Spoiler:
tangent-space normal map
I added a lot of details in 2d image editor and spent several minutes on it, instead of hours of 3d work.
-custom per-vertex normals created in 3d editor
-smooth groups
-mirrored and overlapped texture coordinates for symmetric models.
-deform animation (in future)
Shaders requirements:
1) Your tangent-space normal map should use red channel RIGHT(+) and green channel UP(+).
2) Your object-space normal map should use red channel RIGHT(+), green channel UP(+)
3) If you want to use a normal map, you also have to create and specify a specular map for it.
There are a lot of tools on the internet that create specular map from normal map, i.e. xnormal. Or google any lessons how to create `em manually.
4) We've saved support for object-space normal maps for backward compatibility. To use them a pie model must not have NORMALS directive.
5) We've saved original look of vanilla models. If you want to create a model using original color texture. Do not specify SPECULARMAP directive in PIE model.
We have also upgraded the light model from Phong's to Gaussian which is much better in highlights calculation without losing any performance.
What you need if you want to try and test it:
-WZ master build that supports this directive. win or others
-wz shaders that support all these features. (in test4.zip archive)
-Latest WMIT for preview and to convert models from OBJ format to PIE with normals.
example of how to create tangent-space normal maps in GIMP you can find here.