oracle-of-secrets/Docs/Sprites/NPCs/Goron.md

Goron

Overview

The Goron sprite (!SPRID = $F2) is a versatile NPC implementation that can represent two distinct Goron characters: the "Kalyxo Goron" and the "Eon Goron." Their specific behaviors and appearances are determined by the global WORLDFLAG and the current AreaIndex. These Gorons primarily serve as interactive NPCs, engaging Link through dialogue and potentially triggering game events.

Sprite Properties

• !SPRID: $F2 (Vanilla sprite ID, likely for a generic NPC)
• !NbrTiles: 04
• !Harmless: 01
• !HVelocity: 00
• !Health: 00
• !Damage: 00
• !DeathAnimation: 00
• !ImperviousAll: 00
• !SmallShadow: 00
• !Shadow: 00
• !Palette: 00
• !Hitbox: 02
• !Persist: 00
• !Statis: 00
• !CollisionLayer: 00
• !CanFall: 00
• !DeflectArrow: 00
• !WaterSprite: 00
• !Blockable: 00
• !Prize: 00
• !Sound: 00
• !Interaction: 00
• !Statue: 00
• !DeflectProjectiles: 00
• !ImperviousArrow: 00
• !ImpervSwordHammer: 00
• !Boss: 00

Main Structure (Sprite_Goron_Long)

This routine acts as a dispatcher, selecting the appropriate drawing routine based on the WORLDFLAG (Kalyxo Goron if 0, Eon Goron otherwise). It also handles shadow drawing and dispatches to the main logic if the sprite is active.

Sprite_Goron_Long:
{
  PHB : PHK : PLB
  LDA.w WORLDFLAG : BEQ .kalyxo
    JSR Sprite_EonGoron_Draw
    JMP +
  .kalyxo
  JSR Sprite_KalyxoGoron_Draw
  +
  JSL Sprite_DrawShadow
  JSL Sprite_CheckActive : BCC .SpriteIsNotActive
    JSR Sprite_Goron_Main
  .SpriteIsNotActive
  PLB
  RTL
}

Initialization (Sprite_Goron_Prep)

This routine initializes the Goron upon spawning. It sets SprDefl, X to $80. The initial SprAction, X is determined by WORLDFLAG and AreaIndex. For Eon Gorons, it can randomly set their initial action to EonGoron_Main, EonGoron_Sing, or EonGoron_Punch. For Kalyxo Gorons, it checks a specific flag ($7EF280, X) to set their initial action to KalyxoGoron_Main or KalyxoGoron_MinesOpened.

Sprite_Goron_Prep:
{
  PHB : PHK : PLB
  LDA.w WORLDFLAG : BEQ +
    LDA.w AreaIndex : CMP.b #$55 : BNE .not_sing
      LDA.b #$04 : STA.w SprAction, X
    .not_sing
    JSL GetRandomInt : AND.b #$01 : BEQ .rand
      LDA.b #$05 : STA.w SprAction, X
      JMP ++
    .rand
    LDA.b #$03 : STA.w SprAction, X
    JMP ++
  +
  PHX
  LDX $8A
  LDA.l $7EF280, X : CMP.b #$20 : BEQ +++
    PLX
    STZ.w SprAction, X
  ++
  PLB
  RTL
  +++
  PLX
  LDA.b #$02 : STA.w SprAction, X
  PLB
  RTL
}

Main Logic & State Machine (Sprite_Goron_Main)

This routine manages the various states and behaviors of both Kalyxo and Eon Gorons.

• Player Collision: Prevents Link from passing through the Goron (Sprite_PlayerCantPassThrough).
• KalyxoGoron_Main: Displays messages (%ShowSolicitedMessage) based on the RockMeat item count. Can transition to KalyxoGoron_OpenMines under certain conditions.
• KalyxoGoron_OpenMines: Plays an animation, sets a flag ($04C6) to open mines, and transitions to KalyxoGoron_MinesOpened.
• KalyxoGoron_MinesOpened: Plays an animation.
• EonGoron_Main: Plays an animation and displays a message.
• EonGoron_Sing: Plays a singing animation and displays a message.
• EonGoron_Punch: Plays a punching animation and displays a message.

Sprite_Goron_Main:
{
  JSL Sprite_PlayerCantPassThrough

  LDA.w SprAction, X
  JSL JumpTableLocal

  dw KalyxoGoron_Main
  dw KalyxoGoron_OpenMines
  dw KalyxoGoron_MinesOpened
  dw EonGoron_Main
  dw EonGoron_Sing
  dw EonGoron_Punch

  KalyxoGoron_Main:
  {
    LDA.l RockMeat : BEQ +
                     CMP.b #$05 : BCC ++
                     %ShowSolicitedMessage($01A9) : BCC +++
                     INC.w SprAction, X
                     +++
                     RTS
    +
    %ShowSolicitedMessage($01A7)
    RTS
    ++
    %ShowSolicitedMessage($01A8)
    RTS
  }

  KalyxoGoron_OpenMines:
  {
    %PlayAnimation(1,1,10)
    LDA.b #$04 : STA $04C6
    INC.w SprAction, X
    RTS
  }

  KalyxoGoron_MinesOpened:
  {
    %PlayAnimation(1,1,10)
    RTS
  }

  EonGoron_Main:
  {
    %PlayAnimation(0, 1, 10)
    %ShowSolicitedMessage($01B0)
    RTS
  }

  EonGoron_Sing:
  {
    %PlayAnimation(2, 3, 10)
    %ShowSolicitedMessage($01B2)
    RTS
  }

  EonGoron_Punch:
  {
    %PlayAnimation(4, 5, 10)
    %ShowSolicitedMessage($01B1)
    RTS
  }
}

Drawing (Sprite_KalyxoGoron_Draw and Sprite_EonGoron_Draw)

Both drawing routines handle OAM allocation and animation for their respective Goron types. They explicitly use REP #$20 and SEP #$20 for 16-bit coordinate calculations.

Design Patterns

• Multi-Character NPC (Conditional Drawing/Logic): A single sprite definition is used to represent two distinct Goron characters (Kalyxo and Eon) based on WORLDFLAG, demonstrating efficient resource utilization and context-sensitive character representation.
• Quest Progression Integration: The Gorons' dialogue and actions are tied to game state (e.g., RockMeat item count, AreaIndex), indicating their role in advancing the narrative and triggering specific events like opening mines.
• Conditional Behavior: Extensive use of conditional logic based on WORLDFLAG and AreaIndex allows for dynamic changes in the Goron's role, dialogue, and actions.
• NPC Interaction: Provides rich interaction with the player through dialogue (%ShowSolicitedMessage) and can trigger game events.
• Player Collision: Implements Sprite_PlayerCantPassThrough to make the NPC a solid object that Link cannot walk through.
• 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.