examples: Add rainbow effect

Signed-off-by: Patrick José Pereira <[email protected]>

examples/rainbow.rs

@@ -0,0 +1,30 @@
+use navigator_rs::Navigator;
+use std::thread::sleep;
+use std::time::Duration;
+
+fn color_from_sine(percentage: f32) -> [u8; 3] {
+    let pi = std::f32::consts::PI;
+    let red = (percentage * 2.0 * pi).sin() * 0.5 + 0.5;
+    let green = ((percentage + 0.33) * 2.0 * pi).sin() * 0.5 + 0.5;
+    let blue = ((percentage + 0.67) * 2.0 * pi).sin() * 0.5 + 0.5;
+    [
+        (red * 255.0) as u8,
+        (green * 255.0) as u8,
+        (blue * 255.0) as u8,
+    ]
+}
+
+fn main() {
+    let mut nav = Navigator::new();
+    nav.init();
+
+    println!("Creating rainbow effect!");
+    loop {
+        let steps = 1000;
+        for i in 0..=steps {
+            let ratio = i as f32 / steps as f32;
+            nav.set_neopixel(&[color_from_sine(ratio)]);
+            sleep(Duration::from_millis(10));
+        }
+    }
+}