Shading Models are what processes how a model is lit, this is typically is the final step and output of your shader.

Consumes your Material and shades the output with lighting, atmospheric, and deals with everything needed to show specific stages of rendering if Debug Views are enabled.

The traditional flow of a lit shader is Input Interpolants > Material Definition > Output Shading Model

ShadingModelStandard

The default Source 2 Lighting.

float4 MainPs(PixelInput i)  : SV_Target0
{
   Material m = Material::From( i );
   return ShadingModelStandard::Shade( m );
}

float4 ShadingModelStandard::Shade( Material m )

• Consumes the material set from m and does the standard lighting from it.

  Returns the final output of the shader in a float4

Custom Shading Model Example

The default Shading Model should have everything you need, but if your game has a custom art style you can try to implement your own Shading Model with ease.

When implementing your own Shading Model, the best practice is to segmenting it by Direct/Indirect and each of these again in Specular/Diffuse lighting.

This is an example of a simple toon shader:

class ShadingModelToon
{
    static float4 Shade( Material m )
    {
        float4 color = 0;
        
        // Direct Lighting
        for( int i=0; i < DynamicLight::Count(); i++ )
        {
            Light l = DynamicLight::From( ScreenPosition, WorldPosition, i );
            ...
            
            float3 diffuse = /* */
            float3 specular = /* */
            
            color += diffuse + specular;
        }
        
        // Indirect Lighting
        {
            float3 diffuse = 0;
            {
                diffuse = /* ambient light */
                diffuse *= min( m.AmbientOcclusion, ScreenSpaceAmbientOcclusion::Sample( m.ScreenPosition );
            }
            
            float3 specular = 0;
            {
                specular = /* envmap */
                specular += /* toon fresnel */
            }
            
            color += diffuse + specular;
        }
        
        if( DepthNormal::WantsDepthNormal() )
            return DepthNormal::Output( m );

        if( ToolVis::WantsToolVis() )
            return ToolVis::Output( color, m );

        // Composite atmospherics after lighting
        color.xyz = Fog::Apply( m.WorldPosition, m.ScreenPosition.xy, color );
        
        return color;
    }
}