Object texture file

This is the texture/graphics format used by objects.

It contains graphics for all body parts / limbs in the same file, and objects use TexQuad frames to locate pos/size of each limb:

Graphics data for the ELEMENTAL object. (For reference, ELEMENTAL object data is in file ID 25257, and its graphics data is in file ID 7303).

File format

The file itself starts with its own color palette table, and is followed by its dimensions and graphics data:

u8 color_count;
u16 colors[color_count];
u8 width;
u8 height;
u8 char_data[width * height / 2];

Color and pixel formats

Colors are XBGR1555 format: 5-bits per color, where the final bit is ignored (see below how alpha is dealt with).

The implicit format for graphic character data is 4BPP, hence each char data u8 contains information for two pixels (low 4-bits for the first pixel, high 4-bits for the next one). Each of these 4-bit values is just a color index (index in the preceding color table).

The first color is considered transparent by the game: although the first color table entry usually has a purple color (full red+blue color, #FF00FF if it were converted to RGB). In other words, if the 4-bit char data value is 0 for a given pixel, then that pixel is seen as transparent in-game.

Note: this is something frequently seen as well in other DS games