this-city/engine/core/math/rect2.cpp
2026-07-10 17:04:34 +02:00

411 lines
11 KiB
C++
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/**************************************************************************/
/* rect2.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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. */
/**************************************************************************/
#include "rect2.h"
#include "core/math/rect2i.h"
#include "core/math/transform_2d.h"
#include "core/string/ustring.h"
bool Rect2::is_equal_approx(const Rect2 &p_rect) const {
return position.is_equal_approx(p_rect.position) && size.is_equal_approx(p_rect.size);
}
bool Rect2::is_same(const Rect2 &p_rect) const {
return position.is_same(p_rect.position) && size.is_same(p_rect.size);
}
bool Rect2::is_finite() const {
return position.is_finite() && size.is_finite();
}
bool Rect2::intersects_segment(const Point2 &p_from, const Point2 &p_to, Point2 *r_pos, Point2 *r_normal) const {
#ifdef MATH_CHECKS
if (unlikely(size.x < 0 || size.y < 0)) {
ERR_PRINT("Rect2 size is negative, this is not supported. Use Rect2.abs() to get a Rect2 with a positive size.");
}
#endif
real_t min = 0, max = 1;
int axis = 0;
real_t sign = 0;
for (int i = 0; i < 2; i++) {
real_t seg_from = p_from[i];
real_t seg_to = p_to[i];
real_t box_begin = position[i];
real_t box_end = box_begin + size[i];
real_t cmin, cmax;
real_t csign;
if (seg_from < seg_to) {
if (seg_from > box_end || seg_to < box_begin) {
return false;
}
real_t length = seg_to - seg_from;
cmin = (seg_from < box_begin) ? ((box_begin - seg_from) / length) : 0;
cmax = (seg_to > box_end) ? ((box_end - seg_from) / length) : 1;
csign = -1.0;
} else {
if (seg_to > box_end || seg_from < box_begin) {
return false;
}
real_t length = seg_to - seg_from;
cmin = (seg_from > box_end) ? (box_end - seg_from) / length : 0;
cmax = (seg_to < box_begin) ? (box_begin - seg_from) / length : 1;
csign = 1.0;
}
if (cmin > min) {
min = cmin;
axis = i;
sign = csign;
}
if (cmax < max) {
max = cmax;
}
if (max < min) {
return false;
}
}
Vector2 rel = p_to - p_from;
if (r_normal) {
Vector2 normal;
normal[axis] = sign;
*r_normal = normal;
}
if (r_pos) {
*r_pos = p_from + rel * min;
}
return true;
}
bool Rect2::intersects_transformed(const Transform2D &p_xform, const Rect2 &p_rect) const {
#ifdef MATH_CHECKS
if (unlikely(size.x < 0 || size.y < 0 || p_rect.size.x < 0 || p_rect.size.y < 0)) {
ERR_PRINT("Rect2 size is negative, this is not supported. Use Rect2.abs() to get a Rect2 with a positive size.");
}
#endif
//SAT intersection between local and transformed rect2
Vector2 xf_points[4] = {
p_xform.xform(p_rect.position),
p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y)),
p_xform.xform(Vector2(p_rect.position.x, p_rect.position.y + p_rect.size.y)),
p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y + p_rect.size.y)),
};
real_t low_limit;
//base rect2 first (faster)
if (xf_points[0].y > position.y) {
goto next1;
}
if (xf_points[1].y > position.y) {
goto next1;
}
if (xf_points[2].y > position.y) {
goto next1;
}
if (xf_points[3].y > position.y) {
goto next1;
}
return false;
next1:
low_limit = position.y + size.y;
if (xf_points[0].y < low_limit) {
goto next2;
}
if (xf_points[1].y < low_limit) {
goto next2;
}
if (xf_points[2].y < low_limit) {
goto next2;
}
if (xf_points[3].y < low_limit) {
goto next2;
}
return false;
next2:
if (xf_points[0].x > position.x) {
goto next3;
}
if (xf_points[1].x > position.x) {
goto next3;
}
if (xf_points[2].x > position.x) {
goto next3;
}
if (xf_points[3].x > position.x) {
goto next3;
}
return false;
next3:
low_limit = position.x + size.x;
if (xf_points[0].x < low_limit) {
goto next4;
}
if (xf_points[1].x < low_limit) {
goto next4;
}
if (xf_points[2].x < low_limit) {
goto next4;
}
if (xf_points[3].x < low_limit) {
goto next4;
}
return false;
next4:
Vector2 xf_points2[4] = {
position,
Vector2(position.x + size.x, position.y),
Vector2(position.x, position.y + size.y),
Vector2(position.x + size.x, position.y + size.y),
};
real_t maxa = p_xform.columns[0].dot(xf_points2[0]);
real_t mina = maxa;
real_t dp = p_xform.columns[0].dot(xf_points2[1]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
dp = p_xform.columns[0].dot(xf_points2[2]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
dp = p_xform.columns[0].dot(xf_points2[3]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
real_t maxb = p_xform.columns[0].dot(xf_points[0]);
real_t minb = maxb;
dp = p_xform.columns[0].dot(xf_points[1]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
dp = p_xform.columns[0].dot(xf_points[2]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
dp = p_xform.columns[0].dot(xf_points[3]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
if (mina > maxb) {
return false;
}
if (minb > maxa) {
return false;
}
maxa = p_xform.columns[1].dot(xf_points2[0]);
mina = maxa;
dp = p_xform.columns[1].dot(xf_points2[1]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
dp = p_xform.columns[1].dot(xf_points2[2]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
dp = p_xform.columns[1].dot(xf_points2[3]);
maxa = MAX(dp, maxa);
mina = MIN(dp, mina);
maxb = p_xform.columns[1].dot(xf_points[0]);
minb = maxb;
dp = p_xform.columns[1].dot(xf_points[1]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
dp = p_xform.columns[1].dot(xf_points[2]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
dp = p_xform.columns[1].dot(xf_points[3]);
maxb = MAX(dp, maxb);
minb = MIN(dp, minb);
if (mina > maxb) {
return false;
}
if (minb > maxa) {
return false;
}
return true;
}
Rect2 Rect2::intersection_transformed(const Transform2D &p_xform, const Rect2 &p_rect) const {
#ifdef MATH_CHECKS
if (unlikely(size.x < 0 || size.y < 0 || p_rect.size.x < 0 || p_rect.size.y < 0)) {
ERR_PRINT("Rect2 size is negative, this is not supported. Use Rect2.abs() to get a Rect2 with a positive size.");
}
#endif
if ((Math::is_zero_approx(p_xform.columns[0].y) && Math::is_zero_approx(p_xform.columns[1].x)) ||
(Math::is_zero_approx(p_xform.columns[0].x) && Math::is_zero_approx(p_xform.columns[1].y))) {
return intersection(p_xform.xform(p_rect));
}
if (!intersects_transformed(p_xform, p_rect)) {
return Rect2();
}
const Vector2 xf_points[4] = {
p_xform.xform(p_rect.position),
p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y)),
p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y + p_rect.size.y)),
p_xform.xform(Vector2(p_rect.position.x, p_rect.position.y + p_rect.size.y)),
};
// Use SutherlandHodgman algorithm.
Vector2 subject[8];
int subject_count = 4;
subject[0] = xf_points[0];
subject[1] = xf_points[1];
subject[2] = xf_points[2];
subject[3] = xf_points[3];
const Vector2 min = position;
const Vector2 max = position + size;
Vector2 intersected;
for (int edge = 0; edge < 4; edge++) {
const int axis = edge % 2;
const int another_axis = 1 - axis;
const bool is_min = (edge < 2);
intersected[axis] = is_min ? min[axis] : max[axis];
Vector2 output[8];
int output_count = 0;
Vector2 prev = subject[subject_count - 1];
bool prev_in_halfplane = is_min ? (prev[axis] >= intersected[axis]) : (prev[axis] <= intersected[axis]);
for (int i = 0; i < subject_count; i++) {
const Vector2 &curr = subject[i];
bool curr_in_halfplane = is_min ? (curr[axis] >= intersected[axis]) : (curr[axis] <= intersected[axis]);
if (prev_in_halfplane != curr_in_halfplane) {
// Entering/exiting the half-plane.
real_t t = (intersected[axis] - prev[axis]) / (curr[axis] - prev[axis]);
intersected[another_axis] = prev[another_axis] + (curr[another_axis] - prev[another_axis]) * t;
output[output_count++] = intersected;
}
if (curr_in_halfplane) {
output[output_count++] = curr;
}
prev = curr;
prev_in_halfplane = curr_in_halfplane;
}
for (int i = 0; i < output_count; i++) {
subject[i] = output[i];
}
subject_count = output_count;
if (subject_count == 0) {
break;
}
}
if (subject_count > 0) {
return Rect2::from_points(subject, subject_count);
}
// Perform a reverse containment test; the current rect may be inside the transformed rect.
const Vector2 corners[4] = {
position,
Vector2(max.x, min.y),
max,
Vector2(min.x, max.y)
};
Vector2 inside_points[4];
int inside_count = 0;
for (int point_idx = 0; point_idx < 4; point_idx++) {
bool has_pos = false;
bool has_neg = false;
for (int idx = 0; idx < 4; idx++) {
const int next_idx = (idx + 1) % 4;
Vector2 v0 = xf_points[next_idx] - xf_points[idx];
Vector2 v1 = corners[point_idx] - xf_points[idx];
real_t cross = v0.cross(v1);
if (cross > CMP_EPSILON) {
has_pos = true;
}
if (cross < -CMP_EPSILON) {
has_neg = true;
}
if (has_pos && has_neg) {
break;
}
}
if (!(has_pos && has_neg)) {
inside_points[inside_count++] = corners[point_idx];
}
}
return inside_count > 0 ? Rect2::from_points(inside_points, inside_count) : Rect2();
}
Rect2::operator String() const {
return "[P: " + position.operator String() + ", S: " + size.operator String() + "]";
}
Rect2::operator Rect2i() const {
return Rect2i(position, size);
}