What does deduplicate do to "include_background_gfx!"?

[sigmasoldi3r]

I have a boot sequence in mind: A splash screen, and then, an animated background (If that's possible).

include_background_gfx!(backgrounds,
    splash => deduplicate "assets/boot_splash.aseprite",
    title => deduplicate "assets/main_menu.aseprite"
);

And my sequence:

    sfx.play_main_sound().expect("Could not start the song!");
    splash.show(&gfx);
    let mut i = 0;
    loop {
        sfx.frame();
        i += 1;
        if i > 200000 {
            break;
        }
    }
    splash.destroy(&gfx);
    title.show(&gfx);
    agb::display::busy_wait_for_vblank();
    input.update();
    sfx.frame();

The point

If I remove the deduplicate keyword:

Note: The second background contains some frames instead of being a static image, that may be related?

[gwilymk]

Deduplicate will look at every tile that's needed to show a background, along with every horizontal and vertical flip to try and reduce the amount of space needed. Because if you show the same tile in multiple places in your background, then we only need to put it into video ram (vram) once and reference the same tile multiple times. You'll see a big difference if you look at the vram viewer in your emulator between enabling deduplicate and disabling it.

There isn't enough space in vram in the GBA for every tile to be unique when working with 256 colour palettes, so in that case you will need some repetition to make sure it fits in the limited space you have.

[sigmasoldi3r]

Thanks for the answer!

Another thing that I don't understand from the library is, that there are mentions to that 256 colour palettes. But, the macro include_background_gfx!() panics if my pictures include more than 16 colours.

[corwinkuiper]

You need to import them specifying 256 mode, see this as an example:

agb/examples/combo/src/lib.rs

Lines 41 to 48 in 288789f

	include_background_gfx!(
	games, "121105",
	hat => 256 deduplicate "gfx/hat.png",
	purple => 256 deduplicate "gfx/purple.png",
	hyperspace => 256 deduplicate "gfx/hyperspace.png",
	dungeon_puzzler => 256 deduplicate "gfx/dungeon_puzzler.png",
	amplitude => 256 deduplicate "gfx/amplitude.png",
	);