Module palette 

Palettes: what the two bits of a pixel turn into.

A tile pixel is two bits, so it names a colour index rather than a colour. The palette turns that index into a colour, which is why you can draw the same tile light in one place and dark in another.

On the original Game Boy the four shades are fixed in hardware and a palette only chooses which index gets which of them. On the Game Boy Color a palette holds four real colours. See https://gbdev.io/pandocs/Palettes.html.

Index 0 is transparent for objects, which leaves the lowest two bits of an object palette unused.

An original Game Boy ignores the colour registers and keeps drawing with the shades set_background chose, so a cartridge that runs on both machines can set colours without asking which it is on.

Structs

Colorcgb

One colour, five bits per channel.

Enums

ObjSlot

Which of the two object palettes, as OamAttr::dmg_palette picks between.

Constants

COLORScgb

Colours in one palette.

PALETTEScgb

Palettes of each kind: this many for the background, and as many again for objects.

Functions

background

The palette the background and window are drawn with.

object

One of the two object palettes.

set_background

Set the palette the background and window are drawn with.

set_background_colorscgb

Set one background palette.

set_object

Set one of the two object palettes.

set_object_colorscgb

Set one object palette.