opentreelib-devel — OpenTree's Development Discussion Mailing List

Re: [Opentreelib-devel] OTL usage

[Enrico Z. <enr...@gm...>]

Hi,

PK wrote:
> Well, billboards are made out of vertices as well...
> they are big quads, or to be accurate: big quads divided in two triangles :)
I tried it and it looks horrible with my lighting :-( I will try to 
exclude every second/third leaf tomorrow from loading and rendering. 
Maybe it will help...

Thanks, Enrico

Re: [Opentreelib-devel] OTL usage

[PK <kir...@us...>]

Hey

> > We were developing an algorithm to create billboard clouds to solve the 
> > problem of the high polygon count.
 >
> This is no option for me currently :-( I need vertices, but not so many 
> as most of the trees have.

Well, billboards are made out of vertices as well...
they are big quads, or to be accurate: big quads divided in two triangles :)

+---+
|\  |
| \ |
|  \|
+---+

There is only problem with such billboards if you try to implement windsway.

 > Are there any other possibilities?

You can use triangles instead of quads, that will reduce the vertices a 
little and you can always create trees with less leaves :)

http://opentreelib.sourceforge.net/screenshots/opentree006_g.jpg

- PK

Re: [Opentreelib-devel] OTL usage

[Enrico Z. <enr...@gm...>]

Hi,

PK wrote:
> We were developing an algorithm to create billboard clouds to solve the 
> problem of the high polygon count.
This is no option for me currently :-( I need vertices, but not so many 
as most of the trees have.
Are there any other possibilities?

Thanks, Enrico

Re: [Opentreelib-devel] OTL usage

[PK <kir...@us...>]

Hey Enrico

We were developing an algorithm to create billboard clouds to solve the 
problem of the high polygon count.

The code is still experimental, but it works already quite good.

You can try it out by enabling this line in treeview.cpp:

#define BBC //BillBoard Cloud

Of course there is a snag to it :-)

You will need to implement some "render to texture" procedures in order 
to create fitting leaf textures.

It could work like this:

1) Create the tree with full detail leaves.
2) Create the billboard clouds.
3) Render the leaves from multiple views to a texture.
    You need one image per billboard.
4) Draw the billboard clouds with the r2t texture.

I have to admit that I've never done that before and I don't know how 
smooth it will work.

I once tried it out with a predefined texture instead of using r2t.
Here are some screenshots of that:

http://opentreelib.sourceforge.net/misc/low-poly-teaser01.jpg
http://opentreelib.sourceforge.net/misc/low-poly-teaser02.jpg
http://opentreelib.sourceforge.net/misc/low-poly-teaser03.jpg
http://opentreelib.sourceforge.net/misc/low-poly-teaser04.jpg

But with rendered textures it would look a lot better.

Please let me know if you have any problems with the library.

- PK

[Opentreelib-devel] OTL usage

[Enrico Z. <enr...@gm...>]

Hi,

I just downloaded the nightly build of OTL and began to integrate it in my application. Now the problem is that I require a LoD for the trees. I found this application http://opentreelib.sourceforge.net/wiki/index.php/CS_Simple1 which uses LoD, but only for the stem. The vertices and indices for the leaves are always the same. Is there a way to get LoD for the leaves to? 

Thanks, Enrico 
-- 
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[Opentreelib-devel] OpenTree Newsletter

[Pascal K. <kir...@us...>]

Hello everyone,

We would like to inform you about what has happened in the last few months.

Contents:
------------------
 1) Contest
 2) Wiki
 3) Release 0.1


1) Contest
------------

On October 11th we announced a coding contest to celebrate the 1st birthday
of OpenTree.
Unfortunately, no one participated. We did not announce it broadly enough,
so we will learn for next time.

If you have tips for how to setup such a contest more professionally, please
let us know.

2) Wiki
---------

We have opened a Wiki on the OpenTree website.
There we will document the existing code and plan for future code.

Please read it, create an account and extend the Wiki where you think it is
needed.

3) Release 0.1
---------------

More game developers have started to ask us about OpenTree as they need
trees in their games. The project was rather idle over the past few months.
We had planned not to make big changes during the contest, but that just
increased the idleness. So we would like to release the first version of
OpenTree and to help people integrate it into their game, 3d engine, or
application. We hope this will spur some activity and that people will begin
to contribute code to improve OpenTree.

In our new Wiki, we created a page about the release where you can write
down what you feel must be done for this very first and basic release.

If you have a cool codename for it, something like 'Offspring' or 'Bonsai',
let us know :)

We are looking forward to announce OpenTree Version 0.1 :)

Regards,
  PK (Pascal Kirchdorfer <kir...@us...>)
  iceeey (Seth Yastrov <sya...@us...>)

[Opentreelib-devel] OpenTree Library Anniversary Coding Contest 2005

[Pascal K. <kir...@us...>]

Hi,

It's been exactly one year since SourceForge accepted our project request
and the project is still going. That's a reason to celebrate!

OpenTree is a library which provides 3d tree generation for real-time
applications such as games and visualization software.

Impressed by what commercial engines provide, we wanted to have nice trees
in our games too. Unfortunately, those commercial engines were not open
source and far from cheap. Aware of what effort it would take to create
decent trees, we started a cross-platform, engine-independent library in
hope that others who would like trees in their games as well will join.

To celebrate the one year birthday of OpenTree, we hereby announce a coding
contest!
Currently, we have a total pot of $200.00 USD that we can give away for
code. If there are a lot of good contributions, we might donate $100.00 USD
extra or so. Depending on the quality of the contribution and the amount of
participants, the size of prizes will range from $20.00 to $100.00 USD.

For further information about the OpenTree Coding Contest, please visit:
http://opentreelib.sourceforge.net/coding-contest-2005.php

Everyone may participate but Iceeey and I.

Good Luck
- PK

[Opentreelib-devel] Code Structure of OpenTree

[Pascal K. <kir...@us...>]

As promised, here is the short description of the OpenTree source code.
If you have questions or additions, feel free to post.

Code Structure of OpenTree
==========================

OpenTree consists of two modular parts:
 - Generator
 - Mesher

and one core part between the modular parts:
 - TreeStructure.

TreeStructure:
--------------

In OpenTree, a tree is being defined with the help of 3 classes:
 - otTree: Represents one tree.
   http://opentreelib.sf.net/docs/html/apidev/classopentree_1_1otTree.html
 - otStem: Represents one stem.
   http://opentreelib.sf.net/docs/html/apidev/classopentree_1_1otStem.html
 - otLeaf: Represents one leaf.
   http://opentreelib.sf.net/docs/html/apidev/classopentree_1_1otLeaf.html

The otTree class contains a list of all trunks. In addition it does also
contain a copy of all leaves since it's often wanted to access all leaves of
a tree regardless the stems. This saves us the iteration through all stems
and speeds up the library.

The otStem class describes a stem. For this, it contains a otSpline3 class
which describes the curves of the stem though the room as well as a otSprine
class which defines the radius of the stem along the spline.
It contains also a level number which defines the level of subbranch. So
the trunk has level 0, the branch from the trunk level 1, the branch from
the branch from the trunk level 2 and so on. This is helpful since some
childstems are not real substems but just a split of the parent stem. It's
not possible to split a spline, so a new stem is needed with the same level
number.
Finally, the otStem class contains also a list of all child stems as well as
a list of leaves connected to this stem.

otLeaf is a rather simple class. It contains the positions and rotation of
the leaf as well as the length and width of it.

Generator:
----------

The generator takes custom inputs and generates an otTree class with all its
otStems and otLeafs.

Mesher:
-------

The Mesher takes an otTree, otStem or otLeaf object as input and creates a
vertex and index list which can be rendered to the screen.


This abstraction between Generator and Mesher has been made to allow the
modular use of different Meshers and Generators.

Current Implementation (9-2005):
--------------------------------

Generator:
We have two generator implementations which are both based on the tree
generation and rendering paper of J. Weber and J. Penn. otWeberArbaro is a
modified port of Arbaro (http://arbaro.sf.net) and is therefore under the
GPL license. otWeber is our own, more object oriented implementation of the
Weber algorithm and is, like the rest of OpenTree under the ZLIB license.
Unfortunately it is not as mature as Arbaro yet.

Mesher:
We have currently six Mesher classes in the cvs whereas two are not
implemented yet. Those are MesherBillbox which is meant to generate a box
around the tree containing an image of the tree on each side of the box and
MesherBillCloud which is meant to generate a cloud of
billboards (http://www.cgl.uwaterloo.ca/~gmoreno/bclouds.html) representing
the tree.
The implemented Mesher classes are MesherBillboard which crates a single
billboard; MesherLeaf which creates the vertices for one leaf; MesherStem
which creates the vertices for one stem; and finally MesherTree which is
just
a helper class that generates the vertices of multiple stems and childstems
using the MesherStem class.