fix(shaders): the highlight of the sun is multiplied by the cosine of its light, so surfaces no longer glare milky white under a low sun; headlights light a surface with 1.35 of its diffuse colour and add a GGX highlight of their own scaled by specgloss and param_specular instead of multiplying the whole light by one plus param_specular; normalmap, parallax, detail, shadowless, sunless and default_detail materials read param_glossiness as a Phong exponent, roughness = (2 / (n + 2))^1/4, instead of 1 - 1/n or a fixed mirror

shaders/mat_normalmap.frag

@@ -49,6 +49,7 @@ void main()
 	float reflectivity = param[1].z * texture(normalmap, f_coord).a;
 	float specularity = (tex_color.r + tex_color.g + tex_color.b) * 0.5;
 
+	glossiness = phong_glossiness();
 	fragcolor = apply_lights(fragcolor, fragnormal, tex_color.rgb, reflectivity, specularity, shadow_tone);
 
 	vec4 color = vec4(apply_fog(fragcolor), tex_color.a * alpha_mult);