CH_Support.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:        Channel Library (C++)
 *
 * COMMENTS:    Support glue between channel and expression libraries
 *
*/

#ifndef __CH_Support_h__
#define __CH_Support_h__

#include "CH_API.h"
#include <SYS/SYS_Types.h>

//
//  Some defines for expressions.  These defines may be used by anyone
//      who needs them.  They are the lower bits in the EV_Expression
//      flag and are accessible by the method for getting flags in the
//      CH_Expression class. Some (CH_SYM...) are flags for the EV_SYMBOL,
//      which are or'ed into the expression flags and so must use the
//      same bit-range.
//

#define CH_EXPRTIME      0x00008000     // Expression uses time
#define CH_EXPRCHAN      0x00010000     // Expression uses channel
#define CH_EXPRIVALUE    0x00020000     // Expression uses in value
#define CH_EXPROVALUE    0x00040000     // Expression uses out value
#define CH_EXPRSLOPE     0x00080000     // Expression uses in slope/out slope
//#define CH_EXPRPARAM   0x00100000     // Now Unused, free for use
#define CH_EXPRACCEL     0x00200000     // Expression uses in accel/out accel
#define CH_EXPRKNOTS     0x00400000     // Expression uses spline knots
#define CH_EXPRMATCH     0x00800000     // Expression has a match() function
//#define CH_SYMHARDWIRED 0x01000000    // Now unused, free for use
#define CH_EXPRDATA      0x02000000     // Expression sets a data interest
#define CH_EXPRVALUE     (CH_EXPRIVALUE | CH_EXPROVALUE)

// Flags above 0x00008000 are reserved for the channel library
// Flags above 0x02000000 are reserved by the expression library
//      Applications may use any flags between 0x0001 and 0x4000
//      for their own custom flags

//
// It is possible to define constants for the user to use.  For each
//      define, there is a name for the label and a corresponding value.
//      for example:  "XMIN", 0.  This would allow the user to type
//      XMIN instead of having to remember that XMIN is always 0.

class CH_API CH_ExprDefine {
public:
    const char  *label;
    fpreal       value;
};

class CH_SegmentValues;
class CH_Segment;
class CH_Cubic;

class CH_API CH_Bezier
{
public:
    fpreal      x[4];
    fpreal      y[4];

    CH_Bezier() {}

    CH_Bezier( CH_SegmentValues const& sv ) { init( sv ); }

    CH_Bezier( CH_Segment const& seg );
    CH_Bezier( CH_Segment const& seg, fpreal vscale, fpreal voff );

    void        init( CH_SegmentValues const& sv );

    void        getValues( CH_SegmentValues &v );

    static void getCubicFromCVs( fpreal x[4], CH_Cubic &c );

    static void splitInternal( fpreal t, fpreal xin[4],
                                    fpreal xout1[4], fpreal xout2[4] );

    void        splitP( fpreal u, CH_Bezier &a, CH_Bezier &b );

    void        split( fpreal t, CH_Bezier &a, CH_Bezier &b );

    void        splitAndFindSlopeLengths( fpreal t,
                    fpreal &left_in, fpreal &left_out,
                    fpreal &right_in, fpreal &right_out );

    fpreal      timeToParametric( fpreal t );

    fpreal      evalP( fpreal u );

    fpreal      eval( fpreal t );       // t is local

    void        display();
};

class CH_API CH_Cubic
{
public:
    fpreal      t0, t1;
    fpreal      x0, x1, x2, x3;

    fpreal      timeToParametric( fpreal t );   // t -> u

    fpreal      reverseEvalP( fpreal y );       // y -> u

    fpreal      evalP( fpreal u )               // u -> y
    {
        return x0 + u*(x1 + u*(x2 + u*x3));
    }

    fpreal      eval( fpreal t );               // t -> y

    fpreal      calculateSlopeP( fpreal u );

    fpreal      calculateAccelP( fpreal u );

    void        display();
};

#endif