Texture shading in the PS1 era

scientifik

I'm looking though the Metal Gear Solid assets to see how things were done back in the day and I can't figure out how the texture shading is done.

The texture fades to black along the bottom of the ceiling rock where it meets the wall:

But I can't see how this is achieved. It's not a different texture:

it doesn't seem to be achieved with normal weighting:

or vertex colors (unless I'm not visualizing it correctly):

What is this black magic? Apologies if I'm just missing something really obvious.

Eric Chadwick

Probably just vertex color, and when you ripped the asset it didn’t preserve that data. 

scientifik

If it wasn't preserved how is blender shading it darker in places though?

Alex_J

you can test the idea by doing an obj export and disable vertex colors to be exported, and then import that back in and see if the gradient is still there.

scientifik

I did that and the shading persisted which caused me to look a little closer and I found out despite thinking that I could read and also had an eye for detail, aparently I cannot and do not. The texture in the UV window in my first post is 007fa0 and the main texture on the dock ceiling is 007fa2. a0 is a smaller, lighter variant used on the distant area from where snake swims in, while a2 has the shadow and they just avoid using that area in the unwrap in areas where it's not needed.

a0:

a2:

Apologies.