learn-wgpu/code/beginner/tutorial5-textures/src/challenge.rs

use winit::{
    event::*,
    event_loop::{EventLoop, ControlFlow},
    window::{Window, WindowBuilder},
};
use wgpu::util::DeviceExt;

mod texture;

#[repr(C)]
#[derive(Copy, Clone, Debug)]
struct Vertex {
    position: [f32; 3],
    tex_coords: [f32; 2],
}

unsafe impl bytemuck::Pod for Vertex {}
unsafe impl bytemuck::Zeroable for Vertex {}

impl Vertex {
    fn desc<'a>() -> wgpu::VertexBufferDescriptor<'a> {
        use std::mem;
        wgpu::VertexBufferDescriptor {
            stride: mem::size_of::<Vertex>() as wgpu::BufferAddress,
            step_mode: wgpu::InputStepMode::Vertex,
            attributes: &[
                wgpu::VertexAttributeDescriptor {
                    offset: 0,
                    shader_location: 0,
                    format: wgpu::VertexFormat::Float3,
                },
                wgpu::VertexAttributeDescriptor {
                    offset: mem::size_of::<[f32; 3]>() as wgpu::BufferAddress,
                    shader_location: 1,
                    format: wgpu::VertexFormat::Float2,
                },
            ]
        }
    }
}

const VERTICES: &[Vertex] = &[
    Vertex { position: [-0.0868241, 0.49240386, 0.0], tex_coords: [0.4131759, 0.00759614], }, // A
    Vertex { position: [-0.49513406, 0.06958647, 0.0], tex_coords: [0.0048659444, 0.43041354], }, // B
    Vertex { position: [-0.21918549, -0.44939706, 0.0], tex_coords: [0.28081453, 0.949397057], }, // C
    Vertex { position: [0.35966998, -0.3473291, 0.0], tex_coords: [0.85967, 0.84732911], }, // D
    Vertex { position: [0.44147372, 0.2347359, 0.0], tex_coords: [0.9414737, 0.2652641], }, // E
];

const INDICES: &[u16] = &[
    0, 1, 4,
    1, 2, 4,
    2, 3, 4,
];


struct State {
    surface: wgpu::Surface,
    device: wgpu::Device,
    queue: wgpu::Queue,
    sc_desc: wgpu::SwapChainDescriptor,
    swap_chain: wgpu::SwapChain,
    size: winit::dpi::PhysicalSize<u32>,
    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,
    #[allow(dead_code)]
    cartoon_texture: texture::Texture,
    cartoon_bind_group: wgpu::BindGroup,
    is_space_pressed: bool,
}

impl State {
    async fn new(window: &Window) -> Self {
        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::BackendBit::PRIMARY);
        let surface = unsafe { instance.create_surface(window) };
        let adapter = instance.request_adapter(
            &wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::Default,
                compatible_surface: Some(&surface),
            },
        ).await.unwrap();
        let (device, queue) = adapter.request_device(
            &wgpu::DeviceDescriptor {
                features: wgpu::Features::empty(),
                limits: wgpu::Limits::default(),
                shader_validation: true,
            },
            None, // Trace path
        ).await.unwrap();

        let sc_desc = wgpu::SwapChainDescriptor {
            usage: wgpu::TextureUsage::OUTPUT_ATTACHMENT,
            format: wgpu::TextureFormat::Bgra8UnormSrgb,
            width: size.width,
            height: size.height,
            present_mode: wgpu::PresentMode::Fifo,
        };
        let swap_chain = device.create_swap_chain(&surface, &sc_desc);

        let texture_bind_group_layout = device.create_bind_group_layout(
            &wgpu::BindGroupLayoutDescriptor {
                entries: &[
                    wgpu::BindGroupLayoutEntry {
                        binding: 0,
                        visibility: wgpu::ShaderStage::FRAGMENT,
                        ty: wgpu::BindingType::SampledTexture {
                            multisampled: false,
                            dimension: wgpu::TextureViewDimension::D2,
                            component_type: wgpu::TextureComponentType::Uint,
                        },
                        count: None,
                    },
                    wgpu::BindGroupLayoutEntry {
                        binding: 1,
                        visibility: wgpu::ShaderStage::FRAGMENT,
                        ty: wgpu::BindingType::Sampler {
                            comparison: false,
                        },
                        count: None,
                    },
                ],
                label: Some("texture_bind_group_layout"),
            }
        );

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

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

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

        let vs_module = device.create_shader_module(wgpu::include_spirv!("shader.vert.spv"));
        let fs_module = device.create_shader_module(wgpu::include_spirv!("shader.frag.spv"));

        let render_pipeline_layout = device.create_pipeline_layout(
            &wgpu::PipelineLayoutDescriptor {
                label: Some("Render Pipeline Layout"),
                bind_group_layouts: &[&texture_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_stage: wgpu::ProgrammableStageDescriptor {
                    module: &vs_module,
                    entry_point: "main",
                },
                fragment_stage: Some(wgpu::ProgrammableStageDescriptor {
                    module: &fs_module,
                    entry_point: "main",
                }),
                rasterization_state: Some(
                    wgpu::RasterizationStateDescriptor {
                        front_face: wgpu::FrontFace::Ccw,
                        cull_mode: wgpu::CullMode::Back,
                        depth_bias: 0,
                        depth_bias_slope_scale: 0.0,
                        depth_bias_clamp: 0.0,
                        clamp_depth: false,
                    }
                ),
                primitive_topology: wgpu::PrimitiveTopology::TriangleList,
                color_states: &[
                    wgpu::ColorStateDescriptor {
                        format: sc_desc.format,
                        color_blend: wgpu::BlendDescriptor::REPLACE,
                        alpha_blend: wgpu::BlendDescriptor::REPLACE,
                        write_mask: wgpu::ColorWrite::ALL,
                    },
                ],
                depth_stencil_state: None,
                vertex_state: wgpu::VertexStateDescriptor {
                    index_format: wgpu::IndexFormat::Uint16,
                    vertex_buffers: &[Vertex::desc()],
                },
                sample_count: 1,
                sample_mask: !0,
                alpha_to_coverage_enabled: false,
            }
        );

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

        Self {
            surface,
            device,
            queue,
            sc_desc,
            swap_chain,
            render_pipeline,
            vertex_buffer,
            index_buffer,
            num_indices,
            diffuse_texture,
            diffuse_bind_group,
            cartoon_texture,
            cartoon_bind_group,
            size,
            is_space_pressed: false,
        }
    }


    fn resize(&mut self, new_size: winit::dpi::PhysicalSize<u32>) {
        self.size = new_size;
        self.sc_desc.width = new_size.width;
        self.sc_desc.height = new_size.height;
        self.swap_chain = self.device.create_swap_chain(&self.surface, &self.sc_desc);
    }

    fn input(&mut self, event: &WindowEvent) -> bool {
        match event {
            WindowEvent::KeyboardInput {
                input: KeyboardInput {
                    state,
                    virtual_keycode: Some(VirtualKeyCode::Space),
                    ..
                },
                ..
            } => {
                self.is_space_pressed = *state == ElementState::Pressed;
                true
            }
            _ => false,
        }
    }

    fn update(&mut self) {

    }

    fn render(&mut self) {
        let frame = self.swap_chain.get_current_frame()
            .expect("Timeout getting texture")
            .output;

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

        {
            let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                color_attachments: &[
                    wgpu::RenderPassColorAttachmentDescriptor {
                        attachment: &frame.view,
                        resolve_target: None,
                        ops: wgpu::Operations {
                            load: wgpu::LoadOp::Clear(
                                wgpu::Color {
                                    r: 0.1,
                                    g: 0.2,
                                    b: 0.3,
                                    a: 1.0,
                                }
                            ),
                            store: true,
                        }
                    }
                ],
                depth_stencil_attachment: None,
            });

            let bind_group = if self.is_space_pressed {
                &self.cartoon_bind_group
            } else {
                &self.diffuse_bind_group
            };

            render_pass.set_pipeline(&self.render_pipeline);
            render_pass.set_bind_group(0, bind_group, &[]);
            render_pass.set_vertex_buffer(0, self.vertex_buffer.slice(..));
            render_pass.set_index_buffer(self.index_buffer.slice(..));
            render_pass.draw_indexed(0..self.num_indices, 0, 0..1);
        }

        self.queue.submit(Some(encoder.finish()));
    }
}

fn main() {
    env_logger::init();
    let event_loop = EventLoop::new();
    let window = WindowBuilder::new()
        .build(&event_loop)
        .unwrap();

    use futures::executor::block_on;

    // Since main can't be async, we're going to need to block
    let mut state = block_on(State::new(&window));

    event_loop.run(move |event, _, control_flow| {
        match event {
            Event::WindowEvent {
                ref event,
                window_id,
            } if window_id == window.id() => if !state.input(event) {
                match event {
                    WindowEvent::CloseRequested => *control_flow = ControlFlow::Exit,
                    WindowEvent::KeyboardInput {
                        input,
                        ..
                    } => {
                        match input {
                            KeyboardInput {
                                state: ElementState::Pressed,
                                virtual_keycode: Some(VirtualKeyCode::Escape),
                                ..
                            } => *control_flow = ControlFlow::Exit,
                            _ => {}
                        }
                    }
                    WindowEvent::Resized(physical_size) => {
                        state.resize(*physical_size);
                    }
                    WindowEvent::ScaleFactorChanged { new_inner_size, .. } => {
                        // new_inner_size is &mut so w have to dereference it twice
                        state.resize(**new_inner_size);
                    }
                    _ => {}
                }
            }
            Event::RedrawRequested(_) => {
                state.update();
                state.render();
            }
            Event::MainEventsCleared => {
                // RedrawRequested will only trigger once, unless we manually
                // request it.
                window.request_redraw();
            }
            _ => {}
        }
    });
}