Computer Science Canada :: View topic - Multiple ball colision physics

const SIZE := 50
const MID_Y := maxy div 2
const MID_X := maxx div 2
const SPEED := 9
const SIZE_P := 10
const SIZE_C := 5
const DIV_F := 1

var X, Y, Dx, Dy, Sy, Sx, C : array 1 .. SIZE of int
var Length : array 1 .. SIZE of real4
var Key : array char of boolean
var XP, YP, Click : int
setscreen ("graphics:max,max,nobuttonbar,offscreenonly")

process Sound
sound (100, 100)

end Sound

for Index : 1 .. SIZE
randint (X (Index), 20, maxx - 20)
randint (Y (Index), 20, maxy - 20)
loop
randint (C (Index), 1, 15)
exit when C (Index) not= 7
end loop
Dx (Index) := 0
Dy (Index) := 0

end for

XP := MID_X
YP := MID_Y
colorback (7)
loop

drawfillbox (1, 1, maxx, maxy, 15)
drawfillbox (20, 20, maxx - 20, maxy - 20, 7)
mousewhere (XP, YP, Click)
drawfilloval (XP, YP, SIZE_P, SIZE_P, 0)

if Click = 1 then
for Index : 1 .. SIZE
Dx (Index) := 0
Dy (Index) := 0
% drawline (XP, YP, X (Index), Y (Index), 12)
end for
% else
% for Index : 1 .. SIZE
%
% drawline (XP, YP, X (Index), Y (Index), C (Index))
% end for
end if

for Index : 1 .. SIZE

drawfilloval (X (Index), Y (Index), SIZE_C, SIZE_C, C (Index))
%drawfilloval (X (Index), Y (Index), SIZE_C, SIZE_C, 0)

if X (Index) > maxx - 20 or X (Index) < 20 then
Dx (Index) := -Dx (Index)
end if

if Y (Index) > maxy - 20 or Y (Index) < 20 then
Dy (Index) := -Dy (Index)
end if

Length (Index) := sqrt (((XP - X (Index)) ** 2) + ((YP - Y (Index)) ** 2))

if Length (Index) <= SIZE_C + SIZE_P then
% fork Sound
Sy (Index) := - (YP - Y (Index))
Sx (Index) := - (XP - X (Index))

Dx (Index) := Sx (Index) div DIV_F
Dy (Index) := Sy (Index) div DIV_F

end if

for Index2 : 1 .. SIZE
Length (Index2) := sqrt (((X (Index2) - X (Index)) ** 2) + ((Y (Index2) - Y (Index)) ** 2))

if Length (Index2) <= SIZE_C + SIZE_C and Index not= Index2 then
%fork Sound
Sy (Index2) := Y (Index2) - Y (Index)
Sx (Index2) := X (Index2) - X (Index)

Dx (Index2) := Sx (Index2) div DIV_F
Dy (Index2) := Sy (Index2) div DIV_F

end if
%drawline (X (Index), Y (Index), X (Index2), Y (Index2), 0)
end for

X (Index) := X (Index) + Dx (Index)
Y (Index) := Y (Index) + Dy (Index)

end for

View.Update
end loop

Author:	DemonZ [ Fri Nov 10, 2006 6:21 pm ]
Post subject:
Very Nice.... This would be useful for a pool game.

Author:	Windsurfer [ Fri Nov 10, 2006 7:54 pm ]
Post subject:
The physics seem... weird. I'm going to be blunt here. All the balls move at the same speed. It doesn't matter what angle their collisions are, they move at the same speed, just different directions. That's not proper. Now for coding: Naming convention is nonexistent. In fact, some names are incorrect. "SIZE" should not be used to describe the number of balls, in my opinion. Also, although not a rule, it is common practice to name variables and arrays in all lowercase. Don't use parallel arrays, use records instead. Commenting should be used to explain code, not just disable a part of code. ...Good spacing. Keep that up.

Author:	Cervantes [ Fri Nov 10, 2006 11:07 pm ]
Post subject:
The telltale clue that something is wrong here is that if you give the system a little bit of energy at the start of the program by jostling a few balls, then move the white ball into the corner, what happens? Eventually all the balls are moving pretty fast. There's a lot of energy in the system. Way more than you gave the system in the beginning.

Author:	TripleBla [ Mon Nov 13, 2006 1:58 pm ]
Post subject:
Windsurfer wrote: I am jesus. fixed.

Author:	blaster009 [ Mon Nov 13, 2006 11:14 pm ]
Post subject:
Windsurfer wrote: Now for coding: Naming convention is nonexistent. In fact, some names are incorrect. "SIZE" should not be used to describe the number of balls, in my opinion. Also, although not a rule, it is common practice to name variables and arrays in all lowercase. Common for who? I use camelCase. I personally find it a lot easier to read xSizeArrayForBunchOfRandomObjects than xsizearrayforbunchofrandomobjects (of course, I'd never really use a name that long...) As for size as the number, why not? It is HIS code, and if that's how he chooses to remember it, so be it.

Author:	Clayton [ Mon Nov 13, 2006 11:21 pm ]
Post subject:
I think he meant variable names not as MyArray, but as myArray for example. SIZE just doesn't really explain what it is. To me it tells me how big something is (ie the radius of the ball). EDIT: WOOHOO! 700th post