[Gnu3dkit-dev] Goal: Import and Export asset files from and to external formats.

[Brent Gulanowski]

 Note: "Asset files" are scenes (composed of simpler assets), objects 
(vertex lists and mathematical descriptions) and textures.

General Strategy: Provide an Abstract Asset Interface and Specific 
Asset Representations
Sub-goals:
- Distinguish between kinds of representations, and associate each with 
a semantic context. This means identifying if it is used as a file 
format or as a rendering format, and whether it contains a structure 
and what kind, such as: leaf parentage (single/multiple); object groups 
or polygon groups; use of visibility hierarchy (BSP, quadtree, octree).
- Distinguish between scenes and component assets: scenes are organized 
collections of artistic assets (vertex sets, mathematical object 
descriptions, and textures)
- Encapsulate the methods for converting between representations
- Identify a preferred or native file format for 3DKit
- Produce a class cluster interface for asset representations
- Restrict the representations which are used by the renderer
- Optimize the renderer for presentation of one preferred 
representation for each asset category: texture, vertex group, 
mathematical description (for tessellation, if we want to do that), 
scene (our internal scene rep), and visibility information (again, if 
we want to provide that facility -- I research this area regularly)
Caveats:
- Switching between representations during rendering is Very Bad
- Too many representations means a lot of overhead
- We may need an intermediary human-readable file format like XML for 
some/all supported representations
- May have to require that users of 3DKit provide their own conversion 
plug-in code (means we need a plug-in architecture)


--
Brent Gulanowski                                address@hidden

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