1 files changed, 186 insertions, 0 deletions
diff --git a/examples/custom_shader/src/scene.rs b/examples/custom_shader/src/scene.rs
new file mode 100644
index 00000000..a35efdd9
--- /dev/null
+++ b/examples/custom_shader/src/scene.rs
@@ -0,0 +1,186 @@
+mod camera;
+mod pipeline;
+
+use camera::Camera;
+use pipeline::Pipeline;
+
+use crate::wgpu;
+use pipeline::cube::{self, Cube};
+
+use iced::mouse;
+use iced::time::Duration;
+use iced::widget::shader;
+use iced::{Color, Rectangle, Size};
+
+use glam::Vec3;
+use rand::Rng;
+use std::cmp::Ordering;
+use std::iter;
+
+pub const MAX: u32 = 500;
+
+#[derive(Clone)]
+pub struct Scene {
+    pub size: f32,
+    pub cubes: Vec<Cube>,
+    pub camera: Camera,
+    pub show_depth_buffer: bool,
+    pub light_color: Color,
+}
+
+impl Scene {
+    pub fn new() -> Self {
+        let mut scene = Self {
+            size: 0.2,
+            cubes: vec![],
+            camera: Camera::default(),
+            show_depth_buffer: false,
+            light_color: Color::WHITE,
+        };
+
+        scene.change_amount(MAX);
+
+        scene
+    }
+
+    pub fn update(&mut self, time: Duration) {
+        for cube in self.cubes.iter_mut() {
+            cube.update(self.size, time.as_secs_f32());
+        }
+    }
+
+    pub fn change_amount(&mut self, amount: u32) {
+        let curr_cubes = self.cubes.len() as u32;
+
+        match amount.cmp(&curr_cubes) {
+            Ordering::Greater => {
+                // spawn
+                let cubes_2_spawn = (amount - 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 - amount;
+                let new_len = self.cubes.len() - cubes_2_cut as usize;
+                self.cubes.truncate(new_len);
+            }
+            Ordering::Equal => {}
+        }
+    }
+}
+
+impl<Message> shader::Program<Message> for Scene {
+    type State = ();
+    type Primitive = Primitive;
+
+    fn draw(
+        &self,
+        _state: &Self::State,
+        _cursor: mouse::Cursor,
+        bounds: Rectangle,
+    ) -> Self::Primitive {
+        Primitive::new(
+            &self.cubes,
+            &self.camera,
+            bounds,
+            self.show_depth_buffer,
+            self.light_color,
+        )
+    }
+}
+
+/// A collection of `Cube`s that can be rendered.
+#[derive(Debug)]
+pub struct Primitive {
+    cubes: Vec<cube::Raw>,
+    uniforms: pipeline::Uniforms,
+    show_depth_buffer: bool,
+}
+
+impl Primitive {
+    pub fn new(
+        cubes: &[Cube],
+        camera: &Camera,
+        bounds: Rectangle,
+        show_depth_buffer: bool,
+        light_color: Color,
+    ) -> Self {
+        let uniforms = pipeline::Uniforms::new(camera, bounds, light_color);
+
+        Self {
+            cubes: cubes
+                .iter()
+                .map(cube::Raw::from_cube)
+                .collect::<Vec<cube::Raw>>(),
+            uniforms,
+            show_depth_buffer,
+        }
+    }
+}
+
+impl shader::Primitive for Primitive {
+    fn prepare(
+        &self,
+        format: wgpu::TextureFormat,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        _bounds: Rectangle,
+        target_size: Size<u32>,
+        _scale_factor: f32,
+        storage: &mut shader::Storage,
+    ) {
+        if !storage.has::<Pipeline>() {
+            storage.store(Pipeline::new(device, queue, format, target_size));
+        }
+
+        let pipeline = storage.get_mut::<Pipeline>().unwrap();
+
+        //upload data to GPU
+        pipeline.update(
+            device,
+            queue,
+            target_size,
+            &self.uniforms,
+            self.cubes.len(),
+            &self.cubes,
+        );
+    }
+
+    fn render(
+        &self,
+        storage: &shader::Storage,
+        target: &wgpu::TextureView,
+        _target_size: Size<u32>,
+        viewport: Rectangle<u32>,
+        encoder: &mut wgpu::CommandEncoder,
+    ) {
+        //at this point our pipeline should always be initialized
+        let pipeline = storage.get::<Pipeline>().unwrap();
+
+        //render primitive
+        pipeline.render(
+            target,
+            encoder,
+            viewport,
+            self.cubes.len() as u32,
+            self.show_depth_buffer,
+        );
+    }
+}
+
+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),
+    )
+}