Sure... But it's not very good-looking :
function racine(a)
x=1
y=0.5*(1+a)
while math.abs(y-x)>0.001 do
x=y
y=0.5*(x+a/x)
end
return y
end
function renderMap(gc,map,w,h,camera)
for x=0,w,2 do
dirX=math.cos(camera[3])
dirY=math.sin(camera[3])
planeX=math.cos(camera[3]-1.5707963267949)
planeY=math.sin(camera[3]-1.5707963267949)
cameraX=(x*2/w)-1
rayPosX=camera[1]
rayPosY=camera[2]
rayDirX=dirX+planeX*cameraX
rayDirY=dirY+planeY*cameraX
mapX=math.floor(rayPosX)
mapY=math.floor(rayPosY)
deltaDistX=racine(1+(rayDirY*rayDirY)/(rayDirX*rayDirX))
deltaDistY=racine(1+(rayDirX*rayDirX)/(rayDirY*rayDirY))
hit=0
if rayDirX<0 then
stepX=-1
sideDistX=(rayPosX-mapX)*deltaDistX
else
stepX = 1;
sideDistX = (mapX+1-rayPosX)*deltaDistX
end
if rayDirY<0 then
stepY=-1;
sideDistY=(rayPosY-mapY)*deltaDistY
else
stepY=1;
sideDistY=(mapY+1-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
if map[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
hauteurLigne=math.abs(math.floor(h/perpWallDist))
drawStart=math.floor(-hauteurLigne/2+h/2)
drawEnd=math.floor(hauteurLigne/2+h/2)
if drawStart<0 then
drawStart=0
end
if drawEnd>=h then
drawEnd=h-1
end
gc:setColorRGB(10,10,10)
if side==1 then
gc:setColorRGB(100,100,100)
end
gc:fillRect(x,drawStart,2,drawEnd-drawStart)
end
end
function on.escapeKey()
menu=1
platform.window:invalidate()
end
on.escapeKey()
function on.enterKey()
menu=nil
fovy=60
camera={10,10,0.05}
w=320 h=240
planeX=0 planeY=1
map={{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},{1,0,0,1,0,0,1,0,0,0,0,0,0,0,0,1},{1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1},{1,0,0,0,0,0,1,0,0,1,1,1,1,1,1,1},{1,0,0,1,1,1,1,0,0,1,0,0,0,0,0,1},{1,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1},{1,0,0,0,0,0,0,0,0,1,0,0,1,0,0,1},{1,0,0,0,0,0,1,0,0,1,0,0,1,0,0,1},{1,1,1,1,1,1,1,0,0,1,0,0,1,0,0,1},{1,0,0,1,0,0,0,0,0,0,0,0,1,1,1,1},{1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,1},{1,0,0,1,1,1,1,1,1,1,1,1,1,0,0,1},{1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1},{1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1},{1,0,0,1,1,1,0,0,1,1,1,1,1,0,0,1},{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}}
platform.window:invalidate()
end
function on.arrowKey(ar)
turn=nil
if ar=="right" then
camera[3]=camera[3]-0.1
end
if ar=="left" then
camera[3]=camera[3]+0.1
end
if ar=="up" then
if map[math.floor(camera[1]+math.cos(camera[3])/3)][math.floor(camera[2]+math.sin(camera[3])/3)]==0 then
camera[1]=camera[1]+math.cos(camera[3])/3
camera[2]=camera[2]+math.sin(camera[3])/3
end
end
if ar=="down" then
if map[math.floor(camera[1]-math.cos(camera[3])/4)][math.floor(camera[2]-math.sin(camera[3])/4)]==0 then
camera[1]=camera[1]-math.cos(camera[3])/4
camera[2]=camera[2]-math.sin(camera[3])/4
end
end
platform.window:invalidate()
end
function on.paint(gc)
if menu then
gc:setColorRGB(0,0,255)
gc:setFont("sansserif","r",30)
gc:drawString("RayCaster Demo",30,0,"top")
gc:setFont("serif","b",10)
gc:drawString("Press Enter to start",100,100,"top")
else
gc:setColorRGB(200,200,200)
gc:fillRect(0,0,platform.window:width(),platform.window:height())
renderMap(gc,map,platform.window:width(),platform.window:height(),camera)
end
gc:setColorRGB(0,0,0)
gc:setFont("sansserif","r",8)
gc:drawString("Lua RayCaster Demo - Par Loic Pujet",10,200,"top")
end