From aad169f761a5817355d4b32c678cef6b8ce6b419 Mon Sep 17 00:00:00 2001
From: Gavin-Niederman <gavinniederman@gmail.com>
Date: Mon, 20 Nov 2023 14:17:01 -0800
Subject: [PATCH] fix: Line now always includes points at start and end

---
 shark-visualizer-interface/src/lib.rs   | 2 +-
 shark-visualizer/src/shader_compiler.rs | 4 +++-
 shark-visualizer/src/visualization.rs   | 7 ++-----
 shark/src/point/mod.rs                  | 2 +-
 shark/src/point/primitives.rs           | 8 ++++++--
 shark/src/shader/mod.rs                 | 2 +-
 6 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/shark-visualizer-interface/src/lib.rs b/shark-visualizer-interface/src/lib.rs
index cc2164e..ad52600 100644
--- a/shark-visualizer-interface/src/lib.rs
+++ b/shark-visualizer-interface/src/lib.rs
@@ -1,8 +1,8 @@
 use palette::{IntoColor, LinSrgb};
 use shark::point::Point;
-use shark::shader::{Fragment, Shader};
 #[cfg(target_arch = "wasm32")]
 use shark::shader::FragThree;
+use shark::shader::{Fragment, Shader};
 
 #[repr(C)]
 #[derive(Clone)]
diff --git a/shark-visualizer/src/shader_compiler.rs b/shark-visualizer/src/shader_compiler.rs
index 8b8d5b6..4027ba4 100644
--- a/shark-visualizer/src/shader_compiler.rs
+++ b/shark-visualizer/src/shader_compiler.rs
@@ -11,7 +11,9 @@ use shark::shader::{FragThree, Fragment};
 use shark_visualizer_interface::VisualizationExports;
 
 use crate::{
-    ui::ErrorMessageEvent, user_config::{UserConfigState, RespawnLedsEvent}, visualization::VisualizationState,
+    ui::ErrorMessageEvent,
+    user_config::{RespawnLedsEvent, UserConfigState},
+    visualization::VisualizationState,
 };
 
 #[derive(Event)]
diff --git a/shark-visualizer/src/visualization.rs b/shark-visualizer/src/visualization.rs
index 67630df..5cc044f 100644
--- a/shark-visualizer/src/visualization.rs
+++ b/shark-visualizer/src/visualization.rs
@@ -3,9 +3,7 @@ pub use bevy::{prelude::*, window::CursorGrabMode};
 use shark::shader::{FragThree, Shader};
 
 use crate::{
-    shader_compiler::VisualizationExportsWrapper,
-    user_config::RespawnLedsEvent,
-    PlayBackState,
+    shader_compiler::VisualizationExportsWrapper, user_config::RespawnLedsEvent, PlayBackState,
 };
 
 pub struct VisualizationPlugin;
@@ -84,8 +82,7 @@ fn respawn_leds(
         for entity in leds.iter() {
             commands.entity(entity).despawn();
         }
-    
-    
+
         info!("Spawning LEDs");
         let led_root = root.single();
         for led in state.exports.as_ref().unwrap().points() {
diff --git a/shark/src/point/mod.rs b/shark/src/point/mod.rs
index fc138b9..7b048b9 100644
--- a/shark/src/point/mod.rs
+++ b/shark/src/point/mod.rs
@@ -83,4 +83,4 @@ pub mod tests {
 
         let points: Vec<Point> = points.collect();
     }
-}
\ No newline at end of file
+}
diff --git a/shark/src/point/primitives.rs b/shark/src/point/primitives.rs
index d8a11ac..27b4142 100644
--- a/shark/src/point/primitives.rs
+++ b/shark/src/point/primitives.rs
@@ -21,8 +21,12 @@ impl Iterator for Line {
     type Item = Point;
 
     fn next(&mut self) -> Option<Self::Item> {
+        if self.num_points == 0 {
+            return None;
+        }
+
         if self.current_point < self.num_points {
-            let t = self.current_point as f64 / self.num_points as f64;
+            let t = self.current_point as f64 / (self.num_points - 1) as f64;
             self.current_point += 1;
             Some((1.0 - t) * self.a + t * self.b)
         } else {
@@ -33,4 +37,4 @@ impl Iterator for Line {
 
 pub fn line(a: Point, b: Point, num_points: usize) -> Line {
     Line::new(a, b, num_points)
-}
\ No newline at end of file
+}
diff --git a/shark/src/shader/mod.rs b/shark/src/shader/mod.rs
index f66c7ce..a908d46 100644
--- a/shark/src/shader/mod.rs
+++ b/shark/src/shader/mod.rs
@@ -2,11 +2,11 @@ pub mod primitives;
 
 use core::slice;
 
+use palette::{IntoColor, LinSrgb};
 use primitives::{
     checkerboard, extrude, mix, mod_position, mod_time, rotate_hue, Checkerboard, Extrude,
     Interpolate, ModPosition, ModTime, RotateHue,
 };
-use palette::{IntoColor, LinSrgb};
 
 pub trait Shader<F: Fragment> {
     type Output: IntoColor<LinSrgb<f64>>;