Add documentation for custom enemy sprites: Eon Scrub, Keese, Leever, and Octorok
- Created detailed markdown files for Eon Scrub, Keese, Leever, and Octorok sprites. - Included sprite properties, main logic, drawing routines, and design patterns for each sprite. - Highlighted unique behaviors, state machines, and interactions with the player for each enemy type. - Ensured clarity in the implementation details and provided assembly code snippets for reference.
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scawful
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Docs/Sprites/Keese.md
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293
Docs/Sprites/Keese.md
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# Keese
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## Overview
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The Keese sprite (`!SPRID = $11`) is a versatile enemy that encompasses multiple variations: Ice Keese, Fire Keese, and Vampire Bat. Its behavior is dynamically determined by its `SprSubtype`.
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## Subtypes
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* `00` - Ice Keese
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* `01` - Fire Keese
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* `02` - Vampire Bat
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## Sprite Properties
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* **`!SPRID`**: `$11` (Vanilla sprite ID for Keese/Vampire Bat)
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* **`!NbrTiles`**: `08`
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* **`!Harmless`**: `00`
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* **`!HVelocity`**: `00`
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* **`!Health`**: `00` (Dynamically set in `_Prep` based on subtype)
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* **`!Damage`**: `00` (Damage is handled by projectiles or specific attack logic)
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* **`!DeathAnimation`**: `00`
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* **`!ImperviousAll`**: `00`
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* **`!SmallShadow`**: `00`
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* **`!Shadow`**: `01`
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* **`!Palette`**: `00`
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* **`!Hitbox`**: `00`
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* **`!Persist`**: `00`
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* **`!Statis`**: `00`
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* **`!CollisionLayer`**: `00`
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* **`!CanFall`**: `00`
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* **`!DeflectArrow`**: `00`
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* **`!WaterSprite`**: `00`
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* **`!Blockable`**: `00`
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* **`!Prize`**: `00` (Dynamically set in `_Prep` based on subtype)
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* **`!Sound`**: `00`
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* **`!Interaction`**: `00`
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* **`!Statue`**: `00`
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* **`!DeflectProjectiles`**: `00`
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* **`!ImperviousArrow`**: `00`
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* **`!ImpervSwordHammer`**: `00`
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* **`!Boss`**: `00`
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## Main Structure (`Sprite_Keese_Long`)
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This routine dispatches to different drawing and main logic routines based on the sprite's `SprSubtype`.
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```asm
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Sprite_Keese_Long:
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{
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PHB : PHK : PLB
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LDA.w SprSubtype, X : CMP.b #$02 : BEQ +
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JSR Sprite_Keese_Draw
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JSL Sprite_DrawShadow
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JSL Sprite_CheckActive : BCC .SpriteIsNotActive
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JSR Sprite_Keese_Main
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.SpriteIsNotActive
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JMP ++
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+
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JSR Sprite_VampireBat_Draw
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JSL Sprite_DrawShadow
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JSL Sprite_CheckActive : BCC ++
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JSR Sprite_VampireBat_Main
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++
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PLB
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RTL
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}
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```
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## Initialization (`Sprite_Keese_Prep`)
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This routine initializes sprite properties upon spawning, including health and prize, based on its subtype.
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```asm
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Sprite_Keese_Prep:
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{
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PHB : PHK : PLB
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LDA.b #$80 : STA.w SprDefl, X
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LDA.b #$30 : STA.w SprTimerC, X
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LDA.w SprSubtype, X : CMP.b #$02 : BNE +
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LDA.b #$20 : STA.w SprHealth, X
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BRA ++
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+
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LDA.b #$03 : STA.w SprNbrOAM, X
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LDA.b #$03 : STA.w SprPrize, X
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++
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PLB
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RTL
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}
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```
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## Main Logic & State Machine (`Sprite_Keese_Main`)
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The Keese's behavior is managed by a state machine with `Keese_Idle` and `Keese_FlyAround` states.
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* **`Keese_Idle`**: The sprite remains stationary until Link is within a certain distance, then transitions to `Keese_FlyAround`.
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* **`Keese_FlyAround`**: The Keese flies around, plays an animation, checks for collisions with Link and tiles, and can initiate an attack. It uses `GetRandomInt` for varied movement and `Sprite_ProjectSpeedTowardsPlayer` to move towards Link.
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```asm
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Sprite_Keese_Main:
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{
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LDA.w SprAction, X
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JSL JumpTableLocal
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dw Keese_Idle
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dw Keese_FlyAround
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Keese_Idle:
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{
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STZ.w SprFrame, X
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; Wait til the player is nearby then fly around
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LDA.w SprTimerC, X : BEQ .move
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JSL GetDistance8bit_Long : CMP.b #$20 : BCS +
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.move
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INC.w SprAction, X
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JSL GetRandomInt
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STA.w SprTimerA, X
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+
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RTS
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}
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Keese_FlyAround:
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{
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%PlayAnimation(0,5,8)
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JSL Sprite_CheckDamageToPlayer
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JSL Sprite_CheckDamageFromPlayer : BCC +
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JSL ForcePrizeDrop_long
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+
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JSL Sprite_DamageFlash_Long
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JSL Sprite_BounceFromTileCollision
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JSL GetRandomInt : AND.b #$3F : BNE +
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LDA.b #$10 : STA.w SprTimerC, X
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+
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JSR Sprite_Keese_Attack
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LDA.w SprTimerA, X : AND.b #$10 : BNE +
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LDA.b #$40
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JSL Sprite_ProjectSpeedTowardsPlayer
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+
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JSL Sprite_SelectNewDirection
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JSL Sprite_Move
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LDA.w SprTimerA, X : BNE +
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STZ.w SprAction, X
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+
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RTS
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}
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}
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```
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## Attack Logic (`Sprite_Keese_Attack`)
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This routine handles the Keese's attack, which varies by subtype:
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* **Ice Keese (`SprSubtype = 0`)**: Spawns sparkle garnish and a blind laser trail.
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* **Fire Keese (`SprSubtype = 1`)**: Utilizes `Sprite_Twinrova_FireAttack`.
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```asm
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Sprite_Keese_Attack:
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{
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LDA.w SprTimerC, X : BEQ +
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LDA.w SprSubtype, X : BEQ ++
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JSL Sprite_Twinrova_FireAttack
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JMP +
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++
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JSL Sprite_SpawnSparkleGarnish
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JSL BlindLaser_SpawnTrailGarnish
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+
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RTS
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}
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```
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## Drawing (`Sprite_Keese_Draw`)
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The drawing routine handles OAM allocation, animation, and palette adjustments based on the sprite's subtype. It explicitly uses `REP #$20` and `SEP #$20` for 16-bit coordinate calculations.
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```asm
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Sprite_Keese_Draw:
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{
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JSL Sprite_PrepOamCoord
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JSL Sprite_OAM_AllocateDeferToPlayer
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LDA.w SprFrame, X : TAY ;Animation Frame
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LDA .start_index, Y : STA $06
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LDA.w SprFlash, X : STA $08
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LDA.w SprMiscB, X : STA $09
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LDA.w SprSubtype, X : CMP.b #$01 : BNE +
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LDA.b #$0A : EOR $08 : STA $08
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+
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PHX
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LDX .nbr_of_tiles, Y ;amount of tiles -1
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LDY.b #$00
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.nextTile
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PHX ; Save current Tile Index?
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TXA : CLC : ADC $06 ; Add Animation Index Offset
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PHA ; Keep the value with animation index offset?
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ASL A : TAX
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REP #$20
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LDA $00 : CLC : ADC .x_offsets, X : STA ($90), Y
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AND.w #$0100 : STA $0E
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INY
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LDA $02 : CLC : ADC .y_offsets, X : STA ($90), Y
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CLC : ADC #$0010 : CMP.w #$0100
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SEP #$20
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BCC .on_screen_y
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LDA.b #$F0 : STA ($90), Y ;Put the sprite out of the way
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STA $0E
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.on_screen_y
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PLX ; Pullback Animation Index Offset (without the *2 not 16bit anymore)
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INY
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; If SprMiscA != 0, then use 4th sheet
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LDA.b $09 : BEQ +
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LDA .chr_2, X : STA ($90), Y
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JMP ++
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+
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LDA .chr, X : STA ($90), Y
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++
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INY
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LDA .properties, X : ORA $08 : STA ($90), Y
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PHY
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TYA : LSR #2 : TAY
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LDA .sizes, X : ORA $0F : STA ($92), Y ; store size in oam buffer
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PLY : INY
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PLX : DEX : BPL .nextTile
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PLX
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RTS
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.start_index
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db $00, $01, $03, $04, $06, $08
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.nbr_of_tiles
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db 0, 1, 0, 1, 1, 0
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.x_offsets
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dw 0
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dw -4, 4
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dw 0
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dw -4, 4
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dw -4, 4
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dw 0
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.y_offsets
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dw 0
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dw 0, 0
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dw 0
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dw 0, 0
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dw 0, 0
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dw 0
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.chr
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db $80
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db $A2, $A2
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db $82
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db $84, $84
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db $A4, $A4
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db $A0
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.chr_2
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db $C0
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db $E2, $E2
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db $C2
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db $C4, $C4
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db $E4, $E4
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db $E0
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.properties
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db $35
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db $35, $75
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db $35
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db $35, $75
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db $35, $75
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db $35
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.sizes
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db $02
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db $02, $02
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db $02
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db $02, $02
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db $02, $02
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db $02
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}
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```
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## Design Patterns
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* **Subtype-based Behavior**: The sprite uses `SprSubtype` to implement distinct behaviors and appearances for Ice Keese, Fire Keese, and Vampire Bat, all under a single `!SPRID`.
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* **Dynamic Property Initialization**: Health and prize values are set dynamically during the `_Prep` routine based on the sprite's subtype.
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* **Conditional Drawing and Palette**: The drawing routine adjusts the sprite's palette and potentially its graphics based on its subtype, allowing for visual differentiation.
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* **Randomized Movement**: Utilizes `GetRandomInt` to introduce variability in movement patterns, making the enemy less predictable.
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* **Projectile Attacks**: Implements different projectile attacks based on subtype, showcasing varied offensive capabilities.
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* **16-bit OAM Calculations**: Demonstrates explicit use of `REP #$20` and `SEP #$20` for precise 16-bit OAM coordinate calculations, which is crucial for accurate sprite rendering.
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