#🔒 I need to optimise my code, help me (I use bubble algorithm)

36 messages · Page 1 of 1 (latest)

ember scarab
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I want to optimise the collisions between objects in my simulation (I use pygame)

uncut scarabBOT
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@ember scarab

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ember scarab
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So, the problem is, i want to optimise this algorythm because it's too slow, how can I make it faster but still checking all colisions?

narrow oriole
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doesnt pygame already let you handle collisions with other sprites?

ember scarab
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Ok so what I mean by bubble algorithm is this:

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for i in range(1000):
 for j in range(1000):
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So this way you arechecking colisions by iterating through every single element in the lists. an example would be, you have 10 objects in one list and 10 in another, so you would check if the first element of the first list collides with one of the 10 in the other list, and then you would go to check if the second element would collide with one of the 10 in the other list. This makes it be very slow, bc it checks things 1000 * 1000 times

feral raptor
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Real question is : do you need to check all these collisions ?

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You can simplify by putting your objects in chunks: for example, if you divide your map in 4 corners, you check only the collision of entities in the same corner

ember scarab
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Ok so first, no, obviously if the objects are in opposite corners, it's not a good idea to check if they collide (obviously they don't). Now that we have divided the map in 4, I got 2 questions.

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  1. What do I do if they are in 2, 3 or 4 corners at the same time?
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  1. How do I put them in different lists to check colisions depending if they are on the first or the 4th corner?
midnight basin
feral raptor
feral raptor
ember scarab
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Yes

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Exactly that situation

feral raptor
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Keep it in the list of both chunks ig

ember scarab
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Okok I'll start doing it rn

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Let's see what happens

ember scarab
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and a simple more question now that it's done and that it works

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is there any way to check the time spent before and after this modification? I want to calculate the exact number of squares that work best for different situations. I will explain this to you. Imagine you got 1000m in X and 1000m in Y, so you could make 4 squares by dividing the screen(1000, 1000) in squares of 500m of height and width. However, if my characters are too big, maybe they tend to go occupie too much suquares, and maybe dividing it in 2 rectangles of 500meters of width and 1000 of height is better. How can I check the speed of the code?

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Basically I want to make a function that throughout the game knows what's better for them and changes the number of squares if necessary

feral raptor
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You can measure the time spent in a piece of code by using the time module or the pygame's clock

ember scarab
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Ok and another question

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If one list is 200 long

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And thye other is 50 let's say

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how should I do the bubble algorithm, for i in range (200): for j in range(50):

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or

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for i in range(50): for j in range(200)

stable aspen
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the order doesnt matter

ember scarab
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Ok thank you!

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!close

uncut scarabBOT
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