[PICO8] Simple game thing.

x = 127/2
y = 127/2
xvel = 0
yvel = 0
spd  = 3
left  = 0
right = 1
up    = 2
down  = 3
friction = 1.5
spdup    = spd/6
scrsize  = 127
radius   = 3
moved    = false
bump     = false
score    = 0
targets = {}
tarsize = 2
tarmax  = 10
-- game loop functions
function collide(x,y,r,xx,yy,rr)
   return (x < xx+rr  and
           x+r > xx ) and
          (y < yy+rr  and
           y+r > yy )
end

function _init()
    cls()
end
function negcap()
    if(xvel < 0) xvel = 0
    if(yvel < 0) yvel = 0
end
function _update()
     circfill(x,y,8,0)
     moved = false
        if(btn(up))    yvel -= spdup moved=true
        if(btn(down))  yvel += spdup moved=true
        if(btn(left))  xvel -= spdup moved=true
        if(btn(right)) xvel += spdup moved=true
        -- friction
        if(not moved)then
    yvel /= friction
    xvel /= friction
        end
        if(xvel > spd) xvel = spd
        if(yvel > spd) yvel = spd
        if(xvel < -spd) xvel = -spd
        if(yvel < -spd) yvel = -spd
        x += xvel
        y += yvel
        -- x collision
        if(x > scrsize-radius)then
            x = scrsize-radius
            if(moved) sfx(0)
        elseif(x <= radius)then
            x = radius
            if(moved) sfx(0)
        end
        -- y collision
        if(y > scrsize-radius)then
            y = scrsize-radius
            if(moved) sfx(0)
        elseif(y <= radius)then
            y = radius
            if(moved) sfx(0)
        end
        -- draw velocities
        rectfill(1,1,128,10,1)
        print("score:  " .. score,1,1,8)

        -- game loop logic
        spawn() -- spawn targets
        -- target collision
        for i = 1, #targets do
        -- check each target for collision
        if(collide(x,y,radius,
                 targets[i].x,
                 targets[i].y,
                 tarsize)
      )then
         del(targets,targets[i])
         xvel = xvel/2
         yvel = yvel/2
         score += 200
         sfx(1)
         break
      else
        -- clear target
        circfill(
            targets[i].x,
            targets[i].y,tarsize,0)
           -- move target
         targets[i].y += 1
         if(targets[i].y > scrsize)then
           targets[i].y = rnd(scrsize-10)+10
           targets[i].x = rnd(scrsize)
         end
      end
     end
end

function _draw()
        -- draw light green circle.
     circfill(x,y,radius,11)
     for i = 1, #targets do
        -- render each target
        circfill(
          targets[i].x,
          targets[i].y,
          tarsize,
          targets[i].c)
     end
end


-- spawn in targets

function spawn()
 -- randomly spawn
    local spn = rnd(10)
    local rx  = rnd(scrsize)
    local ry  = rnd(scrsize-10)+10
    if(flr(spn) == 5 and #targets < tarmax )then
        targets[#targets+1] = {
            x = rx,
            y = ry,
            c = rnd(14)+1
        }
    end
end