// Copyright (C) 2010, Guy Barrand. All rights reserved.
// See the file tools.license for terms.

#ifndef tools_glprims
#define tools_glprims

//same as OpenGL GL_[POINTS,etc...], but for the case we don't have OpenGL.

#include <cstddef> //size_t

namespace tools {
namespace gl {

typedef unsigned char mode_t;

inline mode_t points()         {return 0x0000;}
inline mode_t lines()          {return 0x0001;} //segments
inline mode_t line_loop()      {return 0x0002;}
inline mode_t line_strip()     {return 0x0003;} //polyline
inline mode_t triangles()      {return 0x0004;}
inline mode_t triangle_strip() {return 0x0005;}
inline mode_t triangle_fan()   {return 0x0006;}
//inline mode_t quads()          {return 0x0007;}
//inline mode_t quad_strip()     {return 0x0008;}
//inline mode_t polygon()        {return 0x0009;}

inline bool is_mode(mode_t a_mode) {
  return a_mode<=0x006?true:false;
}

inline bool is_line(mode_t a_mode) {
  if(a_mode==points())     return true; //0 sz line !
  if(a_mode==lines())      return true;
  if(a_mode==line_loop())  return true;
  if(a_mode==line_strip()) return true;
  return false;
}

inline void cvt_2to3(size_t a_npt,const float* a_xys,float*& a_xyzs) {
  const float* vpos = a_xys;
  float x,y;
  for(size_t i=0;i<a_npt;i++) {
    x = *vpos;vpos++;
    y = *vpos;vpos++;
    *a_xyzs = x;a_xyzs++;
    *a_xyzs = y;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;
  }
}


inline void triangle_fan_to_triangles(size_t a_npt,const float* a_fxyzs,float*& a_xyzs) {

  const float* vpos = a_fxyzs;

  float x1 = *vpos;vpos++;
  float y1 = *vpos;vpos++;
  float z1 = *vpos;vpos++;

  float x2 = *vpos;vpos++;
  float y2 = *vpos;vpos++;
  float z2 = *vpos;vpos++;

  float x3,y3,z3;
  for(size_t i=2;i<a_npt;i++) {
    x3 = *vpos;vpos++;
    y3 = *vpos;vpos++;
    z3 = *vpos;vpos++;
    *a_xyzs = x1;a_xyzs++;
    *a_xyzs = y1;a_xyzs++;
    *a_xyzs = z1;a_xyzs++;

    *a_xyzs = x2;a_xyzs++;
    *a_xyzs = y2;a_xyzs++;
    *a_xyzs = z2;a_xyzs++;

    *a_xyzs = x3;a_xyzs++;
    *a_xyzs = y3;a_xyzs++;
    *a_xyzs = z3;a_xyzs++;

    x2 = x3;
    y2 = y3;
    z2 = z3;
  }

}

inline void triangle_strip_to_triangles(size_t a_npt,const float* a_fxyzs,float*& a_xyzs) {

  const float* vpos = a_fxyzs;

  float x1 = *vpos;vpos++;
  float y1 = *vpos;vpos++;
  float z1 = *vpos;vpos++;

  float x2 = *vpos;vpos++;
  float y2 = *vpos;vpos++;
  float z2 = *vpos;vpos++;

  float x3,y3,z3;
  bool flip = false;
  for(size_t i=2;i<a_npt;i++) {
    x3 = *vpos;vpos++;
    y3 = *vpos;vpos++;
    z3 = *vpos;vpos++;

    if(flip) {
      *a_xyzs = x1;a_xyzs++;
      *a_xyzs = y1;a_xyzs++;
      *a_xyzs = z1;a_xyzs++;

      *a_xyzs = x3;a_xyzs++;
      *a_xyzs = y3;a_xyzs++;
      *a_xyzs = z3;a_xyzs++;

      *a_xyzs = x2;a_xyzs++;
      *a_xyzs = y2;a_xyzs++;
      *a_xyzs = z2;a_xyzs++;
    } else {
      *a_xyzs = x1;a_xyzs++;
      *a_xyzs = y1;a_xyzs++;
      *a_xyzs = z1;a_xyzs++;

      *a_xyzs = x2;a_xyzs++;
      *a_xyzs = y2;a_xyzs++;
      *a_xyzs = z2;a_xyzs++;

      *a_xyzs = x3;a_xyzs++;
      *a_xyzs = y3;a_xyzs++;
      *a_xyzs = z3;a_xyzs++;
    }

    x1 = x2;
    y1 = y2;
    z1 = z2;

    x2 = x3;
    y2 = y3;
    z2 = z3;

    flip = flip?false:true;
  }
}

inline void triangle_fan_to_triangles(size_t a_npt,
                                      const float* a_fxyzs,const float* a_fnms,
                                      float*& a_xyzs,float*& a_nms) {
  triangle_fan_to_triangles(a_npt,a_fxyzs,a_xyzs);
  triangle_fan_to_triangles(a_npt,a_fnms,a_nms);
}

inline void triangle_strip_to_triangles(size_t a_npt,
                                        const float* a_fxyzs,const float* a_fnms,
                                        float*& a_xyzs,float*& a_nms) {
  triangle_strip_to_triangles(a_npt,a_fxyzs,a_xyzs);
  triangle_strip_to_triangles(a_npt,a_fnms,a_nms);
}

inline void triangle_fan_to_triangles_2to3(size_t a_npt,const float* a_xys,float*& a_xyzs) {

  const float* vpos = a_xys;

  float x1 = *vpos;vpos++;
  float y1 = *vpos;vpos++;

  float x2 = *vpos;vpos++;
  float y2 = *vpos;vpos++;

  float x3,y3;
  for(size_t i=2;i<a_npt;i++) {
    x3 = *vpos;vpos++;
    y3 = *vpos;vpos++;

    *a_xyzs = x1;a_xyzs++;
    *a_xyzs = y1;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;

    *a_xyzs = x2;a_xyzs++;
    *a_xyzs = y2;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;

    *a_xyzs = x3;a_xyzs++;
    *a_xyzs = y3;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;

    x2 = x3;
    y2 = y3;
  }

}

inline void triangle_strip_to_triangles_2to3(size_t a_npt,const float* a_xys,float*& a_xyzs) {

  const float* vpos = a_xys;

  float x1 = *vpos;vpos++;
  float y1 = *vpos;vpos++;

  float x2 = *vpos;vpos++;
  float y2 = *vpos;vpos++;

  float x3,y3;
  bool flip = false;
  for(size_t i=2;i<a_npt;i++) {
    x3 = *vpos;vpos++;
    y3 = *vpos;vpos++;

    if(flip) {
      *a_xyzs = x1;a_xyzs++;
      *a_xyzs = y1;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;

      *a_xyzs = x3;a_xyzs++;
      *a_xyzs = y3;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;

      *a_xyzs = x2;a_xyzs++;
      *a_xyzs = y2;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;
    } else {
      *a_xyzs = x1;a_xyzs++;
      *a_xyzs = y1;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;

      *a_xyzs = x2;a_xyzs++;
      *a_xyzs = y2;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;

      *a_xyzs = x3;a_xyzs++;
      *a_xyzs = y3;a_xyzs++;
      *a_xyzs = 0;a_xyzs++;
    }

    x1 = x2;
    y1 = y2;

    x2 = x3;
    y2 = y3;

    flip = flip?false:true;
  }

}

inline void line_strip_to_lines_2to3(size_t a_npt,const float* a_xys,float*& a_xyzs) {

  const float* vpos = a_xys;

  float x1 = *vpos;vpos++;
  float y1 = *vpos;vpos++;

  float x2,y2;
  for(size_t i=1;i<a_npt;i++) {
    x2 = *vpos;vpos++;
    y2 = *vpos;vpos++;

    *a_xyzs = x1;a_xyzs++;
    *a_xyzs = y1;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;

    *a_xyzs = x2;a_xyzs++;
    *a_xyzs = y2;a_xyzs++;
    *a_xyzs = 0;a_xyzs++;

    x1 = x2;
    y1 = y2;
  }

}

}}

#endif