I know I've already posted this but my original post was in the wrong section because I was trying to get a texturepack working on a server... ANYWAY, Classicube has lighting options like "Classic", "Fancy" and "Smooth lighting", but it doesn't have an option for "Realistic lighting".
Realistic lighting would basically make it so instead of having a solid color for shadows, it would have a gradient.
Without Realistic lighting:
With Realistic lighting:
What the Graphics Options would look like with it:
Lighting options is replaced with Fancy lights. The options for Block shadow (use lowercase s for shadow, I made a mistake) is Solid and Gradient, Gradient is the "Realistic lighting".