sync rate 40
sync on
autocam off
screenwidth = 320
halfwidth = screenwidth/2
screenheight = 220
halfheight = screenheight/2
maxspeed = 8
numballs=1
dim ball#(numballs,5)
x=0
y=1
xv=2
yv=3
mass=4
radius=5
randomize timer()
for lp = 0 to numballs
ball#(lp,x) = rnd(screenwidth)-halfwidth
ball#(lp,y) = rnd(screenheight)-halfheight
ball#(lp,xv) = 18
ball#(lp,yv) = rnd(maxspeed)
ball#(lp,radius) = 8
make object sphere lp+1, ball#(lp,radius)
color object lp+1, rgb(rnd(255),rnd(255),rnd(255))
next lp
width = 1
height = 3
dim wall#(1,4)
wall#(1,x) = 0
wall#(1,y) = 0
wall#(1,width) = 1
wall#(1,height) = 125
make object plain 100, wall#(1,width), wall#(1,height)
move camera -200
zrotate object 100,35
half_length# = wall#(1,height)/2
wall_start_x# = wall#(1,x) * cos(35) - (wall#(1,y)+half_length#) * sin(35)
wall_start_y# = wall#(1,x) * sin(35) + (wall#(1,y)+half_length#) * cos(35)
wall_end_x# = wall#(1,x) * cos(35) - (wall#(1,y)-half_length#) * sin(35)
wall_end_y# = wall#(1,x) * sin(35) + (wall#(1,y)-half_length#) * cos(35)
do
for lp=0 to numballs
ball#(lp,x) = ball#(lp,x) + ball#(lp,xv)
ball#(lp,y) = ball#(lp,y) + ball#(lp,yv)
if ball#(lp,x) >= halfwidth then ball#(lp,xv) = 0-ball#(lp,xv): ball#(lp,x) = halfwidth
if ball#(lp,x) <= 0-halfwidth then ball#(lp,xv) = 0-ball#(lp,xv): ball#(lp,x) = 0-halfwidth
if ball#(lp,y) >= halfheight then ball#(lp,yv) = 0-ball#(lp,yv): ball#(lp,y) = halfheight
if ball#(lp,y) <= 0-halfheight then ball#(lp,yv) = 0-ball#(lp,yv): ball#(lp,y) = 0-halfheight
gosub plain_collision
next lp
for lp= 0 to numballs
position object lp+1, ball#(lp,x), ball#(lp,y), 0
next lp
sync
loop
end
plain_collision:
box# = ball#(lp,x) - ball#(lp,xv)
boy# = ball#(lp,y) - ball#(lp,yv)
ptx# = wall_start_x#
pty# = wall_start_y#
sox# = ball#(lp,x)-box#
soy# = ball#(lp,y)-boy#
if (sox#=0 and soy#=0) then return
length# = sqrt(sox#*sox#+soy#*soy#)
soox# = sox#
sooy# = soy#
rem collision test point from the centre of the ball to the leading edge of the ball
sox# = (ball#(lp,x) + 5 *(sox#/length#)) - box#
soy# = (ball#(lp,y) + 5 *(soy#/length#)) - boy#
stx# = wall_end_x#-ptx#
sty# = wall_end_y#-pty#
s# = ((0-soy#) * (box#-ptx#) + sox#*(boy#-pty#)) / ((0-stx#)*soy# + sox#*sty#)
t# = (stx# * (boy#-pty#) - sty# * (box#-ptx#)) / ((0-stx#)*soy# + sox#*sty#)
if s# >=0 and s# <=1
if t#>=0 and t#<=1
rem calculate the return
rem get perpendicular
ball#(lp,x) = box# + t# * soox#
ball#(lp,y) = boy# + t# * sooy#
nPx# = 0-sty#
nPy# = stx#
rem normalise Perpendicular
nPx# = nPx#/wall#(1,height)
nPy# = nPy#/wall#(1,height)
rem get N of ball
Nx# = 0-(ball#(lp,xv)*nPx# + ball#(lp,yv)*nPy#)*nPx#
Ny# = 0-(ball#(lp,xv)*nPx# + ball#(lp,yv)*nPy#)*nPy#
rem compute ball velocities
ball#(lp,xv)= 2*Nx#+ball#(lp,xv)
ball#(lp,yv)= 2*Ny#+ball#(lp,yv)
endif
endif
return
