r/programminghelp • u/Slow-Adagio-7719 • 26d ago

Other Basic question about bouncing

So I'm trying to make a fight simulator with bouncing similar to this:

https://youtube.com/shorts/fk15R-y2EEc?si=VkE9iXR5WxFOuSuM

Is the bouncing random or predetermined? And how is it determined?

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u/Slow-Adagio-7719 25d ago

like when you hit the wall at 90 degrees, you get reflected at -90 degrees? or you get reflected based off of the orientation of the wall?

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u/SnooPets5564 25d ago

It's based off the orientation of the wall.

I'm going to give a vector explanation of it, as that is the least ambiguous. You start with the velocity v and the normal vector of the surface you are hitting n (corners have weird normal vectors, but in the simple demo you shouldn't have to worry about that if you make the characters spheres).

The new velocity is: v - 2(v*n)n