oracle-of-secrets/Docs/Sprites/Kydreeok.md

Kydreeok Sprite Analysis

Overview

The kydreeok sprite (ID: Sprite_Kydreeok, which is $7A) represents the main Kydreeok boss. It orchestrates the entire boss fight, including spawning and managing its child head sprites (kydreeok_head), controlling its own movement phases, and handling its overall defeat. This is a multi-headed boss where the heads are separate sprites.

Key Properties:

• Sprite ID: Sprite_Kydreeok ($7A)
• Description: The main Kydreeok boss, controlling the overall fight and its child heads.
• Number of Tiles: 8
• Health: 00 (The boss's health is managed through its child heads and custom logic, not directly by this sprite's !Health property.)
• Damage: 00 (Damage dealt to Link is likely handled by its heads or custom logic.)
• Special Properties:
  • !Boss = 01 (This sprite is correctly identified as a boss.)
  • !Hitbox = $07

Main States/Actions (Sprite_Kydreeok_Main Jump Table):

The boss's behavior is divided into several phases:

• Kydreeok_Start (0x00): Initial state. Applies graphics and palette, prevents Link from passing through, and transitions to Kydreeok_StageControl after a timer. Stores its own sprite index in Kydreeok_Id.
• Kydreeok_StageControl (0x01): Manages the boss's movement stage, setting velocities and checking boundaries.
• Kydreeok_MoveXandY (0x02): Moves the boss in both X and Y directions towards Link, checking boundaries and handling damage.
• Kydreeok_MoveXorY (0x03): Moves the boss in either X or Y direction towards Link, checking boundaries and handling damage.
• Kydreeok_KeepWalking (0x04): Continues walking, with a random chance to transition to a flying state.
• Kydreeok_Dead (0x05): Handles the boss's death sequence, including visual effects (flickering, explosions) and eventually despawning the sprite.
• Kydreeok_Flying (0x06): The boss enters a flying state, moving towards Link at a set height, checking boundaries and handling damage.

Initialization (Sprite_Kydreeok_Prep):

• Sets initial timers and movement speeds.
• Caches its own origin position.
• Spawns its child heads: Calls JSR SpawnLeftHead and JSR SpawnRightHead. A SpawnCenterHead routine is commented out, suggesting a potential for a three-headed boss.
• Initializes neck offsets to zero.
• Applies a custom palette (JSR ApplyPalette).
• Sets the boss theme music.

Death and Respawn Logic (Sprite_Kydreeok_CheckIfDead, MaybeRespawnHead):

• Sprite_Kydreeok_CheckIfDead: This crucial routine checks the state of its child heads (Offspring1_Id, Offspring2_Id). If both heads are defeated, it triggers a "dead" phase, changes its graphics, respawns both heads, and then transitions to the Kydreeok_Dead state. This indicates a multi-phase boss where heads can be temporarily defeated.
• MaybeRespawnHead: Randomly respawns a head if its corresponding child sprite is dead, adding a dynamic challenge to the fight.

Head Spawning (SpawnLeftHead, SpawnRightHead):

• These routines spawn Sprite_KydreeokHead ($CF) sprites.
• They assign SprSubtype to the spawned heads ($00 for left, $01 for right), allowing the child sprites to differentiate their behavior.
• They store the IDs of the spawned heads in global variables (Offspring1_Id, Offspring2_Id).
• They set the initial position of the heads relative to the main boss and initialize neck segment coordinates.

Movement (MoveBody, StopIfOutOfBounds):

• MoveBody: Manages the main body's movement, calling JSL Sprite_Move and updating background scrolling based on its movement. It reuses logic from Trinexx_MoveBody.
• StopIfOutOfBounds: Prevents the boss from moving beyond screen boundaries. It also subtly adjusts the neck positions when hitting a boundary, creating a visual "pushing" effect.

Palette Management (ApplyPalette, ApplyEndPalette):

• ApplyPalette: Sets the initial palette for the boss.
• ApplyEndPalette: Sets a different palette, likely for a defeated state or phase change.

Graphics Transfer (ApplyKydreeokGraphics):

• Handles DMA transfer of graphics data (kydreeok.bin, kydreeok_phase2.bin) to VRAM, allowing for different graphical appearances across phases.

Global Variables for Neck Control:

• LeftNeck1_X to LeftNeck3_Y, RightNeck1_X to RightNeck3_Y: Global RAM addresses used to store the coordinates of the neck segments, enabling the heads to track them.
• Kydreeok_Id: Stores the sprite index of the main Kydreeok boss.
• Offspring1_Id, Offspring2_Id: Store the sprite indices of the spawned heads.

Discrepancies/Notes:

• The !Health and !Damage properties are 00, confirming that the boss's health and damage are managed through its heads (Sprite_KydreeokHead) and custom logic within Sprite_Kydreeok_CheckIfDead.
• The Sprite_Kydreeok_CheckIfDead routine clearly defines a multi-phase fight where the heads can be defeated, respawned, and ultimately lead to the main boss's defeat.
• The commented-out SpawnCenterHead suggests a potential for a three-headed Kydreeok that was either removed or is an unimplemented feature.
• Reusing movement logic from Trinexx_MoveBody is efficient but should be considered for unique boss feel.
• Hardcoded addresses for JSL calls could be replaced with named labels for better maintainability.