Color changing Rects

main.rs

use bevy::prelude::*;
use bevy::diagnostic::{FrameTimeDiagnosticsPlugin, PrintDiagnosticsPlugin};

use rand::Rng;

struct Fluxel2D {
    width: u32,
    height: u32,
}

impl Plugin for Fluxel2D {
    fn build(&self, app: &mut AppBuilder)
    {
        app.add_startup_system(create_fluxel_field.system())
        .add_system(tick_fluxels.system());
    }
}

fn create_fluxel_field(mut commands: Commands,
    mut materials: ResMut<Assets<ColorMaterial>>,
) {

    commands.spawn(Camera2dComponents::default());

    let start = -(32f32 * 16f32);
    for idx in 0..=32 {
        for idy in 0..=32 {
            commands.spawn(SpriteComponents {
                material: materials.add(Color::rgb(0.2, 0.2, 0.8).into()),
                translation: Translation(Vec3::new(start + idx as f32 * 32.0, start + idy as f32 * 32.0, 0.0)),
                sprite: Sprite {
                    size: Vec2::new(32.0, 32.0),
                },
                ..Default::default()
            }).with(Fluxel{idx, idy});
        }
    }
}

struct Fluxel {
    idx: u32,
    idy: u32,
}

struct FluidMaterials {
    low: Handle<ColorMaterial>,
    mid: Handle<ColorMaterial>,
    high: Handle<ColorMaterial>,
}

impl FromResources for FluidMaterials {
    fn from_resources(resources: &Resources) -> Self {
        let mut materials = resources.get_mut::<Assets<ColorMaterial>>().unwrap();
        FluidMaterials {
            low: materials.add(Color::rgb(0.0, 0.0, 1.0).into()),
            mid: materials.add(Color::rgb(0.5, 0.0, 0.5).into()),
            high: materials.add(Color::rgb(1.0, 0.0, 0.0).into()),
        }
    }
}


// mut fluxel: Mut<Fluxel>, 
fn tick_fluxels(
    fluid_materials: Res<FluidMaterials>,
    mut mat_handle: Mut<Handle<ColorMaterial>>
) {
 
    let mut rng = rand::thread_rng();

    let fluid_amount = rng.gen_range(0.0, 1.0);
    let color = match fluid_amount {
        f if f < 0.33 => fluid_materials.low,
        f if f >= 0.33 && f < 0.66 => fluid_materials.mid,
        _ => fluid_materials.high,
    };
    *mat_handle = color;
    
    println!("Yahaha");
}


fn main() {
    App::build()
        .add_default_plugins()
        .init_resource::<FluidMaterials>()
        // .add_plugin(FrameTimeDiagnosticsPlugin::default())
        // .add_plugin(PrintDiagnosticsPlugin::default())
        .add_plugin(Fluxel2D{width:32, height:32})
        .run();
}