4-directional-lighting.md

Making your shader look cool

Directional lighting

Minecraft already has some directional lighting, but we can amplify it using a simple NdotL check.

In the process, we will restore some lighting to entities and such.

Enhanced directional lighting

To pull this off, we will need two things: the view-space normals, and the normalized sun position. These are very easy to obtain.

In your vertex shader, you will need to add a new out vec3 normal, and initialize it in main with normal = gl_NormalMatrix * gl_Normal.

Add the corresponding in statement to the fragment shader, and now do this.

// Add some new uniforms and your in statement
in vec3 normal;

uniform vec3 shadowLightPosition;

void main() {
    // all code before mixing fog
    
    // 0.2 will be the *minimum* light for objects facing away from the sun. You can mess with this value.
    // The sun/moon position must be normalized.
    float NdotL = max(0.2, dot(normal, normalize(shadowLightPosition)));
    
    finalColor.rgb *= NdotL;
}

Now you can see much more pronounced directional lighting. You can change 0.2 to a higher number to make the world overall brighter.

Adding new programs

Let's make a copy of your gbuffers_terrain program and name it gbuffers_textured. This program will have all code for non-terrain.

Congrats! You now have cool shading on entities.

However, take a look at the sky. You may see the sun is a bit... wider than usual. This is because the vertex position for the sky is nonsense.

To fix this, we will need to make another copy gbuffers_skytextured, and remove the fog calculation. (Don't forget to remove directional lighting too; you don't want the sun shading itself!)