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scawful aede7551a3 Add new sprite documentation for Minecart, Pedestal, Portal, and Switch Track

- 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.

2025-10-03 01:52:48 -04:00

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Pedestal (Magic Pedestal Plaque)

Overview

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.

Vanilla Overrides

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.

`CheckForBook`

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:

Link's Action: Checks $2F (Link's current action/state).
Player Contact: Checks for damage to player (JSL Sprite_CheckDamageToPlayer), which in this context likely means Link is in contact with the pedestal.
Item Held: Checks if Link is holding a specific item ($0202 compared to $0F, which likely corresponds to a book item).
Player Input: Checks if Link is pressing the Y button (BIT.b $F4).
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).
Event Trigger: Calls JSR PedestalPlaque to execute area-specific logic.

CheckForBook:
{
  LDA.b $2F : BNE .exit
    JSL Sprite_CheckDamageToPlayer : BCC .exit
      LDA.w $0202 : CMP.b #$0F : BNE .not_holding_book
        LDY.b #$01 : BIT.b $F4 : BVS .not_pressing_y
      .not_holding_book
        LDY.b #$00
        .not_pressing_y
        CPY.b #$01 : BNE .no_book_pose
          STZ.w $0300
          LDA.b #$20
          STA.w $037A
          STZ.w $012E
        .no_book_pose
      JSR PedestalPlaque
  .exit
  LDA.b AreaIndex : CMP.b #$30
  RTL
}

`PedestalPlaque`

This routine contains the area-specific logic for the pedestal, triggering different events based on the current AreaIndex:

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.
Goron Desert (AreaIndex = $36): No specific logic defined in this file.
Fortress Secrets (AreaIndex = $5E): No specific logic defined in this file.

PedestalPlaque:
{
  LDA.b AreaIndex : CMP.b #$1E : BEQ .zora_temple
                    CMP.b #$36 : BEQ .goron_desert
                    CMP.b #$5E : BEQ .fortress_secrets
                      JMP .return
  .zora_temple

    LDA.l $7EF29E : AND.b #$20 : BNE .return
      LDA.b SongFlag : CMP.b #$03 : BNE .return
        LDA.b #$01 : STA $04C6
        STZ.b SongFlag
        JMP .return
  .goron_desert

  .fortress_secrets

  .return
  RTS
}

Design Patterns

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.
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.
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.
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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