gba dev: gfx and video

Discussion in 'GBA - Game Development, ROM Hacks and Translations' started by NTA, May 26, 2010.

  1. NTA

    NTA Member

    May 26, 2010
    United States
    [​IMG] Hi, I'm NTA and ive been wondering about alot of thing concerning the gba graphics and videos also some concerns with pokemon fire red and emarald

    for the first part i notice that fire red uses mode 4
    i also see wher the bgs are in order in priority too

    i have images for each background
    but what if i wanted to animate a sprite on the title screen? i would mind using the smaller sprites that are used in the game 16x32; but the pokemon sprites are 64x64 and i was wondering if i could animate them? and would i be able to have a delay between the frames? since its only two and im also wondering about playing videos ive seen an avi to gba converter but i dont understand how i could implement a video to a rom in stead of turning the video into a rom like the intro video for the pokemon games

    and also for the 4bgs, which one or two might contain the sprites i want to animate, its fine for them to all have different palettes right? as long as the first color is transparent?

    also would it be possible once ive made a title screen and converted it would it be possible to add that to a rom and replace\insert the title screen thats already there and would i need to repoint? fire red for exmaple

    any help would be appreciated :| [​IMG]
  2. FAST6191

    FAST6191 Techromancer

    pip Reporter
    Nov 21, 2005
    United Kingdom
    Pokemon games are not pleasant to hack courtesy of the odd formats, compression and developers seemingly not wanting such things, however if you can push through that then it is not that bad (better yet if you can not find a spec/breakdown for the rom then the various graphical tools pokemon seems to have spawned should be able to narrow things down/show what you want very quickly.

    First unless you are awesome with cheats and use something like gbaatm (even then it will be impossibly crude) you can not avoid needing to take this down to assembly level and probably not the simple side of things. It is certainly not going to happen as a result of playing with the graphical tools as they presently exist.

    You seem to have video mostly sorted but for the sake of completeness/others reading is a good link.

    Sprite animation usually occurs as a result of fiddling with the OAM ( ) and sprites in other memory spaces (the BG memory rarely does anything with sprites and it is considered bad practice to do so) and swapping between sprites (more accurately making one invisible and showing the other) and maybe using some of the inbuilt stuff ( ). The above link details the timings involved but it should not be hard to hook or otherwise code a delay in there. If you are already sticking a new sprite in there size will not matter beyond having to account for it in memory and with the OAM (big sprites have a habit of being several tiles), I suggest ripping a sprite and sticking it at the end of the rom rather than trying to fiddle with extracting a sprite from the game proper as aside from space in the rom it will reduce the amount of cycles needed if done properly). Fiddle with the memory viewer/editor of VBA to get a feeling for sprites and you will probably want to read something like at some point.

    As for the other question there is no real chance of injecting a video in lieu of the title screen either. Possible but the amount of work would be phenomenal (you might as well learn C and code the thing from scratch sort of difficulty).