if on edge, bounce

when green flag clicked
forever
move (10) steps
if <touching [whatever sprite here] ?> then
set [dir] to (pick random (1) to (4))
if <(dir) = [1]> then
point in direction ( 45)
end
if <(dir) = [2]> then
point in direction (-45)
end
if <(dir) = [3]> then
point in direction (135)
end
if <(dir) = [4]> then
point in direction (-135)
end
end
end

RethinkingVoxels wrote:

do you want to bounce off like the

if on edge, bounce

block?

deck26 wrote:

Imagine a line joining the centres of the two balls. Now imagine a line perpindicular to that and treat that line as a flat surface you're bouncing off - that's a reasonable starting point. But it's not that simple really - if you hit a ball some or all of the momentum may be transferred to the target ball - so all you have is the angle the ball will move if it bounces off another ball but calculating the speed involves a lot more work. Presumably some sort of conservation of momentum calculations are required.

Of course this also ignores things like putting spin on the cue ball to affect how it moves.

sullydux wrote:

RethinkingVoxels wrote:

do you want to bounce off like the

if on edge, bounce

block?

yea

when green flag clicked
point in direction (45) //optional
forever
move (10) steps
if on edge, bounce
if <touching [Ball2 v]?> then
bounce ::custom //run without screen refresh
wait (0.1) secs
end
define bounce
set [last x v] to (x position) //the variable last x needs to be for this sprite only
change x by (9999)
if on edge, bounce
set x to (last x)

RethinkingVoxels wrote:

sullydux wrote:

RethinkingVoxels wrote:

do you want to bounce off like the

if on edge, bounce

block?

yea

simple (kinda)

when green flag clicked
point in direction (45) //optional
forever
move (10) steps
if on edge, bounce
if <touching [Ball2 v]?> then
bounce ::custom //run without screen refresh
wait (0.1) secs
end
define bounce
set [last x v] to (x position) //the variable last x needs to be for this sprite only
change x by (9999)
if on edge, bounce
set x to (last x)

put this script in both sprites

deck26 wrote:

RethinkingVoxels wrote:

sullydux wrote:

RethinkingVoxels wrote:

do you want to bounce off like the

if on edge, bounce

block?

yea

simple (kinda)

when green flag clicked
point in direction (45) //optional
forever
move (10) steps
if on edge, bounce
if <touching [Ball2 v]?> then
bounce ::custom //run without screen refresh
wait (0.1) secs
end
define bounce
set [last x v] to (x position) //the variable last x needs to be for this sprite only
change x by (9999)
if on edge, bounce
set x to (last x)

put this script in both sprites

Have you actually tried that? Doesn't have anything to do with the question. It seems to assume that the natural bounce depends on which edge of the screen the ball would hit if it kept going in its current direction. Do you really think the bounce angle is the same no matter where it hits another ball?

deck26 wrote:

The line I described will be a tangent to both balls - it forms a right angle with the radius of both circles. So it tells you where the contact point is and is, I think, essentially the same as a flat surface for the bounce calculation.

This project https://scratch.mit.edu/projects/174551399/ demonstrates this.

RethinkingVoxels wrote:

deck26 wrote:

RethinkingVoxels wrote:

sullydux wrote:

RethinkingVoxels wrote:

do you want to bounce off like the

if on edge, bounce

block?

yea

simple (kinda)

when green flag clicked
point in direction (45) //optional
forever
move (10) steps
if on edge, bounce
if <touching [Ball2 v]?> then
bounce ::custom //run without screen refresh
wait (0.1) secs
end
define bounce
set [last x v] to (x position) //the variable last x needs to be for this sprite only
change x by (9999)
if on edge, bounce
set x to (last x)

put this script in both sprites

Have you actually tried that? Doesn't have anything to do with the question. It seems to assume that the natural bounce depends on which edge of the screen the ball would hit if it kept going in its current direction. Do you really think the bounce angle is the same no matter where it hits another ball?

yea, i've tried it. it answered what the question was, “How to make a ball bounce off eachother”, they said they wanted it to be like the “if on edge, bounce” block, so i made the solution.

deck26 wrote:

The line I described will be a tangent to both balls - it forms a right angle with the radius of both circles. So it tells you where the contact point is and is, I think, essentially the same as a flat surface for the bounce calculation.

Never mind