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tile_map_backport/geometry_2d.h

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/*************************************************************************/
/* geometry_2d.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#ifndef GEOMETRY_2D_H
#define GEOMETRY_2D_H
#include "core/math/delaunay.h"
#include "core/math/triangulate.h"
#include "vector3i.h"
#include "core/vector.h"
class Geometry2D {
public:
static real_t get_closest_points_between_segments(const Vector2 &p1, const Vector2 &q1, const Vector2 &p2, const Vector2 &q2, Vector2 &c1, Vector2 &c2) {
Vector2 d1 = q1 - p1; // Direction vector of segment S1.
Vector2 d2 = q2 - p2; // Direction vector of segment S2.
Vector2 r = p1 - p2;
real_t a = d1.dot(d1); // Squared length of segment S1, always nonnegative.
real_t e = d2.dot(d2); // Squared length of segment S2, always nonnegative.
real_t f = d2.dot(r);
real_t s, t;
// Check if either or both segments degenerate into points.
if (a <= CMP_EPSILON && e <= CMP_EPSILON) {
// Both segments degenerate into points.
c1 = p1;
c2 = p2;
return Math::sqrt((c1 - c2).dot(c1 - c2));
}
if (a <= CMP_EPSILON) {
// First segment degenerates into a point.
s = 0.0;
t = f / e; // s = 0 => t = (b*s + f) / e = f / e
t = CLAMP(t, 0.0, 1.0);
} else {
real_t c = d1.dot(r);
if (e <= CMP_EPSILON) {
// Second segment degenerates into a point.
t = 0.0;
s = CLAMP(-c / a, 0.0, 1.0); // t = 0 => s = (b*t - c) / a = -c / a
} else {
// The general nondegenerate case starts here.
real_t b = d1.dot(d2);
real_t denom = a * e - b * b; // Always nonnegative.
// If segments not parallel, compute closest point on L1 to L2 and
// clamp to segment S1. Else pick arbitrary s (here 0).
if (denom != 0.0) {
s = CLAMP((b * f - c * e) / denom, 0.0, 1.0);
} else {
s = 0.0;
}
// Compute point on L2 closest to S1(s) using
// t = Dot((P1 + D1*s) - P2,D2) / Dot(D2,D2) = (b*s + f) / e
t = (b * s + f) / e;
//If t in [0,1] done. Else clamp t, recompute s for the new value
// of t using s = Dot((P2 + D2*t) - P1,D1) / Dot(D1,D1)= (t*b - c) / a
// and clamp s to [0, 1].
if (t < 0.0) {
t = 0.0;
s = CLAMP(-c / a, 0.0, 1.0);
} else if (t > 1.0) {
t = 1.0;
s = CLAMP((b - c) / a, 0.0, 1.0);
}
}
}
c1 = p1 + d1 * s;
c2 = p2 + d2 * t;
return Math::sqrt((c1 - c2).dot(c1 - c2));
}
static Vector2 get_closest_point_to_segment(const Vector2 &p_point, const Vector2 *p_segment) {
Vector2 p = p_point - p_segment[0];
Vector2 n = p_segment[1] - p_segment[0];
real_t l2 = n.length_squared();
if (l2 < 1e-20) {
return p_segment[0]; // Both points are the same, just give any.
}
real_t d = n.dot(p) / l2;
if (d <= 0.0) {
return p_segment[0]; // Before first point.
} else if (d >= 1.0) {
return p_segment[1]; // After first point.
} else {
return p_segment[0] + n * d; // Inside.
}
}
static bool is_point_in_triangle(const Vector2 &s, const Vector2 &a, const Vector2 &b, const Vector2 &c) {
Vector2 an = a - s;
Vector2 bn = b - s;
Vector2 cn = c - s;
bool orientation = an.cross(bn) > 0;
if ((bn.cross(cn) > 0) != orientation) {
return false;
}
return (cn.cross(an) > 0) == orientation;
}
static Vector2 get_closest_point_to_segment_uncapped(const Vector2 &p_point, const Vector2 *p_segment) {
Vector2 p = p_point - p_segment[0];
Vector2 n = p_segment[1] - p_segment[0];
real_t l2 = n.length_squared();
if (l2 < 1e-20) {
return p_segment[0]; // Both points are the same, just give any.
}
real_t d = n.dot(p) / l2;
return p_segment[0] + n * d; // Inside.
}
// Disable False Positives in MSVC compiler; we correctly check for 0 here to prevent a division by 0.
// See: https://github.com/godotengine/godot/pull/44274
#ifdef _MSC_VER
#pragma warning(disable : 4723)
#endif
static bool line_intersects_line(const Vector2 &p_from_a, const Vector2 &p_dir_a, const Vector2 &p_from_b, const Vector2 &p_dir_b, Vector2 &r_result) {
// See http://paulbourke.net/geometry/pointlineplane/
const real_t denom = p_dir_b.y * p_dir_a.x - p_dir_b.x * p_dir_a.y;
if (Math::is_zero_approx(denom)) { // Parallel?
return false;
}
const Vector2 v = p_from_a - p_from_b;
const real_t t = (p_dir_b.x * v.y - p_dir_b.y * v.x) / denom;
r_result = p_from_a + t * p_dir_a;
return true;
}
// Re-enable division by 0 warning
#ifdef _MSC_VER
#pragma warning(default : 4723)
#endif
static bool segment_intersects_segment(const Vector2 &p_from_a, const Vector2 &p_to_a, const Vector2 &p_from_b, const Vector2 &p_to_b, Vector2 *r_result) {
Vector2 B = p_to_a - p_from_a;
Vector2 C = p_from_b - p_from_a;
Vector2 D = p_to_b - p_from_a;
real_t ABlen = B.dot(B);
if (ABlen <= 0) {
return false;
}
Vector2 Bn = B / ABlen;
C = Vector2(C.x * Bn.x + C.y * Bn.y, C.y * Bn.x - C.x * Bn.y);
D = Vector2(D.x * Bn.x + D.y * Bn.y, D.y * Bn.x - D.x * Bn.y);
// Fail if C x B and D x B have the same sign (segments don't intersect).
if ((C.y < -CMP_EPSILON && D.y < -CMP_EPSILON) || (C.y > CMP_EPSILON && D.y > CMP_EPSILON)) {
return false;
}
// Fail if segments are parallel or colinear.
// (when A x B == zero, i.e (C - D) x B == zero, i.e C x B == D x B)
if (Math::is_equal_approx(C.y, D.y)) {
return false;
}
real_t ABpos = D.x + (C.x - D.x) * D.y / (D.y - C.y);
// Fail if segment C-D crosses line A-B outside of segment A-B.
if (ABpos < 0 || ABpos > 1.0) {
return false;
}
// Apply the discovered position to line A-B in the original coordinate system.
if (r_result) {
*r_result = p_from_a + B * ABpos;
}
return true;
}
static inline bool is_point_in_circle(const Vector2 &p_point, const Vector2 &p_circle_pos, real_t p_circle_radius) {
return p_point.distance_squared_to(p_circle_pos) <= p_circle_radius * p_circle_radius;
}
static real_t segment_intersects_circle(const Vector2 &p_from, const Vector2 &p_to, const Vector2 &p_circle_pos, real_t p_circle_radius) {
Vector2 line_vec = p_to - p_from;
Vector2 vec_to_line = p_from - p_circle_pos;
// Create a quadratic formula of the form ax^2 + bx + c = 0
real_t a, b, c;
a = line_vec.dot(line_vec);
b = 2 * vec_to_line.dot(line_vec);
c = vec_to_line.dot(vec_to_line) - p_circle_radius * p_circle_radius;
// Solve for t.
real_t sqrtterm = b * b - 4 * a * c;
// If the term we intend to square root is less than 0 then the answer won't be real,
// so it definitely won't be t in the range 0 to 1.
if (sqrtterm < 0) {
return -1;
}
// If we can assume that the line segment starts outside the circle (e.g. for continuous time collision detection)
// then the following can be skipped and we can just return the equivalent of res1.
sqrtterm = Math::sqrt(sqrtterm);
real_t res1 = (-b - sqrtterm) / (2 * a);
real_t res2 = (-b + sqrtterm) / (2 * a);
if (res1 >= 0 && res1 <= 1) {
return res1;
}
if (res2 >= 0 && res2 <= 1) {
return res2;
}
return -1;
}
enum PolyBooleanOperation {
OPERATION_UNION,
OPERATION_DIFFERENCE,
OPERATION_INTERSECTION,
OPERATION_XOR
};
enum PolyJoinType {
JOIN_SQUARE,
JOIN_ROUND,
JOIN_MITER
};
enum PolyEndType {
END_POLYGON,
END_JOINED,
END_BUTT,
END_SQUARE,
END_ROUND
};
static Vector<Vector<Point2>> merge_polygons(const Vector<Point2> &p_polygon_a, const Vector<Point2> &p_polygon_b) {
return _polypaths_do_operation(OPERATION_UNION, p_polygon_a, p_polygon_b);
}
static Vector<Vector<Point2>> clip_polygons(const Vector<Point2> &p_polygon_a, const Vector<Point2> &p_polygon_b) {
return _polypaths_do_operation(OPERATION_DIFFERENCE, p_polygon_a, p_polygon_b);
}
static Vector<Vector<Point2>> intersect_polygons(const Vector<Point2> &p_polygon_a, const Vector<Point2> &p_polygon_b) {
return _polypaths_do_operation(OPERATION_INTERSECTION, p_polygon_a, p_polygon_b);
}
static Vector<Vector<Point2>> exclude_polygons(const Vector<Point2> &p_polygon_a, const Vector<Point2> &p_polygon_b) {
return _polypaths_do_operation(OPERATION_XOR, p_polygon_a, p_polygon_b);
}
static Vector<Vector<Point2>> clip_polyline_with_polygon(const Vector<Vector2> &p_polyline, const Vector<Vector2> &p_polygon) {
return _polypaths_do_operation(OPERATION_DIFFERENCE, p_polyline, p_polygon, true);
}
static Vector<Vector<Point2>> intersect_polyline_with_polygon(const Vector<Vector2> &p_polyline, const Vector<Vector2> &p_polygon) {
return _polypaths_do_operation(OPERATION_INTERSECTION, p_polyline, p_polygon, true);
}
static Vector<Vector<Point2>> offset_polygon(const Vector<Vector2> &p_polygon, real_t p_delta, PolyJoinType p_join_type) {
return _polypath_offset(p_polygon, p_delta, p_join_type, END_POLYGON);
}
static Vector<Vector<Point2>> offset_polyline(const Vector<Vector2> &p_polygon, real_t p_delta, PolyJoinType p_join_type, PolyEndType p_end_type) {
ERR_FAIL_COND_V_MSG(p_end_type == END_POLYGON, Vector<Vector<Point2>>(), "Attempt to offset a polyline like a polygon (use offset_polygon instead).");
return _polypath_offset(p_polygon, p_delta, p_join_type, p_end_type);
}
static Vector<int> triangulate_delaunay(const Vector<Vector2> &p_points) {
Vector<Delaunay2D::Triangle> tr = Delaunay2D::triangulate(p_points);
Vector<int> triangles;
for (int i = 0; i < tr.size(); i++) {
triangles.push_back(tr[i].points[0]);
triangles.push_back(tr[i].points[1]);
triangles.push_back(tr[i].points[2]);
}
return triangles;
}
static Vector<int> triangulate_polygon(const Vector<Vector2> &p_polygon) {
Vector<int> triangles;
if (!Triangulate::triangulate(p_polygon, triangles)) {
return Vector<int>(); //fail
}
return triangles;
}
static bool is_polygon_clockwise(const Vector<Vector2> &p_polygon) {
int c = p_polygon.size();
if (c < 3) {
return false;
}
const Vector2 *p = p_polygon.ptr();
real_t sum = 0;
for (int i = 0; i < c; i++) {
const Vector2 &v1 = p[i];
const Vector2 &v2 = p[(i + 1) % c];
sum += (v2.x - v1.x) * (v2.y + v1.y);
}
return sum > 0.0f;
}
// Alternate implementation that should be faster.
static bool is_point_in_polygon(const Vector2 &p_point, const Vector<Vector2> &p_polygon) {
int c = p_polygon.size();
if (c < 3) {
return false;
}
const Vector2 *p = p_polygon.ptr();
Vector2 further_away(-1e20, -1e20);
Vector2 further_away_opposite(1e20, 1e20);
for (int i = 0; i < c; i++) {
further_away.x = MAX(p[i].x, further_away.x);
further_away.y = MAX(p[i].y, further_away.y);
further_away_opposite.x = MIN(p[i].x, further_away_opposite.x);
further_away_opposite.y = MIN(p[i].y, further_away_opposite.y);
}
// Make point outside that won't intersect with points in segment from p_point.
further_away += (further_away - further_away_opposite) * Vector2(1.221313, 1.512312);
int intersections = 0;
for (int i = 0; i < c; i++) {
const Vector2 &v1 = p[i];
const Vector2 &v2 = p[(i + 1) % c];
Vector2 res;
if (segment_intersects_segment(v1, v2, p_point, further_away, &res)) {
intersections++;
if (res.is_equal_approx(p_point)) {
// Point is in one of the polygon edges.
return true;
}
}
}
return (intersections & 1);
}
static bool is_segment_intersecting_polygon(const Vector2 &p_from, const Vector2 &p_to, const Vector<Vector2> &p_polygon) {
int c = p_polygon.size();
const Vector2 *p = p_polygon.ptr();
for (int i = 0; i < c; i++) {
const Vector2 &v1 = p[i];
const Vector2 &v2 = p[(i + 1) % c];
if (segment_intersects_segment(p_from, p_to, v1, v2, nullptr)) {
return true;
}
}
return false;
}
static real_t vec2_cross(const Point2 &O, const Point2 &A, const Point2 &B) {
return (real_t)(A.x - O.x) * (B.y - O.y) - (real_t)(A.y - O.y) * (B.x - O.x);
}
// Returns a list of points on the convex hull in counter-clockwise order.
// Note: the last point in the returned list is the same as the first one.
static Vector<Point2> convex_hull(Vector<Point2> P) {
int n = P.size(), k = 0;
Vector<Point2> H;
H.resize(2 * n);
// Sort points lexicographically.
P.sort();
// Build lower hull.
for (int i = 0; i < n; ++i) {
while (k >= 2 && vec2_cross(H[k - 2], H[k - 1], P[i]) <= 0) {
k--;
}
H.write[k++] = P[i];
}
// Build upper hull.
for (int i = n - 2, t = k + 1; i >= 0; i--) {
while (k >= t && vec2_cross(H[k - 2], H[k - 1], P[i]) <= 0) {
k--;
}
H.write[k++] = P[i];
}
H.resize(k);
return H;
}
static Vector<Point2i> bresenham_line(const Point2i &p_start, const Point2i &p_end) {
Vector<Point2i> points;
Point2i e_s = p_end - p_start;
Vector2i delta = Vector2i(ABS(e_s.x), ABS(e_s.y)) * 2;
Vector2i step = Vector2i(SIGN(e_s.x), SIGN(e_s.y));
Vector2i current = p_start;
if (delta.x > delta.y) {
int err = delta.x / 2;
for (; current.x != p_end.x; current.x += step.x) {
points.push_back(current);
err -= delta.y;
if (err < 0) {
current.y += step.y;
err += delta.x;
}
}
} else {
int err = delta.y / 2;
for (; current.y != p_end.y; current.y += step.y) {
points.push_back(current);
err -= delta.x;
if (err < 0) {
current.x += step.x;
err += delta.y;
}
}
}
points.push_back(current);
return points;
}
static Vector<Vector<Vector2>> decompose_polygon_in_convex(Vector<Point2> polygon);
static void make_atlas(const Vector<Size2i> &p_rects, Vector<Point2i> &r_result, Size2i &r_size);
static Vector<Point2i> pack_rects(const Vector<Size2i> &p_sizes, const Size2i &p_atlas_size);
static Vector<Vector3i> partial_pack_rects(const Vector<Vector2i> &p_sizes, const Size2i &p_atlas_size);
private:
static Vector<Vector<Point2>> _polypaths_do_operation(PolyBooleanOperation p_op, const Vector<Point2> &p_polypath_a, const Vector<Point2> &p_polypath_b, bool is_a_open = false);
static Vector<Vector<Point2>> _polypath_offset(const Vector<Point2> &p_polypath, real_t p_delta, PolyJoinType p_join_type, PolyEndType p_end_type);
};
#endif // GEOMETRY_2D_H
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