Simple Scene Management
A common question on game programming forums is something like:
I have a bunch of objects moving around the world; how do I render
them? Do I have a Draw() function on each of them and let them call
Here's my proto-typical answer, assuming you know about the Interface
way of structuring code, and some other common software patterns:
You typically want objects implementing your Viewable interface to go
into some scene graph (like an octree).
Then, you use a Visitor to visit all Viewables that intersect the
The protocol for Viewable is typically to return a description of some
sort (i e, group of geometry, material, and pose/matrix state) which the
renderer uses to actually render the thing.
The reason you don't want objects calling renderer->setTexture() and
similar functions directly is that then, if you change your rendering to
require multi-passing (for shadows, reflection, etc) then you have to
update ALL the objects, if the objects do the rendering.
Having objects describe themselves with multiples of
geometry-material-state is much more flexible, as you can easily throw that
at mirroring, cube mapping, shadow maps, shadow volumes, cel shading, and
whatever else you care about implementing.