From 9a420cb99028f56d856f7466b9c1a647633075fe Mon Sep 17 00:00:00 2001
From: Rajas Paranjpe <52586855+ChocolateLoverRaj@users.noreply.github.com>
Date: Sun, 18 Aug 2024 22:34:19 -0700
Subject: [PATCH] rp2040 zero rainbow using palette

---
 boards/waveshare-rp2040-zero/Cargo.toml       |  1 +
 .../waveshare_rp2040_zero_neopixel_rainbow.rs | 46 +++++++++----------
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/boards/waveshare-rp2040-zero/Cargo.toml b/boards/waveshare-rp2040-zero/Cargo.toml
index 801248a..afd49cc 100644
--- a/boards/waveshare-rp2040-zero/Cargo.toml
+++ b/boards/waveshare-rp2040-zero/Cargo.toml
@@ -12,6 +12,7 @@ repository = "https://github.com/rp-rs/rp-hal-boards.git"
 
 [dependencies]
 cortex-m-rt = { workspace = true, optional = true }
+palette = { version = "0.7.6", default-features = false, features = ["libm"] }
 rp2040-boot2 = { workspace = true, optional = true }
 rp2040-hal.workspace = true
 
diff --git a/boards/waveshare-rp2040-zero/examples/waveshare_rp2040_zero_neopixel_rainbow.rs b/boards/waveshare-rp2040-zero/examples/waveshare_rp2040_zero_neopixel_rainbow.rs
index ff49f4d..615e261 100644
--- a/boards/waveshare-rp2040-zero/examples/waveshare_rp2040_zero_neopixel_rainbow.rs
+++ b/boards/waveshare-rp2040-zero/examples/waveshare_rp2040_zero_neopixel_rainbow.rs
@@ -8,6 +8,9 @@
 
 use core::iter::once;
 use embedded_hal::delay::DelayNs;
+use palette::rgb::Rgb;
+use palette::{FromColor, Hsl};
+// use palette::Hsl;
 use panic_halt as _;
 use smart_leds::{brightness, SmartLedsWrite, RGB8};
 use waveshare_rp2040_zero::entry;
@@ -71,31 +74,26 @@ fn main() -> ! {
     );
 
     // Infinite colour wheel loop
-    let mut n: u8 = 128;
+    let mut hue: f64 = 0.0;
     let mut timer = timer; // rebind to force a copy of the timer
     loop {
-        ws.write(brightness(once(wheel(n)), 32)).unwrap();
-        n = n.wrapping_add(1);
-
-        timer.delay_ms(25);
-    }
-}
-
-/// Convert a number from `0..=255` to an RGB color triplet.
-///
-/// The colours are a transition from red, to green, to blue and back to red.
-fn wheel(mut wheel_pos: u8) -> RGB8 {
-    wheel_pos = 255 - wheel_pos;
-    if wheel_pos < 85 {
-        // No green in this sector - red and blue only
-        (255 - (wheel_pos * 3), 0, wheel_pos * 3).into()
-    } else if wheel_pos < 170 {
-        // No red in this sector - green and blue only
-        wheel_pos -= 85;
-        (0, wheel_pos * 3, 255 - (wheel_pos * 3)).into()
-    } else {
-        // No blue in this sector - red and green only
-        wheel_pos -= 170;
-        (wheel_pos * 3, 255 - (wheel_pos * 3), 0).into()
+        ws.write(brightness(
+            once({
+                let hsl = Hsl::<Rgb, _>::new(hue as f64, 1.0, 0.5);
+                let rgb = Rgb::from_color(hsl).into_format();
+                RGB8::new(rgb.red, rgb.green, rgb.blue)
+            }),
+            {
+                // 0 is off and 1 is max brightness
+                let brightness = 0.05 as f64;
+                (brightness * u8::MAX as f64) as u8
+            },
+        ))
+        .unwrap();
+        hue += 360.0 / 6.0 / u8::MAX as f64;
+        if hue >= 360.0 {
+            hue -= 360.0;
+        }
+        timer.delay_ms(1)
     }
 }