I'm gonna put each tile in "one line" so i think this would work:
Where x is tile x position, y is y tile position, and z is the row i want to get from the tile !
I will try, thanks !!!
Edit: my calcul was bad
This work;
((y * (MapWidth - 1) + y + x) * 4) +Z
Where x, y are the tile coordinates ( first tile is 0,0 )
MapWidth is the map number of tiles in width
4 is because one tile contain 4 rows
Z is added to get the rows we want ( 4 rows, 0 -> 3 )
Thanks again !

Find content
Not Telling