 # Coders Strike Back

Hi, how can I get back my code submitted to SF2442?

From a mathematical point of view, the angle should have been computed counter clockwise. http://www.mathopenref.com/trigangle.html

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[quote=“nautilus_me, post:23, topic:1317, full:true”]
From a mathematical point of view, the angle should have been computed counter clockwise. [/quote]
Not if you want “y” to be +90° from “x”

Do you also have the formula to get next angle please ?

You have 2 angles:

1. The angle the pod is “pointing”:
Final_Angle = Something between Initial_Angle-18 and InitialAngle+18, according to the new point you set.

2. The angle the pod is “going”:
You can obtain this angle from vx and vy:
Angle_in_Radian = atan2( vy, vx );

You can calculate v:
v = sqrt ( vxvx + vyvy )

You can decompose the v in vx and vy:
vx = v * cos (angle)
vy = v * sin (angle)

The speed is as I explained before: Final_vx = (Initial_vx + Thrust_vx) * 0,85
The same for vy

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I really like doing the puzzles and taking part in the competitions on the site, but I dislike the idea of the need of reverse engineering in this one. It’s basically the same as we’ve had 2 and a half years ago with Supercell’s racing competition. You need a bigger initial time investment in figuring out how the physics work before being able to do any logic, and this is a huge downside. Just my two cents.

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Great, thank you. That might be a good idea to add it to the game description.

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Hi there! Anyone knows how do collisions work?

Hi,
What is the meaning of vx and vy ?? I mean if it is supposed to be the speed on x and y axis, then why it is often negative?

http://www.plasmaphysics.org.uk/programs/coll2d_cpp.htm (code)
http://www.plasmaphysics.org.uk/collision2d.htm (explanation)

Where did you got Thrust_vx ?? We only have Thrust , for example Thrust 200 but we don’t know how 200 is decomposed for Thrust_X and Thrust_Y

now we just need the ball’s mass without and with shield

It’s decomposed according to the angle of the pod (angle the pod is pointing).

thrust_x = thrust * cos( angle_pod_is_pointing );
thrust_y = thrust * sin ( angle_pod_is_pointing );

So, as explained in the expert rules, you have:

1. Target: New angle the pod is pointing;
2. Thrust: vx = vx + thrust_x & vy = vy + thrust_y
3. Movement: x = x + vx & y = y + vy
4. Friction: vx = vx * 0.85 & vy = vy * 0.85
5. Truncate speed (vx, vy) and Round position (x, y)

They just say: “This will give the pod much more weight”. You may observe/study a collision and deduce the difference.

How does submission work? Can I submit only one solution or can I submit one per language?

I think that you can submit one by language.

I think it’s better to say that you can change your language – but you have just one spot in the leaderboard anyway (your last submission).

Hello.
Could you please fix this bug?
This is annoying because I need to refresh the page one time in five.
Thanks.

is it perfectly elastic collision?

Hello.