Function DrawAtmosphereBlend

Descent3/terrainrender.cpp:1889–1950

Draws the atmosphere over a satellite

}
// Draws the atmosphere over a satellite
void DrawAtmosphereBlend(vector *pos, angle rotAngle, float w, float h, int bm, float r, float g, float b) {
  g3Point pnt;
  if (g3_RotatePoint(&pnt, pos) & CC_BEHIND)
    return;

  // create the rotation matrix
  matrix rotMatrix;
  vm_AnglesToMatrix(&rotMatrix, 0, 0, rotAngle);

  // get the view matrix
  matrix viewToWorld;
  g3_GetUnscaledMatrix(&viewToWorld);
  viewToWorld = ~viewToWorld;

  // combine the matrices into one
  matrix rotationToWorld = rotMatrix * viewToWorld;

  // setup the rotation vectors
  vector rotVectors[4];
  rotVectors[0].x = -w;
  rotVectors[0].y = h;
  rotVectors[1].x = w;
  rotVectors[1].y = h;
  rotVectors[2].x = w;
  rotVectors[2].y = -h;
  rotVectors[3].x = -w;
  rotVectors[3].y = -h;

  // rotate the points
  g3Point rotPoints[8], *pntList[8];
  int i;
  for (i = 0; i < 4; ++i) {
    rotVectors[i].z = 0.0f;
    rotVectors[i] = (rotVectors[i] * rotationToWorld) + (*pos);

    // setup the point
    g3_RotatePoint(&rotPoints[i], &rotVectors[i]);
    rotPoints[i].p3_flags |= PF_UV | PF_RGBA;
    rotPoints[i].p3_r = r;
    rotPoints[i].p3_g = g;
    rotPoints[i].p3_b = b;
    rotPoints[i].p3_a = 0.4f;

    pntList[i] = &rotPoints[i];
  }

  rotPoints[0].p3_u = 0.0f;
  rotPoints[0].p3_v = 0.0f;
  rotPoints[1].p3_u = 1.0f;
  rotPoints[1].p3_v = 0.0f;
  rotPoints[2].p3_u = 1.0f;
  rotPoints[2].p3_v = 1.0f;
  rotPoints[3].p3_u = 0.0f;
  rotPoints[3].p3_v = 1.0f;

  // and draw!!
  rend_SetLighting(LS_NONE);
  rend_SetFlatColor(Terrain_sky.sky_color);