godot/core/math/face3.cpp
Rémi Verschelde a7f49ac9a1 Update copyright statements to 2020
Happy new year to the wonderful Godot community!

We're starting a new decade with a well-established, non-profit, free
and open source game engine, and tons of further improvements in the
pipeline from hundreds of contributors.

Godot will keep getting better, and we're looking forward to all the
games that the community will keep developing and releasing with it.
2020-01-01 11:16:22 +01:00

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/*************************************************************************/
/* face3.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 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. */
/*************************************************************************/
#include "face3.h"
#include "core/math/geometry.h"
int Face3::split_by_plane(const Plane &p_plane, Face3 p_res[3], bool p_is_point_over[3]) const {
ERR_FAIL_COND_V(is_degenerate(), 0);
Vector3 above[4];
int above_count = 0;
Vector3 below[4];
int below_count = 0;
for (int i = 0; i < 3; i++) {
if (p_plane.has_point(vertex[i], CMP_EPSILON)) { // point is in plane
ERR_FAIL_COND_V(above_count >= 4, 0);
above[above_count++] = vertex[i];
ERR_FAIL_COND_V(below_count >= 4, 0);
below[below_count++] = vertex[i];
} else {
if (p_plane.is_point_over(vertex[i])) {
//Point is over
ERR_FAIL_COND_V(above_count >= 4, 0);
above[above_count++] = vertex[i];
} else {
//Point is under
ERR_FAIL_COND_V(below_count >= 4, 0);
below[below_count++] = vertex[i];
}
/* Check for Intersection between this and the next vertex*/
Vector3 inters;
if (!p_plane.intersects_segment(vertex[i], vertex[(i + 1) % 3], &inters))
continue;
/* Intersection goes to both */
ERR_FAIL_COND_V(above_count >= 4, 0);
above[above_count++] = inters;
ERR_FAIL_COND_V(below_count >= 4, 0);
below[below_count++] = inters;
}
}
int polygons_created = 0;
ERR_FAIL_COND_V(above_count >= 4 && below_count >= 4, 0); //bug in the algo
if (above_count >= 3) {
p_res[polygons_created] = Face3(above[0], above[1], above[2]);
p_is_point_over[polygons_created] = true;
polygons_created++;
if (above_count == 4) {
p_res[polygons_created] = Face3(above[2], above[3], above[0]);
p_is_point_over[polygons_created] = true;
polygons_created++;
}
}
if (below_count >= 3) {
p_res[polygons_created] = Face3(below[0], below[1], below[2]);
p_is_point_over[polygons_created] = false;
polygons_created++;
if (below_count == 4) {
p_res[polygons_created] = Face3(below[2], below[3], below[0]);
p_is_point_over[polygons_created] = false;
polygons_created++;
}
}
return polygons_created;
}
bool Face3::intersects_ray(const Vector3 &p_from, const Vector3 &p_dir, Vector3 *p_intersection) const {
return Geometry::ray_intersects_triangle(p_from, p_dir, vertex[0], vertex[1], vertex[2], p_intersection);
}
bool Face3::intersects_segment(const Vector3 &p_from, const Vector3 &p_dir, Vector3 *p_intersection) const {
return Geometry::segment_intersects_triangle(p_from, p_dir, vertex[0], vertex[1], vertex[2], p_intersection);
}
bool Face3::is_degenerate() const {
Vector3 normal = vec3_cross(vertex[0] - vertex[1], vertex[0] - vertex[2]);
return (normal.length_squared() < CMP_EPSILON2);
}
Face3::Side Face3::get_side_of(const Face3 &p_face, ClockDirection p_clock_dir) const {
int over = 0, under = 0;
Plane plane = get_plane(p_clock_dir);
for (int i = 0; i < 3; i++) {
const Vector3 &v = p_face.vertex[i];
if (plane.has_point(v)) //coplanar, don't bother
continue;
if (plane.is_point_over(v))
over++;
else
under++;
}
if (over > 0 && under == 0)
return SIDE_OVER;
else if (under > 0 && over == 0)
return SIDE_UNDER;
else if (under == 0 && over == 0)
return SIDE_COPLANAR;
else
return SIDE_SPANNING;
}
Vector3 Face3::get_random_point_inside() const {
real_t a = Math::random(0, 1);
real_t b = Math::random(0, 1);
if (a > b) {
SWAP(a, b);
}
return vertex[0] * a + vertex[1] * (b - a) + vertex[2] * (1.0 - b);
}
Plane Face3::get_plane(ClockDirection p_dir) const {
return Plane(vertex[0], vertex[1], vertex[2], p_dir);
}
Vector3 Face3::get_median_point() const {
return (vertex[0] + vertex[1] + vertex[2]) / 3.0;
}
real_t Face3::get_area() const {
return vec3_cross(vertex[0] - vertex[1], vertex[0] - vertex[2]).length();
}
ClockDirection Face3::get_clock_dir() const {
Vector3 normal = vec3_cross(vertex[0] - vertex[1], vertex[0] - vertex[2]);
//printf("normal is %g,%g,%g x %g,%g,%g- wtfu is %g\n",tofloat(normal.x),tofloat(normal.y),tofloat(normal.z),tofloat(vertex[0].x),tofloat(vertex[0].y),tofloat(vertex[0].z),tofloat( normal.dot( vertex[0] ) ) );
return (normal.dot(vertex[0]) >= 0) ? CLOCKWISE : COUNTERCLOCKWISE;
}
bool Face3::intersects_aabb(const AABB &p_aabb) const {
/** TEST PLANE **/
if (!p_aabb.intersects_plane(get_plane()))
return false;
#define TEST_AXIS(m_ax) \
/** TEST FACE AXIS */ \
{ \
real_t aabb_min = p_aabb.position.m_ax; \
real_t aabb_max = p_aabb.position.m_ax + p_aabb.size.m_ax; \
real_t tri_min = vertex[0].m_ax; \
real_t tri_max = vertex[0].m_ax; \
for (int i = 1; i < 3; i++) { \
if (vertex[i].m_ax > tri_max) \
tri_max = vertex[i].m_ax; \
if (vertex[i].m_ax < tri_min) \
tri_min = vertex[i].m_ax; \
} \
\
if (tri_max < aabb_min || aabb_max < tri_min) \
return false; \
}
TEST_AXIS(x);
TEST_AXIS(y);
TEST_AXIS(z);
/** TEST ALL EDGES **/
Vector3 edge_norms[3] = {
vertex[0] - vertex[1],
vertex[1] - vertex[2],
vertex[2] - vertex[0],
};
for (int i = 0; i < 12; i++) {
Vector3 from, to;
p_aabb.get_edge(i, from, to);
Vector3 e1 = from - to;
for (int j = 0; j < 3; j++) {
Vector3 e2 = edge_norms[j];
Vector3 axis = vec3_cross(e1, e2);
if (axis.length_squared() < 0.0001)
continue; // coplanar
axis.normalize();
real_t minA, maxA, minB, maxB;
p_aabb.project_range_in_plane(Plane(axis, 0), minA, maxA);
project_range(axis, Transform(), minB, maxB);
if (maxA < minB || maxB < minA)
return false;
}
}
return true;
}
Face3::operator String() const {
return String() + vertex[0] + ", " + vertex[1] + ", " + vertex[2];
}
void Face3::project_range(const Vector3 &p_normal, const Transform &p_transform, real_t &r_min, real_t &r_max) const {
for (int i = 0; i < 3; i++) {
Vector3 v = p_transform.xform(vertex[i]);
real_t d = p_normal.dot(v);
if (i == 0 || d > r_max)
r_max = d;
if (i == 0 || d < r_min)
r_min = d;
}
}
void Face3::get_support(const Vector3 &p_normal, const Transform &p_transform, Vector3 *p_vertices, int *p_count, int p_max) const {
#define _FACE_IS_VALID_SUPPORT_THRESHOLD 0.98
#define _EDGE_IS_VALID_SUPPORT_THRESHOLD 0.05
if (p_max <= 0)
return;
Vector3 n = p_transform.basis.xform_inv(p_normal);
/** TEST FACE AS SUPPORT **/
if (get_plane().normal.dot(n) > _FACE_IS_VALID_SUPPORT_THRESHOLD) {
*p_count = MIN(3, p_max);
for (int i = 0; i < *p_count; i++) {
p_vertices[i] = p_transform.xform(vertex[i]);
}
return;
}
/** FIND SUPPORT VERTEX **/
int vert_support_idx = -1;
real_t support_max = 0;
for (int i = 0; i < 3; i++) {
real_t d = n.dot(vertex[i]);
if (i == 0 || d > support_max) {
support_max = d;
vert_support_idx = i;
}
}
/** TEST EDGES AS SUPPORT **/
for (int i = 0; i < 3; i++) {
if (i != vert_support_idx && i + 1 != vert_support_idx)
continue;
// check if edge is valid as a support
real_t dot = (vertex[i] - vertex[(i + 1) % 3]).normalized().dot(n);
dot = ABS(dot);
if (dot < _EDGE_IS_VALID_SUPPORT_THRESHOLD) {
*p_count = MIN(2, p_max);
for (int j = 0; j < *p_count; j++)
p_vertices[j] = p_transform.xform(vertex[(j + i) % 3]);
return;
}
}
*p_count = 1;
p_vertices[0] = p_transform.xform(vertex[vert_support_idx]);
}
Vector3 Face3::get_closest_point_to(const Vector3 &p_point) const {
Vector3 edge0 = vertex[1] - vertex[0];
Vector3 edge1 = vertex[2] - vertex[0];
Vector3 v0 = vertex[0] - p_point;
real_t a = edge0.dot(edge0);
real_t b = edge0.dot(edge1);
real_t c = edge1.dot(edge1);
real_t d = edge0.dot(v0);
real_t e = edge1.dot(v0);
real_t det = a * c - b * b;
real_t s = b * e - c * d;
real_t t = b * d - a * e;
if (s + t < det) {
if (s < 0.f) {
if (t < 0.f) {
if (d < 0.f) {
s = CLAMP(-d / a, 0.f, 1.f);
t = 0.f;
} else {
s = 0.f;
t = CLAMP(-e / c, 0.f, 1.f);
}
} else {
s = 0.f;
t = CLAMP(-e / c, 0.f, 1.f);
}
} else if (t < 0.f) {
s = CLAMP(-d / a, 0.f, 1.f);
t = 0.f;
} else {
real_t invDet = 1.f / det;
s *= invDet;
t *= invDet;
}
} else {
if (s < 0.f) {
real_t tmp0 = b + d;
real_t tmp1 = c + e;
if (tmp1 > tmp0) {
real_t numer = tmp1 - tmp0;
real_t denom = a - 2 * b + c;
s = CLAMP(numer / denom, 0.f, 1.f);
t = 1 - s;
} else {
t = CLAMP(-e / c, 0.f, 1.f);
s = 0.f;
}
} else if (t < 0.f) {
if (a + d > b + e) {
real_t numer = c + e - b - d;
real_t denom = a - 2 * b + c;
s = CLAMP(numer / denom, 0.f, 1.f);
t = 1 - s;
} else {
s = CLAMP(-d / a, 0.f, 1.f);
t = 0.f;
}
} else {
real_t numer = c + e - b - d;
real_t denom = a - 2 * b + c;
s = CLAMP(numer / denom, 0.f, 1.f);
t = 1.f - s;
}
}
return vertex[0] + s * edge0 + t * edge1;
}