precalc = Timer()
Smooth2D ON
path$="media/map.bmp"
img=LoadImage(path)
imgw = ImageWidth(img)
imgh = ImageHeight(img)
DeleteImage img
SCREEN imgw, imgh
img=LoadImage(path)
Dim bump(imgw-1,imgh-1,2) As Float
Dim gs(imgw-1,imgh-1)
Dim ldir(imgw*2, imgh*2, 2) As Float
Dim cols(255)

For i = 0 To imgw-1//lasketaan harmaasävy(=korkeus)taulu
    For j = 0 To imgh-1
        PickImageColor img, i, j
        rr = getRGB(1)
        gg = getRGB(2)
        bb = getRGB(3)
        gs(i,j)=(rr+gg+bb)/3.0
    Next j
Next i

For i=0 To imgw-1//lasketaan normaalitaulu
    For j=0 To imgh-1
        bump(i,j,0)=gs(i,j)-gs(i+1,j)//ristitulo
        bump(i,j,1)=gs(i,j)-gs(i,j+1)
        bump(i,j,2)=1.0
        l#=Sqrt(bump(i,j,0)^2+bump(i,j,1)^2+bump(i,j,2)^2)//normalisointi
        bump(i,j,0)=bump(i,j,0)/l
        bump(i,j,1)=bump(i,j,1)/l
        bump(i,j,2)=bump(i,j,2)/l
    Next j
Next i

For i = 0 To 255
    k# = i/255.0
    cols(i) = int((k*220) shl 16 + (k*230) shl 8 + k*255)
Next i

For i = 0 To imgw*2//lasketaan valotaulu
    For j = 0 To imgh*2
        mx# = imgw-i
        my# = imgh-j
        mz# = 8.0
        ml# = Sqrt(mx*mx+my*my+mz*mz)*(4+sqrt(mx^2+my^2+mz^2))
        ldir(i, j, 0)=mx/ml
        ldir(i, j, 1)=my/ml
        ldir(i, j, 2)=mz/ml
    Next j
Next i

precalc = Timer() - precalc

Repeat
    mmx = MouseX()//imgw/2.0+(imgw/4.0)*Sin(Timer()*.03)
    mmy = MouseY()//imgh/2.0+(imgh/4.0)*Cos(Timer()*.02)
    mox = Max(0, Min(imgw, imgw-mmx))
    moy = Max(0, Min(imgh, imgh-mmy))
    frame = (frame + 1) Mod 4
    xframe = frame Mod 2
    yframe = (frame/2) Mod 2
    Lock
        For i = xframe To imgw-2 Step 2
            For j = yframe Mod 2 To imgh-2 Step 2
                imox = i+mox
                jmoy = j+moy
                c = min(255, Max(0, 20.0+4000*(ldir(imox, jmoy,0)*bump(i,j,0)+ldir(imox, jmoy,1)*bump(i,j,1)+ldir(imox, jmoy,2)*bump(i,j,2))))
                PutPixel2 i, j, cols(c)
            Next j
        Next i
    Unlock
    SetWindow ""+FPS() + " FPS, "+precalc+"ms precalc"
    DrawScreen OFF
Forever