aede7551a3
- 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.
215 lines
5.9 KiB
Markdown
215 lines
5.9 KiB
Markdown
# Eon Zora
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## Overview
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The Eon Zora is an NPC (Non-Player Character) sprite found in the Eon Abyss. Its behavior is characterized by random movement and context-sensitive dialogue that changes based on Link's current location within the game world.
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## Sprite Properties
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Explicit sprite properties (`!SPRID`, `!NbrTiles`, etc.) are not defined within this file. It is assumed that these properties are either inherited from a vanilla sprite ID or defined in a separate configuration file, as this file focuses on the sprite's behavior and drawing.
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## Main Logic (`Sprite_EonZora_Main`)
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This routine is the main entry point for the Eon Zora, executed every frame. It orchestrates the Zora's dialogue, movement, and animation.
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* **Dialogue**: Calls `EonZora_HandleDialogue` to manage interactions with the player.
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* **Movement**: Calls `EonZora_Walk` for random movement, followed by `JSL Sprite_Move` and `JSL Sprite_BounceFromTileCollision` for physical movement and collision handling.
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* **Directional Animations**: Uses a jump table to play specific animations based on the Zora's current direction (Forward, Left, Right, Back).
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```asm
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Sprite_EonZora_Main:
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{
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JSR EonZora_HandleDialogue
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JSR EonZora_Walk
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JSL Sprite_Move
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JSL Sprite_BounceFromTileCollision
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LDA.w SprAction, X
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JSL JumpTableLocal
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dw EonZora_Forward
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dw EonZora_Left
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dw EonZora_Right
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dw EonZora_Back
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EonZora_Forward:
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%PlayAnimation(0,1,10)
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RTS
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EonZora_Left:
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%PlayAnimation(2,3,10)
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RTS
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EonZora_Right:
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%PlayAnimation(4,5,10)
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RTS
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EonZora_Back:
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%PlayAnimation(6,7,10)
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RTS
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}
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```
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## Movement Routine (`EonZora_Walk`)
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This routine controls the Eon Zora's random walking behavior. It uses a timer (`SprTimerA, X`) to periodically select a new random direction and update the sprite's `SprXSpeed, X` and `SprYSpeed, X`.
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```asm
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EonZora_Walk:
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{
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LDA.w SprTimerA, X : BNE +
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JSL GetRandomInt : AND.b #$03 : STA.w SprAction, X : TAY
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LDA.w .speed_x, Y : STA.w SprXSpeed, X
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LDA.w .speed_y, Y : STA.w SprYSpeed, X
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LDA.b #$6A : STA.w SprTimerA, X
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+
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RTS
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.speed_x
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db 0, -4, 4, 0
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.speed_y
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db 4, 0, 0, -4
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}
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```
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## Dialogue Handling (`EonZora_HandleDialogue`)
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This routine manages the Eon Zora's dialogue, which is context-sensitive based on Link's current `AreaIndex`. It checks for specific `AreaIndex` values to display tailored messages. If no specific area matches, a default message is displayed, and interacting with it can randomly set the `FOUNDRINGS` global variable.
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```asm
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EonZora_HandleDialogue:
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{
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LDA.w AreaIndex : CMP.b #$63 : BNE .not_wisdom
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%ShowSolicitedMessage($01AC)
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JMP ++
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.not_wisdom
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CMP.b #$5B : BNE .not_power
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%ShowSolicitedMessage($01AB)
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JMP ++
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.not_power
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CMP.b #$40 : BNE .not_pyramid
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%ShowSolicitedMessage($01AA)
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JMP ++
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.not_pyramid
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CMP.b #$70 : BNE .not_underwater
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%ShowSolicitedMessage($01AD)
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JMP ++
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.not_underwater
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CMP.b #$42 : BNE .not_portal
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%ShowSolicitedMessage($01AF)
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JMP ++
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.not_portal
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%ShowSolicitedMessage($01AE) : BCC .no_talk
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JSL GetRandomInt : AND.b #$06 : STA.l FOUNDRINGS
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.no_talk
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++
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RTS
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}
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```
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## Drawing (`Sprite_EonZora_Draw`)
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The drawing routine handles OAM allocation and animation. It explicitly uses `REP #$20` and `SEP #$20` for 16-bit coordinate calculations, ensuring accurate sprite rendering.
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```asm
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Sprite_EonZora_Draw:
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{
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JSL Sprite_PrepOamCoord
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JSL Sprite_OAM_AllocateDeferToPlayer
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LDA.w SprFrame, X : TAY ;Animation Frame
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LDA .start_index, Y : STA $06
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PHX
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LDX .nbr_of_tiles, Y ;amount of tiles -1
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LDY.b #$00
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.nextTile
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PHX ; Save current Tile Index?
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TXA : CLC : ADC $06 ; Add Animation Index Offset
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PHA ; Keep the value with animation index offset?
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ASL A : TAX
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REP #$20
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LDA $00 : CLC : ADC .x_offsets, X : STA ($90), Y
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AND.w #$0100 : STA $0E
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INY
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LDA $02 : CLC : ADC .y_offsets, X : STA ($90), Y
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CLC : ADC #$0010 : CMP.w #$0100
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SEP #$20
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BCC .on_screen_y
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LDA.b #$F0 : STA ($90), Y ;Put the sprite out of the way
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STA $0E
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.on_screen_y
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PLX ; Pullback Animation Index Offset (without the *2 not 16bit anymore)
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INY
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LDA .chr, X : STA ($90), Y
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INY
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LDA .properties, X : STA ($90), Y
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PHY
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TYA : LSR #2 : TAY
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LDA .sizes, X : ORA $0F : STA ($92), Y ; store size in oam buffer
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PLY : INY
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PLX : DEX : BPL .nextTile
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PLX
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RTS
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.start_index
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db $00, $02, $04, $06, $08, $0A, $0C, $0D
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.nbr_of_tiles
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db 1, 1, 1, 1, 1, 1, 0, 0
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.x_offsets
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dw 0, 16
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dw 0, -16
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dw 0, 8
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dw 0, 8
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dw 0, -8
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dw 0, -8
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dw 0
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dw 0
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.y_offsets
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dw 0, 0
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dw 0, 0
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dw 0, 0
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dw 0, 0
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dw 0, 0
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dw 0, 0
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dw 0
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dw 0
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.chr
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db $60, $62
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db $60, $62
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db $40, $41
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db $43, $44
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db $40, $41
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db $43, $44
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db $64
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db $64
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.properties
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db $39, $39
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db $79, $79
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db $39, $39
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db $39, $39
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db $79, $79
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db $79, $79
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db $39
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db $79
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.sizes
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db $02, $02
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db $02, $02
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db $02, $02
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db $02, $02
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db $02, $02
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db $02, $02
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db $02
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db $02
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}
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```
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## Design Patterns
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* **Context-Sensitive Dialogue**: The NPC's dialogue dynamically changes based on Link's current `AreaIndex`, providing a rich and immersive storytelling experience tailored to the player's location.
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* **Random Movement**: The Zora exhibits random walking behavior, contributing to the environmental ambiance and making the world feel more alive.
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* **NPC Interaction**: Provides dialogue and has the potential to grant items (randomly setting `FOUNDRINGS`), adding an element of surprise and reward to player interactions.
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* **Animation-Driven Movement**: The sprite's movement states are directly tied to specific animations for each direction, ensuring visual consistency between its actions and appearance.
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* **16-bit OAM Calculations**: Demonstrates explicit use of `REP #$20` and `SEP #$20` for precise 16-bit OAM coordinate calculations, crucial for accurate sprite rendering.
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