https://github.com/coelckers/gzdoom/pull/1133
Continue dpJudas' work on directional contrast. For best results, EvenLighting is advised.
- New MAPINFO option: DirectionalContrastMode. 0 = default (no added contrast), 1 = affect models only, 2 = affect models and world textures (walls and flats).
- New MAPINFO option: DirectionalContrast = <X>, <Y>, <Z>, <Strength>. Sets the directional contrast vector, and strength. All defaults to 0.
- New ZScript functions: Level.SetDirectionalContrast(double x, double y, double z, double w), Level.GetDirectionalContrastVec() and Level.GetDirectionalContrastStr().
- New MODELDEF option: NoDirectionalContrast for disabling contrast effect on specific models.
The purpose of this feature is to improve lighting contrast on models, and optionally the world. Without this, models have flat lighting, and normal/specular maps are only visible when they are touching dynamic lights, which often forces map authors to spam their level with dynamic lights. This addresses that problem.
Example file coming later, I need time to make it.