the_concept_of_space.p8

-- the concept of space
-- by matt hungerford

-- vars
cartdata("tcos") -- savedata for high-scores
l={} -- list of ball objects
tp=2 -- edge padding
tb=92 -- danger-line offset
sa=15 -- shooter angle
u=1   -- shooter moving direction
g=-1 -- game mode (-1=title, 0=playing, 1=credits)
s=0 -- score
h=dget(0) -- high-score
p={} -- list of particles

_set_fps(60) 

-- main loop using label "_" and goto
::_::
 cls()
 -- game bounds using contiguous mode for line
 line(2,tb,2,2,7)
 line(126,2)
 line(126,tb)
 fillp(░)line(2,tb)fillp()  -- dashed danger line

 -- print score/high-score using pinball text "\^p"
 -- scores over 99 go offscreen, so adjust these cases
 ss="\^pscore "..s.." high "..h
 xo=min(2, 128 - ?ss,0,-128)
 ?ss,xo,116

 mv=0

 if (#l > 0) do
  b=l[#l]  -- current ball
  x=b.x    -- temp store frequently-used properties in variables to save on chars
  y=b.y    -- 
  b.v*=.97 -- apply drag/friction to balls' velocities to slow them to a stop
  b.b*=.97 -- 
  x+=b.v   -- apply the velocity to current ball position
  y+=b.b   -- 
  mv=abs(b.v)+abs(b.b)
  -- stop the ball if barely moving
  if (mv < 0.02)do
   mv=0
   b.v = 0
   b.b = 0
  end

  -- expand to fill available space for the last ball
  e=min(96, x - tp - 2)
  e=min(e, 126 - x - 1)
  e=min(e, y - tp - 2)
  e=min(e, tb - y - 1)

  for k,t in pairs(l)do -- compare current ball to all other balls
   circ(t.x,t.y,t.r,({11,9,8})[t.c]) -- draw each ball

   if (k!=#l) then
    a=x-t.x z=y-t.y   -- calculate distance from ball
    d=sqrt(a*a+z*z)   -- 
    e=min(e, d - t.r - 1)
    -- if balls radius touch (ie. hit) trigger action on active ball
    if(d<=b.r+t.r) then
     t.c-=1
     o=(d - b.r - t.r)
     x-=o*(a/d)
     y-=o*(z/d)

     n=(t.x-b.x)/d  -- calc normal vector
     r=(t.y-b.y)/d  -- 
     v=b.v*-r+b.b*n -- calc dot product tangent
     k=t.v*n+t.b*r  -- 
     b.v=(-r*v+n*k) * 1.15  -- calc final velocities
     b.b=(n*v+r*k) * 1.15    --

     -- add a particle effect
     for i=0,20 do
      add(p, {x=t.x-n*(d-b.r),y=t.y-r*(d-b.r),a=rnd(100)/100.0,s=rnd(3)/3,c=max(t.c,1),n=80})
     end

     ?"\as0c",0,0
    end
   end
  end

  -- expand to fill e if stopped moving
  if (mv==0 and e > b.r)b.r+=1

  -- if hit 3 times, delete and add to score
  foreach(l, function(t) 
   if(t.c==0)del(l,t)s+=1
  end)

  if(x+b.r>126 or x-b.r<2+1)b.v*=-1.1  -- if ball hits table boundary,
  if(y-b.r<tp)b.b*=-1.1  -- calc rebound angle (+ a bit of bounce acceleration)
  -- game over if ball goes over dashed line
  if(b.b > 0 and y+b.r>tb)dset(0,h)g=1

  b.x=x b.y=y -- store our temp vars back into the ball object

 end --end of ball handling

 -- draw particles and decimate
 foreach(p, function(o)
  o.x+=rnd(1)*sin(o.a)*o.s
  o.y+=rnd(1)*cos(o.a)*o.s
  pset(o.x,o.y,({11,9,8})[o.c])
  o.n-=1
  if(o.n<=0)del(p,o)
 end)

 -- high-score
 h=max(h,s)
 
 rt=flr(t()%3)*4 - 4
 if (g==1)?"\^t\^wgame over",30+rt,24+rt,12
 if (g!=0)?"\^t\#7the concept of space",25,44,0
 if (g!=0)?"press x to start",34,64,12

 -- x/y on unit circle shooter line
 co=cos(sa/360)
 si=sin(sa/360)

 -- draw the angled shooter line
 line(64,112,64-16*co,112+16*si,7)
 if mv <= 0 and g==0 then
  if (sa<=15) u=1
  if (sa>=165) u=-1
  sa+=u
 end

 -- single-button "x" starts game or shoots ball
 if btnp(5) then
  if g==0 and mv <= 0 then
   -- add current ball to the list (table)
   b=add(l,{x=64,y=112,r=4,c=3,a=0,v=-5.9*co,b=5.9*si})
  elseif g!=0 then
   l={}g=0 s=0
  end
 end

 flip()  
 goto _