BF2_materials
Battlefront 2 Material System
This document explains the key features to understanding material parameters and their affect on the rendering system.
In order to use any of these materials you first select the polygons that you want to tag in XSI and then select EditFlags.
You should see a dialog box similar to the one shown below.
Common Parameters
Per-Pixel Lighting (Xbox/PC)
If this flag is selected all the lighting computations will be performed per-pixel instead of per-vertex.
This flag will give much nicer results because the lighting is not dependent on the tessellation of the mesh.
This flag has some cost to it (don’t over-use it).
https://en.wikipedia.org/wiki/Per-pixel_lighting
Specular Enable
This flag allows specular lighting on an object.
In order to adjust the specular power or specular color, associate the selected polygons with a XSI Phong material.
The color of the material determines the specular color and the specular decay controls how big the specular spot is.
The larger the specular decay the smaller the spot will be.
If there is an alpha channel in the diffuse texture then it serves as a gloss map (which attenuates the specular per pixel).
https://en.wikipedia.org/wiki/Specularity
Hard Edged Transparency
Hard edged transparency enables alpha testing and does not write pixels whose alpha is below a certain value.
Hard edged specifies that each pixel whose alpha channel value is less than 128 (50% opacity) becomes transparent.
So, essentially the image will have either transparent or opaque results ingame.
Hard edged transparency eliminates sorting issues caused by multiple transparent objects in front of each other.
Additive Transparency
Additive transparency will perform an add operation into the frame buffer instead of a blend.
This means if you have a bunch of additive objects in front of each other the objects will get successively brighter.
This property tells the system that the polygons are transparent and the alpha channel controls the transparency.
If the polygons are marked as single-sided then they are back faced culled (move slider to 1).
Polygons that are marked as double-sided are never culled (move slider to 2).
No transparency = 0 on the slider
Lighting
This property controls whether or not a set of polygons gets lit.
If tagged as "Normal" then the object will be lit. If it is tagged as "Emissive" it will not be lit.
Add some comments about Glow
https://msdn.microsoft.com/en-us/library/windows/desktop/bb173352%28v=vs.85%29.aspx
Render Types
Normal
The normal render type is the basic material.
It supports an optional detail map along with a tile value for the detail map.
Detail mapping will give the object the appearance of more texture resolution when close to the camera.
It is useful for simulating finely, rough surface such as cement or rocks.
The detail map should have an average intensity of about 0.5, which insures that the overall brightness of the object will not be affected.
Environment Map (RenderType 6 = Render Chrome)
The environment map render type adds support for a reflection map to give a shiny appearance on a surface.
If an environment map is not specified then it will choose an environment map dynamically at run time.
If the object is static or does not move you should provide an environment map.
Bump Map (RenderType 27 = Render Bumpmap)
A bump mapped object gives the object the appearance of more depth.
Bump mapping an object is useful for surfaces that have grooves such as tree bark and brick.
The bump map uses the same texture coordinates as the diffuse map.
The bump map must have the same alpha channel as the diffuse map.
This render type also supports a detail map that can be tiled.
Bump Detail Map
A bump detail map provides all the same functionality as a bump map however the bump map can be tiled.
Bump Environment Map
Same as a bump map, but provides an optional environment map.
Bump Detail Environment Map
Same as bump detail map, but provides an optional environment map.
Refraction (RenderType 22 = Render Ice Refraction)
The refraction render type behaves as a transparent material except the transparency is distorted.
The alpha channel of the diffuse texture is used to control the opacity while the bump map controls how much to distort the scene behind the object along with the distortion scale.
Since polygons tagged as refraction distorts the scene behind it, it suffers from the same sorting issues as a transparent object.
A refraction object can have an optional environment map associated with it. The Bothan spy uses this render type.
Scrolling (RenderType 3 = Render Scrolling)
Scrolls the diffuse texture according to the scroll speeds specified.
The scroll is unidirectional.
If you want to scroll in the other direction, just flip the texture coordinates.
Blink (RenderType 25 = Render Energy)
The render type is used for blinking the diffuse color.
The blink will oscillate between the original intensity and the min value specified according to the blink speed.
Animated (RenderType 7 = Render Animated)
This render type is used for animated textures.
All the frames must be on the same texture.
Your UV’s should be mapped to the first cell (not the entire texture).
Each individual cell is always square and is determined automatically from the number of frames.
The number of frames must be a perfect square (ie. 4,9,16,25,36…).
The frames are animated from top left to bottom right, the minimum number of frames is 4.
Example of a 64 frame texture set up for this render type