Files
OneCAD-Draft/src/scene/pipeline/wire_gpu.rs
T
2026-03-22 14:56:27 +03:00

213 lines
7.8 KiB
Rust

// Wire GPU buffers — quad (TriangleList) rendering for thick lines.
//
// Each segment [A→B] emits 6 vertices (2 triangles). Every vertex carries
// both endpoints so the vertex shader can compute the screen-space
// perpendicular direction and expand the quad to the correct pixel width.
//
// NaN sentinel: text glyphs pack multiple disconnected strokes into one
// WireModel, separated by [NaN, NaN, NaN] points. Segments where either
// endpoint contains NaN are silently skipped during upload.
//
// Vertex layout (96 bytes, stride = 96):
// pos_a [f32; 3] offset 0 12 B — segment start (world)
// pos_b [f32; 3] offset 12 12 B — segment end (world)
// which_end f32 offset 24 4 B — 0.0 = A end, 1.0 = B end
// side f32 offset 28 4 B — ±1.0 perpendicular side
// color [f32; 4] offset 32 16 B — RGBA [0,1]
// distance f32 offset 48 4 B — arc-length from wire start
// half_width f32 offset 52 4 B — half line width in pixels
// pattern_length f32 offset 56 4 B — dash pattern total length
// _pad f32 offset 60 4 B
// pat0 [f32; 4] offset 64 16 B — pattern elements 0-3
// pat1 [f32; 4] offset 80 16 B — pattern elements 4-7
// ------
// 96 B / vertex
use crate::scene::wire_model::WireModel;
use iced::wgpu;
use iced::wgpu::util::DeviceExt;
// ── Vertex layout ─────────────────────────────────────────────────────────
#[repr(C)]
#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
pub struct WireVertex {
pub pos_a: [f32; 3],
pub pos_b: [f32; 3],
pub which_end: f32,
pub side: f32,
pub color: [f32; 4],
pub distance: f32,
pub half_width: f32,
pub pattern_length: f32,
pub _pad: f32,
pub pat0: [f32; 4],
pub pat1: [f32; 4],
}
impl WireVertex {
pub fn layout<'a>() -> wgpu::VertexBufferLayout<'a> {
wgpu::VertexBufferLayout {
array_stride: std::mem::size_of::<WireVertex>() as u64,
step_mode: wgpu::VertexStepMode::Vertex,
attributes: &[
wgpu::VertexAttribute {
offset: 0,
shader_location: 0,
format: wgpu::VertexFormat::Float32x3,
}, // pos_a
wgpu::VertexAttribute {
offset: 12,
shader_location: 1,
format: wgpu::VertexFormat::Float32x3,
}, // pos_b
wgpu::VertexAttribute {
offset: 24,
shader_location: 2,
format: wgpu::VertexFormat::Float32,
}, // which_end
wgpu::VertexAttribute {
offset: 28,
shader_location: 3,
format: wgpu::VertexFormat::Float32,
}, // side
wgpu::VertexAttribute {
offset: 32,
shader_location: 4,
format: wgpu::VertexFormat::Float32x4,
}, // color
wgpu::VertexAttribute {
offset: 48,
shader_location: 5,
format: wgpu::VertexFormat::Float32,
}, // distance
wgpu::VertexAttribute {
offset: 52,
shader_location: 6,
format: wgpu::VertexFormat::Float32,
}, // half_width
wgpu::VertexAttribute {
offset: 56,
shader_location: 7,
format: wgpu::VertexFormat::Float32,
}, // pattern_length
wgpu::VertexAttribute {
offset: 64,
shader_location: 8,
format: wgpu::VertexFormat::Float32x4,
}, // pat0
wgpu::VertexAttribute {
offset: 80,
shader_location: 9,
format: wgpu::VertexFormat::Float32x4,
}, // pat1
],
}
}
}
// ── GPU handle ────────────────────────────────────────────────────────────
pub struct WireGpu {
pub vertex_buffer: wgpu::Buffer,
pub vertex_count: u32,
}
impl WireGpu {
pub fn new(device: &wgpu::Device, wire: &WireModel) -> Self {
let pat0 = [
wire.pattern[0],
wire.pattern[1],
wire.pattern[2],
wire.pattern[3],
];
let pat1 = [
wire.pattern[4],
wire.pattern[5],
wire.pattern[6],
wire.pattern[7],
];
let half_width = wire.line_weight_px * 0.5;
let n = wire.points.len();
let seg_count = if n >= 2 { n - 1 } else { 0 };
let mut vertices: Vec<WireVertex> = Vec::with_capacity(seg_count * 6);
// Precompute cumulative arc-length at each point.
// NaN points do not contribute to arc length — they are separator sentinels.
let mut dists = vec![0.0_f32; n];
for i in 1..n {
let p = wire.points[i - 1];
let q = wire.points[i];
// If either point is a NaN sentinel, keep the same distance
// (the segment will be skipped anyway).
if p[0].is_nan() || q[0].is_nan() {
dists[i] = dists[i - 1];
} else {
let dx = q[0] - p[0];
let dy = q[1] - p[1];
let dz = q[2] - p[2];
dists[i] = dists[i - 1] + (dx * dx + dy * dy + dz * dz).sqrt();
}
}
for i in 0..seg_count {
let a = wire.points[i];
let b = wire.points[i + 1];
// Skip any segment that involves a NaN sentinel point.
// NaN sentinels are inserted between disconnected glyph strokes
// by tessellate.rs so that multiple strokes can share one WireModel.
if a[0].is_nan()
|| a[1].is_nan()
|| a[2].is_nan()
|| b[0].is_nan()
|| b[1].is_nan()
|| b[2].is_nan()
{
continue;
}
let dist_a = dists[i];
let dist_b = dists[i + 1];
let make = |which_end: f32, side: f32| -> WireVertex {
let dist = if which_end < 0.5 { dist_a } else { dist_b };
WireVertex {
pos_a: a,
pos_b: b,
which_end,
side,
color: wire.color,
distance: dist,
half_width,
pattern_length: wire.pattern_length,
_pad: 0.0,
pat0,
pat1,
}
};
// Triangle 1: A(-1), B(-1), B(+1)
vertices.push(make(0.0, -1.0));
vertices.push(make(1.0, -1.0));
vertices.push(make(1.0, 1.0));
// Triangle 2: A(-1), B(+1), A(+1)
vertices.push(make(0.0, -1.0));
vertices.push(make(1.0, 1.0));
vertices.push(make(0.0, 1.0));
}
let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some(&format!("wire.vbuf.{}", wire.name)),
contents: bytemuck::cast_slice(&vertices),
usage: wgpu::BufferUsages::VERTEX,
});
Self {
vertex_buffer,
vertex_count: vertices.len() as u32,
}
}
}