- Created detailed documentation for the Minecart sprite, outlining its properties, constants, collision setup, main logic, and design patterns. - Added documentation for the Pedestal sprite, including its vanilla overrides, custom logic for item interaction, and event triggering based on area context. - Introduced documentation for the Portal sprite, detailing its two-way warping system, initialization, main logic, and helper routines for seamless transitions. - Documented the Switch Track sprite, explaining its interactive behavior, state-based animation, and integration with external switches for dynamic track manipulation.
222 lines
7.5 KiB
Markdown
222 lines
7.5 KiB
Markdown
# Pols Voice Sprite Analysis
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This document provides a detailed analysis of the `pols_voice.asm` sprite, outlining its properties, core routines, and behavioral patterns.
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## 1. Sprite Properties
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The following `!SPRID` constants define Pols Voice's fundamental characteristics:
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```asm
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!SPRID = Sprite_PolsVoice
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!NbrTiles = 02 ; Number of tiles used in a frame
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!Harmless = 00 ; 00 = Sprite is Harmful, 01 = Sprite is Harmless
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!HVelocity = 00 ; Is your sprite going super fast? put 01 if it is
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!Health = 10 ; Number of Health the sprite have
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!Damage = 00 ; (08 is a whole heart), 04 is half heart
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!DeathAnimation = 00 ; 00 = normal death, 01 = no death animation
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!ImperviousAll = 00 ; 00 = Can be attack, 01 = attack will clink on it
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!SmallShadow = 00 ; 01 = small shadow, 00 = no shadow
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!Shadow = 00 ; 00 = don't draw shadow, 01 = draw a shadow
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!Palette = 00 ; Unused in this template (can be 0 to 7)
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!Hitbox = 00 ; 00 to 31, can be viewed in sprite draw tool
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!Persist = 00 ; 01 = your sprite continue to live offscreen
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!Statis = 00 ; 00 = is sprite is alive?, (kill all enemies room)
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!CollisionLayer = 00 ; 01 = will check both layer for collision
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!CanFall = 00 ; 01 sprite can fall in hole, 01 = can't fall
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!DeflectArrow = 00 ; 01 = deflect arrows
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!WaterSprite = 00 ; 01 = can only walk shallow water
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!Blockable = 00 ; 01 = can be blocked by link's shield?
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!Prize = 00 ; 00-15 = the prize pack the sprite will drop from
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!Sound = 00 ; 01 = Play different sound when taking damage
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!Interaction = 00 ; ?? No documentation
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!Statue = 00 ; 01 = Sprite is statue
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!DeflectProjectiles = 00 ; 01 = Sprite will deflect ALL projectiles
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!ImperviousArrow = 00 ; 01 = Impervious to arrows
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!ImpervSwordHammer = 00 ; 01 = Impervious to sword and hammer attacks
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!Boss = 00 ; 00 = normal sprite, 01 = sprite is a boss
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```
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**Note:** `!Health` is set to `10` and is not dynamically determined by Link's sword level.
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## 2. Core Routines
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### 2.1. `Sprite_PolsVoice_Long` (Main Loop)
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This is the primary entry point for Pols Voice's per-frame execution. It handles drawing, shadow rendering, and then dispatches to the main logic routine if the sprite is active.
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```asm
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Sprite_PolsVoice_Long:
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{
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PHB : PHK : PLB
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JSR Sprite_PolsVoice_Draw
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JSL Sprite_DrawShadow
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JSL Sprite_CheckActive : BCC .SpriteIsNotActive
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JSR Sprite_PolsVoice_Main
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.SpriteIsNotActive
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PLB
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RTL
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}
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```
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### 2.2. `Sprite_PolsVoice_Prep` (Initialization)
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This routine is executed once when Pols Voice is first spawned. It initializes `SprTimerA` to `$80` and clears `SprDefl` and `SprTileDie`.
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```asm
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Sprite_PolsVoice_Prep:
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{
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PHB : PHK : PLB
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LDA.b #$80 : STA.w SprTimerA, X
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STZ.w SprDefl, X
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STZ.w SprTileDie, X
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PLB
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RTL
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}
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```
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### 2.3. `Sprite_PolsVoice_Main` (Behavioral State Machine)
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This routine manages Pols Voice's AI through a state machine, using `SprAction, X` to determine its current behavior. It includes states for moving around and hopping around, with a unique interaction based on the flute song.
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```asm
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Sprite_PolsVoice_Main:
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{
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JSR PolsVoice_CheckForFluteSong ; Check for flute song interaction
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%SpriteJumpTable(PolsVoice_MoveAround,
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PolsVoice_HopAround)
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PolsVoice_MoveAround:
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{
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%StartOnFrame(0)
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%PlayAnimation(0,3,10)
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;$09 = speed, $08 = max height
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LDA #$05 : STA $09
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LDA #$02 : STA $08
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JSL Sprite_BounceTowardPlayer
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JSL Sprite_BounceFromTileCollision
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JSL Sprite_DamageFlash_Long
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%DoDamageToPlayerSameLayerOnContact()
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JSL GetRandomInt : AND #$3F : BNE .not_done ; Random chance to change state
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LDA #$04 : STA.w SprTimerA, X
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%GotoAction(1) ; Transition to PolsVoice_HopAround
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.not_done
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JSL Sprite_CheckDamageFromPlayer : BCC .no_damage ; Check if Link damages Pols Voice
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JSL Sprite_DirectionToFacePlayer
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; Apply the speed positive or negative speed
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LDA $0E : BPL .not_up
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LDA #$20 : STA.w SprYSpeed, X
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BRA .not_down
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.not_up
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LDA #$E0 : STA.w SprYSpeed, X
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.not_down
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LDA $0F : BPL .not_right
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LDA #$20 : STA.w SprXSpeed, X
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BRA .not_left
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.not_right
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LDA #$E0 : STA.w SprXSpeed, X
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.not_left
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LDA #$04 : STA.w SprTimerA, X
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%GotoAction(1) ; Transition to PolsVoice_HopAround
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.no_damage
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RTS
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}
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PolsVoice_HopAround:
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{
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%StartOnFrame(4)
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%PlayAnimation(4,4,10)
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JSL Sprite_MoveXyz
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JSL Sprite_BounceFromTileCollision
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JSL Sprite_DamageFlash_Long
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%DoDamageToPlayerSameLayerOnContact()
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LDA.w SprTimerA, X : BNE .not_done ; If timer A is not 0
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%GotoAction(0) ; Transition back to PolsVoice_MoveAround
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.not_done
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JSL Sprite_CheckDamageFromPlayer : BCC .no_damage ; Check if Link damages Pols Voice
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JSL Sprite_InvertSpeed_XY ; Invert speed
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.no_damage
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RTS
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}
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}
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```
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### 2.4. `PolsVoice_CheckForFluteSong`
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This routine checks if the player is currently playing the flute (`SongFlag`). If the flute is being played, Pols Voice despawns (`STZ.w SprState, X`) and forces a prize drop.
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```asm
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PolsVoice_CheckForFluteSong:
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{
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; If the player plays the flute
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LDA.b SongFlag : BEQ + ; Check SongFlag
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LDA.b #$03 : STA.w SprState, X ; Set sprite state to despawn
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JSL ForcePrizeDrop_long ; Force prize drop
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+
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RTS
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}
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```
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### 2.5. `Sprite_PolsVoice_Draw` (Drawing Routine)
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This routine is responsible for rendering Pols Voice's graphics. It uses the `%DrawSprite()` macro, which reads from a set of data tables to handle its appearance and animation.
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```asm
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Sprite_PolsVoice_Draw:
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{
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%DrawSprite()
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.start_index
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db $00, $01, $02, $03, $04
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.nbr_of_tiles
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db 0, 0, 0, 0, 1
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.x_offsets
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dw 0
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dw 0
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dw 0
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dw 0
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dw 0, 0
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.y_offsets
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dw 0
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dw 0
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dw 0
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dw 0
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dw -4, -20
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.chr
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db $6C
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db $6A
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db $6C
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db $6A
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db $6E, $4E
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.properties
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db $3B
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db $3B
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db $3B
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db $7B
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db $3B, $3B
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.sizes
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db $02
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db $02
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db $02
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db $02
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db $02, $02
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}
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```
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## 3. Key Behaviors and Implementation Details
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* **Fixed Health:** Unlike many other sprites, Pols Voice has a fixed health of `10` and its health is not dynamically scaled based on Link's sword level.
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* **State Management:** Pols Voice uses `SprAction, X` and `%SpriteJumpTable` to manage its `PolsVoice_MoveAround` and `PolsVoice_HopAround` states. Transitions between these states are triggered by timers or random chance.
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* **Movement Patterns:** Pols Voice moves by bouncing towards the player (`Sprite_BounceTowardPlayer`) and also has a hopping movement (`PolsVoice_HopAround`). It reacts to tile collisions by bouncing (`Sprite_BounceFromTileCollision`).
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* **Flute Song Interaction:** A unique and defining characteristic of Pols Voice is its vulnerability to the flute song. When Link plays the flute (`SongFlag` is set), Pols Voice immediately despawns and drops a prize (`ForcePrizeDrop_long`). This is a classic Zelda enemy mechanic.
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* **Damage Reaction:** When damaged by Link, Pols Voice inverts its speed (`Sprite_InvertSpeed_XY`) and transitions to the `PolsVoice_HopAround` state, providing a temporary reprieve or change in behavior.
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* **Custom OAM Drawing:** Pols Voice uses the `%DrawSprite()` macro with OAM data tables to render its appearance and animations.
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* **`SprTimerA` Usage:** This timer controls the duration of the `PolsVoice_HopAround` state before transitioning back to `PolsVoice_MoveAround`.
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