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About nts

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  1. nts

    AJAXifying normal page-to-page links?

    Quote:Original post by Mithrandir By hacking things in such an ungodly way that no mortal should ever be allowed to do that.Ugh what? They update the hash part of the URL (text after the # symbol) and the browser automatically supports back and forth functionality for that. Google HTML anchor labels for more info. Its not hard to setup (written components for it long ago). The only part you can consider a hack is that the browser doesn't provide an event for when the hash changes (might be in latest FF beta now) and you have to manually check at an interval. Quote:Original post by Mithrandir Back when I was still writing AJAX code, no browser would actually allow you to view or modify your browsers history, as it is a serious security violation and privacy concern.You still can't and you never will be able to. Quote:Original post by Mithrandir /Thank god I never have to deal with that abortion of an idea ever again. //All Silverlight now. Designed to not suck like HTML/javascript does.Yes silverlight is nice but javascript isn't bad and I find that usually people who think javascript sucks just suck at it.
  2. Quote:Original post by y2kiah Sorry for the bad link, I guess it only has profile data available. You could check out NACA report 824 here to pull out any useful information. The lift, drag and moment coefficients you are looking for are on page 177 of the report.Thanks for the link but I am not a hundred percent sure how to read those graphs... Looking at page 177 of the document (178 of the pdf). From what I've found 'R' is reynolds number which is essentially a modifier for the coefficients for a certain altitude range? From those graphs which one of the R lines listed should I be using? I've been looking at the ones with R at 6.0 (left facing triangle data points). On the top graph is the drag coefficient expressed in terms of the lift coefficient? For example at 0 aoa the lift coefficient is 1.2, the drag coefficient doesn't doesn't have a data point for that (max at 0.4), will I need to extrapolate?
  3. Quote:Original post by y2kiah you can go here to find out which wing type your airplane of interest uses then start searching for good locations of coefficient data. I found a good source here for the NACA families of airfoils, and many other sources more detailed but not quite as convenientThanks for the links. How would I convert the values on the NACA profiles to lift and drag coefficients? For example I am looking at the F-15 (which has a 'NACA 64A006.6' wing), so this would be the matching profile, not sure how to get the coefficients from the data (google hasn't turned up any good results yet).
  4. Quote:Original post by y2kiah For the lifting surfaces ------------------------ Lift: L = (CL)(1/2)(rho)(V^2)(S) or L = (CL)(q)(S) Drag: D = (CD)(1/2)(rho)(V^2)(S) or D = (CD)(q)(S) Where: CL = coefficient of lift (varies with angle of attack) CD = coefficient of drag (varies with angle of attack) rho = density of fluid (air) V = velocity of free-stream air S = wing planform area q = expressed as "dynamic pressure", is equal to (1/2)(rho)(V^2) Thanks, I'll give that a try. Do you know of any good resources where I could find the coefficients for lift and drag for current aircraft (I'm trying to simulate a few military fighters)? Or is there a good way to generate them?
  5. Quote:Original post by swiftcoder It sounds like you are missing friction completely - are you sure your drag calculations are correct?I did find a problem in there. Should have been taking the absolute value of something that I wasn't. Not the main issue but it would have been down the line. Quote:Original post by TythosEternal The basic physics equation that should be burned into your memory is Newton's second law. Commonly, this is written as: F = m * a ... That was the issue, my implementation of it was wrong. It is looking much better now, not perfect but much better. Probably have to play with my force calculations a bit. Quote:Original post by TythosEternal On a nearly-irrelevant tangent, I'd be very interested to see your equations of flight. In particular, how are you simulating lift and drag? My implementations of those are very basic. The drag calculation is split into drag due to speed and drag due to aoa. To calculate drag due to speed, I take the current speed over the maximum speed (constant). At maximum speed this factor would be 1.0 to counteract the thrust. To calculate drag due to aoa, I take the current aoa over a max drag aoa (constant). At higher aoa's (absolute value) more drag will be generated. The final drag factor is then those two added together and multiplied with the max thrust. At max velocity the drag factor should counteract the thrust force and the velocity shouldn't increase due to thrust. Lift is a bit more complex, my implementation might be wrong (lots of hard coded constants currently) but it is producing the desired results at the moment. Like drag I split the lift calculation into lift due to speed and lift due to aoa. To calculate lift due to speed, I take the current speed over a minimum speed (stall speed) and clamp it to a max value (constant). This will hopefully allow me to simulate takeoffs/landings in the future. The value needs to be clamped otherwise too much lift gets generated at high speeds. Almost the same for the lift due to aoa, I take the current aoa over a maximum lift aoa (less lift is generated if the aoa gets too high) and clamp the value to a min and max (more constants). Those two factors are then combined, clampled to a min and max (even more constants) and then multiplied by the aircrafts mass and gravity. Quote:Original post by jcarrion HI . I think your problem lies in that you are missing the air-resistance alltogether. ... Why is the air resistance a 3 component vector, shouldn't it just be a scalar constant? What's the best way of implementing this? Taking the difference between the direction of the aircrafts nose and direction of velocity and adding an air resistance drag force to the total acceleration? Thanks
  6. I am working on a basic aircraft simulation but have hit a problem. I can calculate the forces on the plane at a time (lift, weight, thrust, drag) which when added together give me an acceleration vector of the plane. Now what's the best way to use that acceleration vector to compute a velocity? I started using an accumulated vector for the velocity but that isn't working out very well. Basically every frame I was calculating the acceleration, adding to velocity vector and then adding the velocity to the position. vector3 acceleration = CalculateAccelVector(); velocity += acceleration; position += velocity;This was causing a few issues. For example if the aircraft was moving along the z-axis and made a quick turn to the x-axis, it would maintain its velocity along the z-axis because there was no force to cancel it out. I've tried dividing the velocity vector every frame by some amount so that eventually the extra force would be cancelled out and fudging the velocity direction toward the thrust direction but haven't found good values for this yet. The aircraft would either act like a very powerful rocket with no drag (not losing any speed in turns) or the heading would take too long to match the thrust direction (flying forward and sideways). I think I am missing something simple here but don't know what, any ideas? Not sure if it matters but the flight model I am trying to implement is not a full blown simulator. Much simpler inputs to the physics simulation. Thanks
  7. nts

    Parallax mapping

    I agree with what you're saying but just wondering if you have seen/implemented Parallax Occlusion with adaptive LOD from ATi. I can't find the paper at the moment (might have been on Humus) but the basic effect was based on calculating the mip map level and then reducing the sampling based on the distance and eventually switching over to normal mapping (blending between the mip map boundary) where parallax would be useless. It was implemented in the toyshop demo for X1800's if I remember correctly.
  8. nts

    Yet another fatal taser incident

    Quote:Original post by trzy ... Tasering is supposed to be near to a last resort ... Got a source for that? I'm not familiar with the police rules. Quote:Not to mention that they already had him restrained and decided to tase him again. "Oh look, you're in pain and having convulsions from being tased the first time and having 3 people trying to pin you down! I'm going to tase you again to calm you down."Was he having convulsions, I don't know. It looked like he was just resisting. Quote:As for his mother being in the next room, my understanding is that he was not being processed and being forced to wait. Does anyone have any more information on this? All of the articles are light on details.If he was waiting in the baggage area then he would have already gone through customs. AFAIK you just get your bags and walk through a door to arrivals (last time I was there). Nobody is going to make you wait in the baggage area for processing, if you are there then you have already been processed. My understanding was he was just waiting in baggage for his mother who was in arrivals.
  9. nts

    Yet another fatal taser incident

    Quote:Original post by Ra Maybe he would have, maybe not. The point was that he posed absolutely no threat to them.The only thing they would have known at that point is that this guy was violent. If the guy is trashing stuff inside the airport, trying to break windows, etc how do you know that he is not going to resist you? What if they tried to restrain him and he became violent towards the cops? Quote:Hell, if they'd actually tried to reason with the man they could have walked out of there without any struggle.That man didn't speak the language and I highly doubt that reasoning would have worked. The guy waited in the baggage area for 10 hours waiting for his mother, who was waiting in the arrivals section, just one door away. Yes he didn't speak the language but why not just grab his bags (if he had any) and follow everybody else. Just simply observing the people around him should have clued him in. And again why did his mother leave?
  10. nts

    Yet another fatal taser incident

    Quote:Original post by Ra The guy is 40 years old and unarmed. Why not just grab him and slap some cuffs on?Do you really believe that he would have allowed the officers to just cuff him? From what the guy was doing the police probably thought that it would be much safer for both parties to taze the guy. Quote:Original post by Ravuya According to testimony, they were trying to talk to him for all of 35 seconds before pulling the tazers.There was only one officer with a tazer. Quote:Original post by NewsArticle His mother, Zofia Cisowski, had gone home to the B.C. Interior after waiting several hours to meet her son. Had she been there maybe all of this could have been averted...
  11. nts

    Yet another fatal taser incident

    How was the use of a taser wrong in this case? You have a man that is going berserk in the airport, trashing luggage, computers, chairs, trying to break windows... The police didn't just show up and taser him, they were trying to talk to him. Should they have tried longer, maybe. Had they just tried to arrest him or tackle him then he would have been fighting back anyway. They probably thought that it would be a safer option (less injuries to the police and victim) to just tazer the guy instead of getting into a fight with him. They had no intention of killing the guy. Hindsight is always 20/20 but put yourself into the position of the police that night. Yes it is sad that he died but I don't think it is the fault of the police. Why was the guy going berserk in the airport, why was he there for ~10 hours after landing, where was his mother who was picking him up, why did she leave the airport?
  12. How is it an XP easter egg if you are telnetting out to another server? Just did a quick google and apparently there is some Star Wars ASCIImation shown.
  13. How are you posting to the web application? If it is just url encoded then you should be able to access the data with either Request.QueryString or Request.Form. Something like...string post_var_value = Request.Form["post_var_name"];
  14. nts

    Under-powered CPU? 3.25GB of RAM?

    Check your BIOS for EIST (Enhanced Intel SpeedStep Technology) and disable it if it is enabled.
  15. It looks like the two quads should match up so I'm guessing that they might be getting clipped at the far plane. Try using 50 for the zFar instead of 35...gluPerspective(90,1,1,50);
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