## RUBICON

by Wick

Funded! This project successfully raised its funding goal on June 2, 2012.

### Update the Second!: Physics, Gravity, and Trigonometry

Update #3 · May 23, 2012 · 6 comments

Helloooo everybody!

Here's the rightnow lowdown on the uphigh: The project has received over \$3000 from 140 backers with 9 days left to go. That is a LOT of haikus that need to be written! (plus at least two bobcats to catch...)

I've just finished moving, and things have settled down enough for me to really start working on Rubicon in earnest. For instance, over the weekend + Monday + Tuesday, I gave the physics engine an overhaul, which allows for pretty little things like black holes (soon to be joined by grappling hooks/tractor beams!):

(music by Sanjay)

# For those of you who are interested in the process of coding the game:

Working on Rubicon is just a CONSTANT re-crash course in trigonometry. Let me regale upon you the sordid tale of updating the physics!

The demo faked a lot of things in the interest of gameplay (things didn't have mass, as per se; collisions used maximum armour to calculate momentum, all the ships had hardcoded acceleration/maximum speed). Of course, in order to have gravity/spring effects, I'd need to put the actual underlying machinery in place. It shouldn't be too hard, I thought- coding 2D physics is relatively straightforward, and most of the time doing so was just killing all of the obsolete workarounds.

But wait! If thrusters provide a constant forward force, everything accelerates up to obscene speeds and it's impossible to tell what's going on. Fake physics for the sake of gameplay are required: once the ship approaches some set maximum speed, have the thrusters provide less and less force.

But wait! That makes it impossible to redirect the ship once you get up to that speed, since your thrusters no longer work. So that means that I need to only look at the speed vector parallel to the angle of thrust, as far as decreasing the efficacy of the thrusters.

So, net problem: I need to take an absolute angle (and force), compare it to the parallel vector of another absolute angle (and speed), and reduce the force according to how close that vector is to a maximum speed.

But wait! This makes it impossible to steer finely- if you're thrusting at an angle close to the one you're moving at, the new thrusting force is almost zero. So I need to keep track of speed-altering and angle-altering forces separately... and so on.

TL;DR: dammit, Jim! I'm a neuroscientist, not a mathematician. :D This is the sort of problem-solving I love about making games.

1. ### CreatorBen Puliafito on May 24, 2012

Pshhh, math.

2. ### CreatorBeatscribe on May 24, 2012

You lost me near 'but wait!' :S Glad you understand all that mathination..

3. ### CreatorLucy Bellwood on May 23, 2012

WHOMAGAWD. You blow my mind, Wick. Keep kicking ass.

4. ### CreatorGabriel on May 23, 2012

Cool black hole! Can't wait to play with it.

5. ### CreatorVeav on May 23, 2012

Oh, this is going to be a fun summer for you. You've scratched the surface. }:D

6. ### CreatorWick on May 23, 2012

And by "update the second", of course, I mean "update the third".
...
I hear that in some cultures those are the same thing?

##### 0seconds to go

Funding period
May 3, 2012 - Jun 2, 2012

• ##### Pledge \$1 or more

15 backers

I will send you a personalized* e-mail, thanking you for your contribution! (* - It will have your name in it.)

Estimated delivery: Jun 2012
• ##### Pledge \$2 or more

6 backers

The e-mail will contain a personalized* haiku. Or haiku-ish set of words. Or fortune-cookie predictions. Or just some words that you get that nobody else does. (* - It might have your name in it.)

Estimated delivery: Jun 2012
• ##### Pledge \$4 or more

20 backers

The e-mail will NOT contain a bobcat.

Estimated delivery: Jun 2012
• ##### Pledge \$8 or more

80 backers

You get to be a beta tester, and will be listed as such in the credits!

Estimated delivery: Sep 2012
• ##### Pledge \$16 or more

111 backers

Inputting a pilot name of your choice (nothing obscene!) will flip the game to SPECIAL EDITION, where you can choose extra ships in arcade mode, alternate color schemes, special missions, and a bunch more goodies. In other words: your name is a cheat code!

Estimated delivery: Sep 2012
• ##### Pledge \$32 or more

22 backers Limited (102 of 124 left)

I'll snail-mail you a handsome stylized RUBICON poster that you can hang on the inside surface of your living space! You also get listed under "special thanks" in the credits!

Estimated delivery: Dec 2012
• ##### Pledge \$64 or more

9 backers Limited (23 of 32 left)

I send YOU ship art and stats. You can then name the ship, come up with flavor text/the story behind it. I'll then include said text into the game. Capiche?

Estimated delivery: Sep 2012
• ##### Pledge \$128 or more

3 backers Limited (5 of 8 left)

You send ME a ship's doodle/scrawling/concept along with the name and flavour text you'd like it to have. I'll then make the art to fit it into the game. Capiche?

Estimated delivery: Sep 2012
• ##### Pledge \$256 or more

1 backer Limited (3 of 4 left)

The email *will* contain a bobcat.

Estimated delivery: Jun 2012
• ##### Pledge \$512 or more

1 backer All gone!

Become a character in the game! I will contact you once I reach the appropriate stage of development, and we'll work out exactly how this will go down.

Estimated delivery: Sep 2012