Overlays - Composer

Package: com.codex.composer.api.v1.overlay

Composer offers a packet-based overlay system. Overlays can be triggered both on the client and server side, and can be fully customized. Composer implements two fully-specified overlays, one which displays colored text and one which displays a texture. You can send these overlays to the player using the class "Overlays", which is also where they are defined. On the client, the "OverlayManager" singleton can be used to manually queue and clear overlays, visible and active separately; Both are displayable using the a command (/overlay), though this command is hardcoded and not modifiable by third party mods.

The main overlay interface is the following:

Canonical Name: com.codex.composer.api.v1.overlay.impl.Overlay;

Inheritors must implement:

void render(DrawContext context, /*? float in 1.20.6 and below, else */RenderTickCounter tickDelta);
void tick();
boolean shouldRemove();
Identifier getId();

/* Whether this overlay is "blocked by" another active one. Ran when overlays are in the queue
   To see if they are able to be displayed. */
boolean blockedBy(Overlay other) default false;

There are two base implementations of this, AlignedOverlay and AnimatedOverlay, but since AnimatedOverlay extends AlignedOverlay only that will be documented.

Inheritors of that must implement (as defined in AnimatedOverlay):

void render(DrawContext context, /*? float in 1.20.6 and below, else */RenderTickCounter tickDelta, int x, int y);
Vec2 getPadding();
Vec2 getSize();

Among this, if you want to take advantage of the builtin overlay packet system, you must register an overlay serializer. You can do this using the vanilla registry system, registering to ComposerRegistries.OVERLAY_SERIALIZERS.

Important!

When registering an overlay serializer, you must register it from a ComposerPostInitialization callback! If you do it from your init method, there is a random chance based on what order mods are loaded that the registry will not exist yet, and the game will crash! You can do this by adding a 'composer-post-init' entrypoint to your fabric.mod.json pointing to a class that implements ComposerPostInitialization.

Example Implementation

From Composer

public static class TextOverlay extends AnimatedOverlay {
    private static final Identifier ID = Composer.identify("text");
    private final [text, color, scale, shadow];

    private TextOverlay(Anchor anchor, Animation animation, String text, int color, double scale, boolean shadow, int duration) {...}
    private TextOverlay(Anchor anchor, Animation animation, String text, int color, double scale, boolean shadow, int enter, int hold, int exit) {...}

    @Override
    protected void render(DrawContext context, /*? if minecraft: <=1.20.6 {*//*float*//*? } else {*/RenderTickCounter/*? }*/ f, int x, int y) {
        TextRenderer textRenderer = MinecraftClient.getInstance().textRenderer;
        float opacity = getOpacity(f);
        Opacitator.drawWithOpacity(opacity, false, (ignored, alpha) -> context.drawText(textRenderer, text, x, y, (alpha << 24) | color, shadow));
    }

    @Override
    protected Vec2 getSize() {
        TextRenderer textRenderer = MinecraftClient.getInstance().textRenderer;
        return new Vec2(textRenderer.getWidth(text), textRenderer.getWrappedLinesHeight(Text.literal(text), Integer.MAX_VALUE));
    }

    @Override protected Vec2 getPadding() { return new Vec2(10, 10); }
    @Override public Identifier getId() { return ID; }

    public static class Serializer implements PacketSerializer<TextOverlay> {
        @Override
        public void write(TextOverlay object, PacketByteBuf buf) {
            buf.writeEnumConstant(object.anchor);
            buf.writeString(object.text);
            buf.writeInt(object.color);
            buf.writeDouble(object.scale);
            buf.writeBoolean(object.shadow);
            object.writeAnimation(buf); // Defined by AnimatedOverlay
        }

        @Override
        public TextOverlay read(PacketByteBuf buf) {
            return new TextOverlay(
                    buf.readEnumConstant(Anchor.class),
                    null,
                    buf.readString(),
                    buf.readInt(),
                    buf.readDouble(),
                    buf.readBoolean(),
                    3
            ).readAnimation(buf);
        }
    }
}