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======================================
OPCODE (OPtimized COllision DEtection)
======================================
Demo version 1.3b
This demo compares RAPID 2.01 vs OPCODE 1.0.
Information about RAPID can be found there:
http://www.cs.unc.edu/~geom/OBB/OBBT.html
Information about OPCODE can be found there:
http://www.codercorner.com/Opcode.htm
-----
I tried to be as fair as possible, and selected several scenes
where both RAPID and OPCODE show their forces. RAPID is usually
faster in close-proximity scenarii, especially when one object
is totally surrounded by another. OPCODE is usually faster when
objects deeply overlap. On my machine (Celeron 500Mhz), I have
found OPCODE to be faster overall. See for yourself.
By the way, don't forget OPCODE's primary goal was *memory*, not
speed. Considering this, I'm quite pleased with the results!
-----
Scenes have been exported with Flexporter:
http://www.codercorner.com/Flexporter.htm
If you don't like them, you can export your own test scenes from
MAX - just ensure there are only 2 meshes in them.
-----
How to proceed:
1) Run Opcode.exe
2) Drag&drop a ZCB file on the window
Messages such as "Chunk MOVE not found" are normal.
3) Play!
-----
OPCODE-related keys:
1 Toggle contact mode
- All contacts: report all colliding triangles
- First contact: report first contact only (a simple yes/no
answer to the overlap question)
2 Toggle BV-BV tests
- full tests: standard SAT (15 separating axes)
- no class III: SAT-lite (6 separating axes)
3 Toggle Prim-BV tests
- full tests: standard SAT (15 separating axes)
- no class III: SAT-lite (6 separating axes)
4 Toggle leaf nodes
- discarded: use N-1 nodes only for a complete tree
- kept: standard complete tree with 2*N-1 nodes
5 Toggle compression
- enabled: use quantized trees
- disabled: use normal trees
6 Toggle temporal coherence (only for first contact mode)
- enabled: test the previous pair of colliding triangles
before everything else.
- disabled: well, do not....
-----
NB: in order to switch from one feature to another quickly, I create
4 trees for each mesh: normal, no-leaf, quantized, quantized no-leaf.
i.e. 4 OPCODE models + 1 RAPID model / mesh, which explains why the
building phase is not very fast... Especially in the last scene, it
takes a while - please wait!
-----
Generic keys to play with:
F1 Texture control
F2 Camera control
F3 Mesh control
F4 Material control
F5 Scene control
F6 Light control
F7 Helper control
To move the camera or a mesh, use the mouse. Should be intuitive.
In camera mode, press +/- to jump from one camera to another.
Actually +/- jump to "next current" or "previous current", where
"current" is a mesh, camera, texture, etc - depends on selected
control mode.
To test collision detection, useful keys are:
- S to spin a model automatically (on/off)
- P to pause any animation
- O (in pause mode) to play one frame only
Other keys shouldn't be useful there but anyway:
- F displays the framerate on/off (BTW, I do 2 collision queries/frame
and displays a lot of slow text, so don't pay too much attention to
the overall framerate)
- T toggles texturing
- G toggles gouraud
- W toggles wireframe
- R toggles the profiling
- I toggles general information
- B toggles bounding boxes
Special keys
- Y should subdivide a mesh with the Butterfly algorithm. Since it
implies rebuilding all collision trees, it may be quite slow.
- L should smooth a mesh (same remark)
- M should make a mesh manifold, in case ICE complains....
- U should unfold a mesh, so beware.
Otherwise, play with the menu *at your own risk*.
-----
In situations where RAPID is really faster (for example when a mesh
is surrounded by another one) try re-enabling leaf nodes....
-----
Pierre Terdiman
May 03, 2001
p.terdiman@wanadoo.fr
p.terdiman@codercorner.com
www.codercorner.com
|
