Blog
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Fire in the Valley Rekindled
Builderman and I hit the Stanford startup job fair on Thursday, looking to recruit a few good software developers for the Roblox team.
| March 4, 2007 -
Fire in the Valley Rekindled
David Baszucki and I hit the Stanford startup job fair on Thursday, looking to recruit a few good software developers for the Roblox team. The fire in Silicon Valley is roaring again and Computer Science majors can’t walk down the street withou...
| March 4, 2007 -
Dear Telamon…
This morning is a momentous occasion. I am emptying my Inbox. Often people send me messages like “… so-and-so was calling me names, please do something…” or “yo dude, give me a custom character plz…”. However, occasionally I get some interesting questions to which I send a thoughtful response. I’m going to start posting some of these. The first is from MrDoomBringer, with whom I exchange several messages a week. MrDoomBringer writes: p Your question touches on two issues: parametric/custom parts and simulation efficiency. The Roblox team has been thinking about adding additional parts to Roblox for a long time. The obvious way to do it would be to add a 3d modeler tool to Roblox Studio that would let you build your own meshes and then create parts out of them. This is probably not a great idea, since 3d modeling is very hard and writing 3d modeling software is not my idea of fun. The way we would introduce new parts would probably be to make parametric parts. For instance, we might make a Window part that you could resize however you wanted, and Roblox would automatically make a nice Window mesh for you, of any size or style that you chose. But to answer your question more directly, we don’t do general-purpose mesh collision detection by default because it is very slow. The only shapes the Roblox physics engine has to worry about right now are boxes and spheres. That means we have to be able to detect 3 types of collisions: Sphere-Sphere, Box-Box, and Box-Sphere. All of these tests are relatively quick to compute - in particular a Sphere-Sphere test is a trivial application of the distance formula. To do general-purpose (often called “Triangle Soup”) collision detection between two objects is very slow. Say I have two user-made meshes that both contain 1000 triangles. I basically have to do 1000^2 tests to see if the two soups are colliding. You can do a little better if you enforce the constraint that the meshes have to be “water-tight” - meaning that there is no path that can be drawn from the inside of the mesh to the outside of the mesh without passing through a face of the mesh. The best way to test for collisions between two “water-tight” meshes is to break the meshes up into convex hulls (if the mesh is not already convex). This can be done once, at resource load time, so does not hurt performance. But then you have to do convex hull collision tests. With various gnarly optimizations you can do these in O(lg n) time against Spheres and Boxes, and O(n lg n) time against other hulls. In comparison, all current collision tests can be done in O(1) - constant time. The bottom line is that we will need to add convex hull collision to the engine someday, but that in order to get good performance we need to be very judicious in choosing when to do the more expensive collision test and when a simple sphere will serve to approximate an object’s geometry. If we did convex hull collision by default and a user makes a pile of 100 rocket launchers, the result is not going to be good. It’s a bigger problem that it seems, which is why it was not thrown into the physics engine when BM first wrote it. If you are interested in learning more about collision detection in games, here are two excellent sources of information: a a - Telamon
| February 26, 2007 -
Where are they now?
The Roblox Team just shipped a fabulous release last week and are celebrating their achievements by living it up on Builderman’s yacht in the Key West, while catching up with some other 49er alumns. Hot tubbin’ it (on the yacht, ‘natch) after a long day of scuba diving, we were discussing the features we are each working on for the next big release. Matt has been working on DB caching to improve website speed and has been working on backend stuff for customized characters. Erik has been working on webpage GUI stuff for customized characters, while kicking back pina coladas and reading through all the dump files that people have been sending him when Roblox crashes. Since the last deploy, we’ve been getting 60% fewer of these. Builderman was busy waterskiing backwards, and so missed most of the team meeting. Though he did shout to us about characters and humanoids and something about slowing down the boat. I’ve been continuing my valiant crusade towards making Capture the Flag games a reality. Next step: Player Spawn Locations. The most exciting feature for scripters in the next release? It’s a little something called a DHTMLWindow. At least I’m excited about it. - Telamon
| February 23, 2007 -
Badges, Statistically Speaking
Have you ever wondered what the most rare badge on Roblox is? Or which is harder to get: the Bloxxer Badge or the Bricksmith? I was wondering the same thing myself on Friday and I found some interesting numbers out of our database. I put together this table (data from February 16th): What does this show? Well first, the Count column tells us how many accounts have earned a particular badge. For example, we can see that, as of Friday, there are 103 Bloxxers on Roblox, but only 25 Bricksmiths. This means it is roughly 4 times harder to get a Bricksmith badge than a Bloxxer. Even more interesting is that almost no one has earned the Inviter badge - it is the rarest badge on Roblox. There are more Admin badges out there than Inviters! a - Telamon
| February 20, 2007 -
Place Protection – quick update
Many people have requested a way to prevent others from
| February 17, 2007 -
Code Bomb
We’ve just pushed a Tools and Teams are both Some initial Tools and Team docs have been published to the wiki - I may write some articles soon that show how to use them in your maps. Post any bugs you find to the Support forum - we will be working through these Friday and early next week for the next release. - Telamon
| February 16, 2007 -
Scripting with Telamon: Debugging
Howdy! Today’s article is for Roblox power users who want to learn how to develop scripts in Roblox.
| February 15, 2007 -
Scripting with Telamon
Howdy! Today’s article is for Roblox power users who want to learn how to develop scripts in Roblox. This is not a programming language tutorial - I will assume you know enough about lua to look at a piece of code and guess at what it does. Rather I am going to teach you how to deal with buggy scripts and show how to debug them. Debugging in general is a mystical art - I use the word “art”, which is the product of innate creative forces, in constrast to “science”, which can be dissected, reduced, and taught. We’ve built some tools into Roblox Studio to help you though. strong We’re going to build a secret door. An easy way to make a secret door is to make a brick and set its CanCollide property to false. Anyone can them walk through such a brick. No. Our secret door is going to be special. It’s eventually going to guard the treasure room in my castle and it’s only going to let approved members of the Pirate Army through (Arrrrr!). Clearly we need some scripting here, me hearties. strong When I’m making a complicated script, I try to test it as I go along. I’ve seen a lot of people in intro programming classes try to write all their code at once and then test it. This is about the most painful way to write code. Don’t do it. Instead, write the shortest bit of code that you can test. Test it. If it works, add some more stuff. Then test it. If something broke, you know where to start looking. A more simple version of the door we want to make is a door that just turns transparent whenever anything touches it. a strong Ok, time to break out the power tools. If you have been scripting without these, I feel sorry for you. There are two that I will talk about today: the Output window and the Command toolbar. The first is by far the most useful, so I will focus on it. To bring up the Output window, use the View -> Output menu option. This is add a window pane to the bottom of your screen. This window will show the output from your scripts while they are running. If your script has an error in it, the error will be printed here along with the line number telling you where the script broke. Let’s look at both of these right now. In your new script, paste the following code: p As you can probably tell, this script prints “Hello world!”, spits out the numbers 1 to 10 and then crashes on an error. If you press the Run button in Studio, you can see this. The output will look like this: p This is telling us that line 7 of our script is bad, which is something we already knew. However, in a more complicated script, it can be very helpful to print out stuff as the script is running so that you can see where things are going wrong. It may seem obvious once I’ve said it, but if something is broken with your script, start printing stuff out - rare is the bug that will not succumb to this level of scrutiny. I once wrote an entire operating system, using only printf to debug it. a p And if you have a part named “Door” in your level, it will be immediately teleported to (0, 100 ,0) while the game is running. This is kindof arcane, but I mention it because I have found the Command Toolbar useful on occassion. strong Here it is: p If you have ever seriously tried to learn lua scripting for Roblox, you have looked at some Roblox scripts. The code for listening to a Touch event should look familiar. Basically I have wired up the Part.Touched event to call the onTouched function whenever the part is touched by another part. When this happens, the door will turn semi-transparent for 5 seconds. Add this to your Door script, save your map, and try it. If you touch or shoot the door, you will see a nice effect. If you have the Output Window up, you will also see a “Door Hit” message printed whenever the door is touched. If you did not see this message, you would know that the onTouch function was not being called and that you had not wired up the event handler correctly. strong Like I said, this is not a tutorial on actually writing code, only debugging it. So here is the finished script: p It has one bug in it. Without using the Output Window, the only thing you will be able to tell is that the script is not working. With the Output Window, the problem becomes obvious: p Since the script prints out “Door Hit”, but not “Human touched door”, we know the problem is somewhere in line 18 or 19 of the code. The Output window tells us that there is a problem on line 18 - findFirstChild is failing. Ah! That is because in Lua methods are invoked using a colon (:) instead of a dot (.) (all other languages of consequence use dots for this - curse the inventors of Lua!) Change the line 18 to be: p a - Telamon
| February 14, 2007 -
RobloxPolice Gives the Low Down on RobloxPolice
strong This week we reprise our Reports From Robloxia column, written by you, the citizens of Robloxia. This week’s article is written by RobloxPolice, one of our most accomplished builders and owner of the current #1 all-time most popular place on Roblox. Due to his skills and possibly his account name, people often assume that RobloxPolice is an official Roblox moderator or admin. To set the record straight: this is not the case. Rest assured, the Roblox Team has strong libertarian leanings; we would never set up a police state in Robloxia. Enough introduction, let’s see what RP has to say… - Telamon strong strong A lonely programmer like me writing an article to an international hit! Hi, this is RobloxPolice and I’m here to give the scoop and me and the Police Force of Roblox. A lot of people have been asking me who I am, so I’ll start there… strong a strong Well the Police Force is open to the best of Roblox. In order to join you have to be an honest trustworthy person above all! The Police Force is here to help and serve the community of Roblox! Here are the requirements for joining as I posted them in the forums: strong strong I’m not gonna tell you it’s as easy as pie! But I’m sure strong Well I can’t release to many details, but yes. There are some goodies coming. There’s some low level secrets like new maps and a new “competition” or “tournament” coming from the Police Force to see who really is the best of Roblox. I plan to start developing more new game types and possibly the First RPG map of Roblox History. But we’ll see what happens. strong I don’t just make awesome maps: sometimes I visit awesome maps and talk to other awesome people! So I’ve compiled a list of my top 5 favorite maps not affiliated with me… - RobloxPolice
| February 7, 2007 -
Encyclopedia Robloxica
The Roblox Community owes a debt to MrDoomBringer who has recently reworked the Roblox Wiki
| February 5, 2007 -
“Report Abuse!!!”
Every regular Robloxian has by now noticed the ubiquitous
| January 31, 2007 -
Reports From Robloxia
Last week the Roblox team decided we would like to experiment with a “Reports From Robloxia” column written directly by our players for the Roblog. I solicited articles from a few of Robloxia’s finest builders and brick warriors, offering th...
| January 30, 2007 -
Reports From Robloxia
Last week the Roblox team decided we would like to experiment with a ”Reports From Robloxia” column written directly by our players for the Roblog. I solicited articles from a few of Robloxia’s finest builders and brick warriors, offering them the chance to write about whatever they like. - Telamon - - - span That is exactly what I told my friend who first showed me Roblox. Ever since then I have been playing this game pretty regularly. It really took me a while to kinda get good at this game… like some of you out there I was a total noob… but after a while and some practice vs. some of the better players like strong Ok well let’s see here - I’ll just start listing them… let’s say you are fighting someone and you and that person are not that far away. When this happens normally I like to whip out my rocket and shoot near them and close to the ground. Now you might be like why close to the ground… well the answer for this would be that you don’t have to hit the person you just have to get the explosion of the rocket to hit them to kill them. Sometimes the person gets lucky and just loses a leg. Another little trick I like to use is what I call head bouncing. So here is the situation someone is shooting from an area up above you… well obviously they have the advantage in most situations by being higher up. So my solution is the super ball. I get out that weapon and aim to hit their head. Now this won’t get you a one hit kill but hey it is more fun for you. If you have a nice shot it will hit your opponent right square in the head and their character will guy flipped over onto their back and bounce around for a bit, fun eh? Well since I don’t want to give away all of my little secrets and tricks here is the last one. Every once in a while you have to go up against a person who is good with the rocket. Well instead of dodging their rockets I like to shoot them down with a super ball. This way you can keep your position, you don’t have to worry about stuff falling down or hitting you, and just on some rare occasions if you do this quick enough the persons rocket will explode right on top of them. Oh yea when fighting if you want to stay alive remember to jump every now and then… ok, I am done now with tips and tricks. strong So what maps are cool out there… well that is all a personal opinion don’t you think? But here are the ones that I like right now. strong Now of course after listing to you all the places I like the most I am going to tell you what I think the coolest users are besides me of course, I mean come on I am the coolest (hope you all got the sarcasm there). These people you definitely want to be friends with. Thunderstealth a.k.a Pilotluke he is a good builder,
| January 30, 2007 -
There is no “i” in Team.
What a fatuous thing to say. When it comes to motivational sentiments about teams, I prefer the following: But I make light of a very important issue. Ever since the beginning of Roblox, players have spontaneously organized themselves into teams and armies. The trend towards mega-armies seemed to die out on the site around November. This probably coincides with the point when we had gathered more users than one social clique could accomodate. However, the demand for team games has not died on Roblox. Quite the opposite. Take a look at this chart from early this morning: If you like to keep track of statistics like I do, you will notice that the top two places on this list are outliers. 564 and 477 visits in one day is an insane number of visits, considering that no longer than a week ago a number like 142 would have been enough to be #1 on this chart. Both the #1 and #2 places on this chart have earned Bricksmith badges in less than two days. Together they are more popular than the next 13 places on this list combined. What do these top two places have that the others don’t? Two things: 1) team play and 2) vehicles. We’ll get to the second one another day. Today I’m talking about teams. The Roblox team has been planning to add teams to the game since December. I’ve personally been working on developing team support in the engine for about a week now. Today I came in and got them mostly working, so I thought it would be a good time to spill some info on this Deep Alpha feature. Keep in mind this is a work in progress - the final product should look more polished. What you are seeing is a team leaderboard for a basic Red vs. Blue BrickBattle game. We have built team support directly into Roblox, so while making a team game today requires a Anyone who has played around with Roblox Studio will recognize what we have done here. A Teams service has been created, similar to the Players service, that contains 0 to N Team objects. These team objects have properties that let you customize how they will appear in-game and on the leaderboard. Isn’t this exciting? You can probably guess where we are going once basic team support is in place… - Telamon
| January 26, 2007 -
Bloxxers Who Roxor
More interesting factoids, mined from the Roblox database. I am working on a set of additional badges for a future release. New badges fall into one of two catagories: they are either entirely unlike any existing badge, or they are “higher level” versions of existing badges. Designing good badges is tricky. If a badge is too easy to get, it is pointless. If a badge is impossible to get, it is pointless. A badge that is challenging to get is fun. One “higher level” badge I am thinking of making is a more difficult to get version of the Bloxxer badge. At the moment, 64 Robloxians have bloxxers. Using my strong Requires: Knockouts > 500, Knockouts > (Wipeouts * 2) We are already planning to make an upgrade of the basic combat badge (Champion Badge), that anyone can get by playing long enough. The Bloxxer++ badge (whatever we decide to call it) is intended to mark the true elite of Robloxia’s battlefields. strong Requires: Knockouts > 1000 I am also toying around with an idea for a badge that is intended to show that you like to fight and is awarded whether or not you are good at it. Do people like this idea? strong Requires: Knockouts + Wipeouts > 1000 I am planning some non-combat oriented badges too - they are potentially even more interesting to talk about, but I’m not ready to spill the beans on those yet. I’m interested in hearing player feedback about these and other combat badges. The following table of all players with Bloxxers might inform your commentary. - Telamon
| January 23, 2007 -
Dreaming in Code
At least once a week I like to go to the Stanford bookstore and drink coffee while I read through books or magazines that I almost never intend to buy.
| January 22, 2007