TIC-80 shoot 'em up sample

stgsample5.lua

-- title:  stg sample 5
-- author: mieki256
-- desc:   short description
-- script: lua

scrw,scrh=240,136

-- --------------------
-- Player class

Player={}
Player.new=function()
 local o={
  alive=true,step=0,
  x=scrw/5,y=scrh/2,
  sprid=5,t=0,
  life=5,dead=false,nodamage=0,
  shott=0
 }
 o.collision={o.x,o.y,1},
 setmetatable(o,{__index=Player})
 return o
end

Player.update=function(self)
 if self.step ==0 then
  if self.nodamage > 0 then
   self.nodamage=self.nodamage-1
  end
  if self.dead then
   self.step=1
   self.t=0
   self.sprid=32
   if self.life > 0 then
    self.life=self.life-1
   end
  else
   local spd=2.0
   local dx,dy=0,0
   if btn(0) then dy=-spd end
   if btn(1) then dy=spd end
   if btn(2) then dx=-spd end
   if btn(3) then dx=spd end
   if dx~=0 and dy~=0 then
    local d=math.cos(math.rad(45))
    dx=dx*d
    dy=dy*d
   end
   self.x=self.x+dx
   self.y=self.y+dy
   self.x=math.min(math.max(self.x,8),scrw-8)
   self.y=math.min(math.max(self.y,8),scrh-8)
   self.collision[1]=self.x
   self.collision[2]=self.y

   -- shot
   if btnp(4) then self.shott=0 end
   if btn(4) and self.shott%7==0 then
    local x,y=self.x,self.y
    spd=6
    table.insert(bullets,Bullet.new(x+10,y,spd,0))
    -- table.insert(bullets,Bullet.new(x,y,spd,12))
    -- table.insert(bullets,Bullet.new(x,y,spd,-12))
    -- table.insert(bullets,Bullet.new(x,y,spd,180))
   end
  end
 elseif self.step==1 then
  self.sprid=32+2*(self.t % 16 // 8)
  if self.t>=90 then
   self.dead=false
   self.step=0
   self.nodamage=180
   self.sprid=5
  end
 end
 self.shott=self.shott+1
 self.t=self.t+1
end

Player.draw=function(self)
 if self.step==0 then
  if self.nodamage>0 and
     (self.nodamage>>2)%2==0 then
   return
  end
 end
 spr(self.sprid,self.x-8,self.y-8,
     14,1,0,0,2,2)
end

Player.hit=function(self,o)
 if self.nodamage<=0 then
  self.dead=true
 end
end

Player.shot=function(self,o)
end

-- --------------------
-- Bullet class

Bullet={}
Bullet.new=function(_x,_y,_spd,_ang)
 local ra=math.rad(_ang)
 local o={
  alive=true,
  x=_x,y=_y,spd=_spd,ang=_ang,
  dx=_spd*math.cos(ra),
  dy=_spd*math.sin(ra),
  collision={_x,_y,5},sprid=7
 }
 setmetatable(o,{__index=Bullet})
 return o
end

Bullet.update=function(self)
 self.x=self.x+self.dx
 self.y=self.y+self.dy
 self.collision[1]=self.x
 self.collision[2]=self.y
 if self.x<-4 or self.x>scrw+4 or
    self.y<-4 or self.y>scrh+4 then
  self.alive=false
 end
end

Bullet.draw=function(self)
 spr(self.sprid,self.x-4,self.y-4,
     0,1,0,0,1,1)
end

Bullet.hit=function(self,o)
end

Bullet.shot=function(self,o)
 self.alive=false
 self.collision={}
end

-- --------------------
-- Enemy Bullet class

Ebullet={}
Ebullet.new=function(_x,_y,_spd,_ang)
 local ra=math.rad(_ang)
 local o={
  alive=true,
  x=_x,y=_y,spd=_spd,ang=_ang,
  dx=_spd*math.cos(ra),
  dy=_spd*math.sin(ra),
  collision={_x,_y,1},sprid=14,t=0
 }
 setmetatable(o,{__index=Ebullet})
 return o
end

Ebullet.update=function(self)
 self.x=self.x+self.dx
 self.y=self.y+self.dy
 self.collision[1]=self.x
 self.collision[2]=self.y
 self.sprid=14+(self.t%10//5)
 if self.x<-4 or self.x>scrw+4 or
    self.y<-4 or self.y>scrh+4 then
  self.alive=false
 end
 self.t=self.t+1
end

Ebullet.draw=function(self)
 spr(self.sprid,self.x-4,self.y-4,
     0,1,0,0,1,1)
end

Ebullet.hit=function(self,o)
end

Ebullet.shot=function(self,o)
 self.alive=false
 self.collision={}
end

function bornEnemyBulletToPlayer(x,y,spd,d)
 local dx,dy
 dx=player.x-x
 dy=player.y-y
 if dx*dx+dy*dy>d*d then
  local ang=math.deg(math.atan2(dy,dx))
  table.insert(ebullets,
               Ebullet.new(x,y,spd,ang))
 end
end

-- --------------------
-- Zako enemy class

Zako={}
Zako.new=function(_x,_y,_spd,_ang)
 local ra=math.rad(_ang)
 local o={
  alive=true,
  x=_x,y=_y,spd=_spd,ang=_ang,
  dx=_spd*math.cos(ra),
  dy=_spd*math.sin(ra),
  sprid=1,t=0,collision={_x,_y,6},
  shotwait=math.random(50,90)
 }
 setmetatable(o,{__index=Zako})
 return o
end

Zako.update=function(self)
 self.x=self.x+self.dx
 self.y=self.y+self.dy
 self.collision[1]=self.x
 self.collision[2]=self.y
 if self.x<-32 or self.x>scrw+32 or
    self.y<-32 or self.y>scrh+32 then
  self.alive=false
 elseif self.shotwait <=0 then
  self.shotwait=90
  bornEnemyBulletToPlayer(self.x,self.y,1,80)
 end
 self.shotwait=self.shotwait-1
 self.t=self.t+1
end

Zako.draw=function(self)
 spr(self.sprid,self.x-8,self.y-8,
     14,1,0,0,2,2)
end

Zako.hit=function(self,o)
 self.alive=false
 self.collision={}
 score=score+10
 bornExplo(self.x,self.y)
end

Zako.shot=function(self,o)
end

-- --------------------
-- Explosion effect class

Explosion={}
Explosion.new=function(_x,_y)
 local o={
  alive=true,x=_x,y=_y,t=0,
  cols={15,15,9,6,0},r=20
 }
 setmetatable(o,{__index=Explosion})
 return o
end

Explosion.update=function(self)
 self.r=self.r-1
 if self.r<3 then self.alive=false end
 self.t=self.t+1
end

Explosion.draw=function(self)
 local x,y,r,c,rr
 rr=6
 c=self.cols[(self.t-1)%(#self.cols)+1]
 for i=1,3 do
  x=self.x+math.random(-rr,rr)
  y=self.y+math.random(-rr,rr)
  r=math.max(2,self.r / i)
  circ(x,y,r,c)
 end
end

function bornExplo(_x,_y)
 local o=Explosion.new(_x,_y)
 table.insert(explosions,o)
end

-- --------------------

function objsUpdate(objs)
 for i,o in ipairs(objs) do
  o:update()
 end
end

function objsDraw(objs)
 for i,o in ipairs(objs) do
  o:draw()
 end
end

function objsRemove(objs)
 local l=#objs
 for i=l,1,-1 do
  if not objs[i].alive then
   table.remove(objs,i)
  end
 end
end

function bornEnemys()
 if t % 25==0 then
  local spd,ang,x,y
  spd=1.5
  x=scrw+16
  y=((scrh-8)/2)*math.sin(math.rad(t%360))+(scrh/2)
  ang=180+20*((y-(scrh/2))/(scrh/2))+math.random(-20,20)
  table.insert(enemys,Zako.new(x,y,spd,ang))
 end
end

function hitcheckCirc(e,b)
 if not next(b.collision) then
  return false
 end
 local x,y,r
 x=e.collision[1]-b.collision[1]
 y=e.collision[2]-b.collision[2]
 r=e.collision[3]+b.collision[3]
 if x*x+y*y <=r*r then return true end
 return false
end

function hitcheck()
 -- enemys vs bullet
 for i,e in ipairs(enemys) do
  if e.alive and next(e.collision) then
   for j,b in ipairs(bullets) do
    if b.alive and hitcheckCirc(e,b) then
     e:hit(b)
     b:shot(e)
     break
    end
   end
  end
 end

 if player.alive==false or
    not next(player.collision) then
  return
 end

 -- enemys vs player
 for i,e in ipairs(enemys) do
  if e.alive and hitcheckCirc(player,e) then
   player:hit(e)
   return
  end
 end

 -- enemy bullets vs player
 for i,b in ipairs(ebullets) do
  if b.alive and hitcheckCirc(player,b) then
   player:hit(b)
   break
  end
 end
end

-- init

score=0
t=0
player=Player.new()
bullets={}
enemys={}
ebullets={}
explosions={}

-- main loop

function TIC()
 -- update
 bornEnemys()
 hitcheck()
 objsUpdate(bullets)
 objsUpdate(enemys)
 objsUpdate(ebullets)
 objsUpdate(explosions)
 player:update()

 objsRemove(bullets)
 objsRemove(enemys)
 objsRemove(ebullets)
 objsRemove(explosions)

 -- draw
 cls(0)
 objsDraw(explosions)
 objsDraw(bullets)
 objsDraw(enemys)
 objsDraw(ebullets)
 player:draw()
 local s="LIFE: "..player.life
 s=s.."  SCORE: "..score
 s=s.."  enemys: "..#enemys
 print(s,2,2)
 t=t+1
end

sprites.gif