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implement point cloud function using convex hull for ConvexPolygonShape2D, fixes #2848

This commit is contained in:
Juan Linietsky 2015-12-14 09:06:53 -03:00
parent f2183a5e09
commit 1312df7fdc
2 changed files with 36 additions and 1 deletions
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31
core/math/geometry.h
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@ -886,7 +886,38 @@ public:
}
static double vec2_cross(const Point2 &O, const Point2 &A, const Point2 &B)
{
return (double)(A.x - O.x) * (B.y - O.y) - (double)(A.y - O.y) * (B.x - O.x);
}
// Returns a list of points on the convex hull in counter-clockwise order.
// Note: the last point in the returned list is the same as the first one.
static Vector<Point2> convex_hull_2d(Vector<Point2> P)
{
int n = P.size(), k = 0;
Vector<Point2> H;
H.resize(2*n);
// Sort points lexicographically
P.sort();
// Build lower hull
for (int i = 0; i < n; ++i) {
while (k >= 2 && vec2_cross(H[k-2], H[k-1], P[i]) <= 0) k--;
H[k++] = P[i];
}
// Build upper hull
for (int i = n-2, t = k+1; i >= 0; i--) {
while (k >= t && vec2_cross(H[k-2], H[k-1], P[i]) <= 0) k--;
H[k++] = P[i];
}
H.resize(k);
return H;
}
static MeshData build_convex_mesh(const DVector<Plane> &p_planes);
static DVector<Plane> build_sphere_planes(float p_radius, int p_lats, int p_lons, Vector3::Axis p_axis=Vector3::AXIS_Z);

6
scene/resources/convex_polygon_shape_2d.cpp
View File

@ -30,6 +30,8 @@
#include "servers/physics_2d_server.h"
#include "servers/visual_server.h"
#include "geometry.h"
void ConvexPolygonShape2D::_update_shape() {
Physics2DServer::get_singleton()->shape_set_data(get_rid(),points);
@ -40,7 +42,9 @@ void ConvexPolygonShape2D::_update_shape() {
void ConvexPolygonShape2D::set_point_cloud(const Vector<Vector2>& p_points) {
Vector<Point2> hull=Geometry::convex_hull_2d(p_points);
ERR_FAIL_COND(hull.size()<3);
set_points(hull);
}
void ConvexPolygonShape2D::set_points(const Vector<Vector2>& p_points) {