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 on: 2018-03-18 04:36:47 
Started by ags1 - Last post by orange451
I used to play a lot of counterstrike in highschool. When oculus first game out, I spent awhile and got it working with it. Played with it for many hours at a time and never felt motion sick.

Guess it's just in the person using it.

I think that people who get motion sick often wont even be using a VR headset, as they'll just always be motion sick. So I don't think you should have to plan your game around that, if you know your audience is already going to be limited.

 on: 2018-03-18 01:50:25 
Started by BurntPizza - Last post by theagentd
Also, how many terms are in your Taylor expansion? And do you just evaluate it with a time since launch or some other variable?
I used 8 coefficients there, but even 3 can sometimes suffice; it depends on the parameters of the simulation. Yeah, I calculate x = (1 - currentTime/totalTime), use x, x^2, x^3, etc with the taylor coefficients and finally do angle = (1.0 - sum) * Math.PI/2 to get the thrust angle. Since my only real requirement is that the sum is 0 at the start and 1 at the end, I just make sure that the coefficients sum up to 1.0 and that handles it.

 on: 2018-03-18 01:18:34 
Started by BurntPizza - Last post by Longarmx
No, the first stage doesn't fly back and land. =P

Ah, but that would be quite fun to watch the simulation calculate the first stage's trajectory!

Also, how many terms are in your Taylor expansion? And do you just evaluate it with a time since launch or some other variable?

 on: 2018-03-18 01:05:15 
Started by BurntPizza - Last post by theagentd
Had my last uni exam today. Now I only have one more left this summer and I'm done with uni.

Decided to have some fun and coded a super simple ok, maybe not that simple Falcon 9 FT rocket launch simulator in 2D. I've inputted the following data in SI units:

 - Earth's radius and mass
 - Earth's rotation and the "bonus" horizontal velocity gotten by launching from Cape Canaveral
 - Earth's atmospheric density approximated with an exponential function of height over ground

 - Target orbit altitude (400 000m Low Earth Orbit, just under the ISS) and the exact velocity needed to maintain that orbit

 - Rocket drag area (circle of radius 2.6315m) and approximated drag coefficient (0.25)

 - The following parameters for the two Falcon 9 FT stages:
    - Weight without fuel (22 tons, 4 tons)
    - Weight of fuel (410.9 tons, 107.5 tons)
    - Thrust (~8 000 000 N (actually 7 607 000 to 8 227 000 depending on altitude), 934 000 N
    - Burn time (162 sec, 397 sec)

The rocket is then assumed to rotate from 0 to 90 degrees over the course of the flight (you never want to point a rocket downwards or you will not go to space today), and this rotation is controlled using a Taylor series controlling the rotation. This allows the rocket to rotate at different rates at different parts of the flight. Basically, this allows the first stage to go more straight up to quickly get out of the thickest part of the atmosphere, and then quickly rotate over to the side to gain orbital speed as efficiently as possible. The Taylor constants are decided using a simple learning algorithm that tries to get rid of the error in altitude and orbital speed/direction. However, if the thrust is simply too high, the rocket will get a too high orbital velocity, so I also added the payload weight as a parameter, so if the rocket overshoots, I just add more weight to it. Also, the rotation of the Earth is taken into consideration, and the drag is calculated (approximately) based on the idea that the atmosphere rotates with the planet (so the rocket starts out travelling at around 408m/s together with the surface, but has zero drag since the air is rotating too).

The learning algorithm just tries random modifications to the taylor constants and the payload weight and checks if the result is a better end orbit than before (= lower error in altitude and orbital speed/direction), and given time it converges on the perfect settings for launching the rocket. After running the program for around 10 minutes and changing the learning rate as it went, I got the calculated error down:
 - -9.909272E-7 meter error in altitude
 - 6.1378614E-8 m/s error in velocity away from the Earth
 - -1.3683348E-8 m/s error in orbital velocity

In other words, the resulting orbit is off by less than a micrometer, and the velocity is off by even less than that. The maximum payload was determined to be 21843.23 kg, which is a bit lower than the payload the Falcon 9 FT is rated for, 22 800kg payload (possibly plus 1 700 kg, not sure if those 1.7 tons are included in the 22 800 number), but at least close enough to be in the same ballpark. Considering it's a 2D simulation I made with information I could Google in a couple of minutes, it's pretty cool.

Image of the trajectory:

The curve at the start comes from the fact that the planet is rotating, so the rocket starts with a high speed to the left but accelerates upwards. The color of the trajectory shows the two stages and how they deplete their fuel (which of course causes the rocket to get MUCH lighter over the course of the flight). Once the first stage is depleted, it instantly switches to stage 2 at which point stage 1 is jettisoned and no longer adding weight to the rocket. It would be possible to add a zero-thrust stage inbetween to add some time for the stage separation. No, the first stage doesn't fly back and land. =P

Some people go out drinking to celebrate, I write rocket simulations...

 on: 2018-03-17 16:07:47 
Started by mateuszd - Last post by Gornova
I'd like to design levels if you want Cheesy

 on: 2018-03-17 14:52:22 
Started by arkisvir - Last post by arkisvir
Welcome To The World Of Spoxel!

<a href=";hl=en_US&amp;start=" target="_blank">;hl=en_US&amp;start=</a>

Spoxel is a sandbox RPG in the same vein as Terraria and Starbound, but with nearly infinite crafting capabilities. Don't believe me, read on!

There are 1000's of materials and components in the game that all have crafting attributes and can be added to any item in order to give it various properties. Here we have a Shark plus a sword hilt to make.. you guessed it, a SHARK SWORD!

You can even completely customized the look of your items as well, but manipulating the size, shape, and placement of all components from scratch! No relying on pre-built recipes!

Click to Play

The spell system is completely customizable as well. You can put together any combination of runes to design your own spells. From an auto-mining spell, to homing fire chickens!

If you want to check it out and give it a try, head over to our discord and grab a key. See you there!

 on: 2018-03-17 12:21:39 
Started by ags1 - Last post by Damocles
I think its an strategic error, to always push using actual 3D (different picture for each eye) for games using a VR headset, instead of first concentrating on the other advantage VR headsets have:
the much larger field of view compared to a classic monitor.

If I would make a game for such a headset, I would project the gameworld flat on a larger virtual screen, similar to I-Max,
while keeping the virtual screen stable relative to the realworld-projection-position. Then turning the rendered scene classically using the controller/mouse.
(eg: its simply simulating having a gigantic 120 degree curved monitor in you livingroom)

That would avoid motion sickness, while giving the player the ability to enjoy the game on a much larger screen.
(and not force the player to turn his head all the time)

Even with perfect technology (optics, speed, resolution, weight), that can make the player feel like standing on a holodeck, you will never get around one essential problem:
to appreciate the scene, and not get motionsick, the player needs to actively move his body. Either standing in his living-room, or in some fancy rig that can simulate acceleration.
And thats the problem: Not everyone wants to have to move actively when playing a game for hours.
I think that the market for games that you can play sitting lazily on the sofa, will always have a larger market than games where you have to move.

 on: 2018-03-17 12:07:09 
Started by ags1 - Last post by Phased
The thing about VR is that it is immersive, you feel like you are really there, a good way to break the immersion would be to constantly switch between first person and a cinema view.

Moving in VR only causes motion sickness when you are using a traditional game movement ( wasd or joystick ). A fair few games offer various ways for the player to move, one is teleporting, which gives no motion sickness, there have been variations to the teleporting, where you see a ghost image of your character moving when you attempt to move (From Other Suns does this).

You would have to be really sensitive to motion sickness to get motion sick from VR from just moving your head / walking around in real life without using controller input to move the character (and without teleportation).

It also varies from games, I played Pavlov for 1-2 hours and I felt fairly sick after it. I played another game Echo Arena, which is based in zero gravity, where I barely got any motion sickness.

@CommanderKeither Level of Detail is important for VR because you can get so close. At the same time, things in the distance can be of less quality, so the things that you are currently close to for sure need to be high quality (if you are aiming for realistic graphics).

 on: 2018-03-17 11:50:55 
Started by mmx358 - Last post by mmx358
Okay, maybe my question is incorrect...

Ho do i render to FBO with multisampling?

 on: 2018-03-17 11:18:13 
Started by ags1 - Last post by CommanderKeith
I've never tried VR, but I've heard that when the accelerometer is good enough and latency is low, motion sickness isn't common.
I like the idea of a 2d world, do you mean a 2d top down world or side scroller style view?
One thing I read is that the detail in a 3d VR game needs to be much higher than a normal fps since people can get really close to the objects and walls if they want, which is hard to maintain with high fps games

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Java Gaming Resources
by philfrei
2017-12-05 19:38:37

Java Gaming Resources
by philfrei
2017-12-05 19:37:39

Java Gaming Resources
by philfrei
2017-12-05 19:36:10

Java Gaming Resources
by philfrei
2017-12-05 19:33:10

List of Learning Resources
by elect
2017-03-13 14:05:44

List of Learning Resources
by elect
2017-03-13 14:04:45

SF/X Libraries
by philfrei
2017-03-02 08:45:19

SF/X Libraries
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