Weather Image Display Implementation

GetWeatherImage:
    ld a, [wBattleWeather]
    dec a
    jr z, .rain
    dec a
    jr z, .sun
    dec a
    jr z, .sand
    ; dec a
    ; jr z, .hail
    ld a, [wTimeOfDay]
    cp 2
    jr z, .clear_night
    jr .clear_day

.rain
    farcall SetPalettes_Rain
    ld de, RainWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8
    jr z, .done

.sun
    farcall SetPalettes_Sun
    ld de, SunWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8
    jr z, .done

.hail
    farcall SetPalettes_Hail
    ld de, HailWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8
    jr z, .done

.sand
    farcall SetPalettes_Sand
    ld de, SandstormWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8
    jr z, .done

.clear_day
    farcall SetPalettes_ClearDay
    ld de, ClearDayWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8
    jr z, .done

.clear_night
    farcall SetPalettes_ClearNight
    ld de, ClearNightWeatherImage
    lb bc, PAL_BATTLE_OB_BROWN, 8

.done
    push bc
    ld b, BANK(WeatherImages) ; c = 4
    ld hl, vTiles0 tile $04
    call Request2bpp
    pop bc
    ld hl, wVirtualOAMSprite04
    ld de, .WeatherImageOAMData
.loop
    ld a, [de]
    inc de
    ld [hli], a
    ld a, [de]
    inc de
    ld [hli], a
    dec c
    ld a, c
    ld [hli], a
    ld a, b
    ld [hli], a
    jr nz, .loop
    ret

.WeatherImageOAMData
; positions are backwards since
; we load them in reverse order
    db $88, $1c ; y/x - bottom right
    db $88, $14 ; y/x - bottom left
    db $80, $1c ; y/x - top right
    db $80, $14 ; y/x - top left