1 /*************************************************************************/
2 /* rect2.cpp */
3 /*************************************************************************/
4 /* This file is part of: */
5 /* GODOT ENGINE */
6 /* https://godotengine.org */
7 /*************************************************************************/
8 /* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
9 /* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
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17 /* the following conditions: */
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24 /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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28 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29 /*************************************************************************/
30
31 #include "core/math/transform_2d.h" // Includes rect2.h but Rect2 needs Transform2D
32
is_equal_approx(const Rect2 & p_rect) const33 bool Rect2::is_equal_approx(const Rect2 &p_rect) const {
34
35 return position.is_equal_approx(p_rect.position) && size.is_equal_approx(p_rect.size);
36 }
37
intersects_segment(const Point2 & p_from,const Point2 & p_to,Point2 * r_pos,Point2 * r_normal) const38 bool Rect2::intersects_segment(const Point2 &p_from, const Point2 &p_to, Point2 *r_pos, Point2 *r_normal) const {
39
40 real_t min = 0, max = 1;
41 int axis = 0;
42 real_t sign = 0;
43
44 for (int i = 0; i < 2; i++) {
45 real_t seg_from = p_from[i];
46 real_t seg_to = p_to[i];
47 real_t box_begin = position[i];
48 real_t box_end = box_begin + size[i];
49 real_t cmin, cmax;
50 real_t csign;
51
52 if (seg_from < seg_to) {
53
54 if (seg_from > box_end || seg_to < box_begin)
55 return false;
56 real_t length = seg_to - seg_from;
57 cmin = (seg_from < box_begin) ? ((box_begin - seg_from) / length) : 0;
58 cmax = (seg_to > box_end) ? ((box_end - seg_from) / length) : 1;
59 csign = -1.0;
60
61 } else {
62
63 if (seg_to > box_end || seg_from < box_begin)
64 return false;
65 real_t length = seg_to - seg_from;
66 cmin = (seg_from > box_end) ? (box_end - seg_from) / length : 0;
67 cmax = (seg_to < box_begin) ? (box_begin - seg_from) / length : 1;
68 csign = 1.0;
69 }
70
71 if (cmin > min) {
72 min = cmin;
73 axis = i;
74 sign = csign;
75 }
76 if (cmax < max)
77 max = cmax;
78 if (max < min)
79 return false;
80 }
81
82 Vector2 rel = p_to - p_from;
83
84 if (r_normal) {
85 Vector2 normal;
86 normal[axis] = sign;
87 *r_normal = normal;
88 }
89
90 if (r_pos)
91 *r_pos = p_from + rel * min;
92
93 return true;
94 }
95
intersects_transformed(const Transform2D & p_xform,const Rect2 & p_rect) const96 bool Rect2::intersects_transformed(const Transform2D &p_xform, const Rect2 &p_rect) const {
97
98 //SAT intersection between local and transformed rect2
99
100 Vector2 xf_points[4] = {
101 p_xform.xform(p_rect.position),
102 p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y)),
103 p_xform.xform(Vector2(p_rect.position.x, p_rect.position.y + p_rect.size.y)),
104 p_xform.xform(Vector2(p_rect.position.x + p_rect.size.x, p_rect.position.y + p_rect.size.y)),
105 };
106
107 real_t low_limit;
108
109 //base rect2 first (faster)
110
111 if (xf_points[0].y > position.y)
112 goto next1;
113 if (xf_points[1].y > position.y)
114 goto next1;
115 if (xf_points[2].y > position.y)
116 goto next1;
117 if (xf_points[3].y > position.y)
118 goto next1;
119
120 return false;
121
122 next1:
123
124 low_limit = position.y + size.y;
125
126 if (xf_points[0].y < low_limit)
127 goto next2;
128 if (xf_points[1].y < low_limit)
129 goto next2;
130 if (xf_points[2].y < low_limit)
131 goto next2;
132 if (xf_points[3].y < low_limit)
133 goto next2;
134
135 return false;
136
137 next2:
138
139 if (xf_points[0].x > position.x)
140 goto next3;
141 if (xf_points[1].x > position.x)
142 goto next3;
143 if (xf_points[2].x > position.x)
144 goto next3;
145 if (xf_points[3].x > position.x)
146 goto next3;
147
148 return false;
149
150 next3:
151
152 low_limit = position.x + size.x;
153
154 if (xf_points[0].x < low_limit)
155 goto next4;
156 if (xf_points[1].x < low_limit)
157 goto next4;
158 if (xf_points[2].x < low_limit)
159 goto next4;
160 if (xf_points[3].x < low_limit)
161 goto next4;
162
163 return false;
164
165 next4:
166
167 Vector2 xf_points2[4] = {
168 position,
169 Vector2(position.x + size.x, position.y),
170 Vector2(position.x, position.y + size.y),
171 Vector2(position.x + size.x, position.y + size.y),
172 };
173
174 real_t maxa = p_xform.elements[0].dot(xf_points2[0]);
175 real_t mina = maxa;
176
177 real_t dp = p_xform.elements[0].dot(xf_points2[1]);
178 maxa = MAX(dp, maxa);
179 mina = MIN(dp, mina);
180
181 dp = p_xform.elements[0].dot(xf_points2[2]);
182 maxa = MAX(dp, maxa);
183 mina = MIN(dp, mina);
184
185 dp = p_xform.elements[0].dot(xf_points2[3]);
186 maxa = MAX(dp, maxa);
187 mina = MIN(dp, mina);
188
189 real_t maxb = p_xform.elements[0].dot(xf_points[0]);
190 real_t minb = maxb;
191
192 dp = p_xform.elements[0].dot(xf_points[1]);
193 maxb = MAX(dp, maxb);
194 minb = MIN(dp, minb);
195
196 dp = p_xform.elements[0].dot(xf_points[2]);
197 maxb = MAX(dp, maxb);
198 minb = MIN(dp, minb);
199
200 dp = p_xform.elements[0].dot(xf_points[3]);
201 maxb = MAX(dp, maxb);
202 minb = MIN(dp, minb);
203
204 if (mina > maxb)
205 return false;
206 if (minb > maxa)
207 return false;
208
209 maxa = p_xform.elements[1].dot(xf_points2[0]);
210 mina = maxa;
211
212 dp = p_xform.elements[1].dot(xf_points2[1]);
213 maxa = MAX(dp, maxa);
214 mina = MIN(dp, mina);
215
216 dp = p_xform.elements[1].dot(xf_points2[2]);
217 maxa = MAX(dp, maxa);
218 mina = MIN(dp, mina);
219
220 dp = p_xform.elements[1].dot(xf_points2[3]);
221 maxa = MAX(dp, maxa);
222 mina = MIN(dp, mina);
223
224 maxb = p_xform.elements[1].dot(xf_points[0]);
225 minb = maxb;
226
227 dp = p_xform.elements[1].dot(xf_points[1]);
228 maxb = MAX(dp, maxb);
229 minb = MIN(dp, minb);
230
231 dp = p_xform.elements[1].dot(xf_points[2]);
232 maxb = MAX(dp, maxb);
233 minb = MIN(dp, minb);
234
235 dp = p_xform.elements[1].dot(xf_points[3]);
236 maxb = MAX(dp, maxb);
237 minb = MIN(dp, minb);
238
239 if (mina > maxb)
240 return false;
241 if (minb > maxa)
242 return false;
243
244 return true;
245 }
246