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runmat_plot/gpu/
area.rs

1use crate::core::renderer::Vertex;
2use crate::core::scene::GpuVertexBuffer;
3use crate::gpu::axis::{axis_storage_buffer, AxisData};
4use crate::gpu::shaders;
5use crate::gpu::{tuning, ScalarType};
6use glam::Vec4;
7use std::sync::Arc;
8use wgpu::util::DeviceExt;
9
10pub struct AreaGpuInputs<'a> {
11    pub x_axis: AxisData<'a>,
12    pub y_buffer: Arc<wgpu::Buffer>,
13    pub rows: u32,
14    pub cols: u32,
15    pub target_col: u32,
16    pub scalar: ScalarType,
17}
18
19pub struct AreaGpuParams {
20    pub color: Vec4,
21    pub baseline: f32,
22}
23
24#[repr(C)]
25#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
26struct AreaUniforms {
27    color: [f32; 4],
28    rows: u32,
29    cols: u32,
30    target_col: u32,
31    baseline: f32,
32    _pad: [f32; 3],
33}
34
35pub fn pack_vertices(
36    device: &Arc<wgpu::Device>,
37    queue: &Arc<wgpu::Queue>,
38    inputs: &AreaGpuInputs<'_>,
39    params: &AreaGpuParams,
40) -> Result<GpuVertexBuffer, String> {
41    if inputs.rows < 2 {
42        return Err("area: GPU path requires at least two points".into());
43    }
44    let workgroup_size = tuning::effective_workgroup_size();
45    let shader = compile_shader(device, workgroup_size, inputs.scalar);
46    let x_buffer = axis_storage_buffer(device, "area-x", &inputs.x_axis, inputs.scalar)?;
47    let segment_count = (inputs.rows - 1) as u64;
48    let vertex_count = segment_count * 6;
49    let output_buffer = Arc::new(device.create_buffer(&wgpu::BufferDescriptor {
50        label: Some("area-gpu-vertices"),
51        size: vertex_count * std::mem::size_of::<Vertex>() as u64,
52        usage: wgpu::BufferUsages::STORAGE
53            | wgpu::BufferUsages::VERTEX
54            | wgpu::BufferUsages::COPY_DST
55            | wgpu::BufferUsages::COPY_SRC,
56        mapped_at_creation: false,
57    }));
58    let uniforms = AreaUniforms {
59        color: params.color.to_array(),
60        rows: inputs.rows,
61        cols: inputs.cols,
62        target_col: inputs.target_col,
63        baseline: params.baseline,
64        _pad: [0.0; 3],
65    };
66    let uniform_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
67        label: Some("area-pack-uniforms"),
68        contents: bytemuck::bytes_of(&uniforms),
69        usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
70    });
71    let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
72        label: Some("area-pack-bind-layout"),
73        entries: &[
74            storage_entry(0, true),
75            storage_entry(1, true),
76            storage_entry(2, false),
77            uniform_entry(3),
78        ],
79    });
80    let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
81        label: Some("area-pack-pipeline-layout"),
82        bind_group_layouts: &[&bind_group_layout],
83        push_constant_ranges: &[],
84    });
85    let pipeline =
86        device.create_compute_pipeline(&crate::wgpu_compat::wgpu_compute_pipeline_descriptor! {
87            label: Some("area-pack-pipeline"),
88            layout: Some(&pipeline_layout),
89            module: &shader,
90            entry_point: "main",
91        });
92    let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
93        label: Some("area-pack-bind-group"),
94        layout: &bind_group_layout,
95        entries: &[
96            wgpu::BindGroupEntry {
97                binding: 0,
98                resource: x_buffer.as_entire_binding(),
99            },
100            wgpu::BindGroupEntry {
101                binding: 1,
102                resource: inputs.y_buffer.as_entire_binding(),
103            },
104            wgpu::BindGroupEntry {
105                binding: 2,
106                resource: output_buffer.as_entire_binding(),
107            },
108            wgpu::BindGroupEntry {
109                binding: 3,
110                resource: uniform_buffer.as_entire_binding(),
111            },
112        ],
113    });
114    let mut encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
115        label: Some("area-pack-encoder"),
116    });
117    {
118        let mut pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor {
119            label: Some("area-pack-pass"),
120            timestamp_writes: None,
121        });
122        pass.set_pipeline(&pipeline);
123        pass.set_bind_group(0, &bind_group, &[]);
124        pass.dispatch_workgroups((inputs.rows - 1).div_ceil(workgroup_size), 1, 1);
125    }
126    queue.submit(Some(encoder.finish()));
127    Ok(GpuVertexBuffer::new(output_buffer, vertex_count as usize))
128}
129
130fn compile_shader(
131    device: &Arc<wgpu::Device>,
132    workgroup_size: u32,
133    scalar: ScalarType,
134) -> wgpu::ShaderModule {
135    let template = match scalar {
136        ScalarType::F32 => shaders::area::F32,
137        ScalarType::F64 => shaders::area::F64,
138    };
139    let source = template.replace("{{WORKGROUP_SIZE}}", &workgroup_size.to_string());
140    device.create_shader_module(wgpu::ShaderModuleDescriptor {
141        label: Some("area-pack-shader"),
142        source: wgpu::ShaderSource::Wgsl(source.into()),
143    })
144}
145
146fn storage_entry(binding: u32, read_only: bool) -> wgpu::BindGroupLayoutEntry {
147    wgpu::BindGroupLayoutEntry {
148        binding,
149        visibility: wgpu::ShaderStages::COMPUTE,
150        ty: wgpu::BindingType::Buffer {
151            ty: wgpu::BufferBindingType::Storage { read_only },
152            has_dynamic_offset: false,
153            min_binding_size: None,
154        },
155        count: None,
156    }
157}
158
159fn uniform_entry(binding: u32) -> wgpu::BindGroupLayoutEntry {
160    wgpu::BindGroupLayoutEntry {
161        binding,
162        visibility: wgpu::ShaderStages::COMPUTE,
163        ty: wgpu::BindingType::Buffer {
164            ty: wgpu::BufferBindingType::Uniform,
165            has_dynamic_offset: false,
166            min_binding_size: None,
167        },
168        count: None,
169    }
170}
171
172#[cfg(test)]
173mod tests {
174    use super::*;
175    use pollster::FutureExt;
176    fn maybe_device() -> Option<(Arc<wgpu::Device>, Arc<wgpu::Queue>)> {
177        if std::env::var("RUNMAT_PLOT_SKIP_GPU_TESTS").is_ok()
178            || std::env::var("RUNMAT_PLOT_FORCE_GPU_TESTS").is_err()
179        {
180            return None;
181        }
182        let instance = wgpu::Instance::default();
183        let adapter = instance
184            .request_adapter(&wgpu::RequestAdapterOptions {
185                power_preference: wgpu::PowerPreference::HighPerformance,
186                compatible_surface: None,
187                force_fallback_adapter: false,
188            })
189            .block_on()?;
190        let (device, queue) = adapter
191            .request_device(
192                &crate::wgpu_compat::device_descriptor(
193                    Some("runmat-plot-area-test-device"),
194                    wgpu::Features::empty(),
195                    adapter.limits(),
196                ),
197                None,
198            )
199            .block_on()
200            .ok()?;
201        Some((Arc::new(device), Arc::new(queue)))
202    }
203
204    #[test]
205    fn gpu_packer_generates_area_vertices() {
206        let Some((device, queue)) = maybe_device() else {
207            return;
208        };
209        let x = [1.0f32, 2.0f32, 3.0f32];
210        let y = Arc::new(
211            device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
212                label: Some("area-test-y"),
213                contents: bytemuck::cast_slice(&[1.0f32, 2.0f32, 3.0f32, 0.5f32, 0.5f32, 0.5f32]),
214                usage: wgpu::BufferUsages::STORAGE,
215            }),
216        );
217        let packed = pack_vertices(
218            &device,
219            &queue,
220            &AreaGpuInputs {
221                x_axis: AxisData::F32(&x),
222                y_buffer: y,
223                rows: 3,
224                cols: 2,
225                target_col: 1,
226                scalar: ScalarType::F32,
227            },
228            &AreaGpuParams {
229                color: Vec4::ONE,
230                baseline: 0.0,
231            },
232        )
233        .expect("area pack should succeed");
234        assert_eq!(packed.vertex_count, 12);
235    }
236}