improved wheel handling + tests

esp32/.cargo/config.toml

@@ -1,14 +1,14 @@
 
 [target.xtensa-esp32-none-elf]
 runner = "espflash flash --monitor"
-
-[build]
-target = "xtensa-esp32-none-elf"
 rustflags = [
     "-C", "link-arg=-Wl,-Tlinkall.x",
     "-C", "link-arg=-nostartfiles",
 ]
 
+[build]
+target = "xtensa-esp32-none-elf"
+
 [unstable]
 build-std = ["core", "alloc", "compiler_builtins"]
 

esp32/build.rs

@@ -1,4 +1,9 @@
 fn main() {
+    let target = std::env::var("TARGET").unwrap_or_default();
+    if !target.starts_with("xtensa-") {
+        return;
+    }
+
     let args: Vec<String> = std::env::args().collect();
     if args.len() > 1 {
         let kind = &args[1];

esp32/src/input.rs

@@ -8,6 +8,7 @@ use esp_hal::time::Rate;
 use esp_println::println;
 
 use crate::WHEEL_VALUE;
+use esp32::{apply_wheel_delta, wheel_delta};
 
 pub static INPUT: Channel<CriticalSectionRawMutex, u8, 64> = Channel::new();
 pub static ANGLE: Mutex<CriticalSectionRawMutex, u16> = Mutex::new(0);
@@ -34,18 +35,24 @@ pub async fn rotation_read_task(config: RotationConfig) {
         let old = *locked as i32;
         *locked = angle;
         drop(locked);
-        let left_diff = old - angle as i32;
-        let right_diff = angle as i32 - old;
-        let diff = if left_diff.abs() < right_diff.abs() { -left_diff } else { right_diff };
+        let diff = wheel_delta(old, angle as i32, crate::WHEEL_INVERTED);
         let mut wheel = WHEEL_VALUE.lock().await;
         if wheel.max != wheel.min {
-            let wheel_range = wheel.max - wheel.min;
-            wheel.value += diff * wheel_range / 4096;
-            if wheel.value < wheel.min {
-                wheel.value = wheel.min;
-            } else if wheel.value > wheel.max {
-                wheel.value = wheel.max;
-            }
+            let min = wheel.min;
+            let max = wheel.max;
+            let mut value = wheel.value;
+            let mut accumulated = wheel.accumulated;
+            let precision = crate::WHEEL_PRECISION;
+            apply_wheel_delta(
+                &mut value,
+                min,
+                max,
+                &mut accumulated,
+                diff,
+                precision,
+            );
+            wheel.value = value;
+            wheel.accumulated = accumulated;
         }
     }
 }

esp32/src/lib.rs

@@ -0,0 +1,5 @@
+#![no_std]
+
+mod wheel;
+
+pub use wheel::{apply_wheel_delta, wheel_delta};

esp32/src/main.rs

@@ -29,6 +29,8 @@ const WIFI_NETWORK: &str = "flamme";
 const WIFI_PASSWORD: &str = "12345678";
 const TARGET_IP: &str = "84.238.32.253";
 const TARGET_PORT: u16 = 7070;
+const WHEEL_PRECISION: i32 = 32;
+const WHEEL_INVERTED: bool = false;
 
 enum QuestionType {
     Choice,
@@ -47,6 +49,7 @@ struct WheelData {
     value: i32,
     min: i32,
     max: i32,
+    accumulated: i32,
 }
 
 static QUESTION: Mutex<CriticalSectionRawMutex, Option<QuestionData>> = Mutex::new(None);
@@ -55,6 +58,7 @@ static WHEEL_VALUE: Mutex<CriticalSectionRawMutex, WheelData> = Mutex::new(Wheel
     value: 0,
     min: 0,
     max: 0,
+    accumulated: 0,
 });
 
 #[panic_handler]
@@ -79,6 +83,7 @@ pub async fn tcp_read_loop(mut read: TcpReader<'_>) {
             value: 0,
             min: 0,
             max: 0,
+            accumulated: 0,
         };
         for line in str.lines() {
             if line == "$$" {
@@ -120,6 +125,7 @@ pub async fn tcp_read_loop(mut read: TcpReader<'_>) {
                 if let QuestionType::Numeric { min, max } = q_type {
                     let diff = max - min;
                     future_wheel.value = min + diff / 2;
+                    future_wheel.accumulated = 0;
                 }
 
                 question_data = Some(QuestionData {

esp32/src/wheel.rs

@@ -0,0 +1,48 @@
+pub const WHEEL_TICKS: i32 = 4096;
+
+pub fn wheel_delta(old_angle: i32, current_angle: i32, inverted: bool) -> i32 {
+    let mut diff = current_angle - old_angle;
+    if diff.abs() > WHEEL_TICKS / 2 {
+        diff = if diff > 0 {
+            diff - WHEEL_TICKS
+        } else {
+            diff + WHEEL_TICKS
+        };
+    }
+
+    if inverted {
+        -diff
+    } else {
+        diff
+    }
+}
+
+pub fn apply_wheel_delta(
+    value: &mut i32,
+    min: i32,
+    max: i32,
+    accumulated: &mut i32,
+    diff: i32,
+    precision: i32,
+) {
+    if max == min || precision <= 0 {
+        return;
+    }
+
+    *accumulated += diff;
+    let step_count = *accumulated / precision;
+    if step_count == 0 {
+        return;
+    }
+
+    *accumulated -= step_count * precision;
+    *value += step_count;
+    if *value < min {
+        *value = min;
+    } else if *value > max {
+        *value = max;
+    }
+    if *value == min || *value == max {
+        *accumulated = 0;
+    }
+}

esp32/test.sh

@@ -0,0 +1 @@
+rustc --test wheel-tests.rs -o wheel-tests && ./wheel-tests

esp32/wheel-tests.rs

@@ -0,0 +1,46 @@
+#![allow(dead_code)]
+
+mod wheel {
+    include!("src/wheel.rs");
+}
+
+use wheel::{apply_wheel_delta, wheel_delta};
+
+#[test]
+fn wraps_forward_across_zero() {
+    assert_eq!(wheel_delta(4090, 5, false), 11);
+}
+
+#[test]
+fn wraps_backward_across_zero() {
+    assert_eq!(wheel_delta(5, 4090, false), -11);
+}
+
+#[test]
+fn inverts_direction() {
+    assert_eq!(wheel_delta(10, 20, true), -10);
+}
+
+#[test]
+fn accumulates_before_applying_selection() {
+    let mut value = 5;
+    let mut accumulated = 0;
+
+    apply_wheel_delta(&mut value, 0, 10, &mut accumulated, 10, 32);
+    assert_eq!(value, 5);
+    assert_eq!(accumulated, 10);
+
+    apply_wheel_delta(&mut value, 0, 10, &mut accumulated, 22, 32);
+    assert_eq!(value, 6);
+    assert_eq!(accumulated, 0);
+}
+
+#[test]
+fn clamps_and_resets_at_bounds() {
+    let mut value = 10;
+    let mut accumulated = 0;
+
+    apply_wheel_delta(&mut value, 0, 10, &mut accumulated, 64, 32);
+    assert_eq!(value, 10);
+    assert_eq!(accumulated, 0);
+}