diff options
Diffstat (limited to 'docs/design_flaws.md')
| -rw-r--r-- | docs/design_flaws.md | 240 |
1 files changed, 54 insertions, 186 deletions
diff --git a/docs/design_flaws.md b/docs/design_flaws.md index 613f90b0c..20b70cac1 100644 --- a/docs/design_flaws.md +++ b/docs/design_flaws.md @@ -461,53 +461,9 @@ PokedexShow_GetDexEntryBank: ```asm _Sine:: ; 84d9 -; A simple sine function. -; Return d * sin(e) in hl. - -; e is a signed 6-bit value. +; a = d * sin(e * pi/32) ld a, e - and %111111 - cp %100000 - jr nc, .negative - call .ApplySineWave - ld a, h - ret - -.negative - and %011111 - call .ApplySineWave - ld a, h - xor $ff - inc a - ret - -.ApplySineWave: ; 84ef - ld e, a - ld a, d - ld d, 0 - ld hl, .sinewave - add hl, de - add hl, de - ld e, [hl] - inc hl - ld d, [hl] - ld hl, 0 -; Factor amplitude -.multiply - srl a - jr nc, .even - add hl, de -.even - sla e - rl d - and a - jr nz, .multiply - ret - -.sinewave ; 850b -; A 32-word table representing a sine wave. -; sin(90 degrees) is index $10 with an amplitude of $100. - sine_wave 32 + calc_sine_wave ``` `Sprites_Cosine` and `Sprites_Sine` in [engine/sprites.asm](/engine/sprites.asm): @@ -515,50 +471,11 @@ _Sine:: ; 84d9 ```asm Sprites_Cosine: ; 8e72a ; a = d * cos(a * pi/32) - add %010000 + add %010000 ; cos(x) = sin(x + pi/2) + ; fallthrough Sprites_Sine: ; 8e72c ; a = d * sin(a * pi/32) - and %111111 - cp %100000 - jr nc, .negative - call .ApplySineWave - ld a, h - ret - -.negative - and %011111 - call .ApplySineWave - ld a, h - xor $ff - inc a - ret -; 8e741 - -.ApplySineWave: ; 8e741 - ld e, a - ld a, d - ld d, 0 - ld hl, .sinewave - add hl, de - add hl, de - ld e, [hl] - inc hl - ld d, [hl] - ld hl, 0 -.multiply - srl a - jr nc, .even - add hl, de -.even - sla e - rl d - and a - jr nz, .multiply - ret -; 8e75d - -.sinewave ; 8e75d - sine_wave 32 + calc_sine_wave ``` `BattleAnim_Cosine` and `BattleAnim_Sine` in [engine/battle_anims/functions.asm](/engine/battle_anims/functions.asm): @@ -566,50 +483,16 @@ Sprites_Sine: ; 8e72c ```asm BattleAnim_Cosine: ; ce732 (33:6732) ; a = d * cos(a * pi/32) - add %010000 + add %010000 ; cos(x) = sin(x + pi/2) + ; fallthrough BattleAnim_Sine: ; ce734 (33:6734) ; a = d * sin(a * pi/32) - and %111111 - cp %100000 - jr nc, .negative - call .ApplySineWave - ld a, h - ret - -.negative - and %011111 - call .ApplySineWave - ld a, h - xor $ff - inc a - ret - -.ApplySineWave: - ld e, a - ld a, d - ld d, 0 - ld hl, BattleAnimSineWave - add hl, de - add hl, de - ld e, [hl] - inc hl - ld d, [hl] - ld hl, 0 -.multiply - srl a - jr nc, .even - add hl, de -.even - sla e - rl d - and a - jr nz, .multiply - ret + calc_sine_wave BattleAnimSineWave ... BattleAnimSineWave: ; ce77f - sine_wave 32 + sine_table 32 ; ce7bf ``` @@ -617,47 +500,7 @@ BattleAnimSineWave: ; ce77f ```asm StartTrainerBattle_DrawSineWave: ; 8c6f7 (23:46f7) -; a = d * sin(a * pi/32) - and %111111 - cp %100000 - jr nc, .negative - call .ApplySineWave - ld a, h - ret - -.negative - and %011111 - call .ApplySineWave - ld a, h - xor $ff - inc a - ret - -.ApplySineWave: ; 8c70c (23:470c) - ld e, a - ld a, d - ld d, 0 - ld hl, .sinewave - add hl, de - add hl, de - ld e, [hl] - inc hl - ld d, [hl] - ld hl, 0 -.multiply - srl a - jr nc, .even - add hl, de -.even - sla e - rl d - and a - jr nz, .multiply - ret -; 8c728 (23:4728) - -.sinewave ; 8c728 - sine_wave 32 + calc_sine_wave ; 8c768 ``` @@ -666,51 +509,76 @@ And `CelebiEvent_Cosine` in [engine/events/celebi.asm](/engine/events/celebi.asm ```asm CelebiEvent_Cosine: ; 49b3b (12:5b3b) ; a = d * cos(a * pi/32) - add %010000 + add %010000 ; cos(x) = sin(x + pi/2) + calc_sine_wave +; 49bae +``` + +They all rely on `calc_sine_wave` in [macros/code.asm](/macros/code.asm): + +```asm +calc_sine_wave: MACRO +; input: a = a signed 6-bit value +; output: a = d * sin(a * pi/32) and %111111 - cp %100000 - jr nc, .negative - call .ApplySineWave + cp %100000 + jr nc, .negative\@ + call .apply\@ ld a, h ret - -.negative +.negative\@ and %011111 - call .ApplySineWave + call .apply\@ ld a, h xor $ff inc a ret - -.ApplySineWave: ; 49b52 (12:5b52) +.apply\@ ld e, a ld a, d ld d, 0 - ld hl, .sinewave +if _NARG == 1 + ld hl, \1 +else + ld hl, .sinetable\@ +endc add hl, de add hl, de ld e, [hl] inc hl ld d, [hl] ld hl, 0 -.multiply +.multiply\@ ; factor amplitude srl a - jr nc, .even + jr nc, .even\@ add hl, de -.even +.even\@ sla e rl d and a - jr nz, .multiply + jr nz, .multiply\@ ret -; 49b6e (12:5b6e) +if _NARG == 0 +.sinetable\@ + sine_table 32 +endc +ENDM +``` -.sinewave ; 49b6e - sine_wave 32 -; 49bae +And on `sine_table` in [macros/data.asm](/macros/data.asm): + +```asm +sine_table: MACRO +; \1 samples of sin(x) from x=0 to x<32768 (pi radians) +x = 0 +rept \1 + dw (sin(x) + (sin(x) & $ff)) >> 8 ; round up +x = x + DIV(32768, \1) ; a circle has 65536 "degrees" +endr +ENDM ``` -**Fix:** Call a single shared copy of the (co)sine code in bank 0. +**Fix:** Edit [home/sine.asm](/home/sine.asm) to contain a single copy of the (co)sine code in bank 0, and call it from those five sites. ## `GetForestTreeFrame` works, but it's still bad |