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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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Fortune Teller

Overview

The fortune_teller.asm file is not a complete sprite definition but rather a set of routines and data that override and extend the behavior of the vanilla Fortune Teller NPC. Its primary function is to provide highly context-sensitive messages to Link, offering guidance or commentary based on his current inventory, collected items, and overall game progression.

Vanilla Overrides

This file directly modifies existing vanilla code related to the Fortune Teller:

org $0DC829: Overrides the FortuneTellerMessage data table, which contains the message IDs that the Fortune Teller can display.
org $0DC849: Overrides the FortuneTeller_PerformPseudoScience routine, which is the core logic for determining and displaying messages.

`FortuneTellerMessage` Data Table

This table stores a sequence of byte values, each representing a message ID. These IDs correspond to specific dialogue options that the Fortune Teller can present to Link.

org $0DC829
FortuneTellerMessage:
.low
#_0DC829: db $EA ; MESSAGE 00EA
#_0DC82A: db $EB ; MESSAGE 00EB
#_0DC82B: db $EC ; MESSAGE 00EC
#_0DC82C: db $ED ; MESSAGE 00ED
#_0DC82D: db $EE ; MESSAGE 00EE
#_0DC82E: db $EF ; MESSAGE 00EF
#_0DC82F: db $F0 ; MESSAGE 00F0
#_0DC830: db $F1 ; MESSAGE 00F1
#_0DC831: db $F6 ; MESSAGE 00F6
#_0DC832: db $F7 ; MESSAGE 00F7
#_0DC833: db $F8 ; MESSAGE 00F8
#_0DC834: db $F9 ; MESSAGE 00F9
#_0DC835: db $FA ; MESSAGE 00FA
#_0DC836: db $FB ; MESSAGE 00FB
#_0DC837: db $FC ; MESSAGE 00FC
#_0DC838: db $FD ; MESSAGE 00FD

.high
#_0DC839: db $00
; ... (rest of the table)

`FortuneTeller_PerformPseudoScience` Routine

This routine is the central logic for the custom Fortune Teller. It dynamically selects which message to display to Link based on a series of checks against his inventory and various game progression flags stored in SRAM.

Initializations: Performs some initial state manipulations (STZ.w $0DC0,X, INC.w $0D80,X, STZ.b $03).
Progression Check ($7EF3D6): Determines a base message category based on a custom progression flag.
Extensive Item and Game State Checks: The routine then proceeds through a series of conditional checks, each corresponding to a specific item or game event. For example, it checks for:
- $7EF344 (Mushroom/Powder)
- $7EF37A (Crystals, specifically if Tail Palace is beaten)
- $7EF355 (Boots)
- $7EF356 (Flippers)
- $7EF345 (Fire Rod)
- $7EF37B (Magic Upgrade)
- $7EF354 (Glove)
- $7EF358 (Wolf Mask)
- $7EF3C9 (Smithy Rescued flag)
- $7EF352 (Cape)
- $7EF354 (Titans Mitt)
- $7EF359 (Sword level)
Message Display: Based on these checks, it calls FortuneTeller_PrepareNextMessage with the appropriate message index and then FortuneTeller_DisplayMessage to show the message to the player.

FortuneTeller_PerformPseudoScience:
#_0DC849: STZ.w $0DC0,X
#_0DC84C: INC.w $0D80,X
#_0DC84F: STZ.b $03
#_0DC851: LDA.l $7EF3D6
#_0DC855: CMP.b #$02
#_0DC857: BCS .map_icon_past_pendants
#_0DC859: STZ.b $00
#_0DC85B: STZ.b $01
#_0DC85D: JMP.w FortuneTeller_DisplayMessage

.map_icon_past_pendants
#_0DC860: LDA.l $7EF344
#_0DC864: BNE .have_shroom_or_powder
#_0DC866: LDA.b #$02
#_0DC868: JSR FortuneTeller_PrepareNextMessage
#_0DC86B: BCC .have_shroom_or_powder
#_0DC86D: JMP.w FortuneTeller_DisplayMessage

; ... (rest of the conditional item checks)

Design Patterns

Vanilla Override: This file exemplifies how to directly modify and extend the behavior of existing vanilla NPCs through targeted code injection.
Context-Sensitive Dialogue: The Fortune Teller's messages are highly dynamic and personalized, adapting to Link's current inventory and game progression. This creates a more engaging and responsive NPC interaction.
Quest Progression Tracking: The routine extensively utilizes SRAM flags and item possession checks to track Link's progress through various quests and milestones, influencing the dialogue provided.
Modular Message System: The use of FortuneTeller_PrepareNextMessage and FortuneTeller_DisplayMessage allows for a structured and modular approach to managing and displaying NPC dialogue.

4.2 KiB Raw Blame History