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.
77 lines
3.9 KiB
Markdown
77 lines
3.9 KiB
Markdown
# Pedestal (Magic Pedestal Plaque)
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## Overview
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The `pedestal.asm` file defines the custom behavior for a "Magic Pedestal" sprite, which is an interactive object that responds to Link's actions. This implementation overrides a vanilla pedestal plaque sprite (`Sprite_B3_PedestalPlaque`) to trigger specific game events based on Link's inventory, input, and the current `AreaIndex`.
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## Vanilla Overrides
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* **`org $1EE05F`**: Injects `JSL CheckForBook` into the `Sprite_B3_PedestalPlaque` routine. This means the custom logic defined in `CheckForBook` will execute when the vanilla pedestal plaque sprite is processed.
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## `CheckForBook`
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This routine is the primary entry point for the custom pedestal logic. It checks several conditions to determine if Link is interacting with the pedestal in a specific way:
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* **Link's Action**: Checks `$2F` (Link's current action/state).
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* **Player Contact**: Checks for damage to player (`JSL Sprite_CheckDamageToPlayer`), which in this context likely means Link is in contact with the pedestal.
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* **Item Held**: Checks if Link is holding a specific item (`$0202` compared to `$0F`, which likely corresponds to a book item).
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* **Player Input**: Checks if Link is pressing the Y button (`BIT.b $F4`).
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* **State Manipulation**: If Link is holding the book and pressing Y, it sets `$0300` to `0`, `$037A` to `$20`, and `$012E` to `0` (these are likely related to Link's animation or state changes).
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* **Event Trigger**: Calls `JSR PedestalPlaque` to execute area-specific logic.
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```asm
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CheckForBook:
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{
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LDA.b $2F : BNE .exit
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JSL Sprite_CheckDamageToPlayer : BCC .exit
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LDA.w $0202 : CMP.b #$0F : BNE .not_holding_book
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LDY.b #$01 : BIT.b $F4 : BVS .not_pressing_y
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.not_holding_book
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LDY.b #$00
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.not_pressing_y
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CPY.b #$01 : BNE .no_book_pose
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STZ.w $0300
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LDA.b #$20
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STA.w $037A
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STZ.w $012E
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.no_book_pose
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JSR PedestalPlaque
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.exit
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LDA.b AreaIndex : CMP.b #$30
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RTL
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}
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```
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## `PedestalPlaque`
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This routine contains the area-specific logic for the pedestal, triggering different events based on the current `AreaIndex`:
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* **Zora Temple (`AreaIndex = $1E`)**: Checks a flag (`$7EF29E` bit `$20`) and `SongFlag` (`$03`). If specific conditions are met (e.g., a certain event has not occurred and a particular song has been played), it sets `$04C6` to `$01` (likely a flag to open a gate or trigger an event) and clears `SongFlag`.
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* **Goron Desert (`AreaIndex = $36`)**: No specific logic defined in this file.
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* **Fortress Secrets (`AreaIndex = $5E`)**: No specific logic defined in this file.
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```asm
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PedestalPlaque:
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{
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LDA.b AreaIndex : CMP.b #$1E : BEQ .zora_temple
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CMP.b #$36 : BEQ .goron_desert
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CMP.b #$5E : BEQ .fortress_secrets
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JMP .return
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.zora_temple
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LDA.l $7EF29E : AND.b #$20 : BNE .return
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LDA.b SongFlag : CMP.b #$03 : BNE .return
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LDA.b #$01 : STA $04C6
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STZ.b SongFlag
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JMP .return
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.goron_desert
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.fortress_secrets
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.return
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RTS
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}
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```
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## Design Patterns
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* **Vanilla Override**: This file directly modifies the vanilla pedestal plaque sprite to implement custom interactive behavior, demonstrating how to integrate new puzzle mechanics into existing game elements.
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* **Context-Sensitive Interaction**: The pedestal responds specifically when Link is holding a particular item (a book) and pressing a button, creating a unique and logical interaction for puzzle solving.
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* **Quest Progression Integration**: The pedestal triggers events based on the `AreaIndex` and various game state flags (e.g., `SongFlag`, `$7EF29E`), indicating its role in advancing specific quests and unlocking new areas.
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* **Game State Manipulation**: Directly modifies WRAM addresses (`$04C6`, `SongFlag`) to trigger game events, such as opening gates or clearing flags, which are crucial for puzzle resolution and progression.
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