Client Events

Being able to listen to events is a fundamental feature. Kursive uses
Arcade's event system and is provided through context.events. All client events live under net.casual.arcade.events.client and implement ClientSideEvent.

While typically fabric mods use events provided by fabric api for example: ClientTickEvents.START_CLIENT_TICK, these should be avoided as registered listeners here are permanent and won't be cleaned up when your script stops.

Registering a Listener

Arcade provides a register extension function that allows you register an event listener based on the type parameter provided. In the below example we send a "Welcome back!" message to the player whenever the join a world/server:

// This extension function is required
import net.casual.arcade.events.utils.register

suspend fun main(minecraft: Minecraft, context: ClientScriptContext) {
    context.events.register<PlayerJoinEvent> { event ->
        event.player.sendSystemMessage(Component.literal("Welcome back!"))
    }
    awaitCancellation()
}

Remember to keep the script alive with awaitCancellation(); if main returns the script stops and your listener goes with it.

To find a full list of listen-able events you can see all implementors of the ClientSideEvent interface in IntelliJ.

For full details about how the event system works you can read arcade's documentation.

More Examples

One of the most useful client events is GuiRenderEvent as that allows you to hook into the gui rendering code, letting you render things to the HUD:

context.events.register<GuiRenderEvent> { event ->
    val player = minecraft.player ?: return@register
    val text = "Health: ${player.health.toInt()}"
    event.graphics.text(minecraft.font, text, 4, 4, 0xFFFFFFFF.toInt())
}

We can also intercept serverbound packets and prevent them from being sent by cancelling the event or replacing the packet being sent entirely:

context.events.register<ServerboundPacketEvent> { event ->
    val packet = event.packet
    if (packet is ServerboundAttackPacket) {
        event.cancel()
    } else if (packet is ServerboundChatPacket) {
        event.packet = ServerboundChatPacket(
            "I replaced your message!", packet.timeStamp, packet.salt, null, packet.lastSeenMessages
        )
    }
}

Missing Events

Arcade doesn't have a very long list of available ClientSideEvents, if there's an event that you'd like to be implemented either make an issue report on the GitHub or send a message on my discord.