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show decimal scores?
test one octave deeper?

do not clear all data for showLevel

make a generic load data function using pile to get all adresses ?

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try to use only 32k ? currentyl using 44k (31k of data, 13k of code)
memory usage (decimal) :
1504 Tiles_jmimu $3910-3330
1536 jmimu_TilemapStart $3f10-3910      -1k
1536 Title_TilemapStart $4530-3f30      -1k
1536 Forest_Tilemap_Start $4b50-4550    -1k
1096 demo4_music $5aec-56a4     
928 Title_Tiles_Start $5f34-5b94    
1536 Tilemap2Start $736e-6d6e           -1k
3072 Tiles_bg10_Start $187a-0c7a    
4864 Tilemap10Start $2b9a-189a          -2k
1536 Tilemap1Start $32e0-2ce0           -1k
7680 Tilemap5Start $a37f-857f           -5k
2554 end_music $ad79-a37f
802 demo_music $b131-ae0f
760 FontData_Start $b9f9-b701


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collisions:
the first 3 bits of each tile in tilemap contains collision data.
000: empty
001: full
010: half low
011: half hi
100: slope down (check x-flip)
101: slope up (check x-flip)
110: half side (check x-flip)
111: special

read collision data from rom (not vram): level data start + yscrolltotal + yscroll mod 8
!!!!! force tilemap w to be a power of 2, make a xy2index function for each w.
=> vram is simpler

make a draw_rocket function that takes "small_rocket" into account.
if small rocket, top collison point is less high.

TODO: implement dumping
TODO: implement color loop for fire
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each level has his onw SpecialTileFunction, called when touching a special case
(most of the time try to land and end en level).
SpecialTileFunction is a variable initialized at each level

add tiles_vram_used in demo too

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 3008 bytes for chars, divided by 4 using 1bpp tiles => 2256 bytes saved
 
 re-arrange rom to have data specific to a level in one file, and chers in an other,
 and be able to load chars using an other function
 
 3590 bytes for Brahms music
 2100 bytes for demo music
 4864 bytes for vertical level
 96 tiles for vertical level bg: 3072 bytes, if compressed : 2603 bytes
 demo sprites :  768, 559 if compressed
 demo tiles : 1536, 1075 if compressed

 1500 bytes for jmimu tilemap => make it 200!
