hewn 0.1.0-alpha.3

use crate::ecs::Entity;
use crate::ecs::EntityId;
use crate::wgpu::texture;
use cgmath::prelude::*;
use cgmath::SquareMatrix;
use std::f32::consts::PI;
use std::mem;
use std::{iter, sync::Arc};
#[cfg(target_arch = "wasm32")]
use wasm_bindgen::prelude::*;
use wgpu::util::DeviceExt;
use winit::{event_loop::ActiveEventLoop, keyboard::KeyCode, window::Window};

#[derive(Default, Copy, Clone)]
pub enum CameraStrategy {
    #[default]
    AllEntities,
    CameraFollow(EntityId),
}

#[repr(C)]
#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
pub struct Vertex {
    position: [f32; 3],
}

fn gen_shape_buffer(points: u16, rotation_deg: f32, size: f32) -> (Vec<Vertex>, Vec<u16>) {
    if points < 3 {
        return (
            vec![
                Vertex {
                    position: [-0.0868241, 0.49240386, 0.0],
                },
                Vertex {
                    position: [-0.49513406, 0.06958647, 0.0],
                },
                Vertex {
                    position: [-0.21918549, -0.44939706, 0.0],
                },
                Vertex {
                    position: [0.35966998, -0.3473291, 0.0],
                },
                Vertex {
                    position: [0.44147372, 0.2347359, 0.0],
                },
            ],
            vec![0, 1, 4, 1, 2, 4, 2, 3, 4],
        );
    }

    let mut vertices = Vec::with_capacity(points as usize);
    let rotation_rad = rotation_deg.to_radians();
    for i in 0..points {
        let theta = 2.0 * PI * (i as f32) / (points as f32) + rotation_rad;
        let x = size * theta.cos();
        let y = size * theta.sin();
        vertices.push(Vertex {
            position: [x, y, 0.0],
        });
    }

    let mut indices = Vec::with_capacity((points as usize - 2) * 3);
    for i in 1..(points - 1) {
        indices.push(0u16);
        indices.push(i);
        indices.push(i + 1);
    }

    (vertices, indices)
}

impl Vertex {
    fn desc() -> wgpu::VertexBufferLayout<'static> {
        wgpu::VertexBufferLayout {
            array_stride: std::mem::size_of::<Vertex>() as wgpu::BufferAddress,
            step_mode: wgpu::VertexStepMode::Vertex,
            attributes: &[wgpu::VertexAttribute {
                offset: 0,
                shader_location: 0,
                format: wgpu::VertexFormat::Float32x3,
            }],
        }
    }
}

#[rustfmt::skip]
pub const OPENGL_TO_WGPU_MATRIX: cgmath::Matrix4<f32> = cgmath::Matrix4::from_cols(
    cgmath::Vector4::new(1.0, 0.0, 0.0, 0.0),
    cgmath::Vector4::new(0.0, 1.0, 0.0, 0.0),
    cgmath::Vector4::new(0.0, 0.0, 0.5, 0.0),
    cgmath::Vector4::new(0.0, 0.0, 0.5, 1.0),
);

pub(crate) struct Camera {
    pub(crate) eye: cgmath::Point3<f32>,
    pub(crate) target: cgmath::Point3<f32>,
    pub(crate) up: cgmath::Vector3<f32>,
    pub(crate) aspect: f32,
    pub(crate) fovy: f32,
    pub(crate) znear: f32,
    pub(crate) zfar: f32,
}

impl Camera {
    pub(crate) fn build_view_projection_matrix(&self) -> cgmath::Matrix4<f32> {
        let view = cgmath::Matrix4::look_at_rh(self.eye, self.target, self.up);
        let proj = cgmath::perspective(cgmath::Deg(self.fovy), self.aspect, self.znear, self.zfar);
        proj * view
    }
}

#[repr(C)]
#[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
pub(crate) struct CameraUniform {
    pub(crate) view_proj: [[f32; 4]; 4],
}

impl CameraUniform {
    pub(crate) fn new() -> Self {
        Self {
            view_proj: cgmath::Matrix4::identity().into(),
        }
    }

    pub(crate) fn update_view_proj(&mut self, camera: &Camera) {
        self.view_proj = (OPENGL_TO_WGPU_MATRIX * camera.build_view_projection_matrix()).into();
    }
}

pub(crate) struct InstancePosition {
    pub(crate) position: cgmath::Vector3<f32>,
    pub(crate) rotation: cgmath::Quaternion<f32>,
}

#[repr(C)]
#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
pub(crate) struct InstancePositionRaw {
    pub(crate) model: [[f32; 4]; 4],
}

impl InstancePositionRaw {
    pub(crate) fn desc() -> wgpu::VertexBufferLayout<'static> {
        wgpu::VertexBufferLayout {
            array_stride: mem::size_of::<InstancePositionRaw>() as wgpu::BufferAddress,
            // We need to switch from using a step mode of Vertex to Instance
            // This means that our shaders will only change to use the next
            // instance when the shader starts processing a new instance
            step_mode: wgpu::VertexStepMode::Instance,
            attributes: &[
                // A mat4 takes up 4 vertex slots as it is technically 4 vec4s. We need to define a slot
                // for each vec4. We'll have to reassemble the mat4 in the shader.
                wgpu::VertexAttribute {
                    offset: 0,
                    // While our vertex shader only uses locations 0, and 1 now, in later tutorials, we'll
                    // be using 2, 3, and 4, for Vertex. We'll start at slot 5, not conflict with them later
                    shader_location: 5,
                    format: wgpu::VertexFormat::Float32x4,
                },
                wgpu::VertexAttribute {
                    offset: mem::size_of::<[f32; 4]>() as wgpu::BufferAddress,
                    shader_location: 6,
                    format: wgpu::VertexFormat::Float32x4,
                },
                wgpu::VertexAttribute {
                    offset: mem::size_of::<[f32; 8]>() as wgpu::BufferAddress,
                    shader_location: 7,
                    format: wgpu::VertexFormat::Float32x4,
                },
                wgpu::VertexAttribute {
                    offset: mem::size_of::<[f32; 12]>() as wgpu::BufferAddress,
                    shader_location: 8,
                    format: wgpu::VertexFormat::Float32x4,
                },
            ],
        }
    }
}

impl InstancePosition {
    pub(crate) fn to_raw(&self) -> InstancePositionRaw {
        InstancePositionRaw {
            model: (cgmath::Matrix4::from_translation(self.position)
                * cgmath::Matrix4::from(self.rotation))
            .into(),
        }
    }
}

pub(crate) struct InstanceColor {
    pub(crate) color: cgmath::Vector3<f32>,
}

#[repr(C)]
#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
pub(crate) struct InstanceColorRaw {
    pub(crate) model: [f32; 3],
}

impl InstanceColorRaw {
    pub(crate) fn desc() -> wgpu::VertexBufferLayout<'static> {
        wgpu::VertexBufferLayout {
            array_stride: mem::size_of::<InstanceColorRaw>() as wgpu::BufferAddress,
            step_mode: wgpu::VertexStepMode::Instance,
            attributes: &[wgpu::VertexAttribute {
                offset: 0,
                shader_location: 9,
                format: wgpu::VertexFormat::Float32x3,
            }],
        }
    }
}

impl InstanceColor {
    pub(crate) fn to_raw(&self) -> InstanceColorRaw {
        InstanceColorRaw {
            model: self.color.into(),
        }
    }
}

pub struct State {
    surface: wgpu::Surface<'static>,
    device: wgpu::Device,
    queue: wgpu::Queue,
    config: wgpu::SurfaceConfiguration,
    is_surface_configured: bool,
    render_pipeline: wgpu::RenderPipeline,
    vertex_buffer: wgpu::Buffer,
    index_buffer: wgpu::Buffer,
    num_indices: u32,
    #[allow(dead_code)]
    diffuse_texture: texture::Texture,
    diffuse_bind_group: wgpu::BindGroup,
    instance_positions: Vec<InstancePosition>,
    instance_colors: Vec<InstanceColor>,
    instance_positions_buffer: wgpu::Buffer,
    instance_colors_buffer: wgpu::Buffer,
    camera_strategy: CameraStrategy,

    vertices: Vec<Vertex>,
    indices: Vec<u16>,

    camera: Camera,
    camera_uniform: CameraUniform,
    camera_buffer: wgpu::Buffer,
    camera_bind_group: wgpu::BindGroup,
    pub(crate) window: Arc<Window>,
    renderable_entities: Vec<Entity>,
}

impl State {
    pub(crate) async fn new(
        window: Arc<Window>,
        renderable_entities: Vec<Entity>,
        camera_strategy: CameraStrategy,
    ) -> anyhow::Result<State> {
        let size = window.inner_size();

        // The instance is a handle to our GPU
        // BackendBit::PRIMARY => Vulkan + Metal + DX12 + Browser WebGPU
        let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor {
            #[cfg(not(target_arch = "wasm32"))]
            backends: wgpu::Backends::PRIMARY,
            #[cfg(target_arch = "wasm32")]
            backends: wgpu::Backends::GL,
            ..Default::default()
        });

        let surface = instance.create_surface(window.clone()).unwrap();

        let adapter = instance
            .request_adapter(&wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::default(),
                compatible_surface: Some(&surface),
                force_fallback_adapter: false,
            })
            .await
            .unwrap();
        let (device, queue) = adapter
            .request_device(&wgpu::DeviceDescriptor {
                label: None,
                required_features: wgpu::Features::empty(),
                // WebGL doesn't support all of wgpu's features, so if
                // we're building for the web we'll have to disable some.
                required_limits: if cfg!(target_arch = "wasm32") {
                    wgpu::Limits::downlevel_webgl2_defaults()
                } else {
                    wgpu::Limits::default()
                },
                memory_hints: Default::default(),
                trace: wgpu::Trace::Off,
            })
            .await
            .unwrap();

        let surface_caps = surface.get_capabilities(&adapter);
        // Shader code in this tutorial assumes an Srgb surface texture. Using a different
        // one will result all the colors comming out darker. If you want to support non
        // Srgb surfaces, you'll need to account for that when drawing to the frame.
        let surface_format = surface_caps
            .formats
            .iter()
            .copied()
            .find(|f| f.is_srgb())
            .unwrap_or(surface_caps.formats[0]);
        let config = wgpu::SurfaceConfiguration {
            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
            format: surface_format,
            width: size.width,
            height: size.height,
            present_mode: surface_caps.present_modes[0],
            alpha_mode: surface_caps.alpha_modes[0],
            view_formats: vec![],
            desired_maximum_frame_latency: 2,
        };

        let diffuse_bytes = include_bytes!("happy-tree.png");
        let diffuse_texture =
            texture::Texture::from_bytes(&device, &queue, diffuse_bytes, "happy-tree.png").unwrap();

        let texture_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                entries: &[
                    wgpu::BindGroupLayoutEntry {
                        binding: 0,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Texture {
                            multisampled: false,
                            view_dimension: wgpu::TextureViewDimension::D2,
                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
                        },
                        count: None,
                    },
                    wgpu::BindGroupLayoutEntry {
                        binding: 1,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
                        count: None,
                    },
                ],
                label: Some("texture_bind_group_layout"),
            });

        let diffuse_bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            layout: &texture_bind_group_layout,
            entries: &[
                wgpu::BindGroupEntry {
                    binding: 0,
                    resource: wgpu::BindingResource::TextureView(&diffuse_texture.view),
                },
                wgpu::BindGroupEntry {
                    binding: 1,
                    resource: wgpu::BindingResource::Sampler(&diffuse_texture.sampler),
                },
            ],
            label: Some("diffuse_bind_group"),
        });

        let camera = Camera {
            eye: (0.0, 1.0, 10.0).into(),
            target: (0.0, 0.0, 0.0).into(),
            up: cgmath::Vector3::unit_y(),
            aspect: config.width as f32 / config.height as f32,
            fovy: 45.0,
            znear: 0.1,
            zfar: 100.0,
        };

        let mut camera_uniform = CameraUniform::new();
        camera_uniform.update_view_proj(&camera);

        let camera_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
            label: Some("Camera Buffer"),
            contents: bytemuck::cast_slice(&[camera_uniform]),
            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
        });

        let camera_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                entries: &[wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::VERTEX,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: None,
                    },
                    count: None,
                }],
                label: Some("camera_bind_group_layout"),
            });

        let camera_bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            layout: &camera_bind_group_layout,
            entries: &[wgpu::BindGroupEntry {
                binding: 0,
                resource: camera_buffer.as_entire_binding(),
            }],
            label: Some("camera_bind_group"),
        });

        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
            label: Some("Shader"),
            source: wgpu::ShaderSource::Wgsl(include_str!("shader.wgsl").into()),
        });

        let render_pipeline_layout =
            device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
                label: Some("Render Pipeline Layout"),
                bind_group_layouts: &[&texture_bind_group_layout, &camera_bind_group_layout],
                push_constant_ranges: &[],
            });

        let render_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
            label: Some("Render Pipeline"),
            layout: Some(&render_pipeline_layout),
            vertex: wgpu::VertexState {
                module: &shader,
                entry_point: Some("vs_main"),
                buffers: &[
                    Vertex::desc(),
                    InstancePositionRaw::desc(),
                    InstanceColorRaw::desc(),
                ],
                compilation_options: Default::default(),
            },
            fragment: Some(wgpu::FragmentState {
                module: &shader,
                entry_point: Some("fs_main"),
                targets: &[Some(wgpu::ColorTargetState {
                    format: config.format,
                    blend: Some(wgpu::BlendState {
                        color: wgpu::BlendComponent::REPLACE,
                        alpha: wgpu::BlendComponent::REPLACE,
                    }),
                    write_mask: wgpu::ColorWrites::ALL,
                })],
                compilation_options: Default::default(),
            }),
            primitive: wgpu::PrimitiveState {
                topology: wgpu::PrimitiveTopology::TriangleList,
                strip_index_format: None,
                front_face: wgpu::FrontFace::Ccw,
                cull_mode: Some(wgpu::Face::Back),
                // Setting this to anything other than Fill requires Features::POLYGON_MODE_LINE
                // or Features::POLYGON_MODE_POINT
                polygon_mode: wgpu::PolygonMode::Fill,
                // Requires Features::DEPTH_CLIP_CONTROL
                unclipped_depth: false,
                // Requires Features::CONSERVATIVE_RASTERIZATION
                conservative: false,
            },
            depth_stencil: None,
            multisample: wgpu::MultisampleState {
                count: 1,
                mask: !0,
                alpha_to_coverage_enabled: false,
            },
            // If the pipeline will be used with a multiview render pass, this
            // indicates how many array layers the attachments will have.
            multiview: None,
            // Useful for optimizing shader compilation on Android
            cache: None,
        });

        let (vertices, indices) = gen_shape_buffer(4, 45.0, 0.08);

        let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
            label: Some("Vertex Buffer"),
            contents: bytemuck::cast_slice(&vertices),
            usage: wgpu::BufferUsages::VERTEX,
        });
        let index_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
            label: Some("Index Buffer"),
            contents: bytemuck::cast_slice(&indices),
            usage: wgpu::BufferUsages::INDEX,
        });
        let num_indices = indices.len() as u32;

        let (instance_positions, instance_colors): (Vec<InstancePosition>, Vec<InstanceColor>) =
            renderable_entities
                .iter()
                .map(|e| {
                    let position = e.components.position.unwrap();
                    let rotation = cgmath::Quaternion::from_axis_angle(
                        cgmath::Vector3::unit_z(),
                        cgmath::Deg(0.0),
                    );
                    let color = e.components.render.unwrap().rgb;

                    let position_3d = cgmath::Vector3 {
                        x: position.x as f32 * 0.1,
                        y: position.y as f32 * 0.1,
                        z: 0.0,
                    };
                    (
                        InstancePosition {
                            position: position_3d,
                            rotation,
                        },
                        InstanceColor { color },
                    )
                })
                .unzip();
        // .collect::<Vec<_>>();

        let instance_positions_raw = instance_positions
            .iter()
            .map(InstancePosition::to_raw)
            .collect::<Vec<_>>();
        let instance_colors_raw = instance_colors
            .iter()
            .map(InstanceColor::to_raw)
            .collect::<Vec<_>>();
        let instance_positions_buffer =
            device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
                label: Some("Instance Position Buffer"),
                contents: bytemuck::cast_slice(&instance_positions_raw),
                usage: wgpu::BufferUsages::VERTEX,
            });
        let instance_colors_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
            label: Some("Instance Color Buffer"),
            contents: bytemuck::cast_slice(&instance_colors_raw),
            usage: wgpu::BufferUsages::VERTEX,
        });

        Ok(Self {
            surface,
            device,
            queue,
            config,
            is_surface_configured: false,
            render_pipeline,
            vertex_buffer,
            index_buffer,
            num_indices,
            diffuse_texture,
            diffuse_bind_group,
            vertices,
            indices,
            camera,
            camera_buffer,
            camera_bind_group,
            camera_uniform,
            instance_positions,
            instance_colors,
            instance_positions_buffer,
            instance_colors_buffer,
            window,
            renderable_entities,
            camera_strategy,
        })
    }

    pub fn window(&self) -> &Window {
        &self.window
    }

    pub(crate) fn resize(&mut self, width: u32, height: u32) {
        if width > 0 && height > 0 {
            self.is_surface_configured = true;
            self.config.width = width;
            self.config.height = height;
            self.surface.configure(&self.device, &self.config);

            self.camera.aspect = self.config.width as f32 / self.config.height as f32;
        }
    }

    pub(crate) fn handle_key(&mut self, event_loop: &ActiveEventLoop, key: KeyCode, pressed: bool) {
        if key == KeyCode::Escape && pressed {
            event_loop.exit();
        }
    }

    pub(crate) fn update(&mut self, renderable_entities: Vec<Entity>) {
        self.renderable_entities = renderable_entities;

        let (instance_positions, instance_colors): (Vec<InstancePosition>, Vec<InstanceColor>) =
            self.renderable_entities
                .iter()
                .map(|e| {
                    let position = e.components.position.unwrap();
                    let render = e.components.render.unwrap();
                    let rotation = cgmath::Quaternion::from_axis_angle(
                        cgmath::Vector3::unit_z(),
                        cgmath::Deg(0.0),
                    );

                    let position_3d = cgmath::Vector3 {
                        x: position.x as f32 * 0.1,
                        y: position.y as f32 * 0.1,
                        z: 0.0,
                    };
                    (
                        InstancePosition {
                            position: position_3d,
                            rotation,
                        },
                        InstanceColor { color: render.rgb },
                    )
                })
                .unzip();
        self.instance_positions = instance_positions;
        self.instance_colors = instance_colors;
        let instance_position_data = self
            .instance_positions
            .iter()
            .map(InstancePosition::to_raw)
            .collect::<Vec<_>>();
        let instance_positions_buffer =
            self.device
                .create_buffer_init(&wgpu::util::BufferInitDescriptor {
                    label: Some("Instance Position Buffer"),
                    contents: bytemuck::cast_slice(&instance_position_data),
                    usage: wgpu::BufferUsages::VERTEX,
                });

        let instance_colors_data = self
            .instance_colors
            .iter()
            .map(InstanceColor::to_raw)
            .collect::<Vec<_>>();
        let instance_colors_buffer =
            self.device
                .create_buffer_init(&wgpu::util::BufferInitDescriptor {
                    label: Some("Instance Position Buffer"),
                    contents: bytemuck::cast_slice(&instance_colors_data),
                    usage: wgpu::BufferUsages::VERTEX,
                });
        // Log the instance positions to stdout so we can see things are moving when keys are hit.
        self.instance_positions_buffer = instance_positions_buffer;
        self.instance_colors_buffer = instance_colors_buffer;

        let camera_points =
            self.renderable_entities
                .iter()
                .fold((0.0, 0.0, 0.0, 0.0), |mut acc, e| {
                    if let Some(position) = e.components.position {
                        if position.x < acc.0 {
                            acc.0 = position.x;
                        }
                        if position.x > acc.1 {
                            acc.1 = position.x;
                        }
                        if position.y < acc.2 {
                            acc.2 = position.y;
                        }
                        if position.y > acc.3 {
                            acc.3 = position.y;
                        }
                    }
                    acc
                });
        let camera_x_position = (camera_points.0 + camera_points.1) / 2.0;
        let camera_y_position = (1.0 - camera_points.2 + camera_points.3) / 2.0;

        match self.camera_strategy {
            CameraStrategy::CameraFollow(entity_id) => {
                let entity = self
                    .renderable_entities
                    .iter()
                    .find(|e| e.id == entity_id)
                    .unwrap(); // what do we do in the case the entity doesn't exist?
                let camera_follow_position = entity.components.position.unwrap();
                self.camera.eye = cgmath::Point3::new(
                    camera_follow_position.x as f32 * 0.1,
                    camera_follow_position.y as f32 * 0.1,
                    4.0,
                );
                self.camera.target = cgmath::Point3::new(
                    camera_follow_position.x as f32 * 0.1,
                    camera_follow_position.y as f32 * 0.1,
                    0.0,
                );
                self.camera_uniform.update_view_proj(&self.camera);
            }
            CameraStrategy::AllEntities => {
                let game_width = camera_points.1 - camera_points.0;
                let z_depth = game_width as f32 / 8.1;
                self.camera.eye =
                    cgmath::Point3::new(camera_x_position * 0.1, camera_y_position * 0.1, z_depth);
                self.camera.target =
                    cgmath::Point3::new(camera_x_position * 0.1, camera_y_position * 0.1, 0.0);
                self.camera_uniform.update_view_proj(&self.camera);
            }
        }

        self.queue.write_buffer(
            &self.camera_buffer,
            0,
            bytemuck::cast_slice(&[self.camera_uniform]),
        );
    }

    pub(crate) fn render(&mut self) -> Result<(), wgpu::SurfaceError> {
        self.window.request_redraw();

        // We can't render unless the surface is configured
        if !self.is_surface_configured {
            return Ok(());
        }

        let output = self.surface.get_current_texture()?;
        let view = output
            .texture
            .create_view(&wgpu::TextureViewDescriptor::default());

        let mut encoder = self
            .device
            .create_command_encoder(&wgpu::CommandEncoderDescriptor {
                label: Some("Render Encoder"),
            });

        {
            let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                label: Some("Render Pass"),
                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                    view: &view,
                    resolve_target: None,
                    ops: wgpu::Operations {
                        load: wgpu::LoadOp::Clear(wgpu::Color {
                            r: 1.0,
                            g: 1.0,
                            b: 1.0,
                            a: 1.0,
                        }),
                        store: wgpu::StoreOp::Store,
                    },
                    depth_slice: None,
                })],
                depth_stencil_attachment: None,
                occlusion_query_set: None,
                timestamp_writes: None,
            });

            render_pass.set_pipeline(&self.render_pipeline);
            render_pass.set_bind_group(0, &self.diffuse_bind_group, &[]);
            render_pass.set_bind_group(1, &self.camera_bind_group, &[]);
            render_pass.set_vertex_buffer(0, self.vertex_buffer.slice(..));
            render_pass.set_vertex_buffer(1, self.instance_positions_buffer.slice(..));
            render_pass.set_vertex_buffer(2, self.instance_colors_buffer.slice(..));
            render_pass.set_index_buffer(self.index_buffer.slice(..), wgpu::IndexFormat::Uint16);
            render_pass.draw_indexed(
                0..self.num_indices,
                0,
                0..self.instance_positions.len() as _,
            );
        }

        self.queue.submit(iter::once(encoder.finish()));
        output.present();

        Ok(())
    }
}