Function g3_StartFrame

renderer/HardwareSetup.cpp:87–147

start the frame

// start the frame
void g3_StartFrame(vector *view_pos, matrix *view_matrix, float zoom) {
  // initialize the viewport transform
  g3_GetViewPortMatrix((float *)gTransformViewPort);
  g3_GetProjectionMatrix(zoom, (float *)gTransformProjection);
  g3_GetModelViewMatrix(view_pos, view_matrix, (float *)gTransformModelView);
  g3_UpdateFullTransform();

  // get window size
  rend_GetProjectionParameters(&Window_width, &Window_height);

  // Set vars for projection
  Window_w2 = ((float)Window_width) * 0.5f;
  Window_h2 = ((float)Window_height) * 0.5f;

  // Compute aspect ratio for this window
  float screen_aspect = rend_GetAspectRatio();
  if (sAspect != 0.0f) {
    // check for user override
    screen_aspect = screen_aspect * 4.0f / 3.0f / sAspect;
  }
  float s = screen_aspect * (float)Window_height / (float)Window_width;

  if (s <= 0.0f) // JEFF: Should this have been 1.0f?
  {
    // scale x
    Matrix_scale.x = s;
    Matrix_scale.y = 1.0f;
  } else {
    Matrix_scale.y = 1.0f / s;
    Matrix_scale.x = 1.0f;
  }

  Matrix_scale.z = 1.0f;

  // Set the view variables
  View_position = *view_pos;
  View_zoom = zoom;
  Unscaled_matrix = *view_matrix;

  // Compute matrix scale for zoom and aspect ratio
  if (View_zoom <= 1.0f) {
    // zoom in by scaling z
    Matrix_scale.z = Matrix_scale.z * View_zoom;
  } else {
    // zoom out by scaling x and y
    float oOZ = 1.0f / View_zoom;
    Matrix_scale.x = Matrix_scale.x * oOZ;
    Matrix_scale.y = Matrix_scale.y * oOZ;
  }

  // Scale the matrix elements
  View_matrix.rvec = Unscaled_matrix.rvec * Matrix_scale.x;
  View_matrix.uvec = Unscaled_matrix.uvec * Matrix_scale.y;
  View_matrix.fvec = Unscaled_matrix.fvec * Matrix_scale.z;

  // Reset the list of free points
  InitFreePoints();