The goal of this challenge is to make bubbles that bounce gracefully around the screen.
This is meant as an introduction to elastic collisions and physics in python and pygame. Circle collisions are the simplest type of general collision that one can solve in an elegant way.
The setup code in base/ contains two classes, Bubble and World,
that together simulate a world full of circle. Those circles don't collide against each other,
and neithers against the side of the screen. Your challenge will be to add glitchless collisions.
There are no provided assets, we only need pygame.draw.circle this time!
The setup can be controlled with the mouse:
- Bubbles tend to go away from the mouse.
- Bubbles spawn when the mouse is clicked. And techincal info can be toggled with:
Dfor the debugUfor unlimited FPSFto show/hide the FPS
- Casual
+3 CP: Make the bubbles collide glitchless against the walls. - Ambitious
+2 CP: Make the bubbles collide against each other. - Adventurous
+1 CP: Choose and make one of the following:- Moving rectangles that also collide with bubbles and each other.
- Bubbles with a smaller world inside them, with other bubbles that bounce inside them (recursively). The small bubbles don't interact with larger bubbles except the one they are in, by giving momentum when colliding its border.
For each challenge, it is required that it is impossible to make a bubble teleport, even if it spawns half into another bubble or a wall. Bubbles should also not glitch or jitter. In such case, no points will be given, but check the tips below, the tips inside the provided code or ask on the pygame server, and you will find answers ;)
Further instructions and more general tips are available on this document.
In any case, remember to always try to make things as reusable as possible, who knows, you may need it in a future project!
Tip 0: This is a more guided challenge and quite a few details about what you are supposed
to do is provided as comments inside the main.py file.
However, feel free to try to find other ways to do so and research how such
behaviours can be obtained.
Tip 1: If you want to be sure that a bubble never teleports, never set its x and y
coordinates directly, modify only its velocity.
Tip 2: To avoid most glitches, you can allow bubbles to overlap a bit for a few frames, and when two bubble do overlap, you apply a strong force on each one that separates them, that is, a force that is on the oposite direction of the collision.
Tip 3: Think about how balls collide in real life: they don't go instantly in the other direction, they overlap (or more likely, compress/squeeze) a bit.
Tip 4: For an explanation of elatic collisions and some formulas, you can read the wikipedia page.
Tip 4: If two objects collide, but already have velocities that pushes them in opposite directions, don't do anything !
Have fun !
- Setup code: CozyFractal