k3d/share/shaders/k3d_brickbump2.sl:38:    float sbump, tbump, stbump;
k3d/share/shaders/k3d_brickbump2.sl:59:    stbump = sbump * tbump;
k3d/share/shaders/k3d_brickbump2.sl:62:    Nf = calculatenormal(P + normalize(N) * stbump);
k3d/share/shaders/k3d_rustymetal.sl:16: *   rustbump - controls the "bumpiness" of the rusty areas.
k3d/share/shaders/k3d_rustymetal.sl:49:	    float rustbump = 0.035;
k3d/share/shaders/k3d_rustymetal.sl:72:  Nrust = calculatenormal (P + rustbump * snoise(PP) * normalize(N));
