[Beginner] Help with Bouncing Circles

[Cadisol87]

The only thing that I can see that you may be noticing is that they still penetrate each other slightly. That is because you're calculating the radius of the filled circle, not including its outline. I believe that outlines expand outwards so you'd have to increase the radius that is tested by half of the outline width. (Not the actual radius otherwise the outline would make it even bigger!)

EDIT: I just removed the outlines and it looks awesome :p

I know, I'll  implement a feature that allows you to add and remove the outlines of the circles by pressing a button soon.

EDIT 2: In slower situations, it glitches. It's because you are moving the discs scaled by the amount of time that has passed. There is not way of knowing how much time is going to pass. It could be five seconds! How far would they move then? You need to break time down into smaller chunks. Try reading up on timesteps. Here's an interesting read (warning: get ready to pay attention to the nitty-gritty!): Fix Your Timestep
You may find reading the previous article on integration useful before the timestep one.

And I thought It couldn't get more complicated anymore...

[Giblit]

You could also use negative outlines where it goes into the fill.

[Hapax]

And I thought It couldn't get more complicated anymore...

I did say that the more accurate you want it, the more involved it becomes 

[Cadisol87]

You could also use negative outlines where it goes into the fill.

Good Idea! Didn't know that this is possible

[Hapax]

You could also use negative outlines where it goes into the fill.

Good Idea! Didn't know that this is possible

It's all here. 
I'd forgotten about this, actually. I got mixed up with line drawing which expands from the centre 

EDIT: fixed the link. Thanks to Giblit for pointing out the error 

[Giblit]

Your link is a bit messed up.

http://sfml-dev.org/documentation/2.1/classsf_1_1Shape.php#a5ad336ad74fc1f567fce3b7e44cf87dc

void sf::Shape::setOutlineThickness   (   float    thickness   )   
Set the thickness of the shape's outline.

Note that negative values are allowed (so that the outline expands towards the center of the shape), and using zero disables the outline. By default, the outline thickness is 0.

Parameters
thickness   New outline thickness

[zsbzsb]

Wow, 6 pages for this thread 

OP, can you please state clearly if you problem is solved, or if there is anything else left to solve? 

[Cadisol87]

OP, can you please state clearly if you problem is solved, or if there is anything else left to solve? 

When everything is solved, I'll post that, no worries

[Cadisol87]

Hmmm, I got an Interesting solution from Geheim via PM.
The solution is a bit 'dirty' but seems to work.

I added this to my if-collusion-statement:

Ball[i].move(-xSpeed[i] * 0.001f, -ySpeed[i] * 0.001f);
Ball[j].move(-xSpeed[j] * 0.001f, -ySpeed[j] * 0.001f);
 

Full Source-Code as attachment

[Geheim]

Thats like I said just a "dirty" approach to avoid the visual jumping you experience. For me your code seems to work like it should, however you should test a bit more yourself before posting again. Of course we could give you fully working source code, but thats not what we want. You should manage it with all the help you got now yourself...

[Cadisol87]

Just noticed that it doesn't work, glitches are still occurring.
Seems like I have to go through the 'Fix your timestep' Article... 

[Cadisol87]

Ok, still trying to fix my timestep, but meanwhile I added two features:

1. Outline can be (de-)activated by pressing the 'r' key
2. Circles change color when colliding with a window-border

But there's one thing I don't understand: It seems like the colors are always nearly the same. What did I do wrong? 

[Azaral]

Ok, still trying to fix my timestep, but meanwhile I added two features:

1. Outline can be (de-)activated by pressing the 'r' key
2. Circles change color when colliding with a window-border

But there's one thing I don't understand: It seems like the colors are always nearly the same. What did I do wrong? 

It looks like you keep resetting the seed for the random function. Take a look at the <random> part of the stl. IT has a lot better functionality than the old random.

[Cadisol87]

It looks like you keep resetting the seed for the random function. Take a look at the <random> part of the stl. IT has a lot better functionality than the old random.

Okay, I now I use the new random:

default_random_engine engine;
uniform_int_distribution<int> distribution(1,255);
auto random = bind ( distribution, engine );
 

I use this no matter which border is touched:

Ball[i].setFillColor(sf::Color(random(), random(), random()));
 

Now it definetely looks better, but do I need to set an extra seed for the generator?

[Giblit]

You only need to seed the generator once.

PRNG use the seed as S₀. Since a PRNG is just a sequence. I don't know the exact forumas but they are something like: S_n+1 = ( A * S_n + B ) % M; Where A , B , M are given before hand. So for example a generator that looks like:
S_n+1 = ( 10 * S_n + 11 ) % 12 with a seed of 0 it would look like this: ( repeats really fast since I used really small values )

11 , 1 , 9 , 5 , 1 , ...now it is repeating

Most of the PRNG won't repeat for a very long time