lookuptable.h

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/*
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**  Copyright 2025 Electronic Arts Inc.
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**  it under the terms of the GNU General Public License as published by
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*/
 
/***********************************************************************************************
 ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               ***
 ***********************************************************************************************
 *                                                                                             *
 *                 Project Name : WWPhys                                                       *
 *                                                                                             *
 *                     $Archive:: /Commando/Code/wwmath/lookuptable.h                         $*
 *                                                                                             *
 *              Original Author:: Greg Hjelstrom                                               *
 *                                                                                             *
 *                      $Author:: Greg_h                                                      $*
 *                                                                                             *
 *                     $Modtime:: 4/18/00 1:20p                                               $*
 *                                                                                             *
 *                    $Revision:: 6                                                           $*
 *                                                                                             *
 *---------------------------------------------------------------------------------------------*
 * Functions:                                                                                  *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 
#ifndef LOOKUPTABLE_H
#define LOOKUPTABLE_H
 
#include "always.h"
#include "simplevec.h"
#include "wwstring.h"
#include "refcount.h"
#include "multilist.h"
#include "wwmath.h"
 
 
class Vector2;
class Curve1DClass;
class ChunkSaveClass;
class ChunkLoadClass;
 

class LookupTableClass : public RefCountClass, public MultiListObjectClass
{
public:
 
    LookupTableClass(int sample_count = 256);
    virtual ~LookupTableClass(void);
 
    void                                Init(const char * name,Curve1DClass * curve);
    float                               Get_Value(float input);
    float                               Get_Value_Quick(float input);
    const char *                    Get_Name(void)                          { return Name; }
protected:
 
    StringClass                      Name;               // name of this table, if it came from a file, this is also the filename
    float                               MinInputValue; 
    float                               MaxInputValue;
    float                               OOMaxMinusMin;
    SimpleVecClass<float>      OutputSamples;
 
};
 
inline float LookupTableClass::Get_Value(float input)
{
    if (input <= MinInputValue) {
        return OutputSamples[0];
    }
    if (input >= MaxInputValue) {
        return OutputSamples[OutputSamples.Length()-1];
    }
    
    float normalized_input = (float)(OutputSamples.Length()-1) * (input - MinInputValue) * OOMaxMinusMin;
    float input0 = WWMath::Floor(normalized_input);
    
    int index0 = WWMath::Float_To_Long(input0);
    int index1 = index0+1;
    float lerp = normalized_input - input0;
 
    return OutputSamples[index0] + lerp * (OutputSamples[index1] - OutputSamples[index0]);
}
 
inline float LookupTableClass::Get_Value_Quick(float input)
{
    if (input <= MinInputValue) {
        return OutputSamples[0];
    }
    if (input >= MaxInputValue) {
        return OutputSamples[OutputSamples.Length()-1];
    }
    
    int index = (OutputSamples.Length()-1) * WWMath::Float_To_Long((input - MinInputValue) * OOMaxMinusMin);
    return OutputSamples[index];
}
 

class LookupTableMgrClass
{
public:
    LookupTableMgrClass(void);
    ~LookupTableMgrClass(void);
 
    // init and shutdown are automatically called from WWMath::Init, WWMath::Shutdown...
    static void                 Init(void);
    static void                 Shutdown(void);
 
    static bool                 Add_Table(LookupTableClass * table);
    static bool                 Remove_Table(LookupTableClass * table);
    static LookupTableClass *   Get_Table(const char * name,bool try_to_load = true);
    
    static void                 Save_Table_Desc(     ChunkSaveClass &  csave,
                                                                Curve1DClass *      curve,
                                                                const Vector2 &  min,
                                                                const Vector2 &  max          );
    
    static void                 Load_Table_Desc(     ChunkLoadClass &  cload,
                                                                Curve1DClass ** curve_ptr,
                                                                Vector2 *            set_min = NULL,
                                                                Vector2 *            set_max = NULL  );
 
    static void                 Reset(void);
 
protected:
 
    static RefMultiListClass<LookupTableClass>   Tables;
 
};
 
 
#endif // LOOKUPTABLE_H