Frog is object that follow player, only when on floor.
|step||mean||iState value||iCounter value||iYD value||iXD value||tileset||tile|
|1||Frog on background||0||0 to 16||unknow||unknow||63||0 (right) 3 (left)|
|2||Frog jumping||1||17||-10||4||63||1 (right) 4 (left)|
|3||Frog jumping||1||17||-9 → -1||4||63||1 (right) 4 (left)|
|4||Frog jumping||1||17||0||4||63||0 (right) 3 (left)|
|5||Frog jumping||1||17||1 → 12||4||63||2 (right) 5 (left)|
iYD and iXD contain value to add to iY and iX.
-10 is special value for iYD. Don't add to iY, juste change picture.
Check always before add to iX if frog can go to new position (block is F_PLAYERTHRU).
For iY check like iX but, check also if block is F_STAIR.
12 is max value of iYD.
In special case, if player is on same position (iX) that the frog, frog doesn't add value to x, iXD = 0.