1 files changed, 99 insertions, 0 deletions
diff --git a/examples/custom_shader/src/cubes.rs b/examples/custom_shader/src/cubes.rs
new file mode 100644
index 00000000..8dbba4b1
--- /dev/null
+++ b/examples/custom_shader/src/cubes.rs
@@ -0,0 +1,99 @@
+use crate::camera::Camera;
+use crate::primitive;
+use crate::primitive::cube::Cube;
+use glam::Vec3;
+use iced::widget::shader;
+use iced::{mouse, Color, Rectangle};
+use rand::Rng;
+use std::cmp::Ordering;
+use std::iter;
+use std::time::Duration;
+
+pub const MAX: u32 = 500;
+
+#[derive(Clone)]
+pub struct Cubes {
+    pub size: f32,
+    pub cubes: Vec<Cube>,
+    pub camera: Camera,
+    pub show_depth_buffer: bool,
+    pub light_color: Color,
+}
+
+impl Cubes {
+    pub fn new() -> Self {
+        let mut cubes = Self {
+            size: 0.2,
+            cubes: vec![],
+            camera: Camera::default(),
+            show_depth_buffer: false,
+            light_color: Color::WHITE,
+        };
+
+        cubes.adjust_num_cubes(MAX);
+
+        cubes
+    }
+
+    pub fn update(&mut self, time: Duration) {
+        for cube in self.cubes.iter_mut() {
+            cube.update(self.size, time.as_secs_f32());
+        }
+    }
+
+    pub fn adjust_num_cubes(&mut self, num_cubes: u32) {
+        let curr_cubes = self.cubes.len() as u32;
+
+        match num_cubes.cmp(&curr_cubes) {
+            Ordering::Greater => {
+                // spawn
+                let cubes_2_spawn = (num_cubes - curr_cubes) as usize;
+
+                let mut cubes = 0;
+                self.cubes.extend(iter::from_fn(|| {
+                    if cubes < cubes_2_spawn {
+                        cubes += 1;
+                        Some(Cube::new(self.size, rnd_origin()))
+                    } else {
+                        None
+                    }
+                }));
+            }
+            Ordering::Less => {
+                // chop
+                let cubes_2_cut = curr_cubes - num_cubes;
+                let new_len = self.cubes.len() - cubes_2_cut as usize;
+                self.cubes.truncate(new_len);
+            }
+            _ => {}
+        }
+    }
+}
+
+impl<Message> shader::Program<Message> for Cubes {
+    type State = ();
+    type Primitive = primitive::Primitive;
+
+    fn draw(
+        &self,
+        _state: &Self::State,
+        _cursor: mouse::Cursor,
+        bounds: Rectangle,
+    ) -> Self::Primitive {
+        primitive::Primitive::new(
+            &self.cubes,
+            &self.camera,
+            bounds,
+            self.show_depth_buffer,
+            self.light_color,
+        )
+    }
+}
+
+fn rnd_origin() -> Vec3 {
+    Vec3::new(
+        rand::thread_rng().gen_range(-4.0..4.0),
+        rand::thread_rng().gen_range(-4.0..4.0),
+        rand::thread_rng().gen_range(-4.0..2.0),
+    )
+}