#include <cmath>

#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glext.h>

#include "view.h"
#include "oct.h"

vector<GLuint> occ_query_objects;

static GLuint begin_occ_query ()
{
  GLuint id;

  if (occ_query_objects.size ())
    {
      id = *(occ_query_objects.end () - 1);
      occ_query_objects.pop_back ();
    }
  else
    glGenQueriesARB (1, &id);

  glBeginQueryARB (GL_SAMPLES_PASSED, id);
  return id;
}

inline void end_occ_query ()
{
  glEndQueryARB (GL_SAMPLES_PASSED);
}

static GLuint occ_query_result (GLuint id)
{
  GLuint count;

  glGetQueryObjectuivARB (id, GL_QUERY_RESULT, &count);
  occ_query_objects.push_back (id);

  return count;
}

view::view ()
: gamma(1.0)
{
}

view::~view ()
{
}

void view::begin_occ_query (recv_occ_query &recv)
{
  occ_queries.push_back (oq_data (&recv, ::begin_occ_query ()));
}

void view::end_occ_query ()
{
  ::end_occ_query ();
}

bool view::may_draw (const entity *e)
{
  if (drawn.find (e) != drawn.end ())
    return false;

  drawn.insert (e);
  return true;
}

void view::reset_projection ()
{
  //renormalize (orig, p);

  glViewport (0, 0, w, h);

  glMatrixMode (GL_PROJECTION);
  glLoadIdentity ();

  GLdouble aspect = (GLdouble)w/h;
  GLdouble ymax = near * tan (fov * (M_PI / 360.0));

  glFrustum (-ymax * aspect, ymax * aspect, -ymax, ymax, near, far);

  d = normalize (d);//D
  u = normalize (u);//D

  vec3 rz = -d;
  vec3 rx = cross (u, rz);
  vec3 ry = cross (rz, rx);

  matrix &m = projection;
  m(0,0) = rx.x; m(0,1) = rx.y; m(0,2) = rx.z; m(0,3) = 0;
  m(1,0) = ry.x; m(1,1) = ry.y; m(1,2) = ry.z; m(1,3) = 0;
  m(2,0) = rz.x; m(2,1) = rz.y; m(2,2) = rz.z; m(2,3) = 0;
  m(3,0) =    0; m(3,1) =    0; m(3,2) =    0; m(3,3) = 1;

  diagfact = abs (rz.x) + abs (rz.y) + abs (rz.z);
  diagfact = sqrtf (3.);//D WHY???
  //printf ("diagfact = %f\n", diagfact);

  glMultMatrixf (m);
  glTranslatef (-p.x, -p.y, -p.z);

  glGetFloatv (GL_PROJECTION_MATRIX, m);

  frustum.l = plane ( m(3,0) + m(0,0), m(3,1) + m(0,1), m(3,2) + m(0,2), m(3,3) + m(0,3) );
  frustum.r = plane ( m(3,0) - m(0,0), m(3,1) - m(0,1), m(3,2) - m(0,2), m(3,3) - m(0,3) );
  frustum.b = plane ( m(3,0) + m(1,0), m(3,1) + m(1,1), m(3,2) + m(1,2), m(3,3) + m(1,3) );
  frustum.t = plane ( m(3,0) - m(1,0), m(3,1) - m(1,1), m(3,2) - m(1,2), m(3,3) - m(1,3) );
  frustum.n = plane ( m(3,0) + m(2,0), m(3,1) + m(2,1), m(3,2) + m(2,2), m(3,3) + m(2,3) );
  frustum.f = plane ( m(3,0) - m(2,0), m(3,1) - m(2,1), m(3,2) - m(2,2), m(3,3) - m(2,3) );

  glMatrixMode (GL_MODELVIEW);
  glLoadIdentity ();
}

void view::begin ()
{
  glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glDepthRange (0, 1. - (1. / pow (2., 16.)));

  vislist.clear ();

  generation++;

  reset_projection ();

  farlist.clear ();

  // check occlusion queries
  for (vector<oq_data>::iterator i = occ_queries.begin (); i != occ_queries.end (); ++i)
    {
      occ_query oq(*this, i->second, occ_query_result (i->second));
      i->first->event (oq);
    }

  occ_queries.clear ();

  nextfar = near + 1.F;
  world.detect_visibility (*this);
  printf ("far %f nf %f RCP %f,%f,%f +%f\n", far, nextfar,
      frustum.r.n.x,
      frustum.r.n.y,
      frustum.r.n.z,
      frustum.r.d
      );//D
  far = nextfar;

  reset_projection ();
}

void view::end ()
{
  vislist.clear ();
}

void view::pass (enum mode m)
{
  mode = m;

  glDisable (GL_ALPHA_TEST);
  glDisable (GL_BLEND);

  if (mode == view::DEPTH)
    {
      glEnable (GL_POLYGON_OFFSET_FILL);
      glPolygonOffset (0, 1);
      glDepthFunc (GL_LESS);
      glDisable (GL_LIGHTING);
      glColorMask (0, 0, 0, 0);
      cgGLDisableProfile (vsh_profile);// z-fighting??
      cgGLDisableProfile (fsh_profile);
    }
  else
    {
      glEnable (GL_MINMAX);
      glDisable (GL_POLYGON_OFFSET_FILL);
      glDepthFunc (GL_LESS);
      glDepthMask (1);
      cgGLEnableProfile (vsh_profile);
      cgGLEnableProfile (fsh_profile);
    }
  
  for (vector<octant *>::iterator i = vislist.begin (); i != vislist.end (); ++i)
    {
      visibility_state &vs = vismap[*i];
      bool oq = (vs.visibility == visibility_state::PARTIAL
                 || vs.visibility == visibility_state::FULL)
                && (vs.last + 1. < timer.now)
                && (mode == LIGHTED);

      if (oq)
        begin_occ_query (**i);

      (*i)->display (*this);

      if (oq)
        end_occ_query ();

    }

  drawn.clear ();

  if (mode == view::DEPTH)
    {
      glEnable (GL_DEPTH_CLAMP_NV);
      glDepthFunc (GL_LESS);
      if (mode == view::LIGHTED) glDepthFunc (GL_LEQUAL);
      glDisable (GL_LIGHTING);
      cgGLDisableProfile (vsh_profile);
      cgGLDisableProfile (fsh_profile);
      //glShadeModel (GL_FLAT);

#if 0
      static int count; count++;
      if (farlist.size ())
        printf ("%d: size %d\n", count, farlist.size ());
#endif

      for (vector<octant *>::iterator i = farlist.begin (); i != farlist.end (); ++i)
        {
          if (mode == view::DEPTH) begin_occ_query (**i);
          if (mode == view::LIGHTED) glColor3f ((((long)*i >> 6) & 15) / 31. + 0.5,0,0);
          (*i)->draw_bbox (*this);
          if (mode == view::DEPTH) end_occ_query ();
       }

      glEnable (GL_DEPTH_TEST);
      glDisable (GL_DEPTH_CLAMP_NV);
      //glShadeModel (GL_SMOOTH);
    }

  glColorMask (1, 1, 1, 0);
  glDepthMask (1);

}