Graphics

VRAM Layouts

Here are some general layouts for the structure of VRAM in various scenarios.

In-game

Bank 0
Address range	Graphics
8000-8fff	Dynamically allocated sprite graphics for npcs, enemies, etc
9000-91ff	gfx_hud (digits for rupees, hearts, etc)
9200-93ff(?)	"Tree" graphics for different treetops (can also be used for other things, ie. vasu's sign in seasons). See data/{game}/treeGfxHeaders.s(ages/seasons).
9400-97ff	Textbox graphics

Bank 1
Address range	Graphics
8000-84df	spr_common_sprites
84e0-851f	Boomerang sprite
8520-85f0(?)	Weapon sprite (sword, cane, etc)
8600-86ff	Companion sprites (w1Companion)
8700-877f(?)	Link sprites
8780-87ff	Inventory item sprites (items on the HUD)
8800-97ff	Tileset graphics

Inventory menu

Bank 0
Address range	Graphics
8000-82ff	gfx_inventory_hud_1
8300-83ff	gfx_present_past_symbols
8400-85ff	gfx_quest_items_5
8600-867f	gfx_save
8680-87ff	gfx_map_compass_keys_bookofseals (first quarter not visible)
8800-89ff	gfx_blank
8a00-8dff	gfx_rings
8e00-8fff	gfx_inventory_hud_2
9000-97ff	Unused

Bank 1
Address range	Graphics
8000-81ff	gfx_item_icons_1_spr
8200-83ff	gfx_item_icons_2
8400-85ff	gfx_item_icons_3
8600-877f	gfx_essences
8780-87ff	A and B button item graphics (dynamically changing)
8800-89ff	gfx_quest_items_1
8a00-8bff	gfx_quest_items_2
8c00-8dff	gfx_quest_items_3
8e00-8fff	gfx_quest_items_4
9000-91ff	Unused
9200-93ff	Text (in the bar at the bottom of the screen)
9400-97ff	Unused

Graphics file list

The disassembly has two folders with graphics, the "gfx" folder and the "gfx_compressible" folder. Files in the "gfx_compressible" folder are, of course, compressible, while files in the "gfx" folder are not. Most graphics are compressible, but there are certain cases where it's advantageous to store graphics uncompressed.

There are four types of graphics files:

• gfx_: Graphics data.
• spr_: Graphics data; assumed to be an interleaved sprite, which affects how the PNG is converted to gameboy tiles.
• map_: A tilemap which specifies where to draw which tiles. Usually has a corresponding "flg_".
• flg_: "Flag" or "attribute" data that determines which palettes to use, whether to flip the tile, etc. (These won't be listed since they always correspond to a "map_".)

This is a list of some files in these folders. It isn't complete; it just lists some of the most important graphics, or the ones that aren't self-explanitory.

gfx folder

Filename	Description
gfx_animations_*	These are tiles used for animating the background layer (ie. water, lava, waterfalls).
spr_dungeon_sprites	Graphics for various objects (minecarts, moving platforms, etc).
gfx_font	This is the font used in textboxes and whatnot. Unlike most other graphics, it's stored in 1bpp format. The first 14 characters are ignored.
gfx_font_jp	This file contains mostly kanji, so it's not used much in the english version. It also contains a triangle symbol, though, which is used. 1bpp format.
gfx_font_tradeitems	These are trade item icons used in textboxes. 2bpp format.
spr_item_icons_[1,2,3]	These are item icons. They're used in the inventory screen (but the A/B buttons always use sprites; see "spr_item_icons_1_spr" in the "gfx_compressible" folder.)
gfx_link	Link.
gfx_past_chest	This file overwrites the chest graphics whenever Link is in the past. This is helpful for indoor areas that use the same tileset in both the past and the present.
gfx_past_sign	Same idea as gfx_past_chest.
map_rings	Each 8 bytes of this file defines the tilemap and the attributes needed to display each ring.

gfx_compressible folder

Filename	Description
gfx_blurb_*	A graphic to show when opening the map in each dungeon.
spr_common_items	Graphics for the most common item drops (rupees, hearts, fairies, seeds, etc).
spr_common_sprites	Graphics for many common sprites (explosions, somaria block, etc). Always loaded in address 1:8000 during normal gameplay.
gfx_dungeon_map_tiles	Graphics for the dungeon map, as well as the cursor (which is also used on the overworld map).
gfx_hud	Status bar tiles (plus arrow tiles used for textboxes). Usually loaded at 0:9000.
gfx_inventory_hud	Tiles used in the inventory and the ring list screen.
spr_item_icons_1_spr	This is analagous to "spr_item_icons_1" in the "gfx" folder, except it's formatted slightly differently to be usable as sprites. Item icons are sprites when on the A or B buttons; otherwise, they're on the background layer. (gfx_item_icons_2 and 3 don't have sprite versions; apparently, they can be used on both the background and sprite layers already.)
gfx_map_icons	Icons that appear when you hover over certain areas of the map; and other miscellaneous things (arrows and sparkles for the time portal)
gfx_map_tiles_common	Tiles used for both the past and present overworld maps.
gfx_map_tiles_[present,past]_*	Tiles used specifically for the present or past overworld maps.
map_inventory_[1-3]	Tilemaps for each of the three subscreens of the inventory.

Object Animations

All of the graphics that can be displayed for an object are handled by animations, even when the "animation" consists of a static image. The animation data is mostly stored in two files: data/<game>/*Animations.s and data/<game>/*OamData.s, where the * can be replaced with interaction, enemy, or specialObject. For special objects, like Link, there is an additional third file called data/<game>/specialObjectAnimationPointers.s. These files exist in both games.

Animations.s

Contents

The bulk of this file is made up of pointer tables.

The first is the Object Animation Table, which maps each object to a list of animations based on that object's ID (interaction ID, enemy ID, or specialObject ID). The second is the Object OAM Table, which maps each object to a list of OAM Blocks. It's also indexed by the object's ID.

Next come the Animation Lists, which are pointed to by the Object Animation Table. These lists point to the actual animation data, which is made up of one or more states. Each state has the following format:

Animation Data Format
Byte	Description
0	State Length, presumably in frames
1	OAM List Offset, an offset into the object's OAM List (described below)
2	Unknown, possibly used by code to trigger events?

Each animation state represents a specific OAM setup for the object to be rendered with.

Animation State Example

For example, the basic NPC idle animation of the sprite moving back and forth, as seen in the GIF on the right, is made up of two states: one that sets up OAM to render the sprite as it appears in the sprite-sheet, and one that sets up OAM to render the sprite flipped horizontally.

The last bits of data in *Animations.s are the OAM Lists. These are pointers to the OAM Tiles located in the *OamData.s files.

OamData.s

Contents

*OamData.s contains the OAM tile data used by the animations to set up OAM to render the object. Each label represents an OAM Block, and each OAM Block is made up of zero or more OAM Tiles.

Each OAM Block is composed of a single byte that dictates how many OAM Tiles there are, followed by the Tiles themselves. They have the following format:

OAM Tile Format
Byte	Description
0	Y Position of the tile
1	X Position of the tile
2	Sprite Tile Number (In 8x16 mode, the lower bit of the tile number is ignored. IE: the upper 8x8 tile is "NN AND FEh", and the lower 8x8 tile is "NN OR 01h".)
3	A bitfield, enumerated below

Byte 3 Bitfield
Bit	Description
0-2	GBC Palette Number (palettes 0-7)
3	Tile VRAM-Bank (should probably be 0 for most things)
4	GB Palette Number (palettes 0-1, probably unused in GBC?)
5	X Flip (0=Normal, 1=Horizontally mirrored)
6	Y Flip (0=Normal, 1=Vertically mirrored)
7	OBJ-to-BG Priority (0=OBJ Above BG, 1=OBJ Behind BG color 1-3); Used for both BG and Window. BG color 0 is always behind OBJ