Experimental shader ranging from metallic to emissive with just one float slider.
A minimalist one-parameter shader that smoothly runs from emissive (0.0), over translucent (0.75), to diffuse (1.0) and opaque (1.25) to metallic (2.0).
float shading = chf('shading');
vector color = chv('color');
vector pos_light = {2.6, 1.2, 0.6};
vector dir = normalize(pos_light - v@P);
float lumen = max(1.0 - shading, 0.0);
float angle = max(dot(dir, v@N), lumen);
shading = fit(shading, 1, 2, 1, 20);
float shade = pow(angle, max(shading, 1.0));
v@Cd = color * shade;
