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open_toontown_panda3d/panda/src/collide/collisionPolygon.cxx

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// Filename: collisionPolygon.cxx
// Created by: drose (25Apr00)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) Carnegie Mellon University. All rights reserved.
//
// All use of this software is subject to the terms of the revised BSD
// license. You should have received a copy of this license along
// with this source code in a file named "LICENSE."
//
////////////////////////////////////////////////////////////////////
#include "collisionPolygon.h"
#include "collisionHandler.h"
#include "collisionEntry.h"
#include "collisionSphere.h"
#include "collisionLine.h"
#include "collisionRay.h"
#include "collisionSegment.h"
#include "collisionParabola.h"
#include "config_collide.h"
#include "cullTraverserData.h"
#include "boundingBox.h"
#include "pointerToArray.h"
#include "geomNode.h"
#include "geom.h"
#include "datagram.h"
#include "datagramIterator.h"
#include "bamReader.h"
#include "bamWriter.h"
#include "transformState.h"
#include "clipPlaneAttrib.h"
#include "nearly_zero.h"
#include "geom.h"
#include "geomTrifans.h"
#include "geomLinestrips.h"
#include "geomVertexWriter.h"
#include "renderState.h"
#include "epvector.h"
#include <algorithm>
PStatCollector CollisionPolygon::_volume_pcollector("Collision Volumes:CollisionPolygon");
PStatCollector CollisionPolygon::_test_pcollector("Collision Tests:CollisionPolygon");
TypeHandle CollisionPolygon::_type_handle;
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::Copy Constructor
// Access: Public
// Description:
////////////////////////////////////////////////////////////////////
CollisionPolygon::
CollisionPolygon(const CollisionPolygon &copy) :
CollisionPlane(copy),
_points(copy._points),
_to_2d_mat(copy._to_2d_mat)
{
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::make_copy
// Access: Public, Virtual
// Description:
////////////////////////////////////////////////////////////////////
CollisionSolid *CollisionPolygon::
make_copy() {
return new CollisionPolygon(*this);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::verify_points
// Access: Public, Static
// Description: Verifies that the indicated set of points will define
// a valid CollisionPolygon: that is, at least three
// non-collinear points, with no points repeated.
//
// This does not check that the polygon defined is
// convex; that check is made later, once we have
// projected the points to 2-d space where the decision
// is easier.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
verify_points(const LPoint3 *begin, const LPoint3 *end) {
int num_points = end - begin;
if (num_points < 3) {
return false;
}
bool all_ok = true;
// First, check for repeated or invalid points.
const LPoint3 *pi;
for (pi = begin; pi != end && all_ok; ++pi) {
if ((*pi).is_nan()) {
all_ok = false;
} else {
// Make sure no points are repeated.
const LPoint3 *pj;
for (pj = begin; pj != pi && all_ok; ++pj) {
if ((*pj) == (*pi)) {
all_ok = false;
}
}
}
}
if (all_ok) {
// Create a plane to determine the planarity of the first three
// points (or the first two points and the nth point thereafter, in
// case the first three points happen to be collinear).
bool got_normal = false;
for (int i = 2; i < num_points && !got_normal; i++) {
LPlane plane(begin[0], begin[1], begin[i]);
LVector3 normal = plane.get_normal();
PN_stdfloat normal_length = normal.length();
got_normal = IS_THRESHOLD_EQUAL(normal_length, 1.0f, 0.001f);
}
if (!got_normal) {
all_ok = false;
}
}
return all_ok;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::is_valid
// Access: Public
// Description: Returns true if the CollisionPolygon is valid
// (that is, it has at least three vertices), or false
// otherwise.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
is_valid() const {
return (_points.size() >= 3);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::is_concave
// Access: Public
// Description: Returns true if the CollisionPolygon appears to be
// concave, or false if it is safely convex.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
is_concave() const {
if (_points.size() < 3) {
// It's not even a valid polygon.
return true;
}
LPoint2 p0 = _points[0]._p;
LPoint2 p1 = _points[1]._p;
PN_stdfloat dx1 = p1[0] - p0[0];
PN_stdfloat dy1 = p1[1] - p0[1];
p0 = p1;
p1 = _points[2]._p;
PN_stdfloat dx2 = p1[0] - p0[0];
PN_stdfloat dy2 = p1[1] - p0[1];
int asum = ((dx1 * dy2 - dx2 * dy1 >= 0.0f) ? 1 : 0);
for (size_t i = 0; i < _points.size() - 1; i++) {
p0 = p1;
p1 = _points[(i+3) % _points.size()]._p;
dx1 = dx2;
dy1 = dy2;
dx2 = p1[0] - p0[0];
dy2 = p1[1] - p0[1];
int csum = ((dx1 * dy2 - dx2 * dy1 >= 0.0f) ? 1 : 0);
if (csum ^ asum) {
// Oops, the polygon is concave.
return true;
}
}
// The polygon is safely convex.
return false;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::xform
// Access: Public, Virtual
// Description: Transforms the solid by the indicated matrix.
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
xform(const LMatrix4 &mat) {
// We need to convert all the vertices to 3-d for this operation,
// and then convert them back. Hopefully we won't lose too much
// precision during all of this.
if (collide_cat.is_spam()) {
collide_cat.spam()
<< "CollisionPolygon transformed by:\n";
mat.write(collide_cat.spam(false), 2);
if (_points.empty()) {
collide_cat.spam(false)
<< " (no points)\n";
}
}
if (!_points.empty()) {
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
epvector<LPoint3> verts;
verts.reserve(_points.size());
Points::const_iterator pi;
for (pi = _points.begin(); pi != _points.end(); ++pi) {
verts.push_back(to_3d((*pi)._p, to_3d_mat) * mat);
}
const LPoint3 *verts_begin = &verts[0];
const LPoint3 *verts_end = verts_begin + verts.size();
setup_points(verts_begin, verts_end);
}
CollisionSolid::xform(mat);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::get_collision_origin
// Access: Public, Virtual
// Description: Returns the point in space deemed to be the "origin"
// of the solid for collision purposes. The closest
// intersection point to this origin point is considered
// to be the most significant.
////////////////////////////////////////////////////////////////////
LPoint3 CollisionPolygon::
get_collision_origin() const {
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
LPoint2 median = _points[0]._p;
for (int n = 1; n < (int)_points.size(); n++) {
median += _points[n]._p;
}
median /= _points.size();
return to_3d(median, to_3d_mat);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::get_viz
// Access: Public, Virtual
// Description: Returns a GeomNode that may be rendered to visualize
// the CollisionSolid. This is used during the cull
// traversal to render the CollisionNodes that have been
// made visible.
////////////////////////////////////////////////////////////////////
PT(PandaNode) CollisionPolygon::
get_viz(const CullTraverser *trav, const CullTraverserData &data,
bool bounds_only) const {
const ClipPlaneAttrib *cpa = DCAST(ClipPlaneAttrib, data._state->get_attrib(ClipPlaneAttrib::get_class_slot()));
if (cpa == (const ClipPlaneAttrib *)NULL) {
// Fortunately, the polygon is not clipped. This is the normal,
// easy case.
return CollisionSolid::get_viz(trav, data, bounds_only);
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "drawing polygon with clip plane " << *cpa << "\n";
}
// The polygon is clipped. We need to render it clipped. We could
// just turn on the ClipPlaneAttrib state and render the full
// polygon, letting the hardware do the clipping, but we get fancy
// and clip it by hand instead, just to prove that our clipping
// algorithm works properly. This does require some more dynamic
// work.
Points new_points;
if (apply_clip_plane(new_points, cpa, data.get_net_transform(trav))) {
// All points are behind the clip plane; just draw the original
// polygon.
return CollisionSolid::get_viz(trav, data, bounds_only);
}
if (new_points.empty()) {
// All points are in front of the clip plane; draw nothing.
return NULL;
}
// Draw the clipped polygon.
PT(GeomNode) viz_geom_node = new GeomNode("viz");
PT(GeomNode) bounds_viz_geom_node = new GeomNode("bounds_viz");
draw_polygon(viz_geom_node, bounds_viz_geom_node, new_points);
if (bounds_only) {
return bounds_viz_geom_node.p();
} else {
return viz_geom_node.p();
}
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::get_volume_pcollector
// Access: Public, Virtual
// Description: Returns a PStatCollector that is used to count the
// number of bounding volume tests made against a solid
// of this type in a given frame.
////////////////////////////////////////////////////////////////////
PStatCollector &CollisionPolygon::
get_volume_pcollector() {
return _volume_pcollector;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::get_test_pcollector
// Access: Public, Virtual
// Description: Returns a PStatCollector that is used to count the
// number of intersection tests made against a solid
// of this type in a given frame.
////////////////////////////////////////////////////////////////////
PStatCollector &CollisionPolygon::
get_test_pcollector() {
return _test_pcollector;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::output
// Access: Public, Virtual
// Description:
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
output(ostream &out) const {
out << "cpolygon, (" << get_plane()
<< "), " << _points.size() << " vertices";
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::write
// Access: Public, Virtual
// Description:
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
write(ostream &out, int indent_level) const {
indent(out, indent_level) << (*this) << "\n";
Points::const_iterator pi;
for (pi = _points.begin(); pi != _points.end(); ++pi) {
indent(out, indent_level + 2) << (*pi)._p << "\n";
}
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
out << "In 3-d space:\n";
for (pi = _points.begin(); pi != _points.end(); ++pi) {
LVertex vert = to_3d((*pi)._p, to_3d_mat);
indent(out, indent_level + 2) << vert << "\n";
}
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::compute_internal_bounds
// Access: Protected, Virtual
// Description:
////////////////////////////////////////////////////////////////////
PT(BoundingVolume) CollisionPolygon::
compute_internal_bounds() const {
if (_points.empty()) {
return new BoundingBox;
}
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
Points::const_iterator pi = _points.begin();
LPoint3 p = to_3d((*pi)._p, to_3d_mat);
LPoint3 x = p;
LPoint3 n = p;
for (++pi; pi != _points.end(); ++pi) {
p = to_3d((*pi)._p, to_3d_mat);
n.set(min(n[0], p[0]),
min(n[1], p[1]),
min(n[2], p[2]));
x.set(max(x[0], p[0]),
max(x[1], p[1]),
max(x[2], p[2]));
}
return new BoundingBox(n, x);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::test_intersection_from_sphere
// Access: Protected, Virtual
// Description: This is part of the double-dispatch implementation of
// test_intersection(). It is called when the "from"
// object is a sphere.
////////////////////////////////////////////////////////////////////
PT(CollisionEntry) CollisionPolygon::
test_intersection_from_sphere(const CollisionEntry &entry) const {
if (_points.size() < 3) {
return NULL;
}
const CollisionSphere *sphere;
DCAST_INTO_R(sphere, entry.get_from(), 0);
CPT(TransformState) wrt_space = entry.get_wrt_space();
CPT(TransformState) wrt_prev_space = entry.get_wrt_prev_space();
const LMatrix4 &wrt_mat = wrt_space->get_mat();
LPoint3 orig_center = sphere->get_center() * wrt_mat;
LPoint3 from_center = orig_center;
bool moved_from_center = false;
PN_stdfloat t = 1.0f;
LPoint3 contact_point(from_center);
PN_stdfloat actual_t = 1.0f;
LVector3 from_radius_v =
LVector3(sphere->get_radius(), 0.0f, 0.0f) * wrt_mat;
PN_stdfloat from_radius_2 = from_radius_v.length_squared();
PN_stdfloat from_radius = csqrt(from_radius_2);
if (wrt_prev_space != wrt_space) {
// If we have a delta between the previous position and the
// current position, we use that to determine some more properties
// of the collision.
LPoint3 b = from_center;
LPoint3 a = sphere->get_center() * wrt_prev_space->get_mat();
LVector3 delta = b - a;
// First, there is no collision if the "from" object is definitely
// moving in the same direction as the plane's normal.
PN_stdfloat dot = delta.dot(get_normal());
if (dot > 0.1f) {
return NULL;
}
if (IS_NEARLY_ZERO(dot)) {
// If we're moving parallel to the plane, the sphere is tested
// at its final point. Leave it as it is.
} else {
// Otherwise, we're moving into the plane; the sphere is tested
// at the point along its path that is closest to intersecting
// the plane. This may be the actual intersection point, or it
// may be the starting point or the final point.
// dot is equal to the (negative) magnitude of 'delta' along the
// direction of the plane normal
// t = ratio of (distance from start pos to plane) to (distance
// from start pos to end pos), along axis of plane normal
PN_stdfloat dist_to_p = dist_to_plane(a);
t = (dist_to_p / -dot);
// also compute the actual contact point and time of contact
// for handlers that need it
actual_t = ((dist_to_p - from_radius) / -dot);
actual_t = min((PN_stdfloat)1.0, max((PN_stdfloat)0.0, actual_t));
contact_point = a + (actual_t * delta);
if (t >= 1.0f) {
// Leave it where it is.
} else if (t < 0.0f) {
from_center = a;
moved_from_center = true;
} else {
from_center = a + t * delta;
moved_from_center = true;
}
}
}
LVector3 normal = (has_effective_normal() && sphere->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
#ifndef NDEBUG
if (!IS_THRESHOLD_EQUAL(normal.length_squared(), 1.0f, 0.001)) {
collide_cat.info()
<< "polygon within " << entry.get_into_node_path()
<< " has normal " << normal << " of length " << normal.length()
<< "\n";
normal.normalize();
}
#endif
// The nearest point within the plane to our center is the
// intersection of the line (center, center - normal) with the plane.
PN_stdfloat dist;
if (!get_plane().intersects_line(dist, from_center, -get_normal())) {
// No intersection with plane? This means the plane's effective
// normal was within the plane itself. A useless polygon.
return NULL;
}
if (dist > from_radius || dist < -from_radius) {
// No intersection with the plane.
return NULL;
}
LPoint2 p = to_2d(from_center - dist * get_normal());
PN_stdfloat edge_dist = 0.0f;
const ClipPlaneAttrib *cpa = entry.get_into_clip_planes();
if (cpa != (ClipPlaneAttrib *)NULL) {
// We have a clip plane; apply it.
Points new_points;
if (apply_clip_plane(new_points, cpa, entry.get_into_node_path().get_net_transform())) {
// All points are behind the clip plane; just do the default
// test.
edge_dist = dist_to_polygon(p, _points);
} else if (new_points.empty()) {
// The polygon is completely clipped.
return NULL;
} else {
// Test against the clipped polygon.
edge_dist = dist_to_polygon(p, new_points);
}
} else {
// No clip plane is in effect. Do the default test.
edge_dist = dist_to_polygon(p, _points);
}
// Now we have edge_dist, which is the distance from the sphere
// center to the nearest edge of the polygon, within the polygon's
// plane.
if (edge_dist > from_radius) {
// No intersection; the circle is outside the polygon.
return NULL;
}
// The sphere appears to intersect the polygon. If the edge is less
// than from_radius away, the sphere may be resting on an edge of
// the polygon. Determine how far the center of the sphere must
// remain from the plane, based on its distance from the nearest
// edge.
PN_stdfloat max_dist = from_radius;
if (edge_dist >= 0.0f) {
PN_stdfloat max_dist_2 = max(from_radius_2 - edge_dist * edge_dist, (PN_stdfloat)0.0);
max_dist = csqrt(max_dist_2);
}
if (dist > max_dist) {
// There's no intersection: the sphere is hanging off the edge.
return NULL;
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "intersection detected from " << entry.get_from_node_path()
<< " into " << entry.get_into_node_path() << "\n";
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
PN_stdfloat into_depth = max_dist - dist;
if (moved_from_center) {
// We have to base the depth of intersection on the sphere's final
// resting point, not the point from which we tested the
// intersection.
PN_stdfloat orig_dist;
get_plane().intersects_line(orig_dist, orig_center, -normal);
into_depth = max_dist - orig_dist;
}
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(from_center - normal * dist);
new_entry->set_interior_point(from_center - normal * (dist + into_depth));
new_entry->set_contact_pos(contact_point);
new_entry->set_contact_normal(get_normal());
new_entry->set_t(actual_t);
return new_entry;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::test_intersection_from_line
// Access: Protected, Virtual
// Description: This is part of the double-dispatch implementation of
// test_intersection(). It is called when the "from"
// object is a line.
////////////////////////////////////////////////////////////////////
PT(CollisionEntry) CollisionPolygon::
test_intersection_from_line(const CollisionEntry &entry) const {
if (_points.size() < 3) {
return NULL;
}
const CollisionLine *line;
DCAST_INTO_R(line, entry.get_from(), 0);
const LMatrix4 &wrt_mat = entry.get_wrt_mat();
LPoint3 from_origin = line->get_origin() * wrt_mat;
LVector3 from_direction = line->get_direction() * wrt_mat;
PN_stdfloat t;
if (!get_plane().intersects_line(t, from_origin, from_direction)) {
// No intersection.
return NULL;
}
LPoint3 plane_point = from_origin + t * from_direction;
LPoint2 p = to_2d(plane_point);
const ClipPlaneAttrib *cpa = entry.get_into_clip_planes();
if (cpa != (ClipPlaneAttrib *)NULL) {
// We have a clip plane; apply it.
Points new_points;
if (apply_clip_plane(new_points, cpa, entry.get_into_node_path().get_net_transform())) {
// All points are behind the clip plane.
if (!point_is_inside(p, _points)) {
return NULL;
}
} else {
if (new_points.size() < 3) {
return NULL;
}
if (!point_is_inside(p, new_points)) {
return NULL;
}
}
} else {
// No clip plane is in effect. Do the default test.
if (!point_is_inside(p, _points)) {
return NULL;
}
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "intersection detected from " << entry.get_from_node_path()
<< " into " << entry.get_into_node_path() << "\n";
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
LVector3 normal = (has_effective_normal() && line->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(plane_point);
return new_entry;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::test_intersection_from_ray
// Access: Protected, Virtual
// Description: This is part of the double-dispatch implementation of
// test_intersection(). It is called when the "from"
// object is a ray.
////////////////////////////////////////////////////////////////////
PT(CollisionEntry) CollisionPolygon::
test_intersection_from_ray(const CollisionEntry &entry) const {
if (_points.size() < 3) {
return NULL;
}
const CollisionRay *ray;
DCAST_INTO_R(ray, entry.get_from(), 0);
const LMatrix4 &wrt_mat = entry.get_wrt_mat();
LPoint3 from_origin = ray->get_origin() * wrt_mat;
LVector3 from_direction = ray->get_direction() * wrt_mat;
PN_stdfloat t;
if (!get_plane().intersects_line(t, from_origin, from_direction)) {
// No intersection.
return NULL;
}
if (t < 0.0f) {
// The intersection point is before the start of the ray.
return NULL;
}
LPoint3 plane_point = from_origin + t * from_direction;
LPoint2 p = to_2d(plane_point);
const ClipPlaneAttrib *cpa = entry.get_into_clip_planes();
if (cpa != (ClipPlaneAttrib *)NULL) {
// We have a clip plane; apply it.
Points new_points;
if (apply_clip_plane(new_points, cpa, entry.get_into_node_path().get_net_transform())) {
// All points are behind the clip plane.
if (!point_is_inside(p, _points)) {
return NULL;
}
} else {
if (new_points.size() < 3) {
return NULL;
}
if (!point_is_inside(p, new_points)) {
return NULL;
}
}
} else {
// No clip plane is in effect. Do the default test.
if (!point_is_inside(p, _points)) {
return NULL;
}
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "intersection detected from " << entry.get_from_node_path()
<< " into " << entry.get_into_node_path() << "\n";
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
LVector3 normal = (has_effective_normal() && ray->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(plane_point);
return new_entry;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::test_intersection_from_segment
// Access: Public, Virtual
// Description: This is part of the double-dispatch implementation of
// test_intersection(). It is called when the "from"
// object is a segment.
////////////////////////////////////////////////////////////////////
PT(CollisionEntry) CollisionPolygon::
test_intersection_from_segment(const CollisionEntry &entry) const {
if (_points.size() < 3) {
return NULL;
}
const CollisionSegment *segment;
DCAST_INTO_R(segment, entry.get_from(), 0);
const LMatrix4 &wrt_mat = entry.get_wrt_mat();
LPoint3 from_a = segment->get_point_a() * wrt_mat;
LPoint3 from_b = segment->get_point_b() * wrt_mat;
LPoint3 from_direction = from_b - from_a;
PN_stdfloat t;
if (!get_plane().intersects_line(t, from_a, from_direction)) {
// No intersection.
return NULL;
}
if (t < 0.0f || t > 1.0f) {
// The intersection point is before the start of the segment or
// after the end of the segment.
return NULL;
}
LPoint3 plane_point = from_a + t * from_direction;
LPoint2 p = to_2d(plane_point);
const ClipPlaneAttrib *cpa = entry.get_into_clip_planes();
if (cpa != (ClipPlaneAttrib *)NULL) {
// We have a clip plane; apply it.
Points new_points;
if (apply_clip_plane(new_points, cpa, entry.get_into_node_path().get_net_transform())) {
// All points are behind the clip plane.
if (!point_is_inside(p, _points)) {
return NULL;
}
} else {
if (new_points.size() < 3) {
return NULL;
}
if (!point_is_inside(p, new_points)) {
return NULL;
}
}
} else {
// No clip plane is in effect. Do the default test.
if (!point_is_inside(p, _points)) {
return NULL;
}
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "intersection detected from " << entry.get_from_node_path()
<< " into " << entry.get_into_node_path() << "\n";
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
LVector3 normal = (has_effective_normal() && segment->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(plane_point);
return new_entry;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::test_intersection_from_parabola
// Access: Public, Virtual
// Description: This is part of the double-dispatch implementation of
// test_intersection(). It is called when the "from"
// object is a parabola.
////////////////////////////////////////////////////////////////////
PT(CollisionEntry) CollisionPolygon::
test_intersection_from_parabola(const CollisionEntry &entry) const {
if (_points.size() < 3) {
return NULL;
}
const CollisionParabola *parabola;
DCAST_INTO_R(parabola, entry.get_from(), 0);
const LMatrix4 &wrt_mat = entry.get_wrt_mat();
// Convert the parabola into local coordinate space.
LParabola local_p(parabola->get_parabola());
local_p.xform(wrt_mat);
PN_stdfloat t1, t2;
if (!get_plane().intersects_parabola(t1, t2, local_p)) {
// No intersection.
return NULL;
}
PN_stdfloat t;
if (t1 >= parabola->get_t1() && t1 <= parabola->get_t2()) {
if (t2 >= parabola->get_t1() && t2 <= parabola->get_t2()) {
// Both intersection points are within our segment of the
// parabola. Choose the first of the two.
t = min(t1, t2);
} else {
// Only t1 is within our segment.
t = t1;
}
} else if (t2 >= parabola->get_t1() && t2 <= parabola->get_t2()) {
// Only t2 is within our segment.
t = t2;
} else {
// Neither intersection point is within our segment.
return NULL;
}
LPoint3 plane_point = local_p.calc_point(t);
LPoint2 p = to_2d(plane_point);
const ClipPlaneAttrib *cpa = entry.get_into_clip_planes();
if (cpa != (ClipPlaneAttrib *)NULL) {
// We have a clip plane; apply it.
Points new_points;
if (apply_clip_plane(new_points, cpa, entry.get_into_node_path().get_net_transform())) {
// All points are behind the clip plane.
if (!point_is_inside(p, _points)) {
return NULL;
}
} else {
if (new_points.size() < 3) {
return NULL;
}
if (!point_is_inside(p, new_points)) {
return NULL;
}
}
} else {
// No clip plane is in effect. Do the default test.
if (!point_is_inside(p, _points)) {
return NULL;
}
}
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "intersection detected from " << entry.get_from_node_path()
<< " into " << entry.get_into_node_path() << "\n";
}
PT(CollisionEntry) new_entry = new CollisionEntry(entry);
LVector3 normal = (has_effective_normal() && parabola->get_respect_effective_normal()) ? get_effective_normal() : get_normal();
new_entry->set_surface_normal(normal);
new_entry->set_surface_point(plane_point);
return new_entry;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::fill_viz_geom
// Access: Protected, Virtual
// Description: Fills the _viz_geom GeomNode up with Geoms suitable
// for rendering this solid.
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
fill_viz_geom() {
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "Recomputing viz for " << *this << "\n";
}
nassertv(_viz_geom != (GeomNode *)NULL && _bounds_viz_geom != (GeomNode *)NULL);
draw_polygon(_viz_geom, _bounds_viz_geom, _points);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::dist_to_line_segment
// Access: Private, Static
// Description: Returns the linear distance of p to the line segment
// defined by f and t, where v = (t - f).normalize().
// The result is negative if p is left of the line,
// positive if it is right of the line. If the result
// is positive, it is constrained by endpoints of the
// line segment (i.e. the result might be larger than it
// would be for a straight distance-to-line test). If
// the result is negative, we don't bother.
////////////////////////////////////////////////////////////////////
PN_stdfloat CollisionPolygon::
dist_to_line_segment(const LPoint2 &p,
const LPoint2 &f, const LPoint2 &t,
const LVector2 &v) {
LVector2 v1 = (p - f);
PN_stdfloat d = (v1[0] * v[1] - v1[1] * v[0]);
if (d < 0.0f) {
return d;
}
// Compute the nearest point on the line.
LPoint2 q = p + LVector2(-v[1], v[0]) * d;
// Now constrain that point to the line segment.
if (v[0] > 0.0f) {
// X+
if (v[1] > 0.0f) {
// Y+
if (v[0] > v[1]) {
// X-dominant.
if (q[0] < f[0]) {
return (p - f).length();
} if (q[0] > t[0]) {
return (p - t).length();
} else {
return d;
}
} else {
// Y-dominant.
if (q[1] < f[1]) {
return (p - f).length();
} if (q[1] > t[1]) {
return (p - t).length();
} else {
return d;
}
}
} else {
// Y-
if (v[0] > -v[1]) {
// X-dominant.
if (q[0] < f[0]) {
return (p - f).length();
} if (q[0] > t[0]) {
return (p - t).length();
} else {
return d;
}
} else {
// Y-dominant.
if (q[1] > f[1]) {
return (p - f).length();
} if (q[1] < t[1]) {
return (p - t).length();
} else {
return d;
}
}
}
} else {
// X-
if (v[1] > 0.0f) {
// Y+
if (-v[0] > v[1]) {
// X-dominant.
if (q[0] > f[0]) {
return (p - f).length();
} if (q[0] < t[0]) {
return (p - t).length();
} else {
return d;
}
} else {
// Y-dominant.
if (q[1] < f[1]) {
return (p - f).length();
} if (q[1] > t[1]) {
return (p - t).length();
} else {
return d;
}
}
} else {
// Y-
if (-v[0] > -v[1]) {
// X-dominant.
if (q[0] > f[0]) {
return (p - f).length();
} if (q[0] < t[0]) {
return (p - t).length();
} else {
return d;
}
} else {
// Y-dominant.
if (q[1] > f[1]) {
return (p - f).length();
} if (q[1] < t[1]) {
return (p - t).length();
} else {
return d;
}
}
}
}
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::compute_vectors
// Access: Private, Static
// Description: Now that the _p members of the given points array
// have been computed, go back and compute all of the _v
// members.
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
compute_vectors(Points &points) {
size_t num_points = points.size();
for (size_t i = 0; i < num_points; i++) {
points[i]._v = points[(i + 1) % num_points]._p - points[i]._p;
points[i]._v.normalize();
}
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::draw_polygon
// Access: Private
// Description: Fills up the indicated GeomNode with the Geoms to
// draw the polygon indicated with the given set of 2-d
// points.
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
draw_polygon(GeomNode *viz_geom_node, GeomNode *bounds_viz_geom_node,
const CollisionPolygon::Points &points) const {
if (points.size() < 3) {
if (collide_cat.is_debug()) {
collide_cat.debug()
<< "(Degenerate poly, ignoring.)\n";
}
return;
}
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
PT(GeomVertexData) vdata = new GeomVertexData
("collision", GeomVertexFormat::get_v3(),
Geom::UH_static);
GeomVertexWriter vertex(vdata, InternalName::get_vertex());
Points::const_iterator pi;
for (pi = points.begin(); pi != points.end(); ++pi) {
vertex.add_data3(to_3d((*pi)._p, to_3d_mat));
}
PT(GeomTrifans) body = new GeomTrifans(Geom::UH_static);
body->add_consecutive_vertices(0, points.size());
body->close_primitive();
PT(GeomLinestrips) border = new GeomLinestrips(Geom::UH_static);
border->add_consecutive_vertices(0, points.size());
border->add_vertex(0);
border->close_primitive();
PT(Geom) geom1 = new Geom(vdata);
geom1->add_primitive(body);
PT(Geom) geom2 = new Geom(vdata);
geom2->add_primitive(border);
viz_geom_node->add_geom(geom1, ((CollisionPolygon *)this)->get_solid_viz_state());
viz_geom_node->add_geom(geom2, ((CollisionPolygon *)this)->get_wireframe_viz_state());
bounds_viz_geom_node->add_geom(geom1, ((CollisionPolygon *)this)->get_solid_bounds_viz_state());
bounds_viz_geom_node->add_geom(geom2, ((CollisionPolygon *)this)->get_wireframe_bounds_viz_state());
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::point_is_inside
// Access: Private
// Description: Returns true if the indicated point is within the
// polygon's 2-d space, false otherwise.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
point_is_inside(const LPoint2 &p, const CollisionPolygon::Points &points) const {
// We insist that the polygon be convex. This makes things a bit simpler.
// In the case of a convex polygon, defined with points in counterclockwise
// order, a point is interior to the polygon iff the point is not right of
// each of the edges.
for (int i = 0; i < (int)points.size() - 1; i++) {
if (is_right(p - points[i]._p, points[i+1]._p - points[i]._p)) {
return false;
}
}
if (is_right(p - points[points.size() - 1]._p,
points[0]._p - points[points.size() - 1]._p)) {
return false;
}
return true;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::dist_to_polygon
// Access: Private
// Description: Returns the linear distance from the 2-d point to the
// nearest part of the polygon defined by the points
// vector. The result is negative if the point is
// within the polygon.
////////////////////////////////////////////////////////////////////
PN_stdfloat CollisionPolygon::
dist_to_polygon(const LPoint2 &p, const CollisionPolygon::Points &points) const {
// We know that that the polygon is convex and is defined with the
// points in counterclockwise order. Therefore, we simply compare
// the signed distance to each line segment; we ignore any negative
// values, and take the minimum of all the positive values.
// If all values are negative, the point is within the polygon; we
// therefore return an arbitrary negative result.
bool got_dist = false;
PN_stdfloat best_dist = -1.0f;
size_t num_points = points.size();
for (size_t i = 0; i < num_points - 1; ++i) {
PN_stdfloat d = dist_to_line_segment(p, points[i]._p, points[i + 1]._p,
points[i]._v);
if (d >= 0.0f) {
if (!got_dist || d < best_dist) {
best_dist = d;
got_dist = true;
}
}
}
PN_stdfloat d = dist_to_line_segment(p, points[num_points - 1]._p, points[0]._p,
points[num_points - 1]._v);
if (d >= 0.0f) {
if (!got_dist || d < best_dist) {
best_dist = d;
got_dist = true;
}
}
return best_dist;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::setup_points
// Access: Private
// Description:
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
setup_points(const LPoint3 *begin, const LPoint3 *end) {
int num_points = end - begin;
nassertv(num_points >= 3);
_points.clear();
// Tell the base CollisionPlane class what its plane will be. To do
// this, we must first compute the polygon normal.
LVector3 normal = LVector3::zero();
// Project the polygon into each of the three major planes and
// calculate the area of each 2-d projection. This becomes the
// polygon normal. This works because the ratio between these
// different areas corresponds to the angle at which the polygon is
// tilted toward each plane.
for (int i = 0; i < num_points; i++) {
const LPoint3 &p0 = begin[i];
const LPoint3 &p1 = begin[(i + 1) % num_points];
normal[0] += p0[1] * p1[2] - p0[2] * p1[1];
normal[1] += p0[2] * p1[0] - p0[0] * p1[2];
normal[2] += p0[0] * p1[1] - p0[1] * p1[0];
}
if (normal.length_squared() == 0.0f) {
// The polygon has no area.
return;
}
#ifndef NDEBUG
// Make sure all the source points are good.
{
if (!verify_points(begin, end)) {
collide_cat.error() << "Invalid points in CollisionPolygon:\n";
const LPoint3 *pi;
for (pi = begin; pi != end; ++pi) {
collide_cat.error(false) << " " << (*pi) << "\n";
}
collide_cat.error(false)
<< " normal " << normal << " with length " << normal.length() << "\n";
return;
}
}
if (collide_cat.is_spam()) {
collide_cat.spam()
<< "CollisionPolygon defined with " << num_points << " vertices:\n";
const LPoint3 *pi;
for (pi = begin; pi != end; ++pi) {
collide_cat.spam(false) << " " << (*pi) << "\n";
}
}
#endif
set_plane(LPlane(normal, begin[0]));
// Construct a matrix that rotates the points from the (X,0,Z) plane
// into the 3-d plane.
LMatrix4 to_3d_mat;
calc_to_3d_mat(to_3d_mat);
// And the inverse matrix rotates points from 3-d space into the 2-d
// plane.
_to_2d_mat.invert_from(to_3d_mat);
// Now project all of the points onto the 2-d plane.
const LPoint3 *pi;
for (pi = begin; pi != end; ++pi) {
LPoint3 point = (*pi) * _to_2d_mat;
_points.push_back(PointDef(point[0], point[2]));
}
nassertv(_points.size() >= 3);
#ifndef NDEBUG
/*
// Now make sure the points define a convex polygon.
if (is_concave()) {
collide_cat.error() << "Invalid concave CollisionPolygon defined:\n";
const LPoint3 *pi;
for (pi = begin; pi != end; ++pi) {
collide_cat.error(false) << " " << (*pi) << "\n";
}
collide_cat.error(false)
<< " normal " << normal << " with length " << normal.length() << "\n";
_points.clear();
}
*/
#endif
compute_vectors(_points);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::legacy_to_3d
// Access: Private
// Description: Converts the indicated point to 3-d space according
// to the way CollisionPolygons used to be stored in bam
// files prior to 4.9.
////////////////////////////////////////////////////////////////////
LPoint3 CollisionPolygon::
legacy_to_3d(const LVecBase2 &point2d, int axis) const {
nassertr(!point2d.is_nan(), LPoint3(0.0f, 0.0f, 0.0f));
LVector3 normal = get_normal();
PN_stdfloat D = get_plane()[3];
nassertr(!normal.is_nan(), LPoint3(0.0f, 0.0f, 0.0f));
nassertr(!cnan(D), LPoint3(0.0f, 0.0f, 0.0f));
switch (axis) {
case 0: // AT_x:
return LPoint3(-(normal[1]*point2d[0] + normal[2]*point2d[1] + D)/normal[0], point2d[0], point2d[1]);
case 1: // AT_y:
return LPoint3(point2d[0],
-(normal[0]*point2d[0] + normal[2]*point2d[1] + D)/normal[1], point2d[1]);
case 2: // AT_z:
return LPoint3(point2d[0], point2d[1],
-(normal[0]*point2d[0] + normal[1]*point2d[1] + D)/normal[2]);
}
nassertr(false, LPoint3(0.0f, 0.0f, 0.0f));
return LPoint3(0.0f, 0.0f, 0.0f);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::clip_polygon
// Access: Private
// Description: Clips the source_points of the polygon by the
// indicated clipping plane, and modifies new_points to
// reflect the new set of clipped points (but does not
// compute the vectors in new_points).
//
// The return value is true if the set of points is
// unmodified (all points are behind the clip plane), or
// false otherwise.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
clip_polygon(CollisionPolygon::Points &new_points,
const CollisionPolygon::Points &source_points,
const LPlane &plane) const {
new_points.clear();
if (source_points.empty()) {
return true;
}
LPoint3 from3d;
LVector3 delta3d;
if (!plane.intersects_plane(from3d, delta3d, get_plane())) {
// The clipping plane is parallel to the polygon. The polygon is
// either all in or all out.
if (plane.dist_to_plane(get_plane().get_point()) < 0.0) {
// A point within the polygon is behind the clipping plane: the
// polygon is all in.
new_points = source_points;
return true;
}
return false;
}
// Project the line of intersection into the 2-d plane. Now we have
// a 2-d clipping line.
LPoint2 from2d = to_2d(from3d);
LVector2 delta2d = to_2d(delta3d);
PN_stdfloat a = -delta2d[1];
PN_stdfloat b = delta2d[0];
PN_stdfloat c = from2d[0] * delta2d[1] - from2d[1] * delta2d[0];
// Now walk through the points. Any point on the left of our line
// gets removed, and the line segment clipped at the point of
// intersection.
// We might increase the number of vertices by as many as 1, if the
// plane clips off exactly one corner. (We might also decrease the
// number of vertices, or keep them the same number.)
new_points.reserve(source_points.size() + 1);
LPoint2 last_point = source_points.back()._p;
bool last_is_in = !is_right(last_point - from2d, delta2d);
bool all_in = last_is_in;
Points::const_iterator pi;
for (pi = source_points.begin(); pi != source_points.end(); ++pi) {
const LPoint2 &this_point = (*pi)._p;
bool this_is_in = !is_right(this_point - from2d, delta2d);
// There appears to be a compiler bug in gcc 4.0: we need to
// extract this comparison outside of the if statement.
bool crossed_over = (this_is_in != last_is_in);
if (crossed_over) {
// We have just crossed over the clipping line. Find the point
// of intersection.
LVector2 d = this_point - last_point;
PN_stdfloat denom = (a * d[0] + b * d[1]);
if (denom != 0.0) {
PN_stdfloat t = -(a * last_point[0] + b * last_point[1] + c) / denom;
LPoint2 p = last_point + t * d;
new_points.push_back(PointDef(p[0], p[1]));
last_is_in = this_is_in;
}
}
if (this_is_in) {
// We are behind the clipping line. Keep the point.
new_points.push_back(PointDef(this_point[0], this_point[1]));
} else {
all_in = false;
}
last_point = this_point;
}
return all_in;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::apply_clip_plane
// Access: Private
// Description: Clips the polygon by all of the clip planes named in
// the clip plane attribute and fills new_points up with
// the resulting points.
//
// The return value is true if the set of points is
// unmodified (all points are behind all the clip
// planes), or false otherwise.
////////////////////////////////////////////////////////////////////
bool CollisionPolygon::
apply_clip_plane(CollisionPolygon::Points &new_points,
const ClipPlaneAttrib *cpa,
const TransformState *net_transform) const {
bool all_in = true;
int num_planes = cpa->get_num_on_planes();
bool first_plane = true;
for (int i = 0; i < num_planes; i++) {
NodePath plane_path = cpa->get_on_plane(i);
PlaneNode *plane_node = DCAST(PlaneNode, plane_path.node());
if ((plane_node->get_clip_effect() & PlaneNode::CE_collision) != 0) {
CPT(TransformState) new_transform =
net_transform->invert_compose(plane_path.get_net_transform());
LPlane plane = plane_node->get_plane() * new_transform->get_mat();
if (first_plane) {
first_plane = false;
if (!clip_polygon(new_points, _points, plane)) {
all_in = false;
}
} else {
Points last_points;
last_points.swap(new_points);
if (!clip_polygon(new_points, last_points, plane)) {
all_in = false;
}
}
}
}
if (!all_in) {
compute_vectors(new_points);
}
return all_in;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::write_datagram
// Access: Public
// Description: Function to write the important information in
// the particular object to a Datagram
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
write_datagram(BamWriter *manager, Datagram &me) {
CollisionPlane::write_datagram(manager, me);
me.add_uint16(_points.size());
for (size_t i = 0; i < _points.size(); i++) {
_points[i]._p.write_datagram(me);
_points[i]._v.write_datagram(me);
}
_to_2d_mat.write_datagram(me);
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::fillin
// Access: Protected
// Description: Function that reads out of the datagram (or asks
// manager to read) all of the data that is needed to
// re-create this object and stores it in the appropiate
// place
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
fillin(DatagramIterator &scan, BamReader *manager) {
CollisionPlane::fillin(scan, manager);
size_t size = scan.get_uint16();
for (size_t i = 0; i < size; i++) {
LPoint2 p;
LVector2 v;
p.read_datagram(scan);
v.read_datagram(scan);
_points.push_back(PointDef(p, v));
}
_to_2d_mat.read_datagram(scan);
if (manager->get_file_minor_ver() < 13) {
// Before bam version 6.13, we were inadvertently storing
// CollisionPolygon vertices clockwise, instead of
// counter-clockwise. Correct that by re-projecting.
if (_points.size() >= 3) {
LMatrix4 to_3d_mat;
rederive_to_3d_mat(to_3d_mat);
epvector<LPoint3> verts;
verts.reserve(_points.size());
Points::const_iterator pi;
for (pi = _points.begin(); pi != _points.end(); ++pi) {
verts.push_back(to_3d((*pi)._p, to_3d_mat));
}
const LPoint3 *verts_begin = &verts[0];
const LPoint3 *verts_end = verts_begin + verts.size();
setup_points(verts_begin, verts_end);
}
}
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::make_CollisionPolygon
// Access: Protected
// Description: Factory method to generate a CollisionPolygon object
////////////////////////////////////////////////////////////////////
TypedWritable* CollisionPolygon::
make_CollisionPolygon(const FactoryParams &params) {
CollisionPolygon *me = new CollisionPolygon;
DatagramIterator scan;
BamReader *manager;
parse_params(params, scan, manager);
me->fillin(scan, manager);
return me;
}
////////////////////////////////////////////////////////////////////
// Function: CollisionPolygon::register_with_factory
// Access: Public, Static
// Description: Factory method to generate a CollisionPolygon object
////////////////////////////////////////////////////////////////////
void CollisionPolygon::
register_with_read_factory() {
BamReader::get_factory()->register_factory(get_class_type(), make_CollisionPolygon);
}
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