Rim Light question

[rosstheblenderanimator]

How to control the rim light direction with light source?

[pragma37]

You would need the light vector in view space and use it as the angle for the rim.
This is not easy to do from nodes, so here's a function that you can drop into a plugin:

#if defined(IS_MESH_SHADER) || defined(IS_SCREEN_SHADER)

#ifdef IS_MESH_SHADER
/*  META
    @normal: subtype=Normal; default=NORMAL;
    @rim_length: default=1.0;
    @length_fallof: default=1.0;
    @thickness: default=0.5;
    @thickness_fallof: default=0.0;
    @light_groups: default=MATERIAL_LIGHT_GROUPS;
*/
#else
/*  META
    @normal: subtype=Normal; default=NORMAL;
    @rim_length: default=1.0;
    @length_fallof: default=1.0;
    @thickness: default=0.5;
    @thickness_fallof: default=0.0;
    @light_groups: default=ivec4(1,0,0,0);
*/
#endif
vec3 NPR_rim_lights(vec3 normal, float rim_length, float length_falloff, float thickness, float thickness_falloff, ivec4 light_groups)
{
    vec3 result = vec3(0,0,0);
    for (int i = 0; i < LIGHTS.lights_count; i++)
    {
        for(int group_index = 0; group_index < 4; group_index++)
        {
            if(LIGHT_GROUP_INDEX(i) != light_groups[group_index])
            {
                continue;
            }
            Light L = LIGHTS.lights[i];
            LitSurface LS = npr_lit_surface(POSITION, normal, ID.x, L, i, false, false);

            vec3 L_vs = transform_direction(CAMERA, LS.L);
            float angle = atan(L_vs.y, L_vs.x) + PI / 2.0;

            float rim = rim_light(normal, angle, rim_length, length_falloff, thickness, thickness_falloff);
            result += rim * LS.light_color;
        }
    }
    
    return result;
}

#endif

[rosstheblenderanimator]

Thanks, How do I do the plugin?

[pragma37]

See https://malt3d.com/documentation/plugins/

So:

• Download and install the PluginExample.
• Paste the code from my post at the end of PluginExample.glsl.
• Now you should have a "NPR Rim Lights" node available.

[rosstheblenderanimator]

Thanks alot