is the current node id (i.e. very likely the node associated
    /// with the OpCaller.  The @c worldId is the node id associated with the
    /// current transform.  That is, the object containing the node.  If the
    /// @c worldId isn't defined, the @c cwd will be used.
    class CVEX_API LookupContext
    {
    public:
         LookupContext();
        ~LookupContext();

        UT_NON_COPYABLE(LookupContext)

        void             clear();

        UT_OpCaller     *opCaller() const       { return myOpCaller; }
        fpreal           time() const           { return myTime; }
        /// Specifies the node for relative path searching
        int              cwdId() const  
                         {
                             if (myCwdId < 0 && myOpCaller)
                                 return myOpCaller->getOpId();
                             return myCwdId;
                         }
        /// Specifies the node that defines the transform space
        int              worldId() const
                         {
                             if (myWorldId < 0)
                             {
                                 // We want to give precedence to the cwd
                                 // rather than the caller.
                                 return cwdId();
                             }
                             return myWorldId;
                         }

        void            setOpCaller(UT_OpCaller *c)     { myOpCaller = c; }
        void            setTime(fpreal t)               { myTime = t; }
        void            setCwdId(int id)                { myCwdId = id; }
        void            setWorldId(int id)              { myWorldId = id; }

        void            setInputXform(int input, const UT_Matrix4D &xform);
        void            getInputXform(int input, UT_Matrix4D &xform) const;
        void            setInputXformId(int input, int nodeid);
        int             getInputXformId(int input) const;

        /// The user data is set by the Lookup class (if set).  This allows the
        /// lookup to keep per-instantiation data.
        void            *getUserData() const    { return myUserData; }

    private:
        void            *myUserData;
        UT_OpCaller     *myOpCaller;
        fpreal           myTime;
        int              myCwdId;
        int              myWorldId;
        UT_Array<UT_Matrix4D>   myInputXform;
        UT_IntArray      myInputXformId;
    };

    /// Class to look-up user defined spaces
    class CVEX_API Lookup
    {
    public:
        Lookup() {}
        virtual ~Lookup();

        UT_NON_COPYABLE(Lookup)

        /// Allocate user data for the lookup context
        virtual void    *allocateUserData() const;
        /// Delete the user data that was allocated for the lookup context
        virtual void     freeUserData(void *) const;
        /// Reset the user data so it can be re-used later
        virtual void     clearUserData(void *) const;

        /// Look up a matrix which will transform the "current" space into the
        /// named space.
        virtual bool    lookup(const char *name, UT_Matrix4D &m,
                                const LookupContext &context) = 0;

        /// Look up a matrix which transforms the named space into "current"
        /// space.  By default, this will call @c lookup() and compute the
        /// inverse.  If you have the inverse available, you may want to make
        /// this more efficient by using it.
        virtual bool    lookupInverse(const char *name, UT_Matrix4D &m,
                                const LookupContext &context);

        /// Lookup NDC space given a name
        virtual bool    lookupToNDC(const char *name,
                                UT_Matrix4D &m,
                                const LookupContext &context,
                                bool &ortho) const;
        virtual bool    lookupFromNDC(const char *name,
                                UT_Matrix4D &m,
                                const LookupContext &context,
                                bool &ortho) const;

        /// Path functions
        virtual bool    abspath(UT_StringHolder &result,
                                const UT_StringHolder &relpath,
                                const LookupContext &context) const;
        virtual int     idFromPath(const UT_StringHolder &relpath,
                                const LookupContext &context) const;
        virtual bool    pathFromId(UT_StringHolder &result, int id,
                                const LookupContext &context) const;
    };

    /// Set the lookup object for arbitrary spaces.
    static void setLookup(const UT_SharedPtr<Lookup> &lookup);

    /// @{
    /// Get information about the context
    UT_OpCaller *opCaller() const       { return myContext.opCaller(); }
    fpreal       time() const           { return myContext.time(); }
    int          cwdId() const          { return myContext.cwdId(); }
    int          worldId() const        { return myContext.worldId(); }
    void         getInputXform(int input, UT_Matrix4D &xform) const { myContext.getInputXform(input, xform); }
    int          getInputXformId(int input) const { return myContext.getInputXformId(input); }
    /// @}

    /// @{
    /// Set information about the context
    void        setOpCaller(UT_OpCaller *c)     { myContext.setOpCaller(c); }
    void        setTime(fpreal t)               { myContext.setTime(t); }
    void        setCwdId(int id)                { myContext.setCwdId(id); }
    void        setWorldId(int id)              { myContext.setWorldId(id); }
    void        setInputXform(int id, const UT_Matrix4D &xform) { myContext.setInputXform(id, xform); }
    void        setInputXformId(int id, int nodeid) { myContext.setInputXformId(id, nodeid); }
    /// @}

private:
    // Note:  The LookupContext must remain in scope during the lifetime of
    // this object.
    VEX_TransformContext        *context() const;

    cvex_TransformData  *myData;
    LookupContext        myContext;

    template <VEX_Precision ALLPREC>
    friend class        CVEX_ContextT;
};

#endif