PICO-8 Raycaster Doors demo

raycaster-doors-demo.p8

pico-8 cartridge // http://www.pico-8.com
version 16
__lua__
-- by @powersaurus, based on
-- https://lodev.org/cgtutor/raycasting.html

m_width=10
m_height=10

world={
{1,1,1,1,1,1,1,1,1,1},
{1,0,0,0,0,0,0,0,0,1},
{1,0,1,2,1,0,1,0,0,1},
{1,0,1,0,0,0,1,0,0,1},
{1,0,0,0,0,0,2,0,0,1},
{1,0,0,0,0,0,1,0,1,1},
{1,0,0,0,0,0,1,0,0,1},
{1,0,1,1,0,0,1,0,0,1},
{1,0,0,0,0,0,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1}
}
doors={
 {x=4,y=3,open_pcnt=0,open_vel=0},
 {x=7,y=5,open_pcnt=0,open_vel=0}
}

player={
 pos={x=5,y=6},
 dr={x=1,y=0},
 plane={x=0,y=0.66},
 v=0.7,
 vr=0
}

function rotate_player(player,rot)
 local old_dr_x=player.dr.x
 player.dr.x=player.dr.x*cos(rot)-player.dr.y*sin(-rot)  player.dr.y=old_dr_x*sin(-rot)+player.dr.y*cos(-rot)  
 local old_plane_x=player.plane.x
 player.plane.x=old_plane_x*cos(-rot)-player.plane.y*sin(-rot)
 player.plane.y=old_plane_x*sin(-rot)+player.plane.y*cos(-rot)
end

function move_in_dir(player,speed)
 local move_x=player.pos.x+player.dr.x*speed
 local move_y=player.pos.y+player.dr.y*speed
 
 local move_sq=world
  [flr(player.pos.y)]
  [flr(move_x)]
  
 if move_sq<1 or 
 (move_sq==2 
  and door_for(
   flr(move_x), 
   flr(player.pos.y)).open_pcnt>70) then
  player.pos.x=move_x
 end
 
 move_sq=world
  [flr(move_y)]
  [flr(player.pos.x)]
  
 if move_sq<1 
 or (move_sq==2 
  and door_for(
   flr(player.pos.x), 
   flr(move_y)).open_pcnt>70) then
  player.pos.y=move_y   
 end
end

function _init()
 rotate_player(player,329/360)
end

function _update60()
 msg=""
 local rot=3/360
 local speed=0.1
 if btn(0) then --rot left
  rotate_player(player,-rot)
 end
 if btn(1) then --rot right
  rotate_player(player,rot)
 end
 if btn(2) then
  move_in_dir(player,speed)
 end
 if btn(3) then
  move_in_dir(player,-speed)
 end
 
 if btnp(5) then
  is_3d= not is_3d
 end
 
 update_doors(doors)
end
 
function update_doors(doors)
 for _,d in pairs(doors) do
  local dx=player.pos.x-(d.x+0.5)
  local dy=player.pos.y-(d.y+0.5)
  local dtd=abs(dx*dx+dy+dy)
 -- msg=player.pos.x.." "..player.pos.y.." "..d.x.." "..d.y.." "..dtd
  if dtd<2 then
--   msg="door "..d.x.." "..d.y
   if d.open_pcnt<100 then
    d.open_vel=2
   end
   
  else
   if d.open_pcnt>0 then
    d.open_vel=-2
   end
  end
  d.open_pcnt=clamp(d.open_pcnt+d.open_vel,0,100)
 end
end

screen_w=128
msg=""
msg2=""
is_3d=true
function _draw()
 if is_3d then
  draw_3d()
 else
  draw_2d()
 end
end

function draw_2d()
 palt(0,false)
 palt(11,true)
 cls(5)
 
 -- move to top left
 camera(8,8)
 -- draw world
 for y=1,#world do
  for x=1,#world[y] do
   local sp=0
   if (world[y][x]==1) sp=1
   if (world[y][x]==2) sp=2
   spr(sp,x*8,y*8)
  end
 end
 --[[for _,d in pairs(doors) do
  spr(3,d.x*8,d.y*8)
 end]]

 local py=player.pos.y*8
 local px=player.pos.x*8
 local pxe=px+player.dr.x*5
 local pye=py+player.dr.y*5
 
 for x=1,screen_w do
  local pos,ray,
   map_x,step_x,
   map_y,step_y,
   tex,side,rxe2,rye2=true_cast(player,x,screen_w)
   if tex==3 then
    if side==0 then
     map_x+=step_x/2
    else
     map_y+=step_y/2
    end
   end

   -- screen coords
   rxe2*=8
   rye2*=8
  
  line(
   px,py,rxe2,rye2,9)
	 --pset(rxe2,rye2,14)
--   print("dx="..ray.y.." dy="..ray.x,2,90,7)
 end 
 line(px,py,pxe,pye,8)
 pset(px,py,10)
 -- reset camera
 camera()
end

test_x=30
function true_cast(player,x,screen_w)
  local pos=player.pos
  local dr=player.dr
  local plane=player.plane
  local cam_x=2*x/screen_w-1
  local ray={
   x=dr.x+plane.x*cam_x,
   y=dr.y+plane.y*cam_x
  }

  local map_x=flr(pos.x)
  local map_y=flr(pos.y)
  
  -- ray casting
  local side_x=0
  local side_y=0
  local delta_x=abs(1/ray.x)
  local delta_y=abs(1/ray.y)

    
  -- which way are we stepping
  -- across the map cells
  local step_x=0
  local step_y=0
  
  -- stop vars 
  local hit=0
  local side=0
  local rxe2=0
  local rye2=0
  
  if ray.x<0 then
   step_x=-1
   side_x=(pos.x-map_x)*delta_x
  elseif ray.x>0 then
   step_x=1
   side_x=(map_x+1-pos.x)*delta_x
  else -- hack
   side_x=20000
  end
  if ray.y<0 then
   step_y=-1
   side_y=(pos.y-map_y)*delta_y
  elseif ray.y>0 then
   step_y=1
   side_y=(map_y+1-pos.y)*delta_y
  else -- hack
   side_y=20000
  end
  
  local tex=0
  while hit==0 do
   if side_x<side_y then -- travel hor
    side_x+=delta_x
    map_x+=step_x
    side=0 -- ew
   else -- travel vert
    side_y+=delta_y
    map_y+=step_y
    side=1 -- ns
   end
   
   tex=world[map_y][map_x]
   if tex>0 then
    if tex==2 then--door texture
     -- weird
     local map_x2=map_x
     local map_y2=map_y
     if (pos.x<map_x) map_x2-=1
     if (pos.y>map_y) map_y2+=1
  
     local adj=1
     local ray_mult=1
     if side==1 then
      adj=map_y2-pos.y
      ray_mult=adj/ray.y
     else
      adj=(map_x2-pos.x)+1
      ray_mult=adj/ray.x
     end
  
     rxe2=pos.x+ray.x*ray_mult
     rye2=pos.y+ray.y*ray_mult
    
     local true_delta_x=sqrt(1+(ray.y*ray.y)/(ray.x*ray.x))
     local true_delta_y=sqrt(1+(ray.x*ray.x)/(ray.y*ray.y))
  
     if abs(ray.x)<0.01 then
      true_delta_x=100
     end
     if abs(ray.y)<0.01 then
      true_delta_y=100
     end
     -- you only need one x/y component
     -- depending on whether you hit a 
     -- horizontal or vertical wall
     local d=door_for(map_x,map_y)
     if side==0 then -- vertical north-south
      local true_y_step=sqrt(true_delta_x*true_delta_x-1)
      
      local half_step_in_y=rye2+(step_y*true_y_step)/2
      if flr(half_step_in_y)==map_y 
      and half_step_in_y-map_y>d.open_pcnt/100
      then
       hit=1
      end
     else -- horizontal east-west
      local true_x_step=sqrt(true_delta_y*true_delta_y-1)
      
      local half_step_in_x=rxe2+(step_x*true_x_step)/2
      if flr(half_step_in_x)==map_x
      and half_step_in_x-map_x>d.open_pcnt/100
      then
       hit=1
      end
     end
    else
     hit=1 --hit a wall
    end
   end
  end
  
  return pos,ray,map_x,step_x,map_y,step_y,tex,side,rxe2,rye2
end

function door_for(x,y)
 for _,d in pairs(doors) do
  if d.x==x and d.y==y then
   return d
  end
 end
 return nil
end

function cast_ray(player,x,screen_w)
  
  local pos,ray,map_x,step_x,map_y,step_y,tex,side=true_cast(player,x,screen_w)
  
  local perp_wall_dist=0
  if side==0 then
   if tex==2 then
    map_x+=step_x/2
   end
   perp_wall_dist=(map_x-pos.x+(1-step_x)/2)/ray.x
  else
   if tex==2 then
    map_y+=step_y/2
   end
   perp_wall_dist=(map_y-pos.y+(1-step_y)/2)/ray.y
  end
  return perp_wall_dist,side,tex
end

function draw_3d()
 cls()
 rectfill(0,64,128,128,5)

 msg2=""
 for x=0,screen_w do
  local perp_wall_dist,side,tex=cast_ray(player,x,screen_w)

  local line_height=flr(128/perp_wall_dist)
  local draw_start=clamp(-line_height/2+64,0,128)
  local draw_end=clamp(line_height/2+64,0,128)
  
  -- pico8 hacks 
  if draw_start>=draw_end then
   draw_start=0
   draw_end=128
  end
  if draw_end==0 then
   draw_end=128
  end
  
  local col=1
  if side==1 then
   col=13
  end
  if tex==2 then
   col=9
  end
  line(x,draw_start,x,draw_end,col)
 end
 
 print(stat(1),0,0,7)
end

function clamp(x,min_val,max_val)
 return min(max(x,min_val),max_val)
end
__gfx__
100110110111111122222222b28888bb000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
100000110000000124949492b288888b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
001100010111551122424242b28bb88b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
011001000555dd5024949492b28bb88b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
011011100ddd66d122424242b28bb88b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
000011001d66665024949492b28bb88b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000001055ddd5022424242b288888b000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
110110110111111022222222b28888bb000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000