bevy_logic

A logic gate simulation plugin for bevy.

Features

• A LogicGraph resource for sorting (potentially cyclic) logic gate circuits.
• A separate LogicUpdate schedule with a fixed timestep.
• LogicGate trait queries.
• World and Commands extensions for spawning and removing logic gates and child fans.
• Events for LogicGraph simulation synchronization.
• Modular plugin design. Pick and choose the features you need.

Running examples

cargo run --release --example 3d

Custom logic gates

You can create your own logic gates by implementing the LogicGate trait...

use bevy_logic::prelude::*;

/// The XOR gate emits a signal if the number of true inputs is odd.
#[derive(Component, Clone, Copy, Debug, Default, Reflect)]
pub struct XorGate;

impl LogicGate for XorGate {
    fn evaluate(&self, inputs: &[Signal], outputs: &mut [Signal]) {
        let signal: Signal = inputs
            .iter()
            .filter(|s| s.is_true())
            .count()
            .is_odd()
            .into();

        outputs.set_all(signal);
    }
}

And then registering the component with bevy_trait_query...

struct CustomLogicPlugin;

impl Plugin for CustomLogicPlugin {
    fn build(&self, app: &mut App) {
        // We must import this trait in order to register our components.
        // If we don't register them, they will be invisible to the game engine.
        use bevy_trait_query::RegisterExt;
        app.register_component_as::<dyn LogicGate, XorGate>()
    }
}

You can use the logic::commands module to spawn gates and fans, and then connect fans with wires.

fn spawn_custom_gate(mut commands: Commands, mut sim: ResMut<LogicGraph>) {
    let xor_gate = commands
        .spawn_gate((Name::new("XOR"), XorGate))
        .with_inputs(2)
        .with_outputs(1)
        .build();

    let not_gate = commands
        .spawn_gate((Name::new("NOT"), NotGate))
        .with_inputs(1)
        .with_outputs(1)
        .build();

    let wire = commands.spawn_wire(&not_gate, 0, &xor_gate, 0).downgrade();

    sim.add_data(vec![xor_gate, not_gate]).add_data(wire);
}

Bevy Compatibility