MonoGame.Samples/Samples/MacOS/SpriteEffects/Content/normalmap.fx

// Effect applies normalmapped lighting to a 2D sprite.

float3 LightDirection;
float3 LightColor = 1.5;
float3 AmbientColor = 0;

sampler TextureSampler : register(s0);
sampler NormalSampler : register(s1);


float4 main(float4 color : COLOR0, float2 texCoord : TEXCOORD0) : COLOR0
{
    // Look up the texture and normalmap values.
    float4 tex = tex2D(TextureSampler, texCoord);
    float3 normal = tex2D(NormalSampler, texCoord);
    
    // Compute lighting.
    float lightAmount = max(dot(normal, LightDirection), 0);
    
    color.rgb *= AmbientColor + lightAmount * LightColor;
    
    return tex * color;
}


technique Normalmap
{
    pass Pass1
    {
        PixelShader = compile ps_2_0 main();
    }
}