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use crate::{self as wgpu, util::DeviceExt, BufferInitDescriptor};
#[derive(Debug)]
pub struct Reshaper {
_vs_mod: wgpu::ShaderModule,
_fs_mod: wgpu::ShaderModule,
bind_group_layout: wgpu::BindGroupLayout,
bind_group: wgpu::BindGroup,
render_pipeline: wgpu::RenderPipeline,
sampler: wgpu::Sampler,
uniform_buffer: Option<wgpu::Buffer>,
vertex_buffer: wgpu::Buffer,
}
#[repr(C)]
#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd)]
struct Vertex {
pub position: [f32; 2],
}
#[repr(C)]
#[derive(Copy, Clone)]
struct Uniforms {
sample_count: u32,
}
impl Reshaper {
pub fn new(
device: &wgpu::Device,
src_texture: &wgpu::TextureViewHandle,
src_sample_count: u32,
src_sample_type: wgpu::TextureSampleType,
dst_sample_count: u32,
dst_format: wgpu::TextureFormat,
) -> Self {
let vs_desc = wgpu::include_wgsl!("shaders/vs.wgsl");
let fs_desc = match src_sample_count {
1 => wgpu::include_wgsl!("shaders/fs.wgsl"),
2 => wgpu::include_wgsl!("shaders/fs_msaa2.wgsl"),
4 => wgpu::include_wgsl!("shaders/fs_msaa4.wgsl"),
8 => wgpu::include_wgsl!("shaders/fs_msaa8.wgsl"),
16 => wgpu::include_wgsl!("shaders/fs_msaa16.wgsl"),
_ => wgpu::include_wgsl!("shaders/fs_msaa.wgsl"),
};
let vs_mod = device.create_shader_module(&vs_desc);
let fs_mod = device.create_shader_module(&fs_desc);
let sampler_desc = wgpu::SamplerBuilder::new().into_descriptor();
let sampler_filtering = wgpu::sampler_filtering(&sampler_desc);
let sampler = device.create_sampler(&sampler_desc);
let bind_group_layout =
bind_group_layout(device, src_sample_count, src_sample_type, sampler_filtering);
let pipeline_layout = pipeline_layout(device, &bind_group_layout);
let render_pipeline = render_pipeline(
device,
&pipeline_layout,
&vs_mod,
&fs_mod,
dst_sample_count,
dst_format,
);
let uniform_buffer = match unrolled_sample_count(src_sample_count) {
true => None,
false => {
let uniforms = Uniforms {
sample_count: src_sample_count,
};
let uniforms_bytes = uniforms_as_bytes(&uniforms);
let usage = wgpu::BufferUsages::UNIFORM;
let buffer = device.create_buffer_init(&BufferInitDescriptor {
label: None,
contents: &uniforms_bytes,
usage,
});
Some(buffer)
}
};
let bind_group = bind_group(
device,
&bind_group_layout,
src_texture,
&sampler,
uniform_buffer.as_ref(),
);
let vertices_bytes = vertices_as_bytes(&VERTICES[..]);
let vertex_usage = wgpu::BufferUsages::VERTEX;
let vertex_buffer = device.create_buffer_init(&BufferInitDescriptor {
label: None,
contents: vertices_bytes,
usage: vertex_usage,
});
Reshaper {
_vs_mod: vs_mod,
_fs_mod: fs_mod,
bind_group_layout,
bind_group,
render_pipeline,
sampler,
uniform_buffer,
vertex_buffer,
}
}
pub fn encode_render_pass(
&self,
dst_texture: &wgpu::TextureViewHandle,
encoder: &mut wgpu::CommandEncoder,
) {
let mut render_pass = wgpu::RenderPassBuilder::new()
.color_attachment(dst_texture, |color| color)
.begin(encoder);
render_pass.set_pipeline(&self.render_pipeline);
render_pass.set_vertex_buffer(0, self.vertex_buffer.slice(..));
render_pass.set_bind_group(0, &self.bind_group, &[]);
let vertex_range = 0..VERTICES.len() as u32;
let instance_range = 0..1;
render_pass.draw(vertex_range, instance_range);
}
}
const VERTICES: [Vertex; 4] = [
Vertex {
position: [-1.0, 1.0],
},
Vertex {
position: [-1.0, -1.0],
},
Vertex {
position: [1.0, 1.0],
},
Vertex {
position: [1.0, -1.0],
},
];
fn unrolled_sample_count(sample_count: u32) -> bool {
match sample_count {
1 | 2 | 4 | 8 | 16 => true,
_ => false,
}
}
fn bind_group_layout(
device: &wgpu::Device,
src_sample_count: u32,
src_sample_type: wgpu::TextureSampleType,
sampler_filtering: bool,
) -> wgpu::BindGroupLayout {
let mut builder = wgpu::BindGroupLayoutBuilder::new()
.texture(
wgpu::ShaderStages::FRAGMENT,
src_sample_count > 1,
wgpu::TextureViewDimension::D2,
src_sample_type,
)
.sampler(wgpu::ShaderStages::FRAGMENT, sampler_filtering);
if !unrolled_sample_count(src_sample_count) {
builder = builder.uniform_buffer(wgpu::ShaderStages::FRAGMENT, false);
}
builder.build(device)
}
fn bind_group(
device: &wgpu::Device,
layout: &wgpu::BindGroupLayout,
texture: &wgpu::TextureViewHandle,
sampler: &wgpu::Sampler,
uniform_buffer: Option<&wgpu::Buffer>,
) -> wgpu::BindGroup {
let mut builder = wgpu::BindGroupBuilder::new()
.texture_view(texture)
.sampler(sampler);
if let Some(buffer) = uniform_buffer {
builder = builder.buffer::<Uniforms>(buffer, 0..1);
}
builder.build(device, layout)
}
fn pipeline_layout(
device: &wgpu::Device,
bind_group_layout: &wgpu::BindGroupLayout,
) -> wgpu::PipelineLayout {
let desc = wgpu::PipelineLayoutDescriptor {
label: Some("nannou_reshaper"),
bind_group_layouts: &[&bind_group_layout],
push_constant_ranges: &[],
};
device.create_pipeline_layout(&desc)
}
fn render_pipeline(
device: &wgpu::Device,
layout: &wgpu::PipelineLayout,
vs_mod: &wgpu::ShaderModule,
fs_mod: &wgpu::ShaderModule,
dst_sample_count: u32,
dst_format: wgpu::TextureFormat,
) -> wgpu::RenderPipeline {
wgpu::RenderPipelineBuilder::from_layout(layout, vs_mod)
.fragment_shader(fs_mod)
.color_format(dst_format)
.color_blend(wgpu::BlendComponent::REPLACE)
.alpha_blend(wgpu::BlendComponent::REPLACE)
.add_vertex_buffer::<Vertex>(&wgpu::vertex_attr_array![0 => Float32x2])
.primitive_topology(wgpu::PrimitiveTopology::TriangleStrip)
.sample_count(dst_sample_count)
.build(device)
}
fn uniforms_as_bytes(uniforms: &Uniforms) -> &[u8] {
unsafe { wgpu::bytes::from(uniforms) }
}
fn vertices_as_bytes(data: &[Vertex]) -> &[u8] {
unsafe { wgpu::bytes::from_slice(data) }
}