Function RenderSingleLightGlow

Descent3/render.cpp:2401–2460

Draws a glow around a light

#define CORONA_DIST_CUTOFF 5.0f
// Draws a glow around a light
void RenderSingleLightGlow(int index) {
  int bm_handle;
  room *rp = &Rooms[LightGlows[index].roomnum];
  face *fp = &rp->faces[LightGlows[index].facenum];
  texture *texp = &GameTextures[fp->tmap];
  bm_handle = Fireballs[DEFAULT_CORONA_INDEX + texp->corona_type].bm_handle;

  // Get size of light
  float size = LightGlows[index].size;
  vector center = LightGlows[index].center;

  // Get alpha of light
  vector tvec = Viewer_eye - rp->verts[fp->face_verts[0]];
  vm_NormalizeVectorFast(&tvec);
  float facing_scalar = (tvec * fp->normal) * 2;
  if (facing_scalar < 0)
    return;
  tvec = center - Viewer_eye;

  float dist = vm_GetMagnitudeFast(&tvec);
  if (dist < (size * CORONA_DIST_CUTOFF))
    return;
  if (dist < (size * (CORONA_DIST_CUTOFF + 15))) {
    float dist_scalar = ((dist - (size * CORONA_DIST_CUTOFF)) / (size * 15));
    facing_scalar *= dist_scalar;
  }

  facing_scalar *= LightGlows[index].scalar;
  facing_scalar = std::min<float>(facing_scalar, 1.0);
  // Take into effect pulsing
  ComputeRoomPulseLight(rp);
  facing_scalar *= Room_light_val;
  rend_SetAlphaValue(facing_scalar * .4 * 255);

  float maxc = std::max({texp->r, texp->g, texp->b});
  float r, g, b;
  if (maxc > 1.0) {
    r = texp->r / maxc;
    g = texp->g / maxc;
    b = texp->b / maxc;
  } else {
    r = texp->r;
    g = texp->g;
    b = texp->b;
  }
  if (LightGlows[index].flags & LGF_FAST) {
    rend_SetZBufferWriteMask(0);
    rend_SetZBias((-size / 2));
  } else {
    rend_SetZBufferState(0);
  }
  ddgr_color color = GR_RGB(r * 255, g * 255, b * 255);
  g3_DrawBitmap(&center, size, (size * bm_h(bm_handle, 0)) / bm_w(bm_handle, 0), bm_handle, color);
  if (LightGlows[index].flags & LGF_FAST) {
    rend_SetZBufferWriteMask(1);
    rend_SetZBias(0);
  } else {
    rend_SetZBufferState(1);