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use crate::types::Line3D;
use wide::f64x4;
use wide::CmpGe;
use wide::CmpLe;
pub struct SoALines {
pub min_x: Vec<f64>,
pub min_y: Vec<f64>,
pub max_x: Vec<f64>,
pub max_y: Vec<f64>,
}
impl SoALines {
pub fn new(lines: &[Line3D]) -> Self {
let len = lines.len();
// Reserve memory + padding
let mut min_x = Vec::with_capacity(len + 3);
let mut min_y = Vec::with_capacity(len + 3);
let mut max_x = Vec::with_capacity(len + 3);
let mut max_y = Vec::with_capacity(len + 3);
for line in lines {
min_x.push(line.start.x.min(line.end.x));
min_y.push(line.start.y.min(line.end.y));
max_x.push(line.start.x.max(line.end.x));
max_y.push(line.start.y.max(line.end.y));
}
// Pad with NaNs so that comparisons always fail (return false)
// preventing false positives at the end of the array.
while min_x.len() % 4 != 0 {
min_x.push(f64::NAN);
min_y.push(f64::NAN);
max_x.push(f64::NAN);
max_y.push(f64::NAN);
}
Self {
min_x,
min_y,
max_x,
max_y,
}
}
pub fn len(&self) -> usize {
self.min_x.len()
}
pub fn is_empty(&self) -> bool {
self.min_x.is_empty()
}
/// Checks a single query line against 4 stored lines simultaneously.
/// Returns a bitmask (u8) where bits 0-3 represent intersection candidates.
///
/// Bit 0 = index
/// Bit 1 = index + 1
/// ...
#[inline]
pub fn intersects_bbox_batch(&self, query: Line3D, index: usize) -> u8 {
// 1. Prepare Query BBox (Splat to all 4 lanes)
let q_min_x_val = query.start.x.min(query.end.x);
let q_max_x_val = query.start.x.max(query.end.x);
let q_min_y_val = query.start.y.min(query.end.y);
let q_max_y_val = query.start.y.max(query.end.y);
let q_min_x = f64x4::splat(q_min_x_val);
let q_max_x = f64x4::splat(q_max_x_val);
let q_min_y = f64x4::splat(q_min_y_val);
let q_max_y = f64x4::splat(q_max_y_val);
self.intersects_bbox_batch_splatted(q_min_x, q_max_x, q_min_y, q_max_y, index)
}
/// Optimized version that accepts pre-splatted query bounding box.
#[inline]
pub fn intersects_bbox_batch_splatted(
&self,
q_min_x: f64x4,
q_max_x: f64x4,
q_min_y: f64x4,
q_max_y: f64x4,
index: usize,
) -> u8 {
// 2. Load Targets (4 at a time) using pre-calculated Min/Max
let t_min_x = f64x4::from(&self.min_x[index..index + 4]);
let t_min_y = f64x4::from(&self.min_y[index..index + 4]);
let t_max_x = f64x4::from(&self.max_x[index..index + 4]);
let t_max_y = f64x4::from(&self.max_y[index..index + 4]);
// 3. Perform Intersection Check
// Logic: Overlap exists if (RectA.min <= RectB.max) && (RectA.max >= RectB.min)
let overlap_x = q_min_x.cmp_le(t_max_x) & q_max_x.cmp_ge(t_min_x);
let overlap_y = q_min_y.cmp_le(t_max_y) & q_max_y.cmp_ge(t_min_y);
let overlap = overlap_x & overlap_y;
// 4. Pack result to u8
overlap.move_mask() as u8
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::types::{Coord3D, Line3D};
fn make_line(x1: f64, y1: f64, x2: f64, y2: f64) -> Line3D {
Line3D::new(Coord3D::new(x1, y1, 0.0), Coord3D::new(x2, y2, 0.0), 0)
}
#[test]
fn test_soa_bbox_batch_simd() {
// Setup 4 lines to test against a query
// Query Line: (0,0) -> (10,10). BBox: [0,0, 10,10]
let query = make_line(0.0, 0.0, 10.0, 10.0);
let lines = vec![
// 0. Inside Query BBox (Should Match)
make_line(1.0, 1.0, 2.0, 2.0),
// 1. Completely Outside to the Right (No Match)
// BBox: [12,0, 14,10] -> MinX(12) > QueryMaxX(10)
make_line(12.0, 0.0, 14.0, 10.0),
// 2. Overlapping Boundary (Touching) (Should Match)
// BBox: [10,5, 15,5]. MinX(10) <= QueryMaxX(10)
make_line(10.0, 5.0, 15.0, 5.0),
// 3. Diagonal Crossing (Should Match)
make_line(0.0, 10.0, 10.0, 0.0),
];
let soa = SoALines::new(&lines);
// Run the SIMD check
let mask = soa.intersects_bbox_batch(query, 0);
// Expected bits:
// Index 0: Match -> 1
// Index 1: No -> 0
// Index 2: Match -> 1
// Index 3: Match -> 1
// Result binary: 1101 (Little Endian order: bit0=idx0, bit3=idx3)
// 1 + 0 + 4 + 8 = 13
assert_eq!(mask, 0b1101, "Mask should match expected intersections");
}
#[test]
fn test_soa_padding_safety() {
// Test that the padding NaNs don't cause false positives
let query = make_line(0.0, 0.0, 10.0, 10.0);
// Only 1 line provided. 3 slots will be padded with NaN.
let lines = vec![make_line(1.0, 1.0, 2.0, 2.0)];
let soa = SoALines::new(&lines);
// Ensure we allocated enough for SIMD width
assert!(soa.min_x.len() >= 4);
let mask = soa.intersects_bbox_batch(query, 0);
// Index 0 is a match.
// Index 1, 2, 3 are NaN padding.
// Comparisons with NaN (e.g. NaN <= 10.0) return False.
// So mask should be 0001 -> 1.
assert_eq!(mask, 1, "Padding slots should never return true");
}
#[test]
fn test_empty_soa() {
// Edge case: Empty input
let lines: Vec<Line3D> = vec![];
let soa = SoALines::new(&lines);
assert_eq!(soa.min_x.len(), 0);
}
#[test]
fn test_crossing_scenario() {
// Reproduction of test_noding_crossing_lines structure
let lines = vec![
make_line(0., 0., 10., 0.), // 0
make_line(10., 0., 10., 10.), // 1
make_line(10., 10., 0., 10.), // 2
make_line(0., 10., 0., 0.), // 3
make_line(0., 0., 10., 10.), // 4
make_line(0., 10., 10., 0.), // 5
];
let soa = SoALines::new(&lines);
// Check 4 vs 5
// 5 is at index 5.
// Block starting at 4 covers 4, 5, 6, 7.
// We query line 4.
let mask = soa.intersects_bbox_batch(lines[4], 4);
// Expected:
// Index 4 (Self): Match
// Index 5 (Cross): Match
// Index 6 (NaN): No
// Index 7 (NaN): No
// Mask: 0011 -> 3
assert_eq!(mask & 2, 2, "Line 4 should intersect Line 5 (bit 1)");
}
}