Re: Pre-rendered scene and 3D character movements

[Atool Varma <varmaa@kenyon.edu>]

On Wed, 22 Sep 1999, Kamel Serend wrote:

> Still, this is only a guess, and I am not certain I am right.
> Can anybody confirm or contradict this solution ? I might need it in the
> future.

	I'm no expert on this, but I think that the z-buffer solution
integrates so well with the way 3D polygon scenes are currently rendered
that such a 2D solution would require more work, and would be less
accurate, especially with complex pre-rendered environments such as those
in Final Fantasy 7 & 8 and Grim Fandango.  But I bet some older games like
Sierra's classic "3-D adventure games" (King's Quest I-VII, etc) might
have used the technique you described, since z-buffers were too expensive
on memory back then and the rendering process didn't even need a z-buffer
in the first place; they could just use a linked list of 2D objects to
draw that's sorted by z-depth.

	Hmm, I just thought of another problem.  In those games like Final
Fantasy 7/8 and Grim Fandango, you also can't move your character past
some of these physical boundaries (e.g., if there's a pre-rendered wall
in front of your character, your character can't move thru the wall).  How
is this done?  The only thing I can think of is that the game could also
store a 3D polygon approximation of all the obstacles in the scene
(like a Quake level) and use those to test whether the player object
intersected with them, but it wouldn't actually pass those polygons onto
the renderer since their graphical form would be in the pre-rendered
image.  Does anyone know if this is actually what happens?

		Atul

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