I think what you want to do is something like this

// Incoming radiance (this would be the color and intensity of the light energy
// that is coming towards your surface/shaded pixel)
float3 Li = LightColor * LightIntensity;  

// This would correspond to your LightIntensity (the cosine factor)
float NdotL = saturate(dot(Normal, LightDirection)); 

// Your final diffuse light output (or composition) 
float3 Diffuse = NdotL * Li;

// Your ambient light term
float3 AmbientLight = AmbientLight;

// Now "add" the ambient light to your diffuse composition
Diffuse += AmbientColor * AmbientIntensity;

// And at last multiply the result of your light computation by your material's
// diffuse color (albedo) -> basically the regular texture color
float3 output = Diffuse * Albedo;

// Incoming radiance (this would be the color and intensity of the light energy// that is coming towards your surface/shaded pixel)float3 Li = LightColor * LightIntensity;  // This would correspond to your LightIntensity (the cosine factor)float NdotL = saturate(dot(Normal, LightDirection)); // Your final diffuse light output (or composition) float3 Diffuse = NdotL * Li;// Your ambient light termfloat3 AmbientLight = AmbientLight;// Now "add" the ambient light to your diffuse compositionDiffuse += AmbientColor * AmbientIntensity;// And at last multiply the result of your light computation by your material's// diffuse color (albedo) -> basically the regular texture colorfloat3 output = Diffuse * Albedo;

// Incoming radiance (this would be the color and intensity of the light energy// that is coming towards your surface/shaded pixel)float3 Li = LightColor * LightIntensity;  // This would correspond to your LightIntensity (the cosine factor)float NdotL = saturate(dot(Normal, LightDirection)); // Your final diffuse light output (or composition) float3 Diffuse = NdotL * Li;// Your ambient light termfloat3 AmbientLight = AmbientLight;// Now "add" the ambient light to your diffuse compositionDiffuse += AmbientColor * AmbientIntensity;// And at last multiply the result of your light computation by your material's// diffuse color (albedo) -> basically the regular texture colorfloat3 output = Diffuse * Albedo;

I think what you want to do is something like this:

// Incoming radiance (this would be the color and intensity of the light energy
// that is coming towards your surface/shaded pixel)
float3 Li = LightColor * LightIntensity;  

// This would correspond to your LightIntensity (the cosine factor)
float NdotL = saturate(dot(Normal, LightDirection)); 

// Your final diffuse light output (or composition) 
float3 Diffuse = NdotL * Li;

// Your ambient light term
float3 AmbientLight = AmbientColor * AmbientIntensity;

// Now "add" the ambient light to your diffuse composition
Diffuse += AmbientColor * AmbientIntensity;

// And at last multiply the result of your light computation by your material's
// diffuse color (albedo) -> basically the regular texture color
float3 output = Diffuse * Albedo;