|
|
| |
In lugnet.cad.dev.mac, Roland Melkert wrote:
| |
Your method is roughly the same as what LD4DStdudio does, except I use VBO to
stuff whole high level parts in index-ed arrays. The indices are then grouped
per color (16 being also a color) so a minimum of glcolor’s are needed during
rendering. So it seems display lists aren’t ‘less’ then VBO at all to me.
|
One drawback with VBOs is that - unlike displaylists - you can’t stick arbitrary
GL calls in them. I’m using lists because I need to be able to put matrix
operations in them as well as geometry.
| |
Only problem with the highlevel part approach is you can’t support mirrored
submodels higher up in the rendering tree (like eg the star destroyed mpd
uses) cause it will mess up the normals. Or did you find a way around that?
|
Change the cull-face orientation ;-)
| |
Optimizations I was thinking of for my new renderer are using only triangles
instead of 1 on 1 ld quads and triangles cause quads will be split by the
driver anyway. (not sure if it’s actually faster doing it yourself but I’ll
have to test that.)
|
I can’t say I’ve noticed the difference myself, but I suspect it’ll depend on
the hardware and drivers as much as anything.
| |
The conditional lines are indeed a pain, normal lines can go in vbo/display
lists much like the triangles but you have to test all conlines against the
the current projection matrix for every redraw. I was planning to do this
multithreaded (like LDView does).
|
See my previous post :-) Offload the grunt-work to the graphics-card, and it
flies!
Alex
|
|
| |
In lugnet.cad.dev.mac, Allen Smith wrote:
snip
| |
Bricksmith now recursively flattens the geometry for each referenced
top-level part then sorts it according to primitive type (triangles, quads,
lines). Since the primitives are sorted, each type can be enclosed in a
single glBegin while display lists are compiled. I create a unique display
list for each color variation of the part. Flattening and sorting the
primitives allowed the display lists to perform vastly improved internal
optimizations over what they were able to do with the unsorted data from the
previous version of Bricksmith.
Unfortunately, all this is a bit beside the point because display lists are
on their way out, deprecated, not even available on the iPhone, etc. You are
supposed to be using VBOs and VAOs nowadays. Unfortunately I am not a 3D
guru, wrote my program using obsolete methods to begin with, and it has taken
me a while to plan a transition.
By the way, Bricksmith does not render conditional lines. I consider shading
to be a sufficient substitute, and conditional lines sound difficult to
optimize.
Allen
|
Thanks for the insight Allen,
I’m also not a 3D guru, but I like to fool around with it as much as anyone
interested in 3d programming.
Your method is roughly the same as what LD4DStdudio does, except I use VBO to
stuff whole high level parts in index-ed arrays. The indices are then grouped
per color (16 being also a color) so a minimum of glcolor’s are needed during
rendering. So it seems display lists aren’t ‘less’ then VBO at all to me.
Only problem with the highlevel part approach is you can’t support mirrored
submodels higher up in the rendering tree (like eg the star destroyed mpd uses)
cause it will mess up the normals. Or did you find a way around that?
Optimizations I was thinking of for my new renderer are using only triangles
instead of 1 on 1 ld quads and triangles cause quads will be split by the driver
anyway. (not sure if it’s actually faster doing it yourself but I’ll have to
test that.)
The conditional lines are indeed a pain, normal lines can go in vbo/display
lists much like the triangles but you have to test all conlines against the the
current projection matrix for every redraw. I was planning to do this
multithreaded (like LDView does).
Roland
|
|
| |
In lugnet.cad.dev.mac, Don Heyse wrote:
| |
In lugnet.cad.dev.mac, Don Heyse wrote:
| |
In lugnet.cad.dev.mac, Remi Gagne wrote:
| |
In lugnet.cad.dev.mac, Allen Smith wrote:
| |
By the way, Bricksmith does not render conditional lines. I consider
shading to be a sufficient substitute, and conditional lines sound
difficult to optimize.
|
Heh, you hit that problem too? I’ve played around writing an OpenGL LDraw
renderer based exclusively on display lists, but I can’t for the life of me
figure out how to handle conditional lines in this setup. Has anyone else
solved this peculiarly specific problem?
|
You can ignore the conditional lines and achieve the same effect with
display lists using the stencil buffer techniques presented here:
http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node108.html
|
And here’s a silhouette technique using BFC:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.71.8503&rep=rep1&type=pdf
This technique and the conditional lines both target the same edges lines
where the front facing polygons meet the back facing polygons, so the
results should be quite similar.
|
And another thing...
The BFC technique actually has an advantage over conditional lines
because it works on the entire scene after it’s been assembled. Whereas
the conditional lines at the edges of the primitives are created in
advance, and must predict what they’re going to butt up against when the
entire scene has been assembled. This prediction may not always be
right, resulting in missing conditional lines and some visible where
they should not be.
|
|
| |
In lugnet.cad.dev.mac, Don Heyse wrote:
| |
In lugnet.cad.dev.mac, Remi Gagne wrote:
| |
In lugnet.cad.dev.mac, Allen Smith wrote:
| |
By the way, Bricksmith does not render conditional lines. I consider
shading to be a sufficient substitute, and conditional lines sound
difficult to optimize.
|
Heh, you hit that problem too? I’ve played around writing an OpenGL LDraw
renderer based exclusively on display lists, but I can’t for the life of me
figure out how to handle conditional lines in this setup. Has anyone else
solved this peculiarly specific problem?
|
You can ignore the conditional lines and achieve the same effect with
display lists using the stencil buffer techniques presented here:
http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node108.html
|
And here’s a silhouette technique using BFC:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.71.8503&rep=rep1&type=pdf
This technique and the conditional lines both target the same edges lines
where the front facing polygons meet the back facing polygons, so the
results should be quite similar.
|
|
| |
In lugnet.cad.dev.mac, Remi Gagne wrote:
| |
In lugnet.cad.dev.mac, Allen Smith wrote:
| |
By the way, Bricksmith does not render conditional lines. I consider shading
to be a sufficient substitute, and conditional lines sound difficult to
optimize.
|
Heh, you hit that problem too? I’ve played around writing an OpenGL LDraw
renderer based exclusively on display lists, but I can’t for the life of me
figure out how to handle conditional lines in this setup. Has anyone else
solved this peculiarly specific problem?
|
You can ignore the conditional lines and achieve the same effect with
display lists using the stencil buffer techniques presented here:
http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node108.html
|
|
|
