| 1 | //! One instanced SDF shader for rects, rounded rects, borders and dots. |
| 2 | |
| 3 | use bytemuck::{Pod, Zeroable}; |
| 4 | use wgpu::util::DeviceExt; |
| 5 | |
| 6 | /// A primitive in physical pixels; colours are linear with straight alpha. |
| 7 | #[repr(C)] |
| 8 | #[derive(Clone, Copy, Debug, Pod, Zeroable)] |
| 9 | pub struct Prim { |
| 10 | pub rect: [f32; 4], |
| 11 | pub color: [f32; 4], |
| 12 | pub border_color: [f32; 4], |
| 13 | /// x: corner radius, y: border width. |
| 14 | pub params: [f32; 4], |
| 15 | } |
| 16 | |
| 17 | impl Prim { |
| 18 | pub fn rect(rect: [f32; 4], color: [f32; 4]) -> Self { |
| 19 | Self { |
| 20 | rect, |
| 21 | color, |
| 22 | border_color: [0.0; 4], |
| 23 | params: [0.0; 4], |
| 24 | } |
| 25 | } |
| 26 | } |
| 27 | |
| 28 | pub struct PrimPipeline { |
| 29 | pipeline: wgpu::RenderPipeline, |
| 30 | globals: wgpu::Buffer, |
| 31 | bind_group: wgpu::BindGroup, |
| 32 | instances: wgpu::Buffer, |
| 33 | capacity: usize, |
| 34 | count: u32, |
| 35 | } |
| 36 | |
| 37 | const ATTRS: [wgpu::VertexAttribute; 4] = |
| 38 | wgpu::vertex_attr_array![0 => Float32x4, 1 => Float32x4, 2 => Float32x4, 3 => Float32x4]; |
| 39 | |
| 40 | fn instance_buffer(device: &wgpu::Device, capacity: usize) -> wgpu::Buffer { |
| 41 | device.create_buffer(&wgpu::BufferDescriptor { |
| 42 | label: Some("prims"), |
| 43 | size: (capacity * size_of::<Prim>()) as u64, |
| 44 | usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST, |
| 45 | mapped_at_creation: false, |
| 46 | }) |
| 47 | } |
| 48 | |
| 49 | impl PrimPipeline { |
| 50 | pub fn new(device: &wgpu::Device, target: wgpu::TextureFormat) -> Self { |
| 51 | let globals = device.create_buffer_init(&wgpu::util::BufferInitDescriptor { |
| 52 | label: Some("prim globals"), |
| 53 | contents: bytemuck::bytes_of(&[0.0f32; 4]), |
| 54 | usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST, |
| 55 | }); |
| 56 | let layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor { |
| 57 | label: Some("prims"), |
| 58 | entries: &[wgpu::BindGroupLayoutEntry { |
| 59 | binding: 0, |
| 60 | visibility: wgpu::ShaderStages::VERTEX, |
| 61 | ty: wgpu::BindingType::Buffer { |
| 62 | ty: wgpu::BufferBindingType::Uniform, |
| 63 | has_dynamic_offset: false, |
| 64 | min_binding_size: None, |
| 65 | }, |
| 66 | count: None, |
| 67 | }], |
| 68 | }); |
| 69 | let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor { |
| 70 | label: Some("prims"), |
| 71 | layout: &layout, |
| 72 | entries: &[wgpu::BindGroupEntry { |
| 73 | binding: 0, |
| 74 | resource: globals.as_entire_binding(), |
| 75 | }], |
| 76 | }); |
| 77 | let shader = device.create_shader_module(wgpu::include_wgsl!("shaders/prims.wgsl")); |
| 78 | let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor { |
| 79 | label: Some("prims"), |
| 80 | bind_group_layouts: &[Some(&layout)], |
| 81 | immediate_size: 0, |
| 82 | }); |
| 83 | let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor { |
| 84 | label: Some("prims"), |
| 85 | layout: Some(&pipeline_layout), |
| 86 | vertex: wgpu::VertexState { |
| 87 | module: &shader, |
| 88 | entry_point: Some("vs"), |
| 89 | compilation_options: Default::default(), |
| 90 | buffers: &[Some(wgpu::VertexBufferLayout { |
| 91 | array_stride: size_of::<Prim>() as u64, |
| 92 | step_mode: wgpu::VertexStepMode::Instance, |
| 93 | attributes: &ATTRS, |
| 94 | })], |
| 95 | }, |
| 96 | primitive: wgpu::PrimitiveState::default(), |
| 97 | depth_stencil: None, |
| 98 | multisample: wgpu::MultisampleState::default(), |
| 99 | fragment: Some(wgpu::FragmentState { |
| 100 | module: &shader, |
| 101 | entry_point: Some("fs"), |
| 102 | compilation_options: Default::default(), |
| 103 | targets: &[Some(wgpu::ColorTargetState { |
| 104 | format: target, |
| 105 | blend: Some(wgpu::BlendState::PREMULTIPLIED_ALPHA_BLENDING), |
| 106 | write_mask: wgpu::ColorWrites::ALL, |
| 107 | })], |
| 108 | }), |
| 109 | multiview_mask: None, |
| 110 | cache: None, |
| 111 | }); |
| 112 | let capacity = 64; |
| 113 | Self { |
| 114 | pipeline, |
| 115 | globals, |
| 116 | bind_group, |
| 117 | instances: instance_buffer(device, capacity), |
| 118 | capacity, |
| 119 | count: 0, |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | pub fn prepare( |
| 124 | &mut self, |
| 125 | device: &wgpu::Device, |
| 126 | queue: &wgpu::Queue, |
| 127 | prims: &[Prim], |
| 128 | viewport: [f32; 2], |
| 129 | ) { |
| 130 | queue.write_buffer( |
| 131 | &self.globals, |
| 132 | 0, |
| 133 | bytemuck::bytes_of(&[viewport[0], viewport[1], 0.0, 0.0]), |
| 134 | ); |
| 135 | if prims.len() > self.capacity { |
| 136 | self.capacity = prims.len().next_power_of_two(); |
| 137 | self.instances = instance_buffer(device, self.capacity); |
| 138 | } |
| 139 | if !prims.is_empty() { |
| 140 | queue.write_buffer(&self.instances, 0, bytemuck::cast_slice(prims)); |
| 141 | } |
| 142 | self.count = prims.len() as u32; |
| 143 | } |
| 144 | |
| 145 | pub fn draw(&self, pass: &mut wgpu::RenderPass<'_>) { |
| 146 | if self.count == 0 { |
| 147 | return; |
| 148 | } |
| 149 | pass.set_pipeline(&self.pipeline); |
| 150 | pass.set_bind_group(0, &self.bind_group, &[]); |
| 151 | pass.set_vertex_buffer(0, self.instances.slice(..)); |
| 152 | pass.draw(0..6, 0..self.count); |
| 153 | } |
| 154 | } |