slugs.p8

leveltime=0
width=256
sealevel=20
screenshake=0
--slug
px=64
py=20
pdx=0
pdy=0
pflip=false
shootangle=180
--bullet
bx=-10
by=-10
bdx=0
bdy=0
bh=0
expt=0
--wind
wind=0
landscape2d={}

function _init()
 landscape = {}
 for i=1,width do
  landscape[i]=50
 end
 --landscape[1]=50
 --landscape[width]=50
 
 pos=0
 var=50
 left=1
 right=width
 step=flr(width/2)
 while(step>=1) do
  t=1
  while(t<=width) do
   left=t
   right=t+step
   if right>width then right-=width end
   pos=flr(t+step/2)
 	 landscape[pos]=
 	  ((landscape[left]+
 	    landscape[right])/2)
 	    +(rnd(var)-(var/2)) 
   t+=step
  end
  var/=2
  step/=2
 end
 
 -- generate terrain
 local c=1
 for x=1,width do
  landscape2d[x]={}
  for y=1,landscape[x] do
   if y>=landscape[x]-2 then
    c=11
   elseif y>=landscape[x]-4 then
    c=3
   elseif flr(rnd(2))==0 then
    c=4
   else
    c=2
   end
   landscape2d[x][y]=c
  end
 end
end

function updateplayer()
 -- can't climb cliffs
 if py<4+120-landscape[flr(px+pdx)] then
  px+=pdx
  pdx*=0.1
 else
  pdx=0
 end
 if pdy<4 then pdy+=0.4 end
 py+=pdy
 if py>120-landscape[flr(px)] then
  pdy=0
  py=120-landscape[flr(px)]
 end
end

function updatebullet()
 expt-=1
 if bh==1 and by>120-landscape[flr(bx)] then
  bh=0
  bdx=0
  bdy=0
  --a2 + b2 = c2
  --x*x + ? = 25
  --25-x*x = ?
  r=15
  expt=7
  screenshake=4
  
  -- bounce slugs
  if (px-bx)*(px-bx)+(py-by)*(py-by)<r*r then
    pdy-=6
  end
  -- destroy landscape
  for x=-r,r do
   dy=sqrt(r*r-x*x)
   landscape[flr(bx)+x]=
    min(landscape[flr(bx)+x],
        (120-by)-dy)
  end
 elseif bh==1 then
  bdy+=0.4
  bdx+=wind
  bx+=bdx
  by+=bdy
  if bx<1 or bx>width then
   bdx=-bdx
   bx+=bdx
  end
 end
end

function updateinput()
if btn(0) then 
  if shootangle>270 then
   shootangle-=180
  end
  pflip=true
  pdx-=1
 end
 if btn(1) then
  if shootangle<90 then
   shootangle+=180
  end
  pflip=false
  pdx+=1
 end
 if btn(2) then shootangle+=2 end
 if btn(3) then shootangle-=2 end
 if btn(5) and pdy==0 then
  pdy-=3
 end
 if btn(4) then
  bx=px
  by=py
  bdy=-sin(shootangle/360)*6
  bdx=-cos(shootangle/360)*4
  bh=1
 end
end

function _update()
 leveltime+=1
 updateplayer()
 updatebullet()
 updateinput()
 
 if (screenshake>0) screenshake-=1
end

function _draw()
  local cx=flr(px-64)
  if screenshake>0 then
   camera(cx+rnd(3),rnd(3))
  else
   camera(cx, 0)
  end
  
  rectfill(cx,0,cx+128,128,12)
  --for i=max(1,cx),min(cx+128,width) do
  -- line(i-1,128,i-1,128-(landscape[i]-4),4)
  -- line(i-1,128-(landscape[i]-4),i-1,128-(landscape[i]-2),3)
  -- line(i-1,128-(landscape[i]-2),i-1,128-landscape[i],11)
  --end
  for x=max(1,cx),min(cx+128,width) do
   for y=1,landscape[x] do
     pset(
      x-1,
      127-y,
      landscape2d[x][y])
      --landscape2d[x % width + flr(y / width)])
   end
  end
  spr(000,px-4,py,1,1,pflip,false)
  --
  -- xy\ 10
  -- \  \
  -- \--xy
  local tx=px+3-cos(shootangle/360)*10
  local ty=py+3-sin(shootangle/360)*10
  rectfill(tx-1,ty-1,tx+1,ty+1,7)
  if bh>0 then
   spr(001,bx,by)
  end
  if expt>0 then
   local br=-sin((expt/7)/2)*15
   circfill(bx,by,br,8)
   circfill(bx,by,br-1,9)
   circfill(bx,by,br-2,7)
  end
  sealevel+=sin(leveltime%60/60)/4
  rectfill(cx,128-sealevel,cx+128,128,1)
end