zbf.h

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/*
** ---------------------------------------------------------------
** zbf.h -  Definition of class to fill polygons in raster (image) 
**          coordinates using the z-buffer algorithm.
*/

#ifndef _ZBF_H
#define _ZBF_H

class Zbf
{
 private:
/*
** ---------------------------------------------------------------
** Private data type definitions:
*/

  struct NscPnt {
    double    x;
    double    y;
    double    z;
   };

  struct Edge {
    int    y_max;
    int    y_min;
    double xs;
    double dxs;
    double zs;
    double dzs;
   };

  struct Pixel {
    int    x;
    double z;
   };

 private:
/*
** ---------------------------------------------------------------
** Private class variables and constants:
**
*/
  static NscPnt* poly;

  static int sizepoly;

  static int npolyverts;

  static Edge* poly_edge;

  static Pixel* scanline_vtx;

  static long int curr_color;

  static int cv_width;

  static int cv_height;

/* Memory for z-buffer */
  static unsigned int* zbuff;

 private:
/*
** ---------------------------------------------------------------
** Private class functions:
*/
/* --------------------------------------------------------------- */
  static inline double MAX( double a, double b )
  {
   return( (a > b) ? a : b );
  }

/* --------------------------------------------------------------- */
  static inline double MIN( double a, double b )
  {
   return( (a < b) ? a : b );
  }

/* --------------------------------------------------------------- */
  static void NSCtoRaster( double xnsc, double ynsc, double znsc,
                           int* xr, int* yr, unsigned int* zr );

/* --------------------------------------------------------------- */
  static void OrderIntersections( Pixel* vtx, int left, int right );

/* --------------------------------------------------------------- */
  static void ScanLine( Pixel* vtx_lft, Pixel* vtx_rgt, int ys );

/* --------------------------------------------------------------- */
  static int MountEdges( Edge* edge, int* ymin, int* ymax,
                         int npoints, NscPnt* poly );

/* --------------------------------------------------------------- */
  static int MountInt( Pixel* vtx, Edge* edge, int* nedges, int ys );

/* --------------------------------------------------------------- */
  static void FillPoly( int npoints, NscPnt* poly );

/* --------------------------------------------------------------- */
  static void Release( void );

/* --------------------------------------------------------------- */
  static int Alloc( void  );

 public:
/*
** ---------------------------------------------------------------
** Public class functions:
*/
/* --------------------------------------------------------------- */
  static int Init( int width, int height );

/* --------------------------------------------------------------- */
  static void Close( void );

/* --------------------------------------------------------------- */
  static void BeginPoly( long int color );

/* --------------------------------------------------------------- */
  static void Vertex( double x, double y, double z );

/* --------------------------------------------------------------- */
  static void EndPoly( void );

};

#endif

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