Specular Shaders

Specular Shader is the algorithm that controls the way light bounces  from the surface creating the highlight. There are many specular shaders out there, but Dark Engine supports only three: FLAT, GOURAUD and PHONG.

In my opinion it should be called a Diffuse Shader rather then Specular because Dark Engine simply doesn't support specularity. I've chosen the specular name because it's where Blender has Phong algorithm located. In other words, Blender uses Phong only in its specular shader. That's why I've initially decided to call it a specular shader.

To tell the truth I don't know if Dark Engine really supports all three shaders, but I saw some examples of the intermediate files (.E) generated by n3ds2e.exe where all three shaders were used. Moreover looking at the bsp.exe and n3ds2e.exe file structure with Notepad++ (or any other hex editor) reveals these three shaders plus one additional named METAL.

A difference between Gouraud and Phong may be very hard to notice in game. That's why I can't say if both are used by Dark Engine. Only Flat vs (Phong or Gouraud) is clearly noticeable.

If Dark Engine really supports Gouraud and Phong than the difference between them should be visible during rendering more complicated meshes. It's because Gouraud shading should be faster than Phong. Dark Engine is however over a decade old, so running such tests on modern computers my lead to nowhere.  I tested a few objects with Gouraud and Phong and didn't see any difference.

On the below screenshot you can see a typical difference between Flat and (Phong or Gouraud) on the example of one of my meshes created in Blender and exported with Dark Exporter:

How To Deal With Specular Shader In Blender

Blender doesn't use such simple shaders as Flat or Gouraud, except for Phong which is also not a default one.  I had to solve that problem by means of some mapping. So here is what you need to do to get the proper shader in the exported file. Select the material of your choice and navigate to the Materials panel and then Specular section (see the screenshot below):

This is where you can select the specular shader of the material. Take a look at the below mapping to get the right shader:

Shader in Blender      ------>     Shader in Dark Engine (E file)

CookTorr (default)     ------>     (empty field)

Phong                  ------>     PHONG

Blinn                  ------>     GOURAUD

Wardiso                ------>     FLAT

Toon                   ------>     (NOT IMPLEMENTED)

Select in Blender one of its specular shaders for a material and export your model. Spec shader will be translated to PHONG, GOURAUD or FLAT accordingly to the above mapping.

How To Debug

Blender console displays debug information about the materials of your exported meshes. The below screenshot reveals how the above mentioned mapping is logged in the Blender Console: