_runtimePath_ "../../../Contrib/at67/gbas/runtime"
_runtimeStart_ &h26FF
_arraysStart_ &h26FF
_codeRomType_ ROMv5a

cls

y=0 : x=y : i=x : j=i : a=j : pitch=a : yy=pitch
color1 = &h3F : color2 = &h03 : horizonY = 32

dim c1(3) = &h3F, &h2A, &h15, &h00
dim c2(3) = &h03, &h02, &h01, &h00

fade=0 : cIndex=fade : decay = 54

' Draw tiles in perspective in screen memory
for y=119 downto horizonY
    color1 = c1(cIndex) : color2 = c2(cIndex)
    inc fade
    if fade &&= decay
        inc cIndex
        fade = 0
        decay = decay LSR 1
    endif

    yy = y
    gosub calcPitch

    if((400 / (y-horizonY+40)) AND 1) &&= 0
        j = color1 XOR color2
    else
        j = 0
    endif

    i = 80 % pitch
    a = ((y + 8) LSL 8)

    for x=0 to pitch + 159
        if i &&= 0
            i = pitch - 1
        else
            i = i - 1
        endif

        if i+i &>= pitch
            p = color1 XOR j
        else
            p = color2 XOR j
        endif

        poke a+x,p 
    next x
    set VIDEO_TOP, y+y
next y
set VIDEO_TOP, 0

x=0 : v=8
loop:   i = x AND 255
        j = 0
        q = &h0100 + 240
        yy = horizonY
        gosub calcPitch
        for y=0 &to pitch
            j = j + i
        next y
        
        i = i + i
        p = &h0101 + horizonY + horizonY            

        wait
        repeat
            poke p, j LSR 8
            j = i + (j AND 255)
        p = p + 4 : until p &&>= q
        
        gosub get("BUTTON_STATE")
        
        x = x + v
goto loop

254: v = v + 1 : if v &&> 32 then v = 32
     return
253: v = v - 1 : if v &&< -32 then v = -32
     return
191: v = 0 : return
127: v = 0 : return

calcPitch: pitch = yy + (96 - 120 + 1)
           pitch = (pitch + 1) AND &hfffe
           return