Re: Modifying $FG_ROOT/materials (was Re: [Flightgear-devel] Grand Canyon Demo)

[David M. <da...@me...>]

Curtis L. Olson writes:

 > 2. If you wanted to assign textures to each triangle individually in
 > the scenery, you will have to break up fans/strips to do it with the
 > associated performance implications.

What are the characteristics of FlightGear's fans and strips (other
than the fact that they share vertices and speed up rendering)?

1. Do all triangles in a fan or strip share the same material?
2. Do all triangles in a fan or strip share the same slope?
3. ???

 > 3. This stuff looks a lot nicer if you can blend smoothly between the
 > different texture types.  I'm not sure how that could be easily done
 > without a regular grid and a lot of transition textures.

This would be something to look at in the future, especially if some
kind of hardware-based texture blending is available then.  For now,
we'll have to live with harsh transitions.

 > 4. I'm not sure if the materials file is the best place to handle
 > this?  Although if we ended up with a materials.xml, I wouldn't
 > complain about that.

We could put another file on top of it; it comes out to the same
thing.  The idea is that the material in the scenery file becomes an
abstraction ("generally forested") rather than a link to a single
texture.

 > 5. If someone is actually going to look into this, they might also
 > consider how we'd impliment seasonal effects.  Again, I'm not sure if
 > the materials file is the best place to concentrate all the
 > configurability and options.  We might want to build some sort of
 > layer in between with all the actual smarts.

We would get seasonal effects by using the date constraint, though
we'd have to enter them manually for different areas.

 > 6. It maybe in the future that some scenery designers have picked
 > specific textures for specific reasons.  We wouldn't want a system
 > that always overwrote those choices arbitrarily using our own
 > heuristics.

Presumably, they'd use a different material name and there would be no
conflict.