VRAM Tile Data

Tile data is stored in VRAM in the memory area at $8000-$97FF; with each tile taking 16 bytes, this area defines data for 384 tiles. In CGB Mode, this is doubled (768 tiles) because of the two VRAM banks.

Each tile (or character) has 8×8 pixels and has a color depth of 2 bits per pixel, allowing each pixel to use one of 4 colors or gray shades. Tiles can be displayed as part of the Background/Window maps, and/or as objects (movable sprites). Color 0 has a special meaning in objects - it’s transparent, allowing the background or other objects behind it to show through.

There are three “blocks” of 128 tiles each:

Tile IDs for... Block 0 Block 1 Block 2
$8000–87FF $8800–8FFF $9000–97FF
Objects 0–127 128–255 —
BG/Win, if LCDC.4=1 0–127 128–255 —
BG/Win, if LCDC.4=0 — 128–255 0–127

Tiles are always indexed using an 8-bit integer, but the addressing method may differ:

  • The “$8000 method” uses $8000 as its base pointer and uses an unsigned addressing, meaning that tiles 0-127 are in block 0, and tiles 128-255 are in block 1.
  • The “$8800 method” uses $9000 as its base pointer and uses a signed addressing, meaning that tiles 0-127 are in block 2, and tiles -128 to -1 are in block 1; or, to put it differently, “$8800 addressing” takes tiles 0-127 from block 2 and tiles 128-255 from block 1.

(You can notice that block 1 is shared by both addressing methods)

Objects always use “$8000 addressing”, but the BG and Window can use either mode, controlled by LCDC bit 4.

Data format

Each tile occupies 16 bytes, where each line is represented by 2 bytes:

Byte1st2nd3rd4th...
ExplanationTopmost line (top 8 pixels)Second lineEtc.

For each line, the first byte specifies the least significant bit of the color ID of each pixel, and the second byte specifies the most significant bit. In both bytes, bit 7 represents the leftmost pixel, and bit 0 the rightmost. For example, the tile data $3C $7E $42 $42 $42 $42 $42 $42 $7E $5E $7E $0A $7C $56 $38 $7C appears as follows:

$3C $7E $42 $42 $42 $42 $42 $42 $7E $5E $7E $0A $7C $56 $38 $7C = a b c d e f g h 0 0 1 1 1 1 0 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 0 0 1 1 1 1 1 1 0 0 1 1 1 1 1 0 0 0 0 1 1 1 0 0 0 a b c d e f g h + i j k l m n o p 0 1 1 1 1 1 1 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 1 0 0 1 0 1 1 1 1 0 0 0 0 0 1 0 1 0 0 1 0 1 0 1 1 0 0 1 1 1 1 1 0 0 i j k l m n o p = ia jb kc ld me nf og ph 00 10 11 11 11 11 10 00 00 11 00 00 00 00 11 00 00 11 00 00 00 00 11 00 00 11 00 00 00 00 11 00 00 11 01 11 11 11 11 00 00 01 01 01 11 01 11 00 00 11 01 11 01 11 10 00 00 10 11 11 11 10 00 00 ia jb kc ld me nf og ph
Sample tile data

For the first row, the values $3C $7E are 00111100 and 01111110 in binary. The leftmost bits are 0 and 0, thus the color index is binary 00, or 0. The next bits are 0 and 1, thus the color index is binary 10, or 2 (remember to flip the order of the bits!). The full eight-pixel row evaluates to 0 2 3 3 3 3 2 0.

A tool for viewing tiles can be found here.

So, each pixel has a color index of 0 to 3. The color numbers are translated into real colors (or gray shades) depending on the current palettes, except that when the tile is used in an OBJ the color index 0 means transparent. The palettes are defined through registers BGP, OBP0 and OBP1, and BCPS/BGPI, BCPD/BGPD, OCPS/OBPI and OCPD/OBPD (CGB Mode).