330 lines
11 KiB
C++
330 lines
11 KiB
C++
/*
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Copyright (C) 1999-2006 Id Software, Inc. and contributors.
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For a list of contributors, see the accompanying CONTRIBUTORS file.
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This file is part of GtkRadiant.
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GtkRadiant is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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GtkRadiant is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GtkRadiant; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "winding.h"
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#include <algorithm>
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#include "math/line.h"
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inline double plane3_distance_to_point(const Plane3 &plane, const DoubleVector3 &point)
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{
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return vector3_dot(point, plane.normal()) - plane.dist();
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}
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inline double plane3_distance_to_point(const Plane3 &plane, const Vector3 &point)
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{
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return vector3_dot(point, plane.normal()) - plane.dist();
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}
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/// \brief Returns the point at which \p line intersects \p plane, or an undefined value if there is no intersection.
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inline DoubleVector3 line_intersect_plane(const DoubleLine &line, const Plane3 &plane)
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{
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return line.origin + vector3_scaled(
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line.direction,
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-plane3_distance_to_point(plane, line.origin)
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/ vector3_dot(line.direction, plane.normal())
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);
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}
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inline bool float_is_largest_absolute(double axis, double other)
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{
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return fabs(axis) > fabs(other);
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}
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/// \brief Returns the index of the component of \p v that has the largest absolute value.
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inline int vector3_largest_absolute_component_index(const DoubleVector3 &v)
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{
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return (float_is_largest_absolute(v[1], v[0]))
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? (float_is_largest_absolute(v[1], v[2]))
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? 1
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: 2
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: (float_is_largest_absolute(v[0], v[2]))
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? 0
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: 2;
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}
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/// \brief Returns the infinite line that is the intersection of \p plane and \p other.
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inline DoubleLine plane3_intersect_plane3(const Plane3 &plane, const Plane3 &other)
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{
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DoubleLine line;
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line.direction = vector3_cross(plane.normal(), other.normal());
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switch (vector3_largest_absolute_component_index(line.direction)) {
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case 0:
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line.origin.x() = 0;
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line.origin.y() =
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(-other.dist() * plane.normal().z() - -plane.dist() * other.normal().z()) / line.direction.x();
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line.origin.z() =
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(-plane.dist() * other.normal().y() - -other.dist() * plane.normal().y()) / line.direction.x();
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break;
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case 1:
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line.origin.x() =
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(-plane.dist() * other.normal().z() - -other.dist() * plane.normal().z()) / line.direction.y();
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line.origin.y() = 0;
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line.origin.z() =
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(-other.dist() * plane.normal().x() - -plane.dist() * other.normal().x()) / line.direction.y();
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break;
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case 2:
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line.origin.x() =
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(-other.dist() * plane.normal().y() - -plane.dist() * other.normal().y()) / line.direction.z();
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line.origin.y() =
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(-plane.dist() * other.normal().x() - -other.dist() * plane.normal().x()) / line.direction.z();
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line.origin.z() = 0;
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break;
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default:
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break;
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}
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return line;
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}
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/// \brief Keep the value of \p infinity as small as possible to improve precision in Winding_Clip.
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void Winding_createInfinite(FixedWinding &winding, const Plane3 &plane, double infinity)
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{
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double max = -infinity;
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int x = -1;
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for (int i = 0; i < 3; i++) {
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double d = fabs(plane.normal()[i]);
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if (d > max) {
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x = i;
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max = d;
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}
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}
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if (x == -1) {
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globalErrorStream() << "invalid plane\n";
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return;
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}
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DoubleVector3 vup = g_vector3_identity;
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switch (x) {
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case 0:
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case 1:
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vup[2] = 1;
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break;
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case 2:
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vup[0] = 1;
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break;
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}
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vector3_add(vup, vector3_scaled(plane.normal(), -vector3_dot(vup, plane.normal())));
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vector3_normalise(vup);
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DoubleVector3 org = vector3_scaled(plane.normal(), plane.dist());
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DoubleVector3 vright = vector3_cross(vup, plane.normal());
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vector3_scale(vup, infinity);
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vector3_scale(vright, infinity);
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// project a really big axis aligned box onto the plane
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DoubleLine r1, r2, r3, r4;
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r1.origin = vector3_added(vector3_subtracted(org, vright), vup);
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r1.direction = vector3_normalised(vright);
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winding.push_back(FixedWindingVertex(r1.origin, r1, c_brush_maxFaces));
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r2.origin = vector3_added(vector3_added(org, vright), vup);
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r2.direction = vector3_normalised(vector3_negated(vup));
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winding.push_back(FixedWindingVertex(r2.origin, r2, c_brush_maxFaces));
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r3.origin = vector3_subtracted(vector3_added(org, vright), vup);
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r3.direction = vector3_normalised(vector3_negated(vright));
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winding.push_back(FixedWindingVertex(r3.origin, r3, c_brush_maxFaces));
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r4.origin = vector3_subtracted(vector3_subtracted(org, vright), vup);
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r4.direction = vector3_normalised(vup);
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winding.push_back(FixedWindingVertex(r4.origin, r4, c_brush_maxFaces));
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}
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inline PlaneClassification Winding_ClassifyDistance(const double distance, const double epsilon)
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{
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if (distance > epsilon) {
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return ePlaneFront;
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}
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if (distance < -epsilon) {
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return ePlaneBack;
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}
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return ePlaneOn;
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}
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/// \brief Returns true if
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/// !flipped && winding is completely BACK or ON
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/// or flipped && winding is completely FRONT or ON
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bool Winding_TestPlane(const Winding &winding, const Plane3 &plane, bool flipped)
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{
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const int test = (flipped) ? ePlaneBack : ePlaneFront;
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for (Winding::const_iterator i = winding.begin(); i != winding.end(); ++i) {
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if (test == Winding_ClassifyDistance(plane3_distance_to_point(plane, (*i).vertex), ON_EPSILON)) {
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return false;
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}
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}
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return true;
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}
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/// \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
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bool Winding_PlanesConcave(const Winding &w1, const Winding &w2, const Plane3 &plane1, const Plane3 &plane2)
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{
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return !Winding_TestPlane(w1, plane2, false) || !Winding_TestPlane(w2, plane1, false);
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}
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brushsplit_t Winding_ClassifyPlane(const Winding &winding, const Plane3 &plane)
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{
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brushsplit_t split;
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for (Winding::const_iterator i = winding.begin(); i != winding.end(); ++i) {
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++split.counts[Winding_ClassifyDistance(plane3_distance_to_point(plane, (*i).vertex), ON_EPSILON)];
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}
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return split;
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}
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#define DEBUG_EPSILON ON_EPSILON
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const double DEBUG_EPSILON_SQUARED = DEBUG_EPSILON * DEBUG_EPSILON;
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#define WINDING_DEBUG 0
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/// \brief Clip \p winding which lies on \p plane by \p clipPlane, resulting in \p clipped.
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/// If \p winding is completely in front of the plane, \p clipped will be identical to \p winding.
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/// If \p winding is completely in back of the plane, \p clipped will be empty.
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/// If \p winding intersects the plane, the edge of \p clipped which lies on \p clipPlane will store the value of \p adjacent.
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void Winding_Clip(const FixedWinding &winding, const Plane3 &plane, const Plane3 &clipPlane, std::size_t adjacent,
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FixedWinding &clipped)
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{
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PlaneClassification classification = Winding_ClassifyDistance(
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plane3_distance_to_point(clipPlane, winding.back().vertex), ON_EPSILON);
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PlaneClassification nextClassification;
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// for each edge
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for (std::size_t next = 0, i = winding.size() - 1;
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next != winding.size(); i = next, ++next, classification = nextClassification) {
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nextClassification = Winding_ClassifyDistance(plane3_distance_to_point(clipPlane, winding[next].vertex),
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ON_EPSILON);
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const FixedWindingVertex &vertex = winding[i];
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// if first vertex of edge is ON
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if (classification == ePlaneOn) {
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// append first vertex to output winding
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if (nextClassification == ePlaneBack) {
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// this edge lies on the clip plane
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clipped.push_back(
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FixedWindingVertex(vertex.vertex, plane3_intersect_plane3(plane, clipPlane), adjacent));
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} else {
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clipped.push_back(vertex);
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}
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continue;
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}
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// if first vertex of edge is FRONT
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if (classification == ePlaneFront) {
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// add first vertex to output winding
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clipped.push_back(vertex);
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}
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// if second vertex of edge is ON
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if (nextClassification == ePlaneOn) {
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continue;
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}
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// else if second vertex of edge is same as first
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else if (nextClassification == classification) {
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continue;
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}
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// else if first vertex of edge is FRONT and there are only two edges
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else if (classification == ePlaneFront && winding.size() == 2) {
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continue;
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}
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// else first vertex is FRONT and second is BACK or vice versa
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else {
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// append intersection point of line and plane to output winding
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DoubleVector3 mid(line_intersect_plane(vertex.edge, clipPlane));
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if (classification == ePlaneFront) {
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// this edge lies on the clip plane
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clipped.push_back(FixedWindingVertex(mid, plane3_intersect_plane3(plane, clipPlane), adjacent));
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} else {
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clipped.push_back(FixedWindingVertex(mid, vertex.edge, vertex.adjacent));
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}
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}
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}
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}
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std::size_t Winding_FindAdjacent(const Winding &winding, std::size_t face)
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{
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for (std::size_t i = 0; i < winding.numpoints; ++i) {
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ASSERT_MESSAGE(winding[i].adjacent != c_brush_maxFaces, "edge connectivity data is invalid");
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if (winding[i].adjacent == face) {
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return i;
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}
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}
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return c_brush_maxFaces;
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}
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std::size_t Winding_Opposite(const Winding &winding, const std::size_t index, const std::size_t other)
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{
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ASSERT_MESSAGE(index < winding.numpoints && other < winding.numpoints, "Winding_Opposite: index out of range");
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double dist_best = 0;
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std::size_t index_best = c_brush_maxFaces;
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Ray edge(ray_for_points(winding[index].vertex, winding[other].vertex));
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for (std::size_t i = 0; i < winding.numpoints; ++i) {
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if (i == index || i == other) {
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continue;
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}
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double dist_squared = ray_squared_distance_to_point(edge, winding[i].vertex);
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if (dist_squared > dist_best) {
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dist_best = dist_squared;
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index_best = i;
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}
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}
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return index_best;
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}
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std::size_t Winding_Opposite(const Winding &winding, const std::size_t index)
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{
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return Winding_Opposite(winding, index, Winding_next(winding, index));
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}
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/// \brief Calculate the \p centroid of the polygon defined by \p winding which lies on plane \p plane.
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void Winding_Centroid(const Winding &winding, const Plane3 &plane, Vector3 ¢roid)
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{
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double area2 = 0, x_sum = 0, y_sum = 0;
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const ProjectionAxis axis = projectionaxis_for_normal(plane.normal());
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const indexremap_t remap = indexremap_for_projectionaxis(axis);
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for (std::size_t i = winding.numpoints - 1, j = 0; j < winding.numpoints; i = j, ++j) {
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const double ai = winding[i].vertex[remap.x] * winding[j].vertex[remap.y] -
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winding[j].vertex[remap.x] * winding[i].vertex[remap.y];
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area2 += ai;
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x_sum += (winding[j].vertex[remap.x] + winding[i].vertex[remap.x]) * ai;
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y_sum += (winding[j].vertex[remap.y] + winding[i].vertex[remap.y]) * ai;
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}
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centroid[remap.x] = static_cast<float>( x_sum / (3 * area2));
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centroid[remap.y] = static_cast<float>( y_sum / (3 * area2));
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{
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Ray ray(Vector3(0, 0, 0), Vector3(0, 0, 0));
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ray.origin[remap.x] = centroid[remap.x];
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ray.origin[remap.y] = centroid[remap.y];
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ray.direction[remap.z] = 1;
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centroid[remap.z] = static_cast<float>( ray_distance_to_plane(ray, plane));
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}
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}
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