Difference between revisions of "Background/Arena File Format (.BK)"
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There then follows an
There then follows an (.AF).
== Footer ==
== Footer ==
Revision as of 02:33, 4 January 2013
The BK file format is similar in many ways to the AF file format, however, there are some signifigant differences.
|Unknown||1 DWORD||0 for INTRO, 2 for ending cutscenes,4 for main menu/newsroom/VS/Mechlab/melee, 6 for credits,
8 for Arena0, 16 for Arena1, 32 for Arena2, 64 for Arena3 and 128 for Arena4
|Unknown||1 BYTE||? 1, 2 or variable|
|Width||1 WORD||Background width (always 320?)|
|Height||1 WORD||Background height (always 200?)|
Each animation is preceded by the offset of the next animation stored as a DWORD, along with an animation number. Reading the animation and advancing the file pointer should result in the file pointer being the same as the next animation offset. An animation number >= 50 marks the end of the animations section. When this occurs, the next animation offset is set to the offset of the current animation.
|Next animation||1 DWORD||Position of next animation relative to start of file, in bytes|
|Animation number||1 BYTE||Unique identifier for animation|
|Unknown||1 BYTE||Nul padding? (not for fire pit wandering orb)|
|Unknown A||1 BYTE||Animation to chain to if collision/hit (eg. fire orb 15 -> fire ball 17)|
|Unknown B||1 BYTE||Animation to chain to on no collision/hit(?) (eg. fire orb 15 -> fire orb fade 16)|
|Repeat||1 BYTE||255 for repeating animations (eg. spotlights on main menu, torches in fire pit, newscaster's lips/eyes), Desert animation (spawn the planes) 0 has 254 in this field.|
|Probability||1 WORD||How likely this is to happen, lower is higher probability, 0 means never. 1 for torches/'cloud of dust' in fire pit, 200 for 'cloud of dust' in desert, 1000 for spikes in spike pit. For example, setting this to 1 for animation 0 in the desert means that planes will always be strafing you.|
|Unknown E||1 BYTE||Arena hazard damage (eg. spike pit, fire pit fireball, electric walls in powerplant)?|
|Something size||1 WORD|
|Something||N BYTES||Animation string, size is determined by the previous value|
There then follows an AF Animation Structure.
After the animations there is a footer structure:
|Background image||W*H BYTES||W and H are the width and height in the file header|
|Num palettes||1 BYTE||Specifies the number of palettes which follow|
|Palette data||256 * 3 BYTES||A palette|
|Palette remapping tables||19 * 256 BYTES||See below|
The palette remapping tables are maps from image colour indices into palette indices, for various different colour effects. The tables are for:
|0-3||Fade to black, for shadows|
|4||Dark blue, for menu backgrounds|
|Most BK files|
|5-8||Saturating to white, then black-and-white (newsroom transition?)|
|9-13||Saturating light blue -> white (lightning flashes?)|
|Fire pit [3 palettes: normal, fire, ice]|
|Desert [4 palettes]|
|5-18||Slow fade to white|