Two specific solutions for you:
You mentioned earlier ( I think it was you ) that the jump in Quake resulted in people being able to jump different distances because of it being calculated on a delta and not on fixed rate, I argue its because John Carmack isn't as good as everyone thinks.
I'm not an engineer or a mathematician, according to IQ tests i'm quite clever but I consider myself relatively stupid - my approach is to simply things sufficiently for me to understand them rather than tackle a complex problem with complexity, so my explanation will be on that basis...
The point at which the jump is started is 0 in time.
During the jump the player will rise to a peak and drop to 0 from their starting point - and then below, this is a plottable curve, we know at the start of the jump at what altitude the player will be at at any given time after the jump is made.
We do not need to calculate the difference in position during this jump from point A (0.1 seconds in) to point B (0.11 seconds in) because we already know where the player was, is, and will be.
We simply position the player at point start + delta along the plotted trajectory. Bang, naff all computational time and syncronisable between all participants.
Like I said, time is a dimension. It's so rudimentary to quantum mechanics that you don't need to do differential equations to solve it.
Sadly, most people solve this problem with a differential equation.
-*-
Second problem, calculating when a car intersected with a barrier. You already have the speed and the position of the car at two points in time and you have the difference in time between those two points in time.
You do not need to sample at 100hz to come with +/-1hz of when the car collided, calculating the proportion of the distance travelled prior to intersection and apply that same proportion to the difference in time between start and finish - if you need to allow for acceleration and decelleration within that timeframe it does get more complicated, likewise relative rotations - the solution isnt simple.
Bearing in mind that fixed rate physics is prone to errors in the sample rate too, if the above does not generate comparable accuracy to a fully time stepped simulation in your given application, which it often will as the delta speed is usually not far off a 100Hz system (and often exceeds it) then you may need to detach the calculation from the delta.
However my point that time stepping alone was not the fault is utterly right, I think Scawen mentioned something along the lines of an error in the rebound calculation which LFS experienced with the red and white barriers.
You deal in physics in your day job, where precision is required.
Computer games are not physics. If anything, games should steer clear of them. Given some solutions out there I can't help but feel that they'd could do a much more realistic job if they did!
Running at a set frequency will suffer the same problem because of the same hardware flaw, this is nothing at all to do with techniques and totally related to hardware discrepancies and whether you use a delta or not it is fixed using the same method, network syncronisation.
Oscillation within a delta, agreed. I recall tackling it on a project once (calculating the up and down time within a delta) but I have no recollection of the product that code resulted in, I may have gone to fixed rate.
Some calculations are either done outside of the delta, or more likely executed a factor of <delta> times per sync.
I do get it, but like I said when you drill it down to maths: additions and subtractions are no problem to a delta but multiplication, division and most other operators are. Solution - simply the maths where possible, deploy techniques which allow you to delta via a combination of tabled results.
I am getting to thinking that you guys are understanding physics only at the level of where something is in the now considering where something used to be the last time the maths where run.
You do realise that time is a dimension too right?
One other point, I think the original discussion (circa 2006) may have been in general gaming terms and not specifically vehicle phsyics, but I can't be arsed to read back now. Vehicle physics is not something I have spent a great deal of time on.
No that's shoddy programming and nothing at all to do with how often your physics execute. For instance LFS runs at a constant 100fps and it used to have diabolical crashes with barriers, now they are improved yet the physics runs at the same speed. Ergo, that wasn't the issue ;P
An entirely subjective standpoint, iRacing is popular and it's physics are imperfect (I didn't code it afterall *snicker*). LFS is less popular and it's physics are also imperfect. *shrug* I don't know what you are trying to say, there are games where the physics are real? I don't think so.
All I have said is that if I was to tackle a modern driving game I think I would still use a delta [for more of the code than what most others would].
I reject wholeheartedly the notion that an entire system needs to be coded at a fixed rate, ESPECIALLY those aspects which are not syncronisation dependant.
What I do not reject is that there are difficulties in using a delta, that it is complex to code when parts of an algorythm needs to run more frequently than other parts - but if the result does not impact the sum, or if the result impacts the sum in the form of an addition or subtraction, then a delta can be used.
If you dig back to the 2006 parts of this thread you'll note that I do not multiply or divide with a delta, I stick to addition and subtraction. Multiplications, divisions and some other operators must be done on locked rates, or performed 'delta' number of times per use.
Some calculations cannot be done on a delta, but part of why I think delta has always worked very well for me as a technique is because I simplify things very well, which enables them to be delta'd.
The standard way of doing physics is to simulate as much of a real car as possible using real world calculations, many of which are available online. I would never take that approach, because scientifically accurate equations do three things:
A) Are slow
B) Are still rarely truly accurate as some factor is always overlooked
C) Miss the point
The important thing is that the car feels right, and this can be done without using physics white papers from automotive engineers. I say this despite my brother - and co-worker on so many computer games in the past - being an automotive engineer.
In a computer game the most important thing is that the car feels right. rFactor proved this, there are a couple of brilliantly modded cars that handle well, the physics are straight off a look-up table and none of it's many players are bothered that the physics are not calculated in real time.
I'm not saying I would necessarily use a look-up table for significant aspects of the physics. Personally when it comes to making games I tend to take the view that if I can see it or feel it then I should simulate it, and the manner of the simulation should be the simplest and most efficient method possible, I certainly don't start by reading up complex equations on wikipedia.
So i'm not wrong in my approach, just different. And the best bit is that these days some bugger pays me an awful lot of money to approach problems the way that I do
Last edited by Becky Rose, .
In fairness my original post you are quoting was in 2006 which is long before multi-core systems had established themselves as the de facto standard so multi-threaded programming still wasn't that common and I had never done it at that time.
The change in software architecture as a result is really quite massive, I've not been coding all that much on the application/game side of things during the interim period but on the whole I am generally inclined to agree with your approach.
However I still feel there is a place for delta timing, for much the same reason as before, there is no need to calculate something twice if you do not use it's result twice. That's just insane, and yet it is standard practice.
Further, a locked rate of physics at say 100fps might provide smooth gameplay at 25/50 or 100fps. But a framerate of 30fps which would normally be playable will now appear less smooth and more clunky.
Locked rates are still evil, the only difference is that multi-threading has made the practice
A) More Common
B) The Easy Solution
I don't do things because they are easy. Easy things bore me. So do conventions.
I am disinterested in the popularity discussion, instead I am more disappointed to note that Victor isnt confirmed yet this year - and still no sign of Scawen. They've given up on us! *WAILS IN SELF PITTY*.
I will pay in full after the next pay day, would you mind if I did a bank transfer rather than paypal? Just a preference thing, if you prefer Paypal that's doable.
A lot of old names aren't yet on the list, it'll be a shame - I will miss them.
I will pay in full after the next pay day, would you mind if I did a bank transfer rather than paypal? Just a preference thing, if you prefer Paypal that's doable.
A lot of old names aren't yet on the list, it'll be a shame - I will miss them.
Could be:
- Background task
- Malware
- System temperature too high
- Insufficient system memory (background tasks running in virtual memory space)
He's refering to the work Eric has announced but not submitted as complete to Scawen.
Sat under a tree in a field just outside Amsterdam listening to Xandria - India
And this phone has auto correct in Dutch so dont even think of asking for a link
And this phone has auto correct in Dutch so dont even think of asking for a link
What does this meen for the sexual harassment case against him going through the courts at the moment?
I want to know if he was guilty or not!
Or am I meant to say RIP Carrol Shelby?
I want to know if he was guilty or not!
Or am I meant to say RIP Carrol Shelby?
Content is the one thing LFS desperately needs to re-appeal to it's longer time players.
Licence restrictions prohibit producing content that would appeal to a wider audience.
So as is LFS is a flash in the pan game for most players.
There is nothing about that model which suggests sustainability to me, which I suggest is a contributing factor to why LFS has slowed to a development crawl.
Licence restrictions prohibit producing content that would appeal to a wider audience.
So as is LFS is a flash in the pan game for most players.
There is nothing about that model which suggests sustainability to me, which I suggest is a contributing factor to why LFS has slowed to a development crawl.
As somebody who makes a substantial part of their income from people who rice their cars I am perhaps the least empathetic to the crazy shit that they do, but I figure - each to their own.
Personally I drive a beat up silver Ford Mondeo diesel which I crashed into my garden wall a week after buying it. If you took that as an indicator of my personality you may find yourself somewhat shocked at the reality!
Perhaps the inner me is a tiny Fiat with a unicorn paint job and I am just in denial?
For me personally charity is just part of being a good person and I believe that the only true charity is when you do something without seeking reward or opportunity to promote yourself by it, and as nice as a G27 would be - and it is a fantastic prize - I am not motivated by it to do something I would not otherwise be doing, which stays between me and the taxman.
But I want to post in support of your initiative, because there are so many things out there that need fixing and need help.
I know charities get a bad rap for wasting money and funding nice homes for executives, although not all are like that - but that doesn't stop you doing something like buying some blankets and giving them to the homeless.
Or even something small and less overt like spending time with a grandparent if yours are still alive, who if they are getting on a bit might just be delighted to have some company for a while.
Charity isn't about giving money to collectors in the street, it's about caring. It doesn't matter who for, as long as you care.
/applaude CheerioDM
But I want to post in support of your initiative, because there are so many things out there that need fixing and need help.
I know charities get a bad rap for wasting money and funding nice homes for executives, although not all are like that - but that doesn't stop you doing something like buying some blankets and giving them to the homeless.
Or even something small and less overt like spending time with a grandparent if yours are still alive, who if they are getting on a bit might just be delighted to have some company for a while.
Charity isn't about giving money to collectors in the street, it's about caring. It doesn't matter who for, as long as you care.
/applaude CheerioDM
I must confess to not staying interested for long, as there were two critical flaws right from the start:
1) The choice of camera at the start, a special start of race directive needs to be there to show the action at the front, and passes nearest the front - perhaps with more use of cameras looking back at the field to get a clearer image of the race start.
2) The camera focus' on 1 car, it's a classic sim racing mistake in every sim out there... But real TV does not do that, the camera typically tracks two cars and it is possible to do this in Insim as I did it for X-Cam. ( http://www.youtube.com/watch?v ... 5myGUc&feature=relmfu )
1) The choice of camera at the start, a special start of race directive needs to be there to show the action at the front, and passes nearest the front - perhaps with more use of cameras looking back at the field to get a clearer image of the race start.
2) The camera focus' on 1 car, it's a classic sim racing mistake in every sim out there... But real TV does not do that, the camera typically tracks two cars and it is possible to do this in Insim as I did it for X-Cam. ( http://www.youtube.com/watch?v ... 5myGUc&feature=relmfu )
The actual limit of human perception is in the 50-60 fps region.
25fps is the threshold for observing movement rather than individual images.
So it transpires he didnt die driving, he'd gotten out and was trying to get back in to save a dog when the vehicle, being carried downstream, overturned on him.
If I die in a horrible accident I hope I am doing something noble at the time. Or having sex, either works.
If I die in a horrible accident I hope I am doing something noble at the time. Or having sex, either works.
Being a country bumpkin I am familiar with fords, many city folk aren't.
But also the water level marker is typically at the deepest point, which in high water can place it some distance from the edge, some water markers are not that clear when viewed from afar, especially with the eyesight deterioration of age.
This could just be a lack of relevant awareness, or over confidence from familiarity with ford and a lack of considered thought as so the conditions due to a prevailing distraction.
I have certainly misjudged fords in the past, okay not one at 5ft deep but certainly some deeper than I expected, but with a nagging wife / grumpy old sod in the car it's easy to see how an elderly driver might make a decision which at other times wouldn't be rational!
I have made plenty of errors in my years of driving. Usually such things are only problematical when some other driver is negligent of the mistakes of others, but there is no other driver on the roads as dangerous and powerful as mother nature.
But also the water level marker is typically at the deepest point, which in high water can place it some distance from the edge, some water markers are not that clear when viewed from afar, especially with the eyesight deterioration of age.
This could just be a lack of relevant awareness, or over confidence from familiarity with ford and a lack of considered thought as so the conditions due to a prevailing distraction.
I have certainly misjudged fords in the past, okay not one at 5ft deep but certainly some deeper than I expected, but with a nagging wife / grumpy old sod in the car it's easy to see how an elderly driver might make a decision which at other times wouldn't be rational!
I have made plenty of errors in my years of driving. Usually such things are only problematical when some other driver is negligent of the mistakes of others, but there is no other driver on the roads as dangerous and powerful as mother nature.
The ability to temporarily ban an IP address is a perfectly reasonable request.
Using firewalls to achieve the same thing is a technical process and time consuming so tends to be a bit more permanent, but if you are faced with a multiple account demo user a temporary IP ban is a perfectly reasonable defensive measure.
Using firewalls to achieve the same thing is a technical process and time consuming so tends to be a bit more permanent, but if you are faced with a multiple account demo user a temporary IP ban is a perfectly reasonable defensive measure.
Am I to understand that for some reason or other you were banned with a period of penance for you to reflect on your ban and now that penance is over but after which you have not accepted or learned from your judicial punishment and therefor still believe you have been right all along to have done whatever it is that you did which, if my estimation is correct, was mostly likely an act of terrorist extremism such as posting on an internet forum in a manner that disagreed with another, most probably involving sarcasm and a badly photoshopping meme photograph ?
Fair play.
nothing, because in the same way the physics speed up or slow down so does the timing.
The only thing that changes as the experience of the gameplay, but this is the case for every game and isn't really in LFS' remit.
The justifications are more or less the same. Cruisers are threatening our way of racing and need to be stopped before they get the power to overthrow us. They may even be in possession of wheels of mass direction, and some of them want to wreck us.
So we should wreck them first, before they all emigrate on to our servers and ruin our way of the racer.
...Actually wait, you are right and I concede the point, because what CSU is really saying paraphrases more like this:
The developers are threatening our way of racing and need to be stopped before they don't release a patch and overwhelm us with their lazy work ethic and their doctrine of physics law and take all our grid slots.
So we should target cruisers and wreck them in case they are in support of the evil regime which denies us a patch, which we can prove because some of them are Radical drivers who vob modded the RAC in to a more recent track car.
Yep you are right, his argument is nothing like the analogy I wrote because as soon as you paraphrase it in to the war in Iraq suddenly his argument begins to make sense, unlike the real thing. So I agree 100%, those harbingers of vob modding should be hunted out and wrecked!
We might garner a bit more support by parking some tanks at the airport near Blackwood.
I think it's a pretty astonishing that there is an argument over whether cruisers or racers are faster. Given that they are all drawn from the same community, and some members are caught between deciding which sub-set they are allegedly branded as.
For sure the fastest driver does not always win anyway. To finish first, first you must not be vote-banned by the FXO with the police skin and flashing hazard lights.
For sure the fastest driver does not always win anyway. To finish first, first you must not be vote-banned by the FXO with the police skin and flashing hazard lights.
Lanchesters n-squared law denotes a victory for the men, with 1 wounded man.
If it was 10 women however the result would be down to a committee and group consensus with the rights of the tiger being considered.
If it was 10 women however the result would be down to a committee and group consensus with the rights of the tiger being considered.
I wouldn't worry theirishnoob, the day you qualify as middle class will be long after our sun has gone nova
But this is the same logic that has seen our countries go to war against people with towels on their head because a different group of people flew a plane in to a building owned by a bank. Are you really sure you want to perpetuate that level of stupidity?
After all you call me stupid for not taking part in your "war on decent and honest players in a particular sub-set of the community", surely I am allowed to call you stupid in return for suggesting that you at least direct your protest at the people who are - in your own eyes - responsible.
Why not email the devs with a replay file and a brief description containing the username, lap number and nature of the exploit?
Scawen and Victor are dead easy to reach: just their name followed by @lfs.net. Eric not so much, I have no idea what Eric's email is. I don't even know if his under-volcano lair is even internetted tbh.
You see, by sending details of the hack to, oh I dont know let's say the PROGRAMMER, he can work out the details of the exploit and remove it.
By yelling "OMG HACKERS HACKERS EVERYWHERE" and then crashing in to a bunch of very peculiar people who cruise with LFS (I cant figure it out myself, but whatever floats your boat) the Scawen can do **** all except - if he did what you demand - waste his time playing online like a police man at a speed trap waiting to see something he thinks may not be right.
And as I know from running the CTRA, 60% of drivers reports are because they needed to vent and not because they took the time to confirm their accused transgressor did anything wrong.
50% of those that are left file a report when they themselves are to blame, and of that remaining group most of the rest will be against the same driver - in this case, it'd be YOU.
FGED GREDG RDFGDR GSFDG