Yep, that's an untextured raycaster ported from Lode's computer graphics tutorials:
http://lodev.org/cgtutor/(works in all graphics modes)
-- raycaster for CMLua
-- proof of concept
worldMap =
{{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,2,2,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,3,0,0,0,3,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,2,0,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,0,0,0,5,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1},
{1,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,2,0,1},
{1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}};
local cameraX,rayPosX,rayPosY,rayDirX,rayDirY,posX,posY,dirX,dirY,planeX,planeY,time,oldTime
local sideDistY,sideDistX,deltaDistX,deltaDistY,perpWallDist
local oldDirX,oldPlaneX,frametime,moveSpeed,rotSpeed
local h,lineHeight,drawStart,drawEnd,hit,side,stepX,stepY,mapX,mapY,x,w,key
local CRSLEFT=19200
local CRSRIGHT=19712
local CRSUP=18432
local CRSDOWN=20480
cls()
posX=22; posY=12
dirX=-1; dirY=0
planeX=0; planeY=0.66
time=0
oldTime=0
page = 0
endgame = false
w=screenwidth()
h=screenheight()
repeat
activepage (page)
clear()
ink (hrgb (150,100,50))
fillrectangle (0,0,screenwidth(),screenheight()/2)
ink (hrgb (40,40,40))
fillrectangle (0,screenheight()/2,screenwidth(),screenheight())
for x=0, w do
cameraX=2*x/w-1
rayPosX=posX
rayPosY=posY
rayDirX = dirX + planeX * cameraX
rayDirY = dirY + planeY * cameraX
mapX=int(rayPosX)
mapY=int(rayPosY)
deltaDistX = math.sqrt (1 + (rayDirY * rayDirY) / (rayDirX * rayDirX))
deltaDistY = math.sqrt (1 + (rayDirX * rayDirX) / (rayDirY * rayDirY))
hit=0
if rayDirX < 0 then
stepX = -1
sideDistX = (rayPosX - mapX) * deltaDistX
else
stepX = 1
sideDistX = (mapX + 1.0 - rayPosX) * deltaDistX
end
if rayDirY < 0 then
stepY = -1
sideDistY = (rayPosY - mapY) * deltaDistY
else
stepY = 1
sideDistY = (mapY + 1.0 - rayPosY) * deltaDistY
end
while hit == 0 do
if (sideDistX < sideDistY) then
sideDistX = sideDistX + deltaDistX
mapX = mapX + stepX
side = 0
else
sideDistY = sideDistY + deltaDistY
mapY = mapY+ stepY
side = 1
end
--Check if ray has hit a wall
if (worldMap[mapX][mapY] > 0) then hit = 1 end
end
if side == 0 then
perpWallDist = math.abs((mapX - rayPosX + (1 - stepX) / 2) / rayDirX)
else
perpWallDist = math.abs((mapY - rayPosY + (1 - stepY) / 2) / rayDirY)
end
lineHeight = math.abs(int(h / perpWallDist))
drawStart = int(-lineHeight / 2 + h / 2)
if drawStart < 0 then drawStart = 0 end
drawEnd = int(lineHeight / 2 + h / 2)
if drawEnd >= h then drawEnd = h - 1 end
if (worldMap[mapX][mapY]) == 1 then
ink (hrgb (255,0,0))
elseif (worldMap[mapX][mapY]) == 2 then
ink (hrgb (0,255,0))
elseif (worldMap[mapX][mapY]) == 3 then
ink (hrgb (0,0,255))
elseif (worldMap[mapX][mapY]) == 4 then
ink (hrgb (255,255,255))
else
ink (hrgb (255,255,0))
end
if side == 1 then
if (worldMap[mapX][mapY]) ==1 then
ink (hrgb (128,0,0))
elseif (worldMap[mapX][mapY]) == 2 then
ink (hrgb (0,128,0))
elseif (worldMap[mapX][mapY]) == 3 then
ink (hrgb (0,0,128))
elseif (worldMap[mapX][mapY]) == 4 then
ink (hrgb (128,128,128))
else
ink (hrgb (128,128,0))
end
end
line (x,drawStart,x, drawEnd)
end
oldTime = time;
time = gettickcount()
frameTime = (time - oldTime) / 1000.0
moveSpeed = frameTime * 5.0
rotSpeed = frameTime * 2.0
if keypressed() then
key=getkey()
if key == 27 then
endgame = true
end
if key == (CRSUP) then
if (worldMap[int(posX + dirX * moveSpeed)][int(posY)] ==0) then posX = posX + dirX * moveSpeed end
if(worldMap[int(posX)][int(posY + dirY * moveSpeed)] ==0) then posY = posY + dirY * moveSpeed end
end
if key == (CRSDOWN) then
if (worldMap[int(posX - dirX * moveSpeed)][int(posY)] == 0) then posX = posX - dirX * moveSpeed end
if(worldMap[int(posX)][int(posY - dirY * moveSpeed)] ==0) then posY = posY-dirY * moveSpeed end
end
if key == (CRSRIGHT) then
oldDirX = dirX
dirX = dirX * math.cos(-rotSpeed) - dirY * math.sin(-rotSpeed)
dirY = oldDirX * math.sin(-rotSpeed) + dirY * math.cos(-rotSpeed)
oldPlaneX = planeX
planeX = planeX * math.cos(-rotSpeed) - planeY * math.sin(-rotSpeed)
planeY = oldPlaneX * math.sin(-rotSpeed) + planeY * math.cos(-rotSpeed)
end
if key == (CRSLEFT) then
oldDirX = dirX;
dirX = dirX * math.cos(rotSpeed) - dirY * math.sin(rotSpeed)
dirY = oldDirX * math.sin(rotSpeed) + dirY * math.cos(rotSpeed)
oldPlaneX = planeX
planeX = planeX * math.cos(rotSpeed) - planeY * math.sin(rotSpeed)
planeY = oldPlaneX * math.sin(rotSpeed) + planeY * math.cos(rotSpeed)
end
end
visualpage (page)
sleep (10)
page = page + 1
if page > 1 then
page = 0
end
until endgame == true
