2 Copyright (C) 1999-2006 Id Software, Inc. and contributors.
3 For a list of contributors, see the accompanying CONTRIBUTORS file.
5 This file is part of GtkRadiant.
7 GtkRadiant is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 GtkRadiant is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GtkRadiant; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
26 #include "math/line.h"
29 inline double plane3_distance_to_point(const Plane3 &plane, const DoubleVector3 &point)
31 return vector3_dot(point, plane.normal()) - plane.dist();
34 inline double plane3_distance_to_point(const Plane3 &plane, const Vector3 &point)
36 return vector3_dot(point, plane.normal()) - plane.dist();
39 /// \brief Returns the point at which \p line intersects \p plane, or an undefined value if there is no intersection.
40 inline DoubleVector3 line_intersect_plane(const DoubleLine &line, const Plane3 &plane)
42 return line.origin + vector3_scaled(
44 -plane3_distance_to_point(plane, line.origin)
45 / vector3_dot(line.direction, plane.normal())
49 inline bool float_is_largest_absolute(double axis, double other)
51 return fabs(axis) > fabs(other);
54 /// \brief Returns the index of the component of \p v that has the largest absolute value.
55 inline int vector3_largest_absolute_component_index(const DoubleVector3 &v)
57 return (float_is_largest_absolute(v[1], v[0]))
58 ? (float_is_largest_absolute(v[1], v[2]))
61 : (float_is_largest_absolute(v[0], v[2]))
66 /// \brief Returns the infinite line that is the intersection of \p plane and \p other.
67 inline DoubleLine plane3_intersect_plane3(const Plane3 &plane, const Plane3 &other)
70 line.direction = vector3_cross(plane.normal(), other.normal());
71 switch (vector3_largest_absolute_component_index(line.direction)) {
75 (-other.dist() * plane.normal().z() - -plane.dist() * other.normal().z()) / line.direction.x();
77 (-plane.dist() * other.normal().y() - -other.dist() * plane.normal().y()) / line.direction.x();
81 (-plane.dist() * other.normal().z() - -other.dist() * plane.normal().z()) / line.direction.y();
84 (-other.dist() * plane.normal().x() - -plane.dist() * other.normal().x()) / line.direction.y();
88 (-other.dist() * plane.normal().y() - -plane.dist() * other.normal().y()) / line.direction.z();
90 (-plane.dist() * other.normal().x() - -other.dist() * plane.normal().x()) / line.direction.z();
101 /// \brief Keep the value of \p infinity as small as possible to improve precision in Winding_Clip.
102 void Winding_createInfinite(FixedWinding &winding, const Plane3 &plane, double infinity)
104 double max = -infinity;
106 for (int i = 0; i < 3; i++) {
107 double d = fabs(plane.normal()[i]);
114 globalErrorStream() << "invalid plane\n";
118 DoubleVector3 vup = g_vector3_identity;
130 vector3_add(vup, vector3_scaled(plane.normal(), -vector3_dot(vup, plane.normal())));
131 vector3_normalise(vup);
133 DoubleVector3 org = vector3_scaled(plane.normal(), plane.dist());
135 DoubleVector3 vright = vector3_cross(vup, plane.normal());
137 vector3_scale(vup, infinity);
138 vector3_scale(vright, infinity);
140 // project a really big axis aligned box onto the plane
142 DoubleLine r1, r2, r3, r4;
143 r1.origin = vector3_added(vector3_subtracted(org, vright), vup);
144 r1.direction = vector3_normalised(vright);
145 winding.push_back(FixedWindingVertex(r1.origin, r1, c_brush_maxFaces));
146 r2.origin = vector3_added(vector3_added(org, vright), vup);
147 r2.direction = vector3_normalised(vector3_negated(vup));
148 winding.push_back(FixedWindingVertex(r2.origin, r2, c_brush_maxFaces));
149 r3.origin = vector3_subtracted(vector3_added(org, vright), vup);
150 r3.direction = vector3_normalised(vector3_negated(vright));
151 winding.push_back(FixedWindingVertex(r3.origin, r3, c_brush_maxFaces));
152 r4.origin = vector3_subtracted(vector3_subtracted(org, vright), vup);
153 r4.direction = vector3_normalised(vup);
154 winding.push_back(FixedWindingVertex(r4.origin, r4, c_brush_maxFaces));
158 inline PlaneClassification Winding_ClassifyDistance(const double distance, const double epsilon)
160 if (distance > epsilon) {
163 if (distance < -epsilon) {
169 /// \brief Returns true if
170 /// !flipped && winding is completely BACK or ON
171 /// or flipped && winding is completely FRONT or ON
172 bool Winding_TestPlane(const Winding &winding, const Plane3 &plane, bool flipped)
174 const int test = (flipped) ? ePlaneBack : ePlaneFront;
175 for (Winding::const_iterator i = winding.begin(); i != winding.end(); ++i) {
176 if (test == Winding_ClassifyDistance(plane3_distance_to_point(plane, (*i).vertex), ON_EPSILON)) {
183 /// \brief Returns true if any point in \p w1 is in front of plane2, or any point in \p w2 is in front of plane1
184 bool Winding_PlanesConcave(const Winding &w1, const Winding &w2, const Plane3 &plane1, const Plane3 &plane2)
186 return !Winding_TestPlane(w1, plane2, false) || !Winding_TestPlane(w2, plane1, false);
189 brushsplit_t Winding_ClassifyPlane(const Winding &winding, const Plane3 &plane)
192 for (Winding::const_iterator i = winding.begin(); i != winding.end(); ++i) {
193 ++split.counts[Winding_ClassifyDistance(plane3_distance_to_point(plane, (*i).vertex), ON_EPSILON)];
199 #define DEBUG_EPSILON ON_EPSILON
200 const double DEBUG_EPSILON_SQUARED = DEBUG_EPSILON * DEBUG_EPSILON;
202 #define WINDING_DEBUG 0
204 /// \brief Clip \p winding which lies on \p plane by \p clipPlane, resulting in \p clipped.
205 /// If \p winding is completely in front of the plane, \p clipped will be identical to \p winding.
206 /// If \p winding is completely in back of the plane, \p clipped will be empty.
207 /// If \p winding intersects the plane, the edge of \p clipped which lies on \p clipPlane will store the value of \p adjacent.
208 void Winding_Clip(const FixedWinding &winding, const Plane3 &plane, const Plane3 &clipPlane, std::size_t adjacent,
209 FixedWinding &clipped)
211 PlaneClassification classification = Winding_ClassifyDistance(
212 plane3_distance_to_point(clipPlane, winding.back().vertex), ON_EPSILON);
213 PlaneClassification nextClassification;
215 for (std::size_t next = 0, i = winding.size() - 1;
216 next != winding.size(); i = next, ++next, classification = nextClassification) {
217 nextClassification = Winding_ClassifyDistance(plane3_distance_to_point(clipPlane, winding[next].vertex),
219 const FixedWindingVertex &vertex = winding[i];
221 // if first vertex of edge is ON
222 if (classification == ePlaneOn) {
223 // append first vertex to output winding
224 if (nextClassification == ePlaneBack) {
225 // this edge lies on the clip plane
227 FixedWindingVertex(vertex.vertex, plane3_intersect_plane3(plane, clipPlane), adjacent));
229 clipped.push_back(vertex);
234 // if first vertex of edge is FRONT
235 if (classification == ePlaneFront) {
236 // add first vertex to output winding
237 clipped.push_back(vertex);
239 // if second vertex of edge is ON
240 if (nextClassification == ePlaneOn) {
243 // else if second vertex of edge is same as first
244 else if (nextClassification == classification) {
247 // else if first vertex of edge is FRONT and there are only two edges
248 else if (classification == ePlaneFront && winding.size() == 2) {
251 // else first vertex is FRONT and second is BACK or vice versa
253 // append intersection point of line and plane to output winding
254 DoubleVector3 mid(line_intersect_plane(vertex.edge, clipPlane));
256 if (classification == ePlaneFront) {
257 // this edge lies on the clip plane
258 clipped.push_back(FixedWindingVertex(mid, plane3_intersect_plane3(plane, clipPlane), adjacent));
260 clipped.push_back(FixedWindingVertex(mid, vertex.edge, vertex.adjacent));
266 std::size_t Winding_FindAdjacent(const Winding &winding, std::size_t face)
268 for (std::size_t i = 0; i < winding.numpoints; ++i) {
269 ASSERT_MESSAGE(winding[i].adjacent != c_brush_maxFaces, "edge connectivity data is invalid");
270 if (winding[i].adjacent == face) {
274 return c_brush_maxFaces;
277 std::size_t Winding_Opposite(const Winding &winding, const std::size_t index, const std::size_t other)
279 ASSERT_MESSAGE(index < winding.numpoints && other < winding.numpoints, "Winding_Opposite: index out of range");
281 double dist_best = 0;
282 std::size_t index_best = c_brush_maxFaces;
284 Ray edge(ray_for_points(winding[index].vertex, winding[other].vertex));
286 for (std::size_t i = 0; i < winding.numpoints; ++i) {
287 if (i == index || i == other) {
291 double dist_squared = ray_squared_distance_to_point(edge, winding[i].vertex);
293 if (dist_squared > dist_best) {
294 dist_best = dist_squared;
301 std::size_t Winding_Opposite(const Winding &winding, const std::size_t index)
303 return Winding_Opposite(winding, index, Winding_next(winding, index));
306 /// \brief Calculate the \p centroid of the polygon defined by \p winding which lies on plane \p plane.
307 void Winding_Centroid(const Winding &winding, const Plane3 &plane, Vector3 ¢roid)
309 double area2 = 0, x_sum = 0, y_sum = 0;
310 const ProjectionAxis axis = projectionaxis_for_normal(plane.normal());
311 const indexremap_t remap = indexremap_for_projectionaxis(axis);
312 for (std::size_t i = winding.numpoints - 1, j = 0; j < winding.numpoints; i = j, ++j) {
313 const double ai = winding[i].vertex[remap.x] * winding[j].vertex[remap.y] -
314 winding[j].vertex[remap.x] * winding[i].vertex[remap.y];
316 x_sum += (winding[j].vertex[remap.x] + winding[i].vertex[remap.x]) * ai;
317 y_sum += (winding[j].vertex[remap.y] + winding[i].vertex[remap.y]) * ai;
320 centroid[remap.x] = static_cast<float>( x_sum / (3 * area2));
321 centroid[remap.y] = static_cast<float>( y_sum / (3 * area2));
323 Ray ray(Vector3(0, 0, 0), Vector3(0, 0, 0));
324 ray.origin[remap.x] = centroid[remap.x];
325 ray.origin[remap.y] = centroid[remap.y];
326 ray.direction[remap.z] = 1;
327 centroid[remap.z] = static_cast<float>( ray_distance_to_plane(ray, plane));