1.  01/10/2010, 10:58 AM Dude I love your game and the updated look.
2.  01/11/2010, 05:25 PM Originally Posted by krid So, I'd like to have a control option that would fire the jets such that the nose of the ship would move towards whatever side/corner of the phone is down. I think of this as "gravity control". This approach is VERY promising but unfortunately I can't get the physics right. The ship is bouncing around the desired heading in a range of several degree because the accelerometer isn't really accurate (even if the phone is not moved at all the pitch/roll bounces around in a 5 degree radius) and because I have a hard time calculating the spin acceleration to maintain the desired heading. If someone could help me out here I would be glad. What I have so far: The ship has a spin velocity (degree per second, negative is anti-clockwise and positive is clockwise) A spin acceleration (degree per square second).This spin acceleration is set when the left/right thrusters are fired. Current maximum spin acceleration is 400 degree per square second. This maximum spin acceleration is applied (negative or positive) when the left/right thrusters are fired with 100% power. The current heading in degree (0-360). The desired heading in degree (Calculated from the pitch/roll values coming from the accelerometer) (0-360) Let's say the autopilot updates the thrusters all 25 milliseconds. What I need is a perfect formula which I can use at each of these update intervals which takes the current heading, the desired heading, the current spin velocity and the maximum possible spin acceleration and calculates a spin acceleration which must be applied at this time frame so in the end the ship does a smooth (and fast as possible) rotation to the desired heading. Any physicist/mathematician out there who can give me such a formula? Last edited by kayahr; 01/12/2010 at 02:05 AM.
3.  01/12/2010, 01:45 PM Originally Posted by kayahr ...calculates a spin acceleration which must be applied at this time frame so in the end the ship does a smooth (and fast as possible) rotation to the desired heading. Any physicist/mathematician out there who can give me such a formula? I am so totally not a mathematician, but maybe I can offer some help here. You don't exactly want to get to the desired heading "as fast as possible", you want to get to that heading such that the ship is not spinning when it arrives there. In other words, you need to start braking when you're near the desired heading, so that you don't overshoot it. The problem is analogous to a system with a thermostat and an adjustable heater and an adjustable cooler. A linear motor or actuator is also quite similar; even closer would be control of a rotating robot arm (or maybe even a stepper motor, anything with some momentum). I'm sure that there are examples of appropriate control algorithms out there. You may want to have a look at these Wikipedia entries: Servomechanism - Wikipedia, the free encyclopedia Control theory - Wikipedia, the free encyclopedia Hysteresis - Wikipedia, the free encyclopedia Author of Keyring for webOS - Easy password management on your phone Get Keyring :: Keyring website :: Keyring desktop client :: Keyring bugs :: Desktop client bugs Like what I've done with Keyring? Hire me!
4.  01/12/2010, 05:49 PM Originally Posted by krid I am so totally not a mathematician, but maybe I can offer some help here. You don't exactly want to get to the desired heading "as fast as possible", you want to get to that heading such that the ship is not spinning when it arrives there. That's clear. And still it should do that as fast as possible. So accelerate with full power to the left and when reaching the half of the way it should accelerate with full power to the right. So much for the theory. Give me a formular for the praxis But it's not as easy as that. The formular must take into account that the ship may already be spinning in some direction when a new heading is set and if the ship is already pointing nearly at the desired heading then the thrusters must not fire with full power but instead they should only use a small amount of power because otherwise it will always rotate to far. And this will result in a oscillating movement and this is very annoying.
5.  01/14/2010, 06:13 PM I've been thinking about this and i don't think there is an easy way to implement this without disregarding the physics involved. If you really want to move in that direction i think the most practical way would be to simply ignore the angular momentum and rotate the ship linearly. However, I still prefer controlling the ship with the keyboard and i dont think that accelerator controlls would improve playabilty. I'd keep the controlls as they are and focus on things like weapon upgrades, enemys and other stuff that would make the game more varying.
6.  01/14/2010, 06:30 PM Kayahr, great work with the shield balls. I've been hoping for this update for days. Things I love, - Loving the gradual overcharge. - Loving the E balls give you +25 if you are are below 75 shield. - Love the way if you're not careful you can blow up the E ball, great idea. I would still like to see other drops, I guess the next simplest is a hull repair, which unfortunately is not always useful. You should code it so that Hull Repair balls only appear if you have hull damage. Say 50/50 with shield balls if you have hull damage. Keep up the awesome work. I love the fact that this is a free app, I think I'll be donating more than you would charge for it. Regards, phufbq
7.  01/15/2010, 05:48 PM Originally Posted by palmpreacher 1. sounds, sounds, sounds - should be easy now with 1.3.5 (well, not as hard as) Just published Version 0.1.0 which now has sound effects. But don't expect wonders. webOS has still no usable sound support so Presteroids is only using the default system sounds. And because Presteroids plays a LOT of sounds (Laser fire, Explosions, ...) the sound is sometimes a little bit jerky if too much happens at once. I improved this a little bit by prioritizing sounds (For example an explosion is more important (because it gives feedback about a hit) than a laser shot) and I also tried to make sure that only one sound is played in a 250ms frame (Except when a higher prioritized sound comes in). I think this is quite acceptable. If not, simply deactivate sound in the preferences. I've also implemented "force-feedback". Nothing complicated. When the ship takes damage or is destroyed then the phone vibrates. This can also be deactivated in the preferences. Sound volume can't be adjusted. Don't know why, the system sounds played by the game simply ignore the volume. Hell, I hope Palm is working on the sound issues...
8.  01/15/2010, 08:17 PM I just wanted to stop by and let you know what a great job your doing with this app. The customizable controls are the icing on the cake. If palm gets it right as far as sound is concerned, you've got yourself a perfect app...
9.  01/15/2010, 09:12 PM btw, the accelerometer controls will only feel natural of the strength of the rotational thruster is directly proportional to the change in the phones orientation. this is similar to how the force on an airplanes wing varies with the change of the yolks orientation. the neccisary changes would fundamentally change the engine, but I think the transition between the two control schemes would be seemless for the user...
10.  01/19/2010, 01:10 PM ... So this isn't the official Pre app for steroids? Nice game anyhow.
11.  01/19/2010, 01:41 PM Will you sell the game in the App Catalog? Will it be available through AppSnoop?
12.  01/19/2010, 02:29 PM Originally Posted by MannyZ28 Will you sell the game in the App Catalog? No. It will be available for free in the app catalog. But it will be named "Destroids" there. I'm going to submit it soon. Will it be available through AppSnoop? What the heck is that?
13.  01/19/2010, 07:53 PM Originally Posted by kayahr No. It will be available for free in the app catalog. But it will be named "Destroids" there. I'm going to submit it soon. What the heck is that? Sorry I meant AppScoop. The basic idea taken from PreCentral: Palm today announced that they are opening up the webOS app distribution model. While the official App Catalog remains in play, Palm is adding an open web distribution feed where developers can submit there app and Palm will simply provide them with a URL for direct download with no review and approval process to get in the way. http://www.precentral.net/palm-revea...apps-beta-feed But I am happy to hear that it will be in the App Catalog soon! Thanks for your hard work!
14.  01/20/2010, 02:03 AM Originally Posted by MannyZ28 Sorry I meant AppScoop. Ah, ok Well, I'm not using the web feed. I'm trying to get in the official app catalog because it's free for Open Source programmers. I submitted Destroids a few hours ago. Now I'm not sure what I should do with Presteroids here on Precentral. I'd like to rename it but I'm not sure what happens then in Preware... I think I will wait until Destroids is available in the official app catalog and then I simply try it out. If renaming the project here breaks something then I have to delete it and create it from the scratch (Even if I loose the excellent rating then). I definitely want to continue to use Precentral for testing newer versions of Destroids.
15.  01/20/2010, 05:28 PM Originally Posted by Mhunterjr btw, the accelerometer controls will only feel natural of the strength of the rotational thruster is directly proportional to the change in the phones orientation. This is already the case. ian
16.  01/31/2010, 01:55 PM Originally Posted by kayahr Ah, ok Now I'm not sure what I should do with Presteroids here on Precentral. I'd like to rename it but I'm not sure what happens then in Preware... I think I will wait until Destroids is available in the official app catalog and then I simply try it out. If renaming the project here breaks something then I have to delete it and create it from the scratch (Even if I loose the excellent rating then). I definitely want to continue to use Precentral for testing newer versions of Destroids. I have enjoyed playing your app from PreCentral, like I remember from back in the day. I have also enjoyed reading through your thread as you contemplate the "modified" physics involved in what you imagine reality would be and how to apply it in your game. Brings back memories of modern physics in high school then again in college. That was fun stuff! I say modified because as you know (from what I remember), without atmosphere, ie in space, there can be no sound as there is nothing for sound waves to propagate on, but that would make the game way less interesting! Originally Posted by Maggun The great thing about all that is that it could all be (relatively) easily achieved by extending the game engin with the relevant methods for the conservation of momentum. Perhaps another slight bending of the laws of physics, ie the conservation of momentum, I like the idea Maggun proposes about the particles resulting from an asteroids hit continuing towards the ship, the center of the explosion upon impact with the asteroid will cause the resulting particles to continue towards the ship but this could be at an angle and conserve momentum. If this angle is not enough to clear the ship, you could slightly increase the angle. Anyway, I went on to become an engineer, not a physicist, and have not practiced in that field for some time, so I might have it wrong, but I think I have it mostly right! I see for now that both version numbers are the same, I have not downloaded Desteroids, so don't know, are they the same? Can you have them both installed at the same time? (In the event the PreCentral version becomes a testing ground for the App Catalog version)? Thinking forward, perhaps it will be beneficial to have the 2 versions named differently (Pre vs. De) to run and test side by side a test version and released version on the same Pre. Nice work! Sprint since 01/06/99: Sanyo SCP-4500 -> Audiovox PPC-6700 -> Palm Treo 755p -> Palm Centro -> Palm Pre 1.4.5 -> Jailbroken iPhone 4s
17.  02/01/2010, 11:58 AM Just a heads up on a glitch that happened. I was not able to recreate it though. I was on level 9. A UFO crashed into me and the game froze - the score started increasing. I let this happen a while - hit some buttons the ship finally started moving, crashed and the game ended. It looked like the score would increase by 900 every few seconds. Attached Images presteroids_2010-01-02_100524.png (76.4 KB, 8 views)
18.  02/01/2010, 06:23 PM Originally Posted by jdod Thinking forward, perhaps it will be beneficial to have the 2 versions named differently (Pre vs. De) to run and test side by side a test version and released version on the same Pre. I just renamed Presteroids to Destroids here on Precentral. I think I'm doing it like this: Odd version numbers are always betas and they will be published here on Precentral (like the 0.1.3 which I just published). Production version will have even version numbers (like the 0.1.4 which will appear in the app catalog later).
19.  02/01/2010, 06:28 PM Originally Posted by west33 I was on level 9. A UFO crashed into me and the game froze - the score started increasing. I let this happen a while - hit some buttons the ship finally started moving, crashed and the game ended. I think some javascript error occurred which brought the game into an undefined state. Too bad these error messages are not displayed in an alert box or something like this. It can be found in the application log. If someone encounters this problem and knows how to fetch the app log it would be nice if he could send the log to me.
20.  02/02/2010, 10:14 AM Originally Posted by kayahr I just renamed Presteroids to Destroids here on Precentral. I think I'm doing it like this: Odd version numbers are always betas and they will be published here on Precentral (like the 0.1.3 which I just published). Production version will have even version numbers (like the 0.1.4 which will appear in the app catalog later). To clarify, downloading either version, PreWare or App Catalog, will that now over write Presteroids? Or should Presteroids be removed before installing Desteroids? Or will Presteroids coexist with Desteroids? Finally, is the idea with odd/even versions that a later version of either (PreWare/App Catalog) will over write and earlier version of either, giving you an opportunity to test or not with the PreWare version, or just wait for the fully tested App Catalog version? Sprint since 01/06/99: Sanyo SCP-4500 -> Audiovox PPC-6700 -> Palm Treo 755p -> Palm Centro -> Palm Pre 1.4.5 -> Jailbroken iPhone 4s
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