Archives for: April 2007


Permalink 10:28:07 pm, Categories: World Editor  

Introduction and First Thoughts


Hi! I was accepted to build a Crystal Space World Editor for Google Summer of Code this summer.

A little about me: I'm an 18-year-old computer engineering major at University of Maryland. My main interests beside computers are classical guitar and biking.

In this blog I'll post my ideas and progress on this project. Comments and suggestions will be greatly appreciated.

Here is the abstract as given in the proposal:

Crystal Space, being a 3d engine, deserves a good art pipeline so that applications using it can focus on creating assets, not editing world files by hand. Having worked on several game projects using CS over the past 2 years, I have experienced directly the difficulty of getting art into the engine. I would like to help take a huge step in improving it by creating a usable world editor.

The editor should have a completed framework by the end of the work period, including a working plugin system, undo/redo system, selection system, tool system, save/load functionality, scene browser, factory browser, and property editor. Also, basic selection and transform tools will be implemented. Any remaining time will be used to polish the user interface or implement tools for other CS features, such as terrain.

The project is currently in the design stage, but the ideas are becoming more focused.
Here is some of the progress so far.

Name of the editor

We had nearly an hour-long name-throwing session on IRC about this, but I don't think any of them stuck. The consensus seems to be that the name shouldn't be too serious. Some highlights: Ochre, Composotron IV, Crystal Latte, Crystachino, Deity for Dummies, Quartz, Chainspoon, Turbospoon, CrystalGarden, Plow, Colloid Space. I would choose Anvil, but it is already the name of my old editor. Maybe Anvil Reloaded? ;) Any more ideas?

User interface

The editor will use wxWidgets as a GUI library.
I'll use wxAUI and wxPropertyGrid widgets. wxAUI is a really nice docking toolkit that should give a very flexible, modern-looking interface. wxPropertyGrid will be great for the property editor.

wxAUI has been included in wxWidgets 2.8.0+, but wxPropertyGrid is a contrib widget. To handle the dependency, the editor will probably require wxWidgets 2.8.0+ and wxPropertyGrid will be included in the source tree.

I'll use wxFormBuilder to design the more complex dialogs for the editor (options, material editor, etc) and save them as XRCs. The main window will be done in code, using wxAUI.


Tools allow the interface to remain consistent when switching between different editing functions. Tools will handle events like mouse move, mouse click, keyboard press, and draw to allow for extra information to be drawn on top of the scene. Examples of tools are select, move, rotate, scale. Plugins can also add tools. Tools will be available through a toolbar. In addition, tools can provide a panel for tool-specific settings.

There are several types of tools.

Mesh-specific tools: These tools will be shown based on the type of the selected object.
e.g. for particle system editor, an emitter editor. For a terrain editor, a tool to modify heights with a brush.

Creation tools: Tools which create things, e.g. a tool which creates mesh primitives, or a tool which creates an initial flat terrain.

One-shot tools: Tools which perform one "non-interactive" action, like "compress vertices" or "generate normals".

Scene Browser

The scene browser is basically a tree that will show all of the instances in the world file (e.g. all the stuff that goes in between <sector> tags).

There could possibly be multiple "view modes" for this: Group by sector, group by object type, sort alphabetically.

Plugins should be able to add 3rd party types to the scene browser (e.g. CEL entities).

Project Manager

This should show some of the files that the world file depends on. It will allow you to link or unlink libraries to the world file.

Assets Browser

Formerly named "factory browser", the assets browser will allow you to browse through mesh factories, materials, etc. It should allow you to remove them, or edit their properties when selected (in property editor). Adding mesh factories can be accomplished through importing or linking to a library. Or you can use a tool which creates primitives.

Mesh Browser

This will show all of the available mesh factories, rendered to textures. The selected one will show a rotating preview.

Material Browser

This will show all of the available materials rendered on tiny spheres. You should also be able to create an empty material from here.


With all of these browsers, there seems to be a commonality between them: they generally provide a view of a certain category of objects, and when selected, they should publish an event to listeners, including the property editor which will allow you to edit the selected object. It seems like they could share a lot of code.

Property Editor

There will be a property editor shown for the selected object.

I will need to implement some custom property types, including one for matrices.

Another thing I would like is a "link" to another object. It would basically allow you to choose one of the available objects of that type. And it will allow you to follow the link and show the linked-to object in the property editor. For example, the mesh instance property editor will have a link property "Material", which will allow you to choose which material is used for the mesh.

Saver Improvements

Since the saver doesn't fully support saving all CS objects, and since it is desirable to preserve comments in the world files, I'll be supplementing the loader to attach the original DOM nodes to engine objects when they are loaded (and only when the saveable flag is on). The editor will then keep track of which objects are modified, and only save those. This means that all unsupported nodes will be preserved. A main failure of the current way of using the saver is that it obliterates any unsupported nodes. Judging by the rate at which the loader advances versus the rate at which the saver plugins advance, this will be necessary for some time.

The sooner this is implemented, the sooner the editor will be useful for making small tweaks to existing world files. So I do regard it as quite important, although it is not trivial.


Whew! There are a lot of ideas there. I hope I get some good feedback on this.

I still have approximately 2 more weeks of school, so I'll be trying to think of this and post when I'm not taking exams. Then, summer! :)

Permalink 03:21:05 am, Categories: Pathfinding  

Graph Implementation

Mostly what I have about our graph implementation is that we should use a vector-like structure to store nodes and edges.


Most of the time graphs will be loaded during the begining of the applycation and they will rarely change during the game. This means, we will only add nodes and edges once and almost never erase them. This unless a bridge explodes, an avalanche blocks a way or a door opens(and even in this case we can mark those edges as blocked or unblocked without erasing them).

This means, most of the time, almost every second we will be performing searches over the graph.

Vectors are known for their slow adding/erasing performance but very good searching performance becuase they maintain all their elements within the same memory block (this helps with element indexing).

I am not saying I will use vectors, but something like that. I have to explore what structures CS offers for me to use :). Maybe you can give me some ideas on that.

Besides from that, I think graphs should be aloud to be defined dynamically (by an automatic graph generation algorythm) and statically (defined in world files).

I have some ideas on dynamic graph creation, these are:

Polygonal Meshes
The level is made of polygons connected to other polygons. Each polygon acts as a node in the graph. Nodes are connected if their corresponding polygons share an edge

Dirichlet Domains, also known as Voronoi Diagrams
Graphs can be defined by Dirichlet domains by defining a set of points (called characteristic points) in the level which will serve as nodes. Each node has a region of influence around it, and it is connected to all other nodes within its region of influence.

Points of visibility
I am short on time right now, but I will add a description, later ;)

Permalink 02:58:43 am, Categories: Artificial Intelligence Module  

Project Description

In this project I expect to cover much of what a Game Engine´s AI module needs. This is:


By movement I am referring to all basic steering behaviours that can be achieved by an entity. This includes seeking, fleeing, wandering, formations, flocking, collision avoidance...


This module will include a graph implementation which will include a static and a dynamic graph creation tool. I will use A*, probably with some minor modifications, to accomplish pathfinding.
It is also probable that, if theres time, I include an IDA* implementation which could be use by games with more complex graphs (but I do not think this is a priority in the project).


Crystal Space is very strong in this area because of its quest property class which works as a great state machine. I have a GOAP (Goal Oriented Behaviour with planification) implementation in mind, but I am not sure of what it would be. I am working on that and I will add some info on this as soon as possible :)

There is much more to do, but I am leaving that for further projects as it is not within the scope of a three month project. Further work within this project should include:




Further description of each module will be added under each category:
- Steering Behaviours
- Pathfinding
- Decision Making

Please, feel free to add any comment or idea to this blog. I will get back to you as soon as possible

Permalink 02:40:49 am, Categories: Steering Behaviours  

In order to achieve better movements and steering behaviours from the entities I plan to make a Steering Property Class "pcsteer".
pcsteer will count of a set of properties and a set of functions, these two will blend to achieve more complex behaviours.

Some of the functions defined in pcsteer are:

Seek a target.

Flee from a target.

Pursue a moving target. This is different from seeking because it calculates the targets position in time T and, then, seeks it.

Wander This is done by randomly changing the entities direction between a given range.

Path FollowingThis will follow a sequence of Nodes. It can be used together with a pathfinding algorythm, ie: A*, to reach more complex targets.

Some of the properties are:
SeparationGiven a set of entities and a radius, a force would be created in order to flee from the center of mass of all the entities that are within the radius.

CohesionThis one works just like Separation but it will seek the center of mass of all the creatures that are outside the given radius.

Collision AvoidanceRight now pcmover checks if theres something between the entities and its target. If there is, it stops moving. Collision Avoidance will work like that, but instead of stoping it will add an evasive force to the entities movement.

How would a developer used all of the above?
Lets say we are this LOTR rip-off where three Trolls are trying to catch a Hobbit in the woods. There would be a bunch of trees we would like not to crash with, but besides from that there would not be any difficult spot to seek so we won´t need pathfinding.

Lets say we already created the entity and added pcsteer to it. We would need to define our steering properties:

* We define a weight for each force in our movement and a distance
* from which we will start avoiding obstacles
float weight = 2.0;
float distance = 7.0;
pcsteer[who]->collisionAvoidance(weight, distance);

* We define a radius for cohesion and separation so our trolls will
* work together without bouncing to each other
weight = 1.0;
float radius = 10.0;
pcsteer[who]->cohesion(weight, trolls, radius);

weight = 1.5;
radius = 5.0;
pcsteer[who]->separation(weight, trolls, radius);

//This have to be done for each troll in trolls

Now, we defined our static properties (they are not so static, we can change them whenever we want, but they will remain the same after any function call.
Now we would probably want to define a basic behaviour, lets say we want the Troll to wander through the woods until he sees the Hobbit:

trollBehaviour(int who){
//its more important not to crash than catching the hobbit
float weight = 1.0;
float radius = 5.0;
float offset = 3.0;
pcsteer[who]->pursue(weight, hobit);
} else {
pcsteer[who]->wander(weight, radius, offset);

As you can see we don´t have to worried for collisions, separation or cohesion while defining our behaviour because thats already defined during the creation of the npc. The idea is to have more complex behaviours too like formations, flocking and swarming, but I will add that later.

The only thing left for me to explain is the radius and the offset in wanders call. This is because the wander function I have in mind uses an invisible circle in front of the npc to calculate its new direction. offset is the distance between the entity and the circles center.

Permalink 02:00:24 am, Categories: Artificial Intelligence Module  

About myself and other stuff no one cares about =P

Hi there!

my name is Mauricio Hollando, I am from Caracas Venezuela and I will be working in an Artificial Intelligence Module for Crystal Space (CEL, actually) during this summer.

I am 21 years old, I am currently studying Computer Science at Universidad Simón Bolívar in Caracas, Venezuela. As you can see, my primary language is Spanish, so I would like to apologize in advance for any mistake you may find in my grammar =).

I don´t have much experience with CS or CEL (so please understand and correct any mistakes I may have) but I do have some experience with games AI.

My intention is to have a complete work plan posted in this blog. I don´t have a complete design yet, but I will before I start working. So, please, send me some feedback before I start messing things up =).


Permalink 05:55:00 pm, Categories: general  

Tree of wisom.

Funny I never thought it would end this way, seems everyday you learn a new lesson. Wether or not you'll be alive the next to make use of this new knowledge. Ofcourse this doesn't help you, so I'd better start at the beginning.

Chapter 1

I stopped dancing, my vision was blurry, for some reason I was wearing glasses, I don't wear glasses. So I put them away. I looked around aimlessly untill my vision focussed. I was on what appeared to be a stage infront of 1, 2, 3, 4, ..., 6 billion people. I tried to speak, but no sound came out, instead I cought up a cube with all the colors of the rainbow. It seemed to be some kind of impossible puzzle and God would tell me all the secrets of the universe if I was able to solve it. But God spoke: "It's just a stupid colored cube!" I looked back in my hands ... the cube was gone.

I tried to look around in the room to find someone I knew so they could tell me what happened, but my vision was blurry, I remembered I do wear glasses. But where ever I looked I couldn't find them, so I improvised and made rings with my thumbs and indexfingers and held them to my face.

For some reason all the persons looked like me and were talking to eachother in total silence, which sounded weird. How can someone speak in silence? They made no sound, so it wasn't whispering, but still i could understand them.

"Am I dead?" flashed thru my mind, someone said: "You're mistaken." "Then what is this?", total silence followed, i mean real silence, the persons looked around at each other, with an unknowing-do-you-know?-expression on their faces. "Well", I said, "Where are we?" "A dimensional time-space breach, of a single soul collected into one spacial entity unifying all our consciousnesses." Someone shouted. Another stood up: "Lay off the SciFi? and go back to playing Dungeons and Dragons you total nerd!"

This is going nowhere, I started looking around for an exit, to my amazement a door clearly marked exit was right behind me. I started moving towards the door. Something was wrong, the door kept moving away from me, in my stubborness I started running. I stopped, breathing heavily, I looked behind me, I was still at the same distance of the edgde of the stage. This gives a new meaning to no-endurance. I bended over leaning on my knees, still trying to catch a breath. I lifted my arm and flipped a finger at God, and sat down, looking into the crowd. I check my pulse, and for any bloodstains and pinch myself. Oke I'm not dead, atleast not the HollyWood? dead and I'm not dreaming. Am I high?

Permalink 05:54:35 pm, Categories: general  

Breakfast delusions

I woke up at 7 am this morning, as usual i entered the CS irc channel....

To my suprise all the ops were absent, it was total anarchy! I quote " sueastside: what no ops?? lets party!!!!"

I felt a little draft passing my body, it reminded me to get dressed. Opening my closet, i was blinded by a horrific sight: Dots, dots everywhere!

My deranged subconsciousness has traded my clothes for clown costumes again, he knows dots make me look fat!

I wanted to go outside naked again, but that old lady from across the street stares at me when i do that. So i decided against it and went with the flashy green vest and white with red dots pants ensemble today. And ofcourse ive put on a red nose, i don't want to look ridicilous.

I went downstairs, the floor was softer and warmer then usual, i looked down... it was covered with money, lots of money. The dollarsigns in mother Theresa's eyes were small compared to mine. I wonder if it's a gift of Gates, although i would have prefered flowers.

I sat down at the table, i reached for the cerealbox, and it moved away from me. WTF, i tried to reach again and it moved even further away and tipped over, the cereal bits danced out of the box and started to cover the table, it was like a cloud of negativly charged gibs and my hand was also negativly charged, every time i tried to grasp they moved away from me in a wave pattern.

I decided to skip breakfast.

I needed some fresh air and grabbed my binoculars on the way out.

I made myself comfortable in nature and sat down, it's not that big, but what did you expect in Belgium. Not much foliage here, especially in Jorrit's garden. I've been trying to figure out what he's been doing these last few days, he just keeps staring at his new laptop, i can read the label from here: ACER 5024wmli. Those turion proccesors are quite nice...

A penny for his thoughts.... so i threw a penny at him. That wasn't one of my brightest ideas, as i keep a list of those, and i ended up revealed my position. Luckily he"ll just think i'm pervert clown and doesn't know who i really am: A ordinary perverted stalker.


Permalink 05:53:40 pm, Categories: general  

For crazyness call 1-800-sueastside


Insanity has struck, it was slowly filling my body, making me produce weird noises.

Can't believe i was sane for this long, i think the chocolate cake was slowing it down, or was it the ramen? Well it doesn't matter anymore, too late now.

"turn my nipple nuts wiiirpppssttfooo"

There i did it again. Although i know it just happened, i can't tell what i just did. The crazyness is taking over, my own counciousness is slowly fading.

You'll probably thinking why not go out with a bang, and stop nagging in your blog. Well i tried, oh i tried....

I'll start with my first time, i guess, my momma always said to start at the beginning. I was born on a cold night in february, there was 12 inches of snow that day...

Ow, yeah back to the point...

There i was standing at the edge, i know what you're thinking, it's been done, but i wanted to feel the wind rush thru my long blond hair.

Slowly i shifted my balance over the edge, dropping my body down as a stiff board. With closed eyes ofcourse, im afraid of heights...

I was overwhelmed by strong feeling of calmness, while my body rushed to the ground accelerating with each inch. And then nothing.....

Next thing i remember is waking up next to Bill Gates, in red sexy revealing lingery. I rushed out as soon as possible, ofcourse after he payed me.

I know what youre thinking....

How's Bill Gates in bed? Luckly that the positive side effect of my condition i don't remember a thing.

Ow you were wondering something else?

Well it doesn't matter what you're thinking, it's my blog after all.

The second try: After the Gates incident the urge to finish my existence was even greater, ofcourse i've spend the money first, on GPU Gems if you're wondering, the thing is pretty expensive for just a book, a bundle of wood fibres, to think you can get wood for free...

What my tactic was for the second try?

The classic: a shotgun it the mouth...

Funny thing is, that it didn't matter how much i wanted to end it, my will to live was stronger. So I needed to trick myself with a selfmade trap.

Luckly i've seen my share of Mcguyver episodes, so i can find a solution for everything with my wits.

I ended up with a complicated structure of beams and cords which would swing the shotgun into my mouth and fire it, after setting off the trap by opening the door.

Now to the part making myself forget i've setup a trap for myself. I head down to the nearest liquor store and enter, my eyes swifly explore the scene, my brain gonzing from interperting and working out possible scenarios. I check my pockets for my trusty swiss knive and duckttape.

I head for the door that says private, i open it and quickly take a step back and jump behind one of the shelfs. the tender fell for it and enters the private room looking for me. I quitely close the door behind him and weld it shut with some coins and a carbattery.

I grab a permant marker from behind the pay-desk and write "go home" on my forehead and arms.

Now for the master plan: Getting drunk!

Several hours later i wake up, with blurry vision on the ground. I stand up or i thaught i did, cause i was on the floor again. Not knowing what's going on, i look around and notice writing on my arms: "go home" What does that mean, that little shit ET is here, where is he ill beat him up, after beating up a cardboard box for several minutes i realise that there are no aliens in the room, atleast not visible ones.

Having this terrible headache i decide to go home and go to bed. After kicking the cardboard box, i'm finally strawling home.

Into my own trap, damn i'm brilliant!

After walking into a wrong house, i end up at my own doorstep, i start yelling at my door to open, took me awhile to figure out that that didn't work and i had to use the key to open it.

Madly poking with the key at the door i end up succeeding in getting it in the keyhole. I swing it open....deafened by a loud bang, a feeling of disorientation by a bright flash, i see a projectile moving towards me in what appears to be slowmotion. Knowing this isn't a bullet-time enabled game, i just froze and stood there knowing i coudn't possibly do anything and accepted my faith.

I was overwhelmed by strong feeling of calmness. Hmm i can't put my finger on it, but deja-vu...

I woke up in a bright yellow tanga covered with wipedcream ontop of Barbara Streisand. After recovering from the paralysing gagging spasm and feeling of disgust and thinking i'd rather do Gates again then this. I split like a banana with the same color as my tanga and got the hell out of there after collecting the cash.


Permalink 05:52:34 pm, Categories: general  

God called in sick today.

Meanwhile, in holodeck 2, Junior Ensign Sueastside is busy putting fur on the various holo-creatures. He stares down at the computer podium and then raises his head and stares thougtfully into the distance at nothing in partiuclar.

The platform and the podium are obvious falsities in this forest world, for the 3d modeler has used far too many specular highlights! Well that, and you normally don't see a computerized pedistal in the middle of a jungle. It sticks out like... well like a computerized pedistal in a jungle.

Eureaka! Junior Ensign Sueastside has the answer... more rendering passes!!! His gaze quickly returns to the podium along with his hands. He types madly away, not stopping to format his code or removed unused variables. Symbols fly across the screen madly. For some reason they are not English or any Earth language.

Typing typing madly typing...

Finshed at last.

Now, let's see how it looks.

Gingerly, Junior Ensign Sueastside's hand approaches the `run` button. Reservedly he inches closer and closer. Finally, when his finger is a few centimeters away from the button, he quickly stabs downwards. The virtual button on the virtual podium computer changes from yellow to red.

"Huh, whats happening?", says a bewildered Sueastside. Red lights flash and sirenes go off!

"Ensign what are you doing!?", asks the captain, his shiny head shimmering in the glow of soft bridge light.

"I need more power Captain! Reroute some from the shields!", replies Sueastside.

"I've giving her all shes got, anymore and she'll blow!" -Yelled the Captain.

"More, More!!" -Screamed Sueastside.

'Hull integrity at 0%, Have a nice day.'

"Atleast I had my way with Six of Nine" -Screamed the junior officer over the noise and confusion.

And that is the last thing that ever happened on Enterprise. For unwittingly, Junior Ensign Sueastside had blown it up.

Original story by dfletcher, adapted for screenplay by sueastside.

Permalink 05:52:11 pm, Categories: general  

Random things you _don't_say to your girlfriend

I'd rather walk through hell with gasoline soaked underwear, sitting on Schwarzenegger's head while breastfeeding Gary Coleman, then to spend one minute with you!

Permalink 05:51:29 pm, Categories: general  


I looked behind me. There was nothing to be seen. Was it just paranoia or would it be best to just look infront of me? Thats what i did. There wasnt much to see either. I continued following the road. I didnt have a real mission. Buying some cigarettes, that was about it. Tomorrow i'll stop smoking, but not today. Tomorrow is still a long time. I live one day at a time. Maybe tomorrow i'm already dead. Funeral monday next week.Dogs allowed on the funeral, thats what i wrote in my will. It also says everybody should party and wear a part-hat and only return home when youre dronk like a fair monkey. A man stopped me to ask directions. I ignored him. It was impossible. "The way to the castle, sir?" he asked beggingly. "The castle" said I, "thats real difficult to explain. Wouldn't you rather go somewhere else?" "But where?" the man asked desperatly. It looked like he was about to cry. I would never cry, except with a movie with a sick kid in it. It the recognision that does it. I also was a sick kid. I had troubles with my kidneys, pancreas and my bowels. Later everything turned out fine, thanks to the local pray healer Louis De Gebedgenezer from SF. He rubbed me in with cowshit, stared at me endlessly and then said the magical words: "Damn this kid smells!" The next day i was healed and could resume my duties as a toddler. "Hmm yes where to?" said I,"that has always been the question. You can always try that pub." I pointed to the pub 'The endless drunkness'. A beautiful winehouse, decorated with beatiful Art Nouveau, to lick of your hands and feet. "Will you join me, i'll pay" asked the man. "I can't be bought" said I, "And I don't go to bars anymore since 1993" Alcohol isn't good for my kidneys, pancreas and my bowels. Actually i'm completly insane, do you realise that you old fool? I was about to punch him on the nose. I was that furious. The man started to cry. For some unknown reason that calmed me. Instead of shaking on my legs, I stopped shaking on my legs. I sensed the diffrence immidiatly. "You know what?" I said, "I think I'll give you the directions to the castle now." With complicated handgestures I showed him the directions to the castle. The man thanked me. He stopped crying.

He started walking, and there he went, a man going to the castle. I stopped staring and ran to the cigarrete store. There i acted like a smoker, nothing more then a smoker...

Permalink 05:49:25 pm, Categories: general  

The dream

A faint buzzing wakes me up, im holding up my arms to block the bright light that is shining into my room. My windows open, a thick fog slowly fills my room, its lit by the bright blueish light. I try to open my eyes to see whats going on, but my still moisty eyes diffuse the light into purpleish stars.

This is not the first time this has happend, Six of Nine was here last week to consult my knowledge about *cough* outerspace. But enough about that.

I wonder who it is this time...

A oval face finally is recognisable thru the mist, it's hold up by a small fragile body. It claims to be from a planet Thrujius, that is currently at war.

They're recruiting me to fight by their side, they must have heared about my expertice with a 'gun'. Can't really blaim them, im almost legendary, I just hope they pay really well.

I put on my battle suit that would have made Jango Fett jealous, it was a gift of Adama given to me after i saved his sorry ass from the Cylons.

"Oke im ready, there's just one little thing..." "What?" "I want to be Gold leader!"

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