runmat_plot/gpu/
stairs.rs

1use crate::core::renderer::Vertex;
2use crate::core::scene::GpuVertexBuffer;
3use crate::gpu::shaders;
4use crate::gpu::{tuning, ScalarType};
5use glam::Vec4;
6use std::sync::Arc;
7use wgpu::util::DeviceExt;
8
9/// Inputs required to pack stairs vertices directly on the GPU.
10pub struct StairsGpuInputs {
11    pub x_buffer: Arc<wgpu::Buffer>,
12    pub y_buffer: Arc<wgpu::Buffer>,
13    pub len: u32,
14    pub scalar: ScalarType,
15}
16
17/// Parameters describing how the GPU vertices should be generated.
18pub struct StairsGpuParams {
19    pub color: Vec4,
20}
21
22#[repr(C)]
23#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
24struct StairsUniforms {
25    color: [f32; 4],
26    point_count: u32,
27    _pad: [u32; 3],
28}
29
30/// Builds a GPU-resident vertex buffer for stairs/step plots directly from provider-owned XY arrays.
31pub fn pack_vertices_from_xy(
32    device: &Arc<wgpu::Device>,
33    queue: &Arc<wgpu::Queue>,
34    inputs: &StairsGpuInputs,
35    params: &StairsGpuParams,
36) -> Result<GpuVertexBuffer, String> {
37    if inputs.len < 2 {
38        return Err("stairs: inputs must contain at least two points".to_string());
39    }
40    let segments = inputs.len - 1;
41    let workgroup_size = tuning::effective_workgroup_size();
42    let shader = compile_shader(device, workgroup_size, inputs.scalar);
43
44    let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
45        label: Some("stairs-pack-bind-layout"),
46        entries: &[
47            wgpu::BindGroupLayoutEntry {
48                binding: 0,
49                visibility: wgpu::ShaderStages::COMPUTE,
50                ty: wgpu::BindingType::Buffer {
51                    ty: wgpu::BufferBindingType::Storage { read_only: true },
52                    has_dynamic_offset: false,
53                    min_binding_size: None,
54                },
55                count: None,
56            },
57            wgpu::BindGroupLayoutEntry {
58                binding: 1,
59                visibility: wgpu::ShaderStages::COMPUTE,
60                ty: wgpu::BindingType::Buffer {
61                    ty: wgpu::BufferBindingType::Storage { read_only: true },
62                    has_dynamic_offset: false,
63                    min_binding_size: None,
64                },
65                count: None,
66            },
67            wgpu::BindGroupLayoutEntry {
68                binding: 2,
69                visibility: wgpu::ShaderStages::COMPUTE,
70                ty: wgpu::BindingType::Buffer {
71                    ty: wgpu::BufferBindingType::Storage { read_only: false },
72                    has_dynamic_offset: false,
73                    min_binding_size: None,
74                },
75                count: None,
76            },
77            wgpu::BindGroupLayoutEntry {
78                binding: 3,
79                visibility: wgpu::ShaderStages::COMPUTE,
80                ty: wgpu::BindingType::Buffer {
81                    ty: wgpu::BufferBindingType::Uniform,
82                    has_dynamic_offset: false,
83                    min_binding_size: None,
84                },
85                count: None,
86            },
87        ],
88    });
89
90    let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
91        label: Some("stairs-pack-pipeline-layout"),
92        bind_group_layouts: &[&bind_group_layout],
93        push_constant_ranges: &[],
94    });
95
96    let pipeline = device.create_compute_pipeline(&wgpu::ComputePipelineDescriptor {
97        label: Some("stairs-pack-pipeline"),
98        layout: Some(&pipeline_layout),
99        module: &shader,
100        entry_point: "main",
101    });
102
103    let vertex_count = segments as u64 * 4;
104    let output_size = vertex_count * std::mem::size_of::<Vertex>() as u64;
105    let output_buffer = Arc::new(device.create_buffer(&wgpu::BufferDescriptor {
106        label: Some("stairs-gpu-vertices"),
107        size: output_size,
108        usage: wgpu::BufferUsages::STORAGE
109            | wgpu::BufferUsages::VERTEX
110            | wgpu::BufferUsages::COPY_DST,
111        mapped_at_creation: false,
112    }));
113
114    let uniforms = StairsUniforms {
115        color: params.color.to_array(),
116        point_count: inputs.len,
117        _pad: [0; 3],
118    };
119    let uniform_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
120        label: Some("stairs-pack-uniforms"),
121        contents: bytemuck::bytes_of(&uniforms),
122        usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
123    });
124
125    let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
126        label: Some("stairs-pack-bind-group"),
127        layout: &bind_group_layout,
128        entries: &[
129            wgpu::BindGroupEntry {
130                binding: 0,
131                resource: inputs.x_buffer.as_entire_binding(),
132            },
133            wgpu::BindGroupEntry {
134                binding: 1,
135                resource: inputs.y_buffer.as_entire_binding(),
136            },
137            wgpu::BindGroupEntry {
138                binding: 2,
139                resource: output_buffer.as_entire_binding(),
140            },
141            wgpu::BindGroupEntry {
142                binding: 3,
143                resource: uniform_buffer.as_entire_binding(),
144            },
145        ],
146    });
147
148    let mut encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
149        label: Some("stairs-pack-encoder"),
150    });
151    {
152        let mut pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor {
153            label: Some("stairs-pack-pass"),
154            timestamp_writes: None,
155        });
156        pass.set_pipeline(&pipeline);
157        pass.set_bind_group(0, &bind_group, &[]);
158        let workgroups = segments.div_ceil(workgroup_size);
159        pass.dispatch_workgroups(workgroups, 1, 1);
160    }
161    queue.submit(Some(encoder.finish()));
162
163    Ok(GpuVertexBuffer::new(output_buffer, (vertex_count) as usize))
164}
165
166fn compile_shader(
167    device: &Arc<wgpu::Device>,
168    workgroup_size: u32,
169    scalar: ScalarType,
170) -> wgpu::ShaderModule {
171    let template = match scalar {
172        ScalarType::F32 => shaders::stairs::F32,
173        ScalarType::F64 => shaders::stairs::F64,
174    };
175    let source = template.replace("{{WORKGROUP_SIZE}}", &workgroup_size.to_string());
176    device.create_shader_module(wgpu::ShaderModuleDescriptor {
177        label: Some("stairs-pack-shader"),
178        source: wgpu::ShaderSource::Wgsl(source.into()),
179    })
180}
runmat_plot/gpu/stairs.rs

runmat_plot/gpu/
stairs.rs
