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Diffstat (limited to 'docs/design_flaws.md')
| -rw-r--r-- | docs/design_flaws.md | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/docs/design_flaws.md b/docs/design_flaws.md index 848b4c584..6009d0265 100644 --- a/docs/design_flaws.md +++ b/docs/design_flaws.md @@ -10,6 +10,7 @@ These are parts of the code that do not work *incorrectly*, like [bugs and glitc - [Footprints are split into top and bottom halves](#footprints-are-split-into-top-and-bottom-halves) - [Pokédex entry banks are derived from their species IDs](#pokédex-entry-banks-are-derived-from-their-species-ids) - [`ITEM_C3` and `ITEM_DC` break up the continuous sequence of TM items](#item_c3-and-item_dc-break-up-the-continuous-sequence-of-tm-items) +- [`GetForestTreeFrame` works, but it's still bad](#getforesttreeframe-works-but-its-still-bad) ## Pic banks are offset by `PICS_FIX` @@ -71,6 +72,8 @@ GLOBAL PICS_FIX db BANK(Pics_1) + 23 ``` +**Fix:** Use `dba` instead of `dba_pic`, and don't call `FixPicBank` to modify `a`. + ## `PokemonPicPointers` and `UnownPicPointers` are assumed to start at the same address @@ -90,6 +93,19 @@ SECTION "Unown Pic Pointers", ROMX INCLUDE "data/pokemon/unown_pic_pointers.asm" ``` +In [pokecrystal.link](/pokecrystal.link): + +``` +ROMX $48 + org $4000 + "Pic Pointers" + "Pics 1" +ROMX $49 + org $4000 + "Unown Pic Pointers" + "Pics 2" +``` + Two routines in [gfx/load_pics.asm](/gfx/load_pics.asm) make this assumption; `GetFrontpicPointer`: ```asm @@ -130,6 +146,50 @@ And `GetMonBackpic`: call AddNTimes ``` +**Fix:** + +Don't enforce `org $4000` in pokecrystal.link. + +Modify `GetFrontpicPointer`: + +```asm + ld a, [CurPartySpecies] + cp UNOWN + jr z, .unown + ld a, [CurPartySpecies] + ld d, BANK(PokemonPicPointers) + ld hl, PokemonPicPointers + jr .ok + +.unown + ld a, [UnownLetter] + ld d, BANK(UnownPicPointers) + ld hl, UnownPicPointers + +.ok + dec a + ld bc, 6 + call AddNTimes +``` + +And `GetMonBackpic`: + +```asm + GLOBAL PokemonPicPointers, UnownPicPointers + ld a, b + ld hl, PokemonPicPointers + ld d, BANK(PokemonPicPointers) + cp UNOWN + jr nz, .ok + ld a, c + ld hl, UnownPicPointers + ld d, BANK(UnownPicPointers) +.ok + dec a + ld bc, 6 + call AddNTimes +``` + ## Footprints are split into top and bottom halves @@ -191,6 +251,31 @@ INCBIN "gfx/footprints/wartortle.1bpp", footprint_bottom call Request1bpp ``` +**Fix:** + +Store footprints contiguously: + +```asm +INCBIN "gfx/footprints/bulbasaur.1bpp" +INCBIN "gfx/footprints/ivysaur.1bpp" +INCBIN "gfx/footprints/venusaur.1bpp" +INCBIN "gfx/footprints/charmander.1bpp" +INCBIN "gfx/footprints/charmeleon.1bpp" +INCBIN "gfx/footprints/charizard.1bpp" +INCBIN "gfx/footprints/squirtle.1bpp" +INCBIN "gfx/footprints/wartortle.1bpp" +``` + +Modify `Pokedex_LoadAnyFootprint`: + +```asm + ld e, l + ld d, h + ld hl, VTiles2 tile $62 + lb bc, BANK(Footprints), 4 + call Request1bpp +``` + ## Pokédex entry banks are derived from their species IDs @@ -297,6 +382,8 @@ PokedexShow_GetDexEntryBank: db BANK(PokedexEntries4) ``` +**Fix:** Use `dba` instead of `dw` in `PokedexDataPointerTable`, and modify the code that accesses it to match. + ## `ITEM_C3` and `ITEM_DC` break up the continuous sequence of TM items @@ -355,3 +442,70 @@ GetNumberedTMHM: ; d417 ld c, a ret ``` + +**Fix:** + +Move `ITEM_C3` and `ITEM_DC` above all the TMs in every table of item data. + +Modify engine/items.asm: + +```asm +GetTMHMNumber:: ; d407 +; Return the number of a TM/HM by item id c. + ld a, c + sub TM01 + inc a + ld c, a + ret + +GetNumberedTMHM: ; d417 +; Return the item id of a TM/HM by number c. + ld a, c + add TM01 + dec a + ld c, a + ret +``` + + +## `GetForestTreeFrame` works, but it's still bad + +In [tilesets/animations.asm](/tilesets/animations.asm): + +```asm +GetForestTreeFrame: ; fc54c +; Return 0 if a is even, or 2 if odd. + and a + jr z, .even + cp 1 + jr z, .odd + cp 2 + jr z, .even + cp 3 + jr z, .odd + cp 4 + jr z, .even + cp 5 + jr z, .odd + cp 6 + jr z, .even +.odd + ld a, 2 + scf + ret +.even + xor a + ret +; fc56d +``` + +**Fix:** + +```asm +GetForestTreeFrame: ; fc54c +; Return 0 if a is even, or 2 if odd. + and 1 + add a + ret +; fc56d +``` |