use crate::context::Context;
use crate::Renderable;
use bytemuck::{Pod, Zeroable};
use std::{borrow::Cow, mem};
use wgpu::util::DeviceExt;
const MAX_INSTANCES: usize = 10_000;
#[repr(C)]
#[derive(Debug, Clone, Copy, Zeroable, Pod)]
struct Uniforms {
transform: [f32; 16],
scale: f32,
_padding: [f32; 3],
}
impl Uniforms {
fn new(transformation: [f32; 16], scale: f32) -> Uniforms {
Self {
transform: transformation,
scale,
_padding: [0.0; 3],
}
}
}
impl Default for Uniforms {
fn default() -> Self {
let identity_matrix: [f32; 16] = [
1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0,
1.0,
];
Self {
transform: identity_matrix,
scale: 1.0,
_padding: [0.0; 3],
}
}
}
#[repr(C)]
#[derive(Clone, Copy, Zeroable, Pod)]
pub struct Vertex {
_position: [f32; 2],
}
fn vertex(pos: [f32; 2]) -> Vertex {
Vertex {
_position: [pos[0], pos[1]],
}
}
const QUAD_INDICES: [u16; 6] = [0, 1, 2, 0, 2, 3];
#[derive(Debug, Default, Clone, Copy)]
#[repr(C)]
pub struct Rect {
pub position: [f32; 2],
pub color: [f32; 4],
pub size: [f32; 2],
}
#[allow(unsafe_code)]
unsafe impl bytemuck::Zeroable for Rect {}
#[allow(unsafe_code)]
unsafe impl bytemuck::Pod for Rect {}
fn create_vertices_rect() -> Vec<Vertex> {
let vertex_data = [
vertex([0.0, 0.0]),
vertex([0.5, 0.0]),
vertex([0.5, 1.0]),
vertex([0.0, 1.0]),
];
vertex_data.to_vec()
}
pub const BLEND: Option<wgpu::BlendState> = Some(wgpu::BlendState {
color: wgpu::BlendComponent {
src_factor: wgpu::BlendFactor::SrcAlpha,
dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
operation: wgpu::BlendOperation::Add,
},
alpha: wgpu::BlendComponent {
src_factor: wgpu::BlendFactor::One,
dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
operation: wgpu::BlendOperation::Add,
},
});
pub struct RectBrush {
vertex_buf: wgpu::Buffer,
index_buf: wgpu::Buffer,
instances: wgpu::Buffer,
index_count: usize,
bind_group: wgpu::BindGroup,
transform: wgpu::Buffer,
pipeline: wgpu::RenderPipeline,
current_transform: [f32; 16],
scale: f32,
}
impl Renderable for RectBrush {
fn init(context: &Context) -> Self {
let device = &context.device;
let vertex_data = create_vertices_rect();
let transform = device.create_buffer(&wgpu::BufferDescriptor {
label: None,
size: mem::size_of::<Uniforms>() as wgpu::BufferAddress,
usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
mapped_at_creation: false,
});
let vertex_buf = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some("Vertex Buffer"),
contents: bytemuck::cast_slice(&vertex_data),
usage: wgpu::BufferUsages::VERTEX,
});
let index_buf = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some("Index Buffer"),
contents: bytemuck::cast_slice(&QUAD_INDICES),
usage: wgpu::BufferUsages::INDEX,
});
let bind_group_layout =
device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
label: None,
entries: &[wgpu::BindGroupLayoutEntry {
binding: 0,
visibility: wgpu::ShaderStages::VERTEX,
ty: wgpu::BindingType::Buffer {
ty: wgpu::BufferBindingType::Uniform,
has_dynamic_offset: false,
min_binding_size: wgpu::BufferSize::new(
mem::size_of::<Uniforms>() as wgpu::BufferAddress,
),
},
count: None,
}],
});
let pipeline_layout =
device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
label: None,
bind_group_layouts: &[&bind_group_layout],
push_constant_ranges: &[],
});
let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
layout: &bind_group_layout,
entries: &[wgpu::BindGroupEntry {
binding: 0,
resource: wgpu::BindingResource::Buffer(wgpu::BufferBinding {
buffer: &transform,
offset: 0,
size: None,
}),
}],
label: Some("rect::Pipeline uniforms"),
});
let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
label: None,
source: wgpu::ShaderSource::Wgsl(Cow::Borrowed(include_str!("rect.wgsl"))),
});
let vertex_buffers = [
wgpu::VertexBufferLayout {
array_stride: mem::size_of::<Vertex>() as u64,
step_mode: wgpu::VertexStepMode::Vertex,
attributes: &[wgpu::VertexAttribute {
format: wgpu::VertexFormat::Float32x2,
offset: 0,
shader_location: 0,
}],
},
wgpu::VertexBufferLayout {
array_stride: mem::size_of::<Rect>() as u64,
step_mode: wgpu::VertexStepMode::Instance,
attributes: &wgpu::vertex_attr_array!(
1 => Float32x2,
2 => Float32x4,
3 => Float32x2,
),
},
];
let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
label: None,
layout: Some(&pipeline_layout),
vertex: wgpu::VertexState {
module: &shader,
entry_point: "vs_main",
buffers: &vertex_buffers,
},
fragment: Some(wgpu::FragmentState {
module: &shader,
entry_point: "fs_main",
targets: &[Some(wgpu::ColorTargetState {
format: context.format,
blend: BLEND,
write_mask: wgpu::ColorWrites::ALL,
})],
}),
primitive: wgpu::PrimitiveState {
topology: wgpu::PrimitiveTopology::TriangleStrip,
front_face: wgpu::FrontFace::Cw,
strip_index_format: Some(wgpu::IndexFormat::Uint16),
..Default::default()
},
depth_stencil: None,
multisample: wgpu::MultisampleState::default(),
multiview: None,
});
let instances = device.create_buffer(&wgpu::BufferDescriptor {
label: Some("Instances Buffer"),
size: mem::size_of::<Rect>() as u64 * MAX_INSTANCES as u64,
usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
mapped_at_creation: false,
});
RectBrush {
scale: context.scale,
vertex_buf,
index_buf,
index_count: QUAD_INDICES.len(),
bind_group,
transform,
pipeline,
current_transform: [0.0; 16],
instances,
}
}
fn update(&mut self, _event: winit::event::WindowEvent) {
}
fn resize(
&mut self,
_config: &wgpu::SurfaceConfiguration,
_device: &wgpu::Device,
_queue: &wgpu::Queue,
) {
}
fn render(
&mut self,
encoder: &mut wgpu::CommandEncoder,
view: &wgpu::TextureView,
transform: [f32; 16],
instances: &[Rect],
ctx: &mut Context,
) {
let scale = ctx.scale;
let device = &ctx.device;
let staging_belt = &mut ctx.staging_belt;
if transform != self.current_transform || scale != self.scale {
let uniforms = Uniforms::new(transform, scale);
let mut transform_view = staging_belt.write_buffer(
encoder,
&self.transform,
0,
wgpu::BufferSize::new(mem::size_of::<Uniforms>() as u64).unwrap(),
device,
);
transform_view.copy_from_slice(bytemuck::bytes_of(&uniforms));
self.current_transform = transform;
self.scale = scale;
}
let mut i = 0;
let total = instances.len();
while i < total {
let end = (i + MAX_INSTANCES).min(total);
let amount = end - i;
let instance_bytes = bytemuck::cast_slice(&instances[i..end]);
let mut instance_buffer = staging_belt.write_buffer(
encoder,
&self.instances,
0,
wgpu::BufferSize::new(instance_bytes.len() as u64).unwrap(),
device,
);
instance_buffer.copy_from_slice(instance_bytes);
{
let mut rpass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
label: None,
color_attachments: &[Some(wgpu::RenderPassColorAttachment {
view,
resolve_target: None,
ops: wgpu::Operations {
load: wgpu::LoadOp::Load,
store: true,
},
})],
depth_stencil_attachment: None,
});
rpass.set_pipeline(&self.pipeline);
rpass.set_bind_group(0, &self.bind_group, &[]);
rpass.set_index_buffer(
self.index_buf.slice(..),
wgpu::IndexFormat::Uint16,
);
rpass.set_vertex_buffer(0, self.vertex_buf.slice(..));
rpass.set_vertex_buffer(1, self.instances.slice(..));
rpass.draw_indexed(0..self.index_count as u32, 0, 0..amount as u32);
}
i += MAX_INSTANCES;
}
}
}