cad-editor/src/modules/draw/modify/blend.rs
2026-08-10 15:03:31 +03:00

657 lines
22 KiB
Rust

//! BLEND (BLE) — create a smooth spline between two open curve endpoints.
//!
//! The endpoint nearest each pick is used. Tangent continuity creates a cubic
//! Bezier (G1); curvature continuity creates a quintic Bezier whose endpoint
//! first and second derivatives reproduce the source curves' tangent and
//! geometric curvature (G2).
use acadrust::entities::{EntityCommon, Spline};
use cadkernel::space::curve as space_curve;
use acadrust::types::Vector3;
use acadrust::{EntityType, Handle};
use glam::DVec3;
use crate::t;
use cadkernel::space::NurbsCurve3;
use crate::command::{CadCommand, CmdOption, CmdResult};
use crate::entities::common::BulgeArc;
use crate::scene::model::wire_model::WireModel;
use crate::scene::view::transform::{ocs_axes, ocs_point_to_wcs};
use super::entity_index::ModifyEntityIndex;
const EPS: f64 = 1.0e-10;
#[derive(Clone, Copy, PartialEq, Eq)]
enum Continuity {
Tangent,
Curvature,
}
impl Continuity {
fn label(self) -> &'static str {
match self {
Self::Tangent => "Tangent",
Self::Curvature => "Curvature",
}
}
}
#[derive(Clone, Copy)]
struct EndpointFrame {
point: DVec3,
/// Direction from the source curve interior towards its selected endpoint.
outward: DVec3,
/// Geometric curvature vector at the endpoint.
curvature: DVec3,
}
#[derive(Clone, Copy)]
enum BlendStep {
First,
Continuity {
resume: Option<(Handle, EndpointFrame)>,
},
Second {
handle: Handle,
endpoint: EndpointFrame,
},
}
pub struct BlendCommand {
continuity: Continuity,
step: BlendStep,
all_entities: Vec<EntityType>,
entity_index: ModifyEntityIndex,
}
impl BlendCommand {
pub fn new(all_entities: Vec<EntityType>) -> Self {
let entity_index = ModifyEntityIndex::build(&all_entities);
Self {
continuity: Continuity::Curvature,
step: BlendStep::First,
all_entities,
entity_index,
}
}
fn entity(&self, handle: Handle) -> Option<&EntityType> {
self.entity_index.get(&self.all_entities, handle)
}
fn blend_for(
&self,
first_handle: Handle,
first: EndpointFrame,
second_handle: Handle,
click: DVec3,
) -> Option<Spline> {
if first_handle == second_handle {
return None;
}
let second_entity = self.entity(second_handle)?;
let second = endpoint_frame(second_entity, click)?;
let common = blend_common(self.entity(first_handle)?.common());
build_blend(first, second, self.continuity, common)
}
}
impl CadCommand for BlendCommand {
fn name(&self) -> &'static str {
"BLEND"
}
fn prompt(&self) -> String {
match self.step {
BlendStep::First => {
let c = self.continuity.label();
t!(
"BLEND Select first open curve [Continuity=%{c}]:",
c = c
)
.into_owned()
}
BlendStep::Continuity { .. } => {
let c = self.continuity.label();
t!(
"BLEND Enter continuity [Tangent/Curvature] <%{c}>:",
c = c
)
.into_owned()
}
BlendStep::Second { .. } => {
let c = self.continuity.label();
t!(
"BLEND Select second open curve [Continuity=%{c}]:",
c = c
)
.into_owned()
}
}
}
fn options(&self) -> Vec<CmdOption> {
match self.step {
BlendStep::First | BlendStep::Second { .. } => {
vec![CmdOption::new(t!("Continuity").as_ref(), "C")]
}
BlendStep::Continuity { .. } => vec![
CmdOption::new(t!("Tangent").as_ref(), "T"),
CmdOption::new(t!("Curvature").as_ref(), "C"),
],
}
}
fn wants_text_input(&self) -> bool {
matches!(self.step, BlendStep::Continuity { .. })
}
fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
let upper = text.trim().to_ascii_uppercase();
match self.step {
BlendStep::First => {
if upper == "C" || upper == "CONTINUITY" {
self.step = BlendStep::Continuity { resume: None };
Some(CmdResult::NeedPoint)
} else {
None
}
}
BlendStep::Second { handle, endpoint } => {
if upper == "C" || upper == "CONTINUITY" {
self.step = BlendStep::Continuity {
resume: Some((handle, endpoint)),
};
Some(CmdResult::NeedPoint)
} else {
None
}
}
BlendStep::Continuity { resume } => {
if upper.is_empty() {
self.step = resume
.map(|(handle, endpoint)| BlendStep::Second { handle, endpoint })
.unwrap_or(BlendStep::First);
return Some(CmdResult::NeedPoint);
}
match upper.as_str() {
"T" | "TANGENT" => self.continuity = Continuity::Tangent,
"C" | "CURVATURE" => self.continuity = Continuity::Curvature,
_ => return Some(CmdResult::NeedPoint),
}
self.step = resume
.map(|(handle, endpoint)| BlendStep::Second { handle, endpoint })
.unwrap_or(BlendStep::First);
Some(CmdResult::NeedPoint)
}
}
}
fn needs_entity_pick(&self) -> bool {
!matches!(self.step, BlendStep::Continuity { .. })
}
fn entity_pick_highlights_hover(&self) -> bool {
true
}
fn on_entity_pick(&mut self, handle: Handle, click: DVec3) -> CmdResult {
if handle.is_null() {
return CmdResult::NeedPoint;
}
match self.step {
BlendStep::First => {
let Some(endpoint) = self.entity(handle).and_then(|e| endpoint_frame(e, click))
else {
return CmdResult::NeedPoint;
};
self.step = BlendStep::Second { handle, endpoint };
CmdResult::NeedPoint
}
BlendStep::Second {
handle: first_handle,
endpoint: first,
} => self
.blend_for(first_handle, first, handle, click)
.map(EntityType::Spline)
.map(CmdResult::CommitAndExit)
.unwrap_or(CmdResult::NeedPoint),
BlendStep::Continuity { .. } => CmdResult::NeedPoint,
}
}
fn on_hover_entity(&mut self, handle: Handle, click: DVec3) -> Vec<WireModel> {
let BlendStep::Second {
handle: first_handle,
endpoint: first,
} = self.step
else {
return Vec::new();
};
let Some(spline) = self.blend_for(first_handle, first, handle, click) else {
return Vec::new();
};
vec![WireModel::solid_f64(
"blend_preview".into(),
sample_bezier(&spline.control_points, 64),
WireModel::CYAN,
false,
)]
}
fn on_point(&mut self, _pt: DVec3) -> CmdResult {
CmdResult::NeedPoint
}
fn on_enter(&mut self) -> CmdResult {
if let BlendStep::Continuity { resume } = self.step {
self.step = resume
.map(|(handle, endpoint)| BlendStep::Second { handle, endpoint })
.unwrap_or(BlendStep::First);
CmdResult::NeedPoint
} else {
CmdResult::Cancel
}
}
}
fn blend_common(source: &EntityCommon) -> EntityCommon {
let mut common = EntityCommon::new();
common.layer = source.layer.clone();
common.color = source.color;
common.line_weight = source.line_weight;
common.linetype = source.linetype.clone();
common.linetype_handle = source.linetype_handle;
common.linetype_scale = source.linetype_scale;
common.transparency = source.transparency;
common
}
fn build_blend(
first: EndpointFrame,
second: EndpointFrame,
continuity: Continuity,
common: EntityCommon,
) -> Option<Spline> {
let chord = second.point - first.point;
let length = chord.length();
if length <= EPS || !length.is_finite() {
return None;
}
let t0 = first.outward.try_normalize()?;
// The source's outward direction at the second end points away from the
// blend. Reverse it to get the blend's arrival direction.
let t1 = -second.outward.try_normalize()?;
let (degree, points) = match continuity {
Continuity::Tangent => {
let handle = length / 3.0;
(
3,
vec![
first.point,
first.point + handle * t0,
second.point - handle * t1,
second.point,
],
)
}
Continuity::Curvature => {
// Smaller endpoint speeds prevent a tight source curve joined over
// a long gap from creating enormous inner control points. Changing
// speed does not change the matched geometric curvature.
let speed0 = endpoint_speed(length, first.curvature.length());
let speed1 = endpoint_speed(length, second.curvature.length());
let p0 = first.point;
let p1 = p0 + (speed0 / 5.0) * t0;
let p2 = 2.0 * p1 - p0 + (speed0 * speed0 / 20.0) * first.curvature;
let p5 = second.point;
let p4 = p5 - (speed1 / 5.0) * t1;
let p3 = 2.0 * p4 - p5 + (speed1 * speed1 / 20.0) * second.curvature;
(5, vec![p0, p1, p2, p3, p4, p5])
}
};
let mut spline = Spline::new();
spline.common = common;
spline.degree = degree;
spline.knots = Spline::generate_clamped_knots(degree as usize, points.len());
spline.control_points = points
.into_iter()
.map(|p| Vector3::new(p.x, p.y, p.z))
.collect();
Some(spline)
}
fn endpoint_speed(chord: f64, curvature: f64) -> f64 {
if curvature <= EPS {
chord
} else {
chord.min((2.0 * chord / curvature).sqrt())
}
}
fn endpoint_frame(entity: &EntityType, click: DVec3) -> Option<EndpointFrame> {
match entity {
EntityType::Line(line) => {
let start = to_dvec(line.start);
let end = to_dvec(line.end);
segment_endpoint(start, end, click)
}
EntityType::Arc(arc) => arc_endpoint(arc, click),
EntityType::LwPolyline(poly) if !poly.is_closed => {
let n = poly.vertices.len();
if n < 2 {
return None;
}
let normal = to_dvec(poly.normal).normalize_or_zero();
let selected_start = click.distance_squared(lw_point(poly, 0))
<= click.distance_squared(lw_point(poly, n - 1));
let segment = if selected_start { 0 } else { n - 2 };
planar_segment_endpoint(
[
poly.vertices[segment].location.x,
poly.vertices[segment].location.y,
],
[
poly.vertices[segment + 1].location.x,
poly.vertices[segment + 1].location.y,
],
poly.vertices[segment].bulge,
poly.elevation,
normal,
selected_start,
)
}
EntityType::Polyline2D(poly) if !poly.is_closed() => {
let filtered = crate::entities::polyline::drawn_vertices2d(poly);
let vertices = filtered.as_deref().unwrap_or(&poly.vertices);
let n = vertices.len();
if n < 2 {
return None;
}
let normal = to_dvec(poly.normal).normalize_or_zero();
let first = ocs_to_dvec(
vertices[0].location.x,
vertices[0].location.y,
poly.elevation,
normal,
);
let last = ocs_to_dvec(
vertices[n - 1].location.x,
vertices[n - 1].location.y,
poly.elevation,
normal,
);
let selected_start = click.distance_squared(first) <= click.distance_squared(last);
let segment = if selected_start { 0 } else { n - 2 };
planar_segment_endpoint(
[vertices[segment].location.x, vertices[segment].location.y],
[
vertices[segment + 1].location.x,
vertices[segment + 1].location.y,
],
vertices[segment].bulge,
poly.elevation,
normal,
selected_start,
)
}
EntityType::Polyline(poly) if !poly.is_closed() => {
let points: Vec<_> = poly.vertices.iter().map(|v| to_dvec(v.location)).collect();
polyline_endpoint(&points, click)
}
EntityType::Polyline3D(poly) if !poly.is_closed() => {
let points: Vec<_> = poly.vertices.iter().map(|v| to_dvec(v.position)).collect();
polyline_endpoint(&points, click)
}
EntityType::Spline(spline) if !spline.flags.closed && !spline.flags.periodic => {
spline_endpoint(spline, click)
}
_ => None,
}
}
fn segment_endpoint(start: DVec3, end: DVec3, click: DVec3) -> Option<EndpointFrame> {
let direction = (end - start).try_normalize()?;
if click.distance_squared(start) <= click.distance_squared(end) {
Some(EndpointFrame {
point: start,
outward: -direction,
curvature: DVec3::ZERO,
})
} else {
Some(EndpointFrame {
point: end,
outward: direction,
curvature: DVec3::ZERO,
})
}
}
fn polyline_endpoint(points: &[DVec3], click: DVec3) -> Option<EndpointFrame> {
if points.len() < 2 {
return None;
}
if click.distance_squared(points[0]) <= click.distance_squared(points[points.len() - 1]) {
segment_endpoint(points[0], points[1], points[0])
} else {
segment_endpoint(
points[points.len() - 2],
points[points.len() - 1],
points[points.len() - 1],
)
}
}
fn arc_endpoint(arc: &acadrust::entities::Arc, click: DVec3) -> Option<EndpointFrame> {
if arc.radius <= EPS {
return None;
}
let normal_tuple = (arc.normal.x, arc.normal.y, arc.normal.z);
let normal = to_dvec(arc.normal).try_normalize()?;
let (ax, ay) = ocs_axes(normal_tuple);
let axis_x = DVec3::new(ax.0, ax.1, ax.2);
let axis_y = DVec3::new(ay.0, ay.1, ay.2);
let center = tuple_to_dvec(ocs_point_to_wcs(
(arc.center.x, arc.center.y, arc.center.z),
normal_tuple,
));
let at = |angle: f64| center + arc.radius * (angle.cos() * axis_x + angle.sin() * axis_y);
let start = at(arc.start_angle);
let end = at(arc.end_angle);
let (point, angle, at_start) = if click.distance_squared(start) <= click.distance_squared(end) {
(start, arc.start_angle, true)
} else {
(end, arc.end_angle, false)
};
let tangent = normal
.cross(point - center)
.try_normalize()
.or_else(|| (-angle.sin() * axis_x + angle.cos() * axis_y).try_normalize())?;
Some(EndpointFrame {
point,
outward: if at_start { -tangent } else { tangent },
curvature: (center - point) / (arc.radius * arc.radius),
})
}
fn lw_point(poly: &acadrust::entities::LwPolyline, index: usize) -> DVec3 {
let normal = to_dvec(poly.normal).normalize_or_zero();
let p = poly.vertices[index].location;
ocs_to_dvec(p.x, p.y, poly.elevation, normal)
}
fn planar_segment_endpoint(
p0: [f64; 2],
p1: [f64; 2],
bulge: f64,
elevation: f64,
normal: DVec3,
selected_start: bool,
) -> Option<EndpointFrame> {
if normal.length_squared() <= EPS {
return None;
}
let start = ocs_to_dvec(p0[0], p0[1], elevation, normal);
let end = ocs_to_dvec(p1[0], p1[1], elevation, normal);
let Some(arc) = BulgeArc::from_bulge(p0, p1, bulge) else {
return segment_endpoint(start, end, if selected_start { start } else { end });
};
let center = ocs_to_dvec(arc.center[0], arc.center[1], elevation, normal);
let point = if selected_start { start } else { end };
let traversal_tangent = (normal.cross(point - center) * bulge.signum()).try_normalize()?;
Some(EndpointFrame {
point,
outward: if selected_start {
-traversal_tangent
} else {
traversal_tangent
},
curvature: (center - point) / (arc.radius * arc.radius),
})
}
fn spline_endpoint(spline: &Spline, click: DVec3) -> Option<EndpointFrame> {
if spline.control_points.len() >= 2 {
return spline_control_endpoint(spline, click);
}
let points: Vec<_> = spline.fit_points.iter().copied().map(to_dvec).collect();
if points.len() < 2 {
return None;
}
let at_start =
click.distance_squared(points[0]) <= click.distance_squared(points[points.len() - 1]);
let index = if at_start { 0 } else { points.len() - 1 };
let tangent = if at_start {
let stored = to_dvec(spline.begin_tangent);
if stored.length_squared() > EPS {
stored
} else {
points[1] - points[0]
}
} else {
let stored = to_dvec(spline.end_tangent);
if stored.length_squared() > EPS {
stored
} else {
points[index] - points[index - 1]
}
}
.try_normalize()?;
let curvature = if points.len() >= 3 {
if at_start {
circumcircle_curvature(points[0], points[1], points[2])
} else {
circumcircle_curvature(points[index], points[index - 1], points[index - 2])
}
} else {
DVec3::ZERO
};
Some(EndpointFrame {
point: points[index],
outward: if at_start { -tangent } else { tangent },
curvature,
})
}
fn spline_control_endpoint(spline: &Spline, click: DVec3) -> Option<EndpointFrame> {
let count = spline.control_points.len();
let degree = usize::try_from(spline.degree).ok()?;
if degree == 0 || count <= degree {
return None;
}
// The kernel's space curve holds the rational and the polynomial case
// alike — weights absent means polynomial — so there is nothing here to
// tell apart, and a malformed knot vector is replaced with a clamped
// uniform one rather than refused.
let controls: Vec<[f64; 3]> = spline
.control_points
.iter()
.map(|point| [point.x, point.y, point.z])
.collect();
let weights = (spline.weights.len() == count).then(|| {
spline
.weights
.iter()
.map(|weight| if weight.abs() <= EPS { 1.0 } else { *weight })
.collect()
});
let curve = NurbsCurve3::new(degree, controls, spline.knots.clone(), weights)?;
let (start, end) = curve.domain();
let at_start = click.distance_squared(point_to_dvec(curve.point_at_knot(start)))
<= click.distance_squared(point_to_dvec(curve.point_at_knot(end)));
let parameter = if at_start { start } else { end };
curve_frame(
point_to_dvec(curve.point_at_knot(parameter)),
point_to_dvec(curve.tangent_at_knot(parameter)),
point_to_dvec(curve.acceleration_at_knot(parameter)),
at_start,
)
}
fn curve_frame(
point: DVec3,
first_derivative: DVec3,
second_derivative: DVec3,
at_start: bool,
) -> Option<EndpointFrame> {
let speed_squared = first_derivative.length_squared();
if speed_squared <= EPS {
return None;
}
let tangent = first_derivative / speed_squared.sqrt();
let normal_second = second_derivative - tangent * second_derivative.dot(tangent);
Some(EndpointFrame {
point,
outward: if at_start { -tangent } else { tangent },
curvature: normal_second / speed_squared,
})
}
/// The curvature vector at `point` of the circle through the three points.
fn circumcircle_curvature(point: DVec3, next: DVec3, third: DVec3) -> DVec3 {
let curvature = space_curve::curvature_through(
[point.x, point.y, point.z],
[next.x, next.y, next.z],
[third.x, third.y, third.z],
);
DVec3::new(curvature[0], curvature[1], curvature[2])
}
/// A Bézier control polygon sampled into a polyline.
///
/// De Casteljau, from the kernel. What was here summed Bernstein terms with
/// binomial coefficients out of a lookup table that had entries for degrees
/// three and five and returned one for everything else — correct only for
/// the two the blend happens to build today, and quietly wrong the moment a
/// third was added.
fn sample_bezier(control_points: &[Vector3], segments: usize) -> Vec<[f64; 3]> {
let control: Vec<[f64; 3]> = control_points
.iter()
.map(|p| [p.x, p.y, p.z])
.collect();
space_curve::bezier_points(&control, segments)
}
fn ocs_to_dvec(x: f64, y: f64, z: f64, normal: DVec3) -> DVec3 {
tuple_to_dvec(ocs_point_to_wcs((x, y, z), (normal.x, normal.y, normal.z)))
}
fn tuple_to_dvec(point: (f64, f64, f64)) -> DVec3 {
DVec3::new(point.0, point.1, point.2)
}
fn to_dvec(point: Vector3) -> DVec3 {
DVec3::new(point.x, point.y, point.z)
}
fn point_to_dvec(point: [f64; 3]) -> DVec3 {
DVec3::new(point[0], point[1], point[2])
}
inventory::submit!(crate::command::CommandRegistration {
names: &["BLEND", "BLE"]
});