d_part.c

/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// d_part.c: software driver module for drawing particles

#include "quakedef.h"
#include "d_local.h"


/*
==============
D_EndParticles
==============
*/
void D_EndParticles (void)
{
// not used by software driver
}


/*
==============
D_StartParticles
==============
*/
void D_StartParticles (void)
{
// not used by software driver
}


#if !defined(M68KASM)
/*
==============
D_DrawParticle
==============
*/
void D_DrawParticle (particle_t *pparticle)
{
  vec3_t  local, transformed;
  float zi;
  byte  *pdest;
  short *pz;
  int   i, izi, pix, count, u, v;

// transform point
  VectorSubtract (pparticle->org, r_origin, local);

  transformed[0] = DotProduct(local, r_pright);
  transformed[1] = DotProduct(local, r_pup);
  transformed[2] = DotProduct(local, r_ppn);    

  if (transformed[2] < PARTICLE_Z_CLIP)
    return;

// project the point
// FIXME: preadjust xcenter and ycenter
  zi = 1.0 / transformed[2];
  u = (int)(xcenter + zi * transformed[0] + 0.5);
  v = (int)(ycenter - zi * transformed[1] + 0.5);

  if ((v > d_vrectbottom_particle) || 
    (u > d_vrectright_particle) ||
    (v < d_vrecty) ||
    (u < d_vrectx))
  {
    return;
  }

  pz = d_pzbuffer + (d_zwidth * v) + u;
  pdest = d_viewbuffer + d_scantable[v] + u;
  izi = (int)(zi * 0x8000);

  pix = izi >> d_pix_shift;

  if (pix < d_pix_min)
    pix = d_pix_min;
  else if (pix > d_pix_max)
    pix = d_pix_max;

  switch (pix)
  {
  case 1:
    count = 1 << d_y_aspect_shift;

    for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth)
    {
      if (pz[0] <= izi)
      {
        pz[0] = izi;
        pdest[0] = pparticle->color;
      }
    }
    break;

  case 2:
    count = 2 << d_y_aspect_shift;

    for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth)
    {
      if (pz[0] <= izi)
      {
        pz[0] = izi;
        pdest[0] = pparticle->color;
      }

      if (pz[1] <= izi)
      {
        pz[1] = izi;
        pdest[1] = pparticle->color;
      }
    }
    break;

  case 3:
    count = 3 << d_y_aspect_shift;

    for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth)
    {
      if (pz[0] <= izi)
      {
        pz[0] = izi;
        pdest[0] = pparticle->color;
      }

      if (pz[1] <= izi)
      {
        pz[1] = izi;
        pdest[1] = pparticle->color;
      }

      if (pz[2] <= izi)
      {
        pz[2] = izi;
        pdest[2] = pparticle->color;
      }
    }
    break;

  case 4:
    count = 4 << d_y_aspect_shift;

    for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth)
    {
      if (pz[0] <= izi)
      {
        pz[0] = izi;
        pdest[0] = pparticle->color;
      }

      if (pz[1] <= izi)
      {
        pz[1] = izi;
        pdest[1] = pparticle->color;
      }

      if (pz[2] <= izi)
      {
        pz[2] = izi;
        pdest[2] = pparticle->color;
      }

      if (pz[3] <= izi)
      {
        pz[3] = izi;
        pdest[3] = pparticle->color;
      }
    }
    break;

  default:
    count = pix << d_y_aspect_shift;

    for ( ; count ; count--, pz += d_zwidth, pdest += screenwidth)
    {
      for (i=0 ; i<pix ; i++)
      {
        if (pz[i] <= izi)
        {
          pz[i] = izi;
          pdest[i] = pparticle->color;
        }
      }
    }
    break;
  }
}

#endif  /* !M68KASM */