k3d/share/shaders/k3d_eyeball.sl:68:  float irisstat, pupilstat;
k3d/share/shaders/k3d_eyeball.sl:79:   * pupilstat: 0 inside the pupil/iris boundary, 1 outside
k3d/share/shaders/k3d_eyeball.sl:84:  pupilstat = smoothstep (pupilsize, pupilsize+twidth, tt);
k3d/share/shaders/k3d_eyeball.sl:111:  if (irisstat < 0.9999 && pupilstat > 0.0001) {
k3d/share/shaders/k3d_eyeball.sl:124:  Ct = mix (pupilcolor, Ct, pupilstat);
