Enum Command

pub enum Command {
    MemoryPreset {
        color: u8,
        repeat: u8,
    },
    BorderPreset {
        color: u8,
    },
    TileNormal {
        tile: Tile,
    },
    TileXOR {
        tile: Tile,
    },
    Scroll {
        color: Option<u8>,
        cmd: (ScrollCommand, ScrollCommand),
        offset: (u8, u8),
    },
    SetTransparent {
        color: u8,
    },
    LoadPalette {
        offset: u8,
        clut: [RgbColor; 8],
    },
}

One drawing command

Variants

MemoryPreset

Clear the scren to color. This command will usually appear multiple times in a row with repeat incrementing each time, starting at 0. If you trust your CDG to be without errors, you can therefore ignore MemoryPreset commands with a nonzero repeat value

Fields

color: u8

repeat: u8

BorderPreset

Clear the border region to color. Documents vary as to whether the border region is the outside tile or the outside half-tile.

Fields

color: u8

TileNormal

Draw a tile normally

Fields

tile: Tile

TileXOR

Draw a tile by XORing the color indices in the tile with the colors indices already drawn. Note that this does not operate on RGB values.

Fields

tile: Tile

Scroll

Scroll the screen by the given horizontal and vertical amount, respectively. offset is given as an absolute position within the first tile to begin scanout.

If color is none, the tiles scrolled off one side of the framebuffer should be copied to the other side. Otherwise, they should be filled in with color

Fields

color: Option<u8>

cmd: (ScrollCommand, ScrollCommand)

offset: (u8, u8)

SetTransparent

Set one element of the CLUT to transparent, to enable background video/images

Fields

color: u8

LoadPalette

Load one half of the CLUT. offset will be either 0 or 8, depending on whether the bottom or top half of the CLUT is to be loaded.

These changes take effect immediately, so this can be used to implement color cycling.

Fields

offset: u8

clut: [RgbColor; 8]

Trait Implementations

impl Debug for Command

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.