godot/modules/csg/csg.cpp
2018-09-13 10:59:00 +02:00

1519 lines
43 KiB
C++

/*************************************************************************/
/* csg.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2018 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2018 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
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/* 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.*/
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/*************************************************************************/
#include "csg.h"
#include "core/math/face3.h"
#include "core/math/geometry.h"
#include "core/os/os.h"
#include "core/sort.h"
#include "thirdparty/misc/triangulator.h"
void CSGBrush::clear() {
faces.clear();
}
void CSGBrush::build_from_faces(const PoolVector<Vector3> &p_vertices, const PoolVector<Vector2> &p_uvs, const PoolVector<bool> &p_smooth, const PoolVector<Ref<Material> > &p_materials, const PoolVector<bool> &p_invert_faces) {
clear();
int vc = p_vertices.size();
ERR_FAIL_COND((vc % 3) != 0)
PoolVector<Vector3>::Read rv = p_vertices.read();
int uvc = p_uvs.size();
PoolVector<Vector2>::Read ruv = p_uvs.read();
int sc = p_smooth.size();
PoolVector<bool>::Read rs = p_smooth.read();
int mc = p_materials.size();
PoolVector<Ref<Material> >::Read rm = p_materials.read();
int ic = p_invert_faces.size();
PoolVector<bool>::Read ri = p_invert_faces.read();
Map<Ref<Material>, int> material_map;
faces.resize(p_vertices.size() / 3);
for (int i = 0; i < faces.size(); i++) {
Face &f = faces.write[i];
f.vertices[0] = rv[i * 3 + 0];
f.vertices[1] = rv[i * 3 + 1];
f.vertices[2] = rv[i * 3 + 2];
if (uvc == vc) {
f.uvs[0] = ruv[i * 3 + 0];
f.uvs[1] = ruv[i * 3 + 1];
f.uvs[2] = ruv[i * 3 + 2];
}
if (sc == vc / 3) {
f.smooth = rs[i];
} else {
f.smooth = false;
}
if (ic == vc / 3) {
f.invert = ri[i];
} else {
f.invert = false;
}
if (mc == vc / 3) {
Ref<Material> mat = rm[i];
if (mat.is_valid()) {
const Map<Ref<Material>, int>::Element *E = material_map.find(mat);
if (E) {
f.material = E->get();
} else {
f.material = material_map.size();
material_map[mat] = f.material;
}
} else {
f.material = -1;
}
}
}
materials.resize(material_map.size());
for (Map<Ref<Material>, int>::Element *E = material_map.front(); E; E = E->next()) {
materials.write[E->get()] = E->key();
}
_regen_face_aabbs();
}
void CSGBrush::_regen_face_aabbs() {
for (int i = 0; i < faces.size(); i++) {
faces.write[i].aabb.position = faces[i].vertices[0];
faces.write[i].aabb.expand_to(faces[i].vertices[1]);
faces.write[i].aabb.expand_to(faces[i].vertices[2]);
faces.write[i].aabb.grow_by(faces[i].aabb.get_longest_axis_size() * 0.001); //make it a tad bigger to avoid num precision erros
}
}
void CSGBrush::copy_from(const CSGBrush &p_brush, const Transform &p_xform) {
faces = p_brush.faces;
materials = p_brush.materials;
for (int i = 0; i < faces.size(); i++) {
for (int j = 0; j < 3; j++) {
faces.write[i].vertices[j] = p_xform.xform(p_brush.faces[i].vertices[j]);
}
}
_regen_face_aabbs();
}
////////////////////////
void CSGBrushOperation::BuildPoly::create(const CSGBrush *p_brush, int p_face, MeshMerge &mesh_merge, bool p_for_B) {
//creates the initial face that will be used for clipping against the other faces
Vector3 va[3] = {
p_brush->faces[p_face].vertices[0],
p_brush->faces[p_face].vertices[1],
p_brush->faces[p_face].vertices[2],
};
plane = Plane(va[0], va[1], va[2]);
to_world.origin = va[0];
to_world.basis.set_axis(2, plane.normal);
to_world.basis.set_axis(0, (va[1] - va[2]).normalized());
to_world.basis.set_axis(1, to_world.basis.get_axis(0).cross(to_world.basis.get_axis(2)).normalized());
to_poly = to_world.affine_inverse();
face_index = p_face;
for (int i = 0; i < 3; i++) {
Point p;
Vector3 localp = to_poly.xform(va[i]);
p.point.x = localp.x;
p.point.y = localp.y;
p.uv = p_brush->faces[p_face].uvs[i];
points.push_back(p);
///edge
Edge e;
e.points[0] = i;
e.points[1] = (i + 1) % 3;
e.outer = true;
edges.push_back(e);
}
smooth = p_brush->faces[p_face].smooth;
invert = p_brush->faces[p_face].invert;
if (p_brush->faces[p_face].material != -1) {
material = p_brush->materials[p_brush->faces[p_face].material];
}
base_edges = 3;
}
static Vector2 interpolate_uv(const Vector2 &p_vertex_a, const Vector2 &p_vertex_b, const Vector2 &p_vertex_c, const Vector2 &p_uv_a, const Vector2 &p_uv_c) {
float len_a_c = (p_vertex_c - p_vertex_a).length();
if (len_a_c < CMP_EPSILON) {
return p_uv_a;
}
float len_a_b = (p_vertex_b - p_vertex_a).length();
float c = len_a_b / len_a_c;
return p_uv_a.linear_interpolate(p_uv_c, c);
}
static Vector2 interpolate_triangle_uv(const Vector2 &p_pos, const Vector2 *p_vtx, const Vector2 *p_uv) {
if (p_pos.distance_squared_to(p_vtx[0]) < CMP_EPSILON2) {
return p_uv[0];
}
if (p_pos.distance_squared_to(p_vtx[1]) < CMP_EPSILON2) {
return p_uv[1];
}
if (p_pos.distance_squared_to(p_vtx[2]) < CMP_EPSILON2) {
return p_uv[2];
}
Vector2 v0 = p_vtx[1] - p_vtx[0];
Vector2 v1 = p_vtx[2] - p_vtx[0];
Vector2 v2 = p_pos - p_vtx[0];
float d00 = v0.dot(v0);
float d01 = v0.dot(v1);
float d11 = v1.dot(v1);
float d20 = v2.dot(v0);
float d21 = v2.dot(v1);
float denom = (d00 * d11 - d01 * d01);
if (denom == 0) {
return p_uv[0];
}
float v = (d11 * d20 - d01 * d21) / denom;
float w = (d00 * d21 - d01 * d20) / denom;
float u = 1.0f - v - w;
return p_uv[0] * u + p_uv[1] * v + p_uv[2] * w;
}
void CSGBrushOperation::BuildPoly::_clip_segment(const CSGBrush *p_brush, int p_face, const Vector2 *segment, MeshMerge &mesh_merge, bool p_for_B) {
//keep track of what was inserted
Vector<int> inserted_points;
//keep track of point indices for what was inserted, allowing reuse of points.
int segment_idx[2] = { -1, -1 };
//check if edge and poly share a vertex, of so, assign it to segment_idx
for (int i = 0; i < points.size(); i++) {
for (int j = 0; j < 2; j++) {
if (segment[j].distance_to(points[i].point) < CMP_EPSILON) {
segment_idx[j] = i;
inserted_points.push_back(i);
break;
}
}
}
//check if both segment points are shared with other vertices
if (segment_idx[0] != -1 && segment_idx[1] != -1) {
if (segment_idx[0] == segment_idx[1]) {
return; //segment was too tiny, both mapped to same point
}
bool found = false;
//check if the segment already exists
for (int i = 0; i < edges.size(); i++) {
if (
(edges[i].points[0] == segment_idx[0] && edges[i].points[1] == segment_idx[1]) ||
(edges[i].points[0] == segment_idx[1] && edges[i].points[1] == segment_idx[0])) {
found = true;
break;
}
}
if (found) {
//it does already exist, do nothing
return;
}
//directly add the new segment
Edge new_edge;
new_edge.points[0] = segment_idx[0];
new_edge.points[1] = segment_idx[1];
edges.push_back(new_edge);
return;
}
//check edge by edge against the segment points to see if intersects
for (int i = 0; i < base_edges; i++) {
//if a point is shared with one of the edge points, then this edge must not be tested, as it will result in a numerical precision error.
bool edge_valid = true;
for (int j = 0; j < 2; j++) {
if (edges[i].points[0] == segment_idx[0] || edges[i].points[1] == segment_idx[1] || edges[i].points[0] == segment_idx[1] || edges[i].points[1] == segment_idx[0]) {
edge_valid = false; //segment has this point, can't check against this
break;
}
}
if (!edge_valid) //already hit a point in this edge, so don't test it
continue;
//see if either points are within the edge isntead of crossing it
Vector2 res;
bool found = false;
int assign_segment_id = -1;
for (int j = 0; j < 2; j++) {
Vector2 edgeseg[2] = { points[edges[i].points[0]].point, points[edges[i].points[1]].point };
Vector2 closest = Geometry::get_closest_point_to_segment_2d(segment[j], edgeseg);
if (closest.distance_to(segment[j]) < CMP_EPSILON) {
//point rest of this edge
res = closest;
found = true;
assign_segment_id = j;
}
}
//test if the point crosses the edge
if (!found && Geometry::segment_intersects_segment_2d(segment[0], segment[1], points[edges[i].points[0]].point, points[edges[i].points[1]].point, &res)) {
//point does cross the edge
found = true;
}
//check whether an intersection against the segment happened
if (found) {
//It did! so first, must slice the segment
Point new_point;
new_point.point = res;
//make sure to interpolate UV too
new_point.uv = interpolate_uv(points[edges[i].points[0]].point, new_point.point, points[edges[i].points[1]].point, points[edges[i].points[0]].uv, points[edges[i].points[1]].uv);
int point_idx = points.size();
points.push_back(new_point);
//split the edge in 2
Edge new_edge;
new_edge.points[0] = edges[i].points[0];
new_edge.points[1] = point_idx;
new_edge.outer = edges[i].outer;
edges.write[i].points[0] = point_idx;
edges.insert(i, new_edge);
i++; //skip newly inserted edge
base_edges++; //will need an extra one in the base triangle
if (assign_segment_id >= 0) {
//point did split a segment, so make sure to remember this
segment_idx[assign_segment_id] = point_idx;
}
inserted_points.push_back(point_idx);
}
}
//final step: after cutting the original triangle, try to see if we can still insert
//this segment
//if already inserted two points, just use them for a segment
if (inserted_points.size() >= 2) { //should never be >2 on non-manifold geometry, but cope with error
//two points were inserted, create the new edge
Edge new_edge;
new_edge.points[0] = inserted_points[0];
new_edge.points[1] = inserted_points[1];
edges.push_back(new_edge);
return;
}
// One or no points were inserted (besides splitting), so try to see if extra points can be placed inside the triangle.
// This needs to be done here, after the previous tests were exhausted
for (int i = 0; i < 2; i++) {
if (segment_idx[i] != -1)
continue; //already assigned to something, so skip
//check whether one of the segment endpoints is inside the triangle. If it is, this points needs to be inserted
if (Geometry::is_point_in_triangle(segment[i], points[0].point, points[1].point, points[2].point)) {
Point new_point;
new_point.point = segment[i];
Vector2 point3[3] = { points[0].point, points[1].point, points[2].point };
Vector2 uv3[3] = { points[0].uv, points[1].uv, points[2].uv };
new_point.uv = interpolate_triangle_uv(new_point.point, point3, uv3);
int point_idx = points.size();
points.push_back(new_point);
inserted_points.push_back(point_idx);
}
}
//check again whether two points were inserted, if so then create the new edge
if (inserted_points.size() >= 2) { //should never be >2 on non-manifold geometry, but cope with error
Edge new_edge;
new_edge.points[0] = inserted_points[0];
new_edge.points[1] = inserted_points[1];
edges.push_back(new_edge);
}
}
void CSGBrushOperation::BuildPoly::clip(const CSGBrush *p_brush, int p_face, MeshMerge &mesh_merge, bool p_for_B) {
//Clip function.. find triangle points that will be mapped to the plane and form a segment
Vector2 segment[3]; //2D
int src_points = 0;
for (int i = 0; i < 3; i++) {
Vector3 p = p_brush->faces[p_face].vertices[i];
if (plane.has_point(p)) {
Vector3 pp = plane.project(p);
pp = to_poly.xform(pp);
segment[src_points++] = Vector2(pp.x, pp.y);
} else {
Vector3 q = p_brush->faces[p_face].vertices[(i + 1) % 3];
if (plane.has_point(q))
continue; //next point is in plane, will be added eventually
if (plane.is_point_over(p) == plane.is_point_over(q))
continue; // both on same side of the plane, don't add
Vector3 res;
if (plane.intersects_segment(p, q, &res)) {
res = to_poly.xform(res);
segment[src_points++] = Vector2(res.x, res.y);
}
}
}
//all above or all below, nothing to do. Should not happen though since a precheck was done before.
if (src_points == 0)
return;
//just one point in plane is not worth doing anything
if (src_points == 1)
return;
//transform A points to 2D
if (segment[0].distance_to(segment[1]) < CMP_EPSILON)
return; //too small
_clip_segment(p_brush, p_face, segment, mesh_merge, p_for_B);
}
void CSGBrushOperation::_collision_callback(const CSGBrush *A, int p_face_a, Map<int, BuildPoly> &build_polys_a, const CSGBrush *B, int p_face_b, Map<int, BuildPoly> &build_polys_b, MeshMerge &mesh_merge) {
//construct a frame of reference for both transforms, in order to do intersection test
Vector3 va[3] = {
A->faces[p_face_a].vertices[0],
A->faces[p_face_a].vertices[1],
A->faces[p_face_a].vertices[2],
};
Vector3 vb[3] = {
B->faces[p_face_b].vertices[0],
B->faces[p_face_b].vertices[1],
B->faces[p_face_b].vertices[2],
};
{
//check if either is a degenerate
if (va[0].distance_to(va[1]) < CMP_EPSILON || va[0].distance_to(va[2]) < CMP_EPSILON || va[1].distance_to(va[2]) < CMP_EPSILON)
return;
if (vb[0].distance_to(vb[1]) < CMP_EPSILON || vb[0].distance_to(vb[2]) < CMP_EPSILON || vb[1].distance_to(vb[2]) < CMP_EPSILON)
return;
}
{
//check if points are the same
int equal_count = 0;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (va[i].distance_to(vb[j]) < mesh_merge.vertex_snap) {
equal_count++;
break;
}
}
}
//if 2 or 3 points are the same, there is no point in doing anything. They can't
//be clipped either, so add both.
if (equal_count == 2 || equal_count == 3) {
return;
}
}
// do a quick pre-check for no-intersection using the SAT theorem
{
//b under or over a plane
int over_count = 0, in_plane_count = 0, under_count = 0;
Plane plane_a(va[0], va[1], va[2]);
if (plane_a.normal == Vector3()) {
return; //degenerate
}
for (int i = 0; i < 3; i++) {
if (plane_a.has_point(vb[i]))
in_plane_count++;
else if (plane_a.is_point_over(vb[i]))
over_count++;
else
under_count++;
}
if (over_count == 0 || under_count == 0)
return; //no intersection, something needs to be under AND over
//a under or over b plane
over_count = 0;
under_count = 0;
in_plane_count = 0;
Plane plane_b(vb[0], vb[1], vb[2]);
if (plane_b.normal == Vector3())
return; //degenerate
for (int i = 0; i < 3; i++) {
if (plane_b.has_point(va[i]))
in_plane_count++;
else if (plane_b.is_point_over(va[i]))
over_count++;
else
under_count++;
}
if (over_count == 0 || under_count == 0)
return; //no intersection, something needs to be under AND over
//edge pairs (cross product combinations), see SAT theorem
for (int i = 0; i < 3; i++) {
Vector3 axis_a = (va[i] - va[(i + 1) % 3]).normalized();
for (int j = 0; j < 3; j++) {
Vector3 axis_b = (vb[j] - vb[(j + 1) % 3]).normalized();
Vector3 sep_axis = axis_a.cross(axis_b);
if (sep_axis == Vector3())
continue; //colineal
sep_axis.normalize();
real_t min_a = 1e20, max_a = -1e20;
real_t min_b = 1e20, max_b = -1e20;
for (int k = 0; k < 3; k++) {
real_t d = sep_axis.dot(va[k]);
min_a = MIN(min_a, d);
max_a = MAX(max_a, d);
d = sep_axis.dot(vb[k]);
min_b = MIN(min_b, d);
max_b = MAX(max_b, d);
}
min_b -= (max_a - min_a) * 0.5;
max_b += (max_a - min_a) * 0.5;
real_t dmin = min_b - (min_a + max_a) * 0.5;
real_t dmax = max_b - (min_a + max_a) * 0.5;
if (dmin > CMP_EPSILON || dmax < -CMP_EPSILON) {
return; //does not contain zero, so they don't overlap
}
}
}
}
//if we are still here, it means they most likely intersect, so create BuildPolys if they don't exist
BuildPoly *poly_a = NULL;
if (!build_polys_a.has(p_face_a)) {
BuildPoly bp;
bp.create(A, p_face_a, mesh_merge, false);
build_polys_a[p_face_a] = bp;
}
poly_a = &build_polys_a[p_face_a];
BuildPoly *poly_b = NULL;
if (!build_polys_b.has(p_face_b)) {
BuildPoly bp;
bp.create(B, p_face_b, mesh_merge, true);
build_polys_b[p_face_b] = bp;
}
poly_b = &build_polys_b[p_face_b];
//clip each other, this could be improved by using vertex unique IDs (more vertices may be shared instead of using snap)
poly_a->clip(B, p_face_b, mesh_merge, false);
poly_b->clip(A, p_face_a, mesh_merge, true);
}
void CSGBrushOperation::_add_poly_points(const BuildPoly &p_poly, int p_edge, int p_from_point, int p_to_point, const Vector<Vector<int> > &vertex_process, Vector<bool> &edge_process, Vector<PolyPoints> &r_poly) {
//this function follows the polygon points counter clockwise and adds them. It creates lists of unique polygons
//every time an unused edge is found, it's pushed to a stack and continues from there.
List<EdgeSort> edge_stack;
{
EdgeSort es;
es.angle = 0; //wont be checked here
es.edge = p_edge;
es.prev_point = p_from_point;
es.edge_point = p_to_point;
edge_stack.push_back(es);
}
//attempt to empty the stack.
while (edge_stack.size()) {
EdgeSort e = edge_stack.front()->get();
edge_stack.pop_front();
if (edge_process[e.edge]) {
//nothing to do here
continue;
}
Vector<int> points;
points.push_back(e.prev_point);
int prev_point = e.prev_point;
int to_point = e.edge_point;
int current_edge = e.edge;
edge_process.write[e.edge] = true; //mark as processed
int limit = p_poly.points.size() * 4; //avoid infinite recursion
while (to_point != e.prev_point && limit) {
Vector2 segment[2] = { p_poly.points[prev_point].point, p_poly.points[to_point].point };
//construct a basis transform from the segment, which will be used to check the angle
Transform2D t2d;
t2d[0] = (segment[1] - segment[0]).normalized(); //use as Y
t2d[1] = Vector2(-t2d[0].y, t2d[0].x); // use as tangent
t2d[2] = segment[1]; //origin
if (t2d.basis_determinant() == 0)
break; //abort poly
t2d.affine_invert();
//push all edges found here, they will be sorted by minimum angle later.
Vector<EdgeSort> next_edges;
for (int i = 0; i < vertex_process[to_point].size(); i++) {
int edge = vertex_process[to_point][i];
int opposite_point = p_poly.edges[edge].points[0] == to_point ? p_poly.edges[edge].points[1] : p_poly.edges[edge].points[0];
if (opposite_point == prev_point)
continue; //not going back
EdgeSort e;
Vector2 local_vec = t2d.xform(p_poly.points[opposite_point].point);
e.angle = -local_vec.angle(); //negate so we can sort by minimum angle
e.edge = edge;
e.edge_point = opposite_point;
e.prev_point = to_point;
next_edges.push_back(e);
}
//finally, sort by minimum angle
next_edges.sort();
int next_point = -1;
int next_edge = -1;
for (int i = 0; i < next_edges.size(); i++) {
if (i == 0) {
//minimum angle found is the next point
next_point = next_edges[i].edge_point;
next_edge = next_edges[i].edge;
} else {
//the rest are pushed to the stack IF they were not processed yet.
if (!edge_process[next_edges[i].edge]) {
edge_stack.push_back(next_edges[i]);
}
}
}
if (next_edge == -1) {
//did not find anything, may be a dead-end edge (this should normally not happen)
//just flip the direction and go back
next_point = prev_point;
next_edge = current_edge;
}
points.push_back(to_point);
prev_point = to_point;
to_point = next_point;
edge_process.write[next_edge] = true; //mark this edge as processed
current_edge = next_edge;
limit--;
}
//if more than 2 points were added to the polygon, add it to the list of polygons.
if (points.size() > 2) {
PolyPoints pp;
pp.points = points;
r_poly.push_back(pp);
}
}
}
void CSGBrushOperation::_add_poly_outline(const BuildPoly &p_poly, int p_from_point, int p_to_point, const Vector<Vector<int> > &vertex_process, Vector<int> &r_outline) {
//this is the opposite of the function above. It adds polygon outlines instead.
//this is used for triangulating holes.
//no stack is used here because only the bigger outline is interesting.
r_outline.push_back(p_from_point);
int prev_point = p_from_point;
int to_point = p_to_point;
int limit = p_poly.points.size() * 4; //avoid infinite recursion
while (to_point != p_from_point && limit) {
Vector2 segment[2] = { p_poly.points[prev_point].point, p_poly.points[to_point].point };
//again create a transform to compute the angle.
Transform2D t2d;
t2d[0] = (segment[1] - segment[0]).normalized(); //use as Y
t2d[1] = Vector2(-t2d[0].y, t2d[0].x); // use as tangent
t2d[2] = segment[1]; //origin
if (t2d.basis_determinant() == 0)
break; //abort poly
t2d.affine_invert();
float max_angle;
int next_point_angle = -1;
for (int i = 0; i < vertex_process[to_point].size(); i++) {
int edge = vertex_process[to_point][i];
int opposite_point = p_poly.edges[edge].points[0] == to_point ? p_poly.edges[edge].points[1] : p_poly.edges[edge].points[0];
if (opposite_point == prev_point)
continue; //not going back
float angle = -t2d.xform(p_poly.points[opposite_point].point).angle();
if (next_point_angle == -1 || angle > max_angle) { //same as before but use greater to check.
max_angle = angle;
next_point_angle = opposite_point;
}
}
if (next_point_angle == -1) {
//go back because no route found
next_point_angle = prev_point;
}
r_outline.push_back(to_point);
prev_point = to_point;
to_point = next_point_angle;
limit--;
}
}
void CSGBrushOperation::_merge_poly(MeshMerge &mesh, int p_face_idx, const BuildPoly &p_poly, bool p_from_b) {
//finally, merge the 2D polygon back to 3D
Vector<Vector<int> > vertex_process;
Vector<bool> edge_process;
vertex_process.resize(p_poly.points.size());
edge_process.resize(p_poly.edges.size());
//none processed by default
for (int i = 0; i < edge_process.size(); i++) {
edge_process.write[i] = false;
}
//put edges in points, so points can go through them
for (int i = 0; i < p_poly.edges.size(); i++) {
vertex_process.write[p_poly.edges[i].points[0]].push_back(i);
vertex_process.write[p_poly.edges[i].points[1]].push_back(i);
}
Vector<PolyPoints> polys;
//process points that were not processed
for (int i = 0; i < edge_process.size(); i++) {
if (edge_process[i] == true)
continue; //already processed
int intersect_poly = -1;
if (i > 0) {
//this is disconnected, so it's clearly a hole. lets find where it belongs
Vector2 ref_point = p_poly.points[p_poly.edges[i].points[0]].point;
for (int j = 0; j < polys.size(); j++) {
//find a point outside poly
Vector2 out_point(-1e20, -1e20);
const PolyPoints &pp = polys[j];
for (int k = 0; k < pp.points.size(); k++) {
Vector2 p = p_poly.points[pp.points[k]].point;
out_point.x = MAX(out_point.x, p.x);
out_point.y = MAX(out_point.y, p.y);
}
out_point += Vector2(0.12341234, 0.4123412); // move to a random place to avoid direct edge-point chances
int intersections = 0;
for (int k = 0; k < pp.points.size(); k++) {
Vector2 p1 = p_poly.points[pp.points[k]].point;
Vector2 p2 = p_poly.points[pp.points[(k + 1) % pp.points.size()]].point;
if (Geometry::segment_intersects_segment_2d(ref_point, out_point, p1, p2, NULL)) {
intersections++;
}
}
if (intersections % 2 == 1) {
//hole is inside this poly
intersect_poly = j;
break;
}
}
}
if (intersect_poly != -1) {
//must add this as a hole
Vector<int> outline;
_add_poly_outline(p_poly, p_poly.edges[i].points[0], p_poly.edges[i].points[1], vertex_process, outline);
if (outline.size() > 1) {
polys.write[intersect_poly].holes.push_back(outline);
}
}
_add_poly_points(p_poly, i, p_poly.edges[i].points[0], p_poly.edges[i].points[1], vertex_process, edge_process, polys);
}
//get rid of holes, not the most optiomal way, but also not a common case at all to be inoptimal
for (int i = 0; i < polys.size(); i++) {
if (!polys[i].holes.size())
continue;
//repeat until no more holes are left to be merged
while (polys[i].holes.size()) {
//try to merge a hole with the outline
bool added_hole = false;
for (int j = 0; j < polys[i].holes.size(); j++) {
//try hole vertices
int with_outline_vertex = -1;
int from_hole_vertex = -1;
bool found = false;
for (int k = 0; k < polys[i].holes[j].size(); k++) {
int from_idx = polys[i].holes[j][k];
Vector2 from = p_poly.points[from_idx].point;
//try a segment from hole vertex to outline vertices
from_hole_vertex = k;
bool valid = true;
for (int l = 0; l < polys[i].points.size(); l++) {
int to_idx = polys[i].points[l];
Vector2 to = p_poly.points[to_idx].point;
with_outline_vertex = l;
//try against outline (other points) first
valid = true;
for (int m = 0; m < polys[i].points.size(); m++) {
int m_next = (m + 1) % polys[i].points.size();
if (m == with_outline_vertex || m_next == with_outline_vertex) //do not test with edges that share this point
continue;
if (Geometry::segment_intersects_segment_2d(from, to, p_poly.points[polys[i].points[m]].point, p_poly.points[polys[i].points[m_next]].point, NULL)) {
valid = false;
break;
}
}
if (!valid)
continue;
//try against all holes including self
for (int m = 0; m < polys[i].holes.size(); m++) {
for (int n = 0; n < polys[i].holes[m].size(); n++) {
int n_next = (n + 1) % polys[i].holes[m].size();
if (m == j && (n == from_hole_vertex || n_next == from_hole_vertex)) //contains vertex being tested from current hole, skip
continue;
if (Geometry::segment_intersects_segment_2d(from, to, p_poly.points[polys[i].holes[m][n]].point, p_poly.points[polys[i].holes[m][n_next]].point, NULL)) {
valid = false;
break;
}
}
if (!valid)
break;
}
if (valid) //all passed! exit loop
break;
else
continue; //something went wrong, go on.
}
if (valid) {
found = true; //if in the end this was valid, use it
break;
}
}
if (found) {
//hook this hole with outline, and remove from list of holes
//duplicate point
int insert_at = with_outline_vertex;
polys.write[i].points.insert(insert_at, polys[i].points[insert_at]);
insert_at++;
//insert all others, outline should be backwards (must check)
int holesize = polys[i].holes[j].size();
for (int k = 0; k <= holesize; k++) {
int idx = (from_hole_vertex + k) % holesize;
polys.write[i].points.insert(insert_at, polys[i].holes[j][idx]);
insert_at++;
}
added_hole = true;
polys.write[i].holes.remove(j);
break; //got rid of hole, break and continue
}
}
ERR_BREAK(!added_hole);
}
}
//triangulate polygons
for (int i = 0; i < polys.size(); i++) {
Vector<Vector2> vertices;
vertices.resize(polys[i].points.size());
for (int j = 0; j < vertices.size(); j++) {
vertices.write[j] = p_poly.points[polys[i].points[j]].point;
}
Vector<int> indices = Geometry::triangulate_polygon(vertices);
for (int j = 0; j < indices.size(); j += 3) {
//obtain the vertex
Vector3 face[3];
Vector2 uv[3];
float cp = Geometry::vec2_cross(p_poly.points[polys[i].points[indices[j + 0]]].point, p_poly.points[polys[i].points[indices[j + 1]]].point, p_poly.points[polys[i].points[indices[j + 2]]].point);
if (Math::abs(cp) < CMP_EPSILON)
continue;
for (int k = 0; k < 3; k++) {
Vector2 p = p_poly.points[polys[i].points[indices[j + k]]].point;
face[k] = p_poly.to_world.xform(Vector3(p.x, p.y, 0));
uv[k] = p_poly.points[polys[i].points[indices[j + k]]].uv;
}
mesh.add_face(face[0], face[1], face[2], uv[0], uv[1], uv[2], p_poly.smooth, p_poly.invert, p_poly.material, p_from_b);
}
}
}
//use a limit to speed up bvh and limit the depth
#define BVH_LIMIT 8
int CSGBrushOperation::MeshMerge::_create_bvh(BVH *p_bvh, BVH **p_bb, int p_from, int p_size, int p_depth, int &max_depth, int &max_alloc) {
if (p_depth > max_depth) {
max_depth = p_depth;
}
if (p_size <= BVH_LIMIT) {
for (int i = 0; i < p_size - 1; i++) {
p_bb[p_from + i]->next = p_bb[p_from + i + 1] - p_bvh;
}
return p_bb[p_from] - p_bvh;
} else if (p_size == 0) {
return -1;
}
AABB aabb;
aabb = p_bb[p_from]->aabb;
for (int i = 1; i < p_size; i++) {
aabb.merge_with(p_bb[p_from + i]->aabb);
}
int li = aabb.get_longest_axis_index();
switch (li) {
case Vector3::AXIS_X: {
SortArray<BVH *, BVHCmpX> sort_x;
sort_x.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_x.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Y: {
SortArray<BVH *, BVHCmpY> sort_y;
sort_y.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_y.sort(&p_bb[p_from],p_size);
} break;
case Vector3::AXIS_Z: {
SortArray<BVH *, BVHCmpZ> sort_z;
sort_z.nth_element(0, p_size, p_size / 2, &p_bb[p_from]);
//sort_z.sort(&p_bb[p_from],p_size);
} break;
}
int left = _create_bvh(p_bvh, p_bb, p_from, p_size / 2, p_depth + 1, max_depth, max_alloc);
int right = _create_bvh(p_bvh, p_bb, p_from + p_size / 2, p_size - p_size / 2, p_depth + 1, max_depth, max_alloc);
int index = max_alloc++;
BVH *_new = &p_bvh[index];
_new->aabb = aabb;
_new->center = aabb.position + aabb.size * 0.5;
_new->face = -1;
_new->left = left;
_new->right = right;
_new->next = -1;
return index;
}
int CSGBrushOperation::MeshMerge::_bvh_count_intersections(BVH *bvhptr, int p_max_depth, int p_bvh_first, const Vector3 &p_begin, const Vector3 &p_end, int p_exclude) const {
uint32_t *stack = (uint32_t *)alloca(sizeof(int) * p_max_depth);
enum {
TEST_AABB_BIT = 0,
VISIT_LEFT_BIT = 1,
VISIT_RIGHT_BIT = 2,
VISIT_DONE_BIT = 3,
VISITED_BIT_SHIFT = 29,
NODE_IDX_MASK = (1 << VISITED_BIT_SHIFT) - 1,
VISITED_BIT_MASK = ~NODE_IDX_MASK,
};
int intersections = 0;
int level = 0;
const Vector3 *vertexptr = points.ptr();
const Face *facesptr = faces.ptr();
AABB segment_aabb;
segment_aabb.position = p_begin;
segment_aabb.expand_to(p_end);
int pos = p_bvh_first;
stack[0] = pos;
while (true) {
uint32_t node = stack[level] & NODE_IDX_MASK;
const BVH &b = bvhptr[node];
bool done = false;
switch (stack[level] >> VISITED_BIT_SHIFT) {
case TEST_AABB_BIT: {
if (b.face >= 0) {
const BVH *bp = &b;
while (bp) {
bool valid = segment_aabb.intersects(bp->aabb) && bp->aabb.intersects_segment(p_begin, p_end);
if (valid && p_exclude != bp->face) {
const Face &s = facesptr[bp->face];
Face3 f3(vertexptr[s.points[0]], vertexptr[s.points[1]], vertexptr[s.points[2]]);
Vector3 res;
if (f3.intersects_segment(p_begin, p_end, &res)) {
intersections++;
}
}
if (bp->next != -1) {
bp = &bvhptr[bp->next];
} else {
bp = NULL;
}
}
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
bool valid = segment_aabb.intersects(b.aabb) && b.aabb.intersects_segment(p_begin, p_end);
if (!valid) {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
} else {
stack[level] = (VISIT_LEFT_BIT << VISITED_BIT_SHIFT) | node;
}
}
continue;
}
case VISIT_LEFT_BIT: {
stack[level] = (VISIT_RIGHT_BIT << VISITED_BIT_SHIFT) | node;
stack[level + 1] = b.left | TEST_AABB_BIT;
level++;
continue;
}
case VISIT_RIGHT_BIT: {
stack[level] = (VISIT_DONE_BIT << VISITED_BIT_SHIFT) | node;
stack[level + 1] = b.right | TEST_AABB_BIT;
level++;
continue;
}
case VISIT_DONE_BIT: {
if (level == 0) {
done = true;
break;
} else
level--;
continue;
}
}
if (done)
break;
}
return intersections;
}
void CSGBrushOperation::MeshMerge::mark_inside_faces() {
// mark faces that are inside. This helps later do the boolean ops when merging.
// this approach is very brute force (with a bunch of optimizatios, such as BVH and pre AABB intersection test)
AABB aabb;
for (int i = 0; i < points.size(); i++) {
if (i == 0) {
aabb.position = points[i];
} else {
aabb.expand_to(points[i]);
}
}
float max_distance = aabb.size.length() * 1.2;
Vector<BVH> bvhvec;
bvhvec.resize(faces.size() * 3); //will never be larger than this (todo make better)
BVH *bvh = bvhvec.ptrw();
AABB faces_a;
AABB faces_b;
bool first_a = true;
bool first_b = true;
for (int i = 0; i < faces.size(); i++) {
bvh[i].left = -1;
bvh[i].right = -1;
bvh[i].face = i;
bvh[i].aabb.position = points[faces[i].points[0]];
bvh[i].aabb.expand_to(points[faces[i].points[1]]);
bvh[i].aabb.expand_to(points[faces[i].points[2]]);
bvh[i].center = bvh[i].aabb.position + bvh[i].aabb.size * 0.5;
bvh[i].next = -1;
if (faces[i].from_b) {
if (first_b) {
faces_b = bvh[i].aabb;
first_b = false;
} else {
faces_b.merge_with(bvh[i].aabb);
}
} else {
if (first_a) {
faces_a = bvh[i].aabb;
first_a = false;
} else {
faces_a.merge_with(bvh[i].aabb);
}
}
}
AABB intersection_aabb = faces_a.intersection(faces_b);
intersection_aabb.grow_by(intersection_aabb.get_longest_axis_size() * 0.01); //grow a little, avoid numerical error
if (intersection_aabb.size == Vector3()) //AABB do not intersect, so neither do shapes.
return;
Vector<BVH *> bvhtrvec;
bvhtrvec.resize(faces.size());
BVH **bvhptr = bvhtrvec.ptrw();
for (int i = 0; i < faces.size(); i++) {
bvhptr[i] = &bvh[i];
}
int max_depth = 0;
int max_alloc = faces.size();
_create_bvh(bvh, bvhptr, 0, faces.size(), 1, max_depth, max_alloc);
for (int i = 0; i < faces.size(); i++) {
if (!intersection_aabb.intersects(bvh[i].aabb))
continue; //not in AABB intersection, so not in face intersection
Vector3 center = points[faces[i].points[0]];
center += points[faces[i].points[1]];
center += points[faces[i].points[2]];
center /= 3.0;
Plane plane(points[faces[i].points[0]], points[faces[i].points[1]], points[faces[i].points[2]]);
Vector3 target = center + plane.normal * max_distance + Vector3(0.0001234, 0.000512, 0.00013423); //reduce chance of edge hits by doing a small increment
int intersections = _bvh_count_intersections(bvh, max_depth, max_alloc - 1, center, target, i);
if (intersections & 1) {
faces.write[i].inside = true;
}
}
}
void CSGBrushOperation::MeshMerge::add_face(const Vector3 &p_a, const Vector3 &p_b, const Vector3 &p_c, const Vector2 &p_uv_a, const Vector2 &p_uv_b, const Vector2 &p_uv_c, bool p_smooth, bool p_invert, const Ref<Material> &p_material, bool p_from_b) {
Vector3 src_points[3] = { p_a, p_b, p_c };
Vector2 src_uvs[3] = { p_uv_a, p_uv_b, p_uv_c };
int indices[3];
for (int i = 0; i < 3; i++) {
VertexKey vk;
vk.x = int((double(src_points[i].x) + double(vertex_snap) * 0.31234) / double(vertex_snap));
vk.y = int((double(src_points[i].y) + double(vertex_snap) * 0.31234) / double(vertex_snap));
vk.z = int((double(src_points[i].z) + double(vertex_snap) * 0.31234) / double(vertex_snap));
int res;
if (snap_cache.lookup(vk, res)) {
indices[i] = res;
} else {
indices[i] = points.size();
points.push_back(src_points[i]);
snap_cache.set(vk, indices[i]);
}
}
if (indices[0] == indices[2] || indices[0] == indices[1] || indices[1] == indices[2])
return; //not adding degenerate
MeshMerge::Face face;
face.from_b = p_from_b;
face.inside = false;
face.smooth = p_smooth;
face.invert = p_invert;
if (p_material.is_valid()) {
if (!materials.has(p_material)) {
face.material_idx = materials.size();
materials[p_material] = face.material_idx;
} else {
face.material_idx = materials[p_material];
}
} else {
face.material_idx = -1;
}
for (int k = 0; k < 3; k++) {
face.points[k] = indices[k];
face.uvs[k] = src_uvs[k];
;
}
faces.push_back(face);
}
void CSGBrushOperation::merge_brushes(Operation p_operation, const CSGBrush &p_A, const CSGBrush &p_B, CSGBrush &result, float p_snap) {
CallbackData cd;
cd.self = this;
cd.A = &p_A;
cd.B = &p_B;
MeshMerge mesh_merge;
mesh_merge.vertex_snap = p_snap;
//check intersections between faces. Use AABB to speed up precheck
//this generates list of buildpolys and clips them.
//this was originally BVH optimized, but its not really worth it.
for (int i = 0; i < p_A.faces.size(); i++) {
cd.face_a = i;
for (int j = 0; j < p_B.faces.size(); j++) {
if (p_A.faces[i].aabb.intersects(p_B.faces[j].aabb)) {
_collision_callback(&p_A, i, cd.build_polys_A, &p_B, j, cd.build_polys_B, mesh_merge);
}
}
}
//merge the already cliped polys back to 3D
for (Map<int, BuildPoly>::Element *E = cd.build_polys_A.front(); E; E = E->next()) {
_merge_poly(mesh_merge, E->key(), E->get(), false);
}
for (Map<int, BuildPoly>::Element *E = cd.build_polys_B.front(); E; E = E->next()) {
_merge_poly(mesh_merge, E->key(), E->get(), true);
}
//merge the non clipped faces back
for (int i = 0; i < p_A.faces.size(); i++) {
if (cd.build_polys_A.has(i))
continue; //made from buildpoly, skipping
Vector3 points[3];
Vector2 uvs[3];
for (int j = 0; j < 3; j++) {
points[j] = p_A.faces[i].vertices[j];
uvs[j] = p_A.faces[i].uvs[j];
}
Ref<Material> material;
if (p_A.faces[i].material != -1) {
material = p_A.materials[p_A.faces[i].material];
}
mesh_merge.add_face(points[0], points[1], points[2], uvs[0], uvs[1], uvs[2], p_A.faces[i].smooth, p_A.faces[i].invert, material, false);
}
for (int i = 0; i < p_B.faces.size(); i++) {
if (cd.build_polys_B.has(i))
continue; //made from buildpoly, skipping
Vector3 points[3];
Vector2 uvs[3];
for (int j = 0; j < 3; j++) {
points[j] = p_B.faces[i].vertices[j];
uvs[j] = p_B.faces[i].uvs[j];
}
Ref<Material> material;
if (p_B.faces[i].material != -1) {
material = p_B.materials[p_B.faces[i].material];
}
mesh_merge.add_face(points[0], points[1], points[2], uvs[0], uvs[1], uvs[2], p_B.faces[i].smooth, p_B.faces[i].invert, material, true);
}
//mark faces that ended up inside the intersection
mesh_merge.mark_inside_faces();
//regen new brush to start filling it again
result.clear();
switch (p_operation) {
case OPERATION_UNION: {
int outside_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (mesh_merge.faces[i].inside)
continue;
outside_count++;
}
result.faces.resize(outside_count);
outside_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (mesh_merge.faces[i].inside)
continue;
for (int j = 0; j < 3; j++) {
result.faces.write[outside_count].vertices[j] = mesh_merge.points[mesh_merge.faces[i].points[j]];
result.faces.write[outside_count].uvs[j] = mesh_merge.faces[i].uvs[j];
}
result.faces.write[outside_count].smooth = mesh_merge.faces[i].smooth;
result.faces.write[outside_count].invert = mesh_merge.faces[i].invert;
result.faces.write[outside_count].material = mesh_merge.faces[i].material_idx;
outside_count++;
}
result._regen_face_aabbs();
} break;
case OPERATION_INTERSECTION: {
int inside_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (!mesh_merge.faces[i].inside)
continue;
inside_count++;
}
result.faces.resize(inside_count);
inside_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (!mesh_merge.faces[i].inside)
continue;
for (int j = 0; j < 3; j++) {
result.faces.write[inside_count].vertices[j] = mesh_merge.points[mesh_merge.faces[i].points[j]];
result.faces.write[inside_count].uvs[j] = mesh_merge.faces[i].uvs[j];
}
result.faces.write[inside_count].smooth = mesh_merge.faces[i].smooth;
result.faces.write[inside_count].invert = mesh_merge.faces[i].invert;
result.faces.write[inside_count].material = mesh_merge.faces[i].material_idx;
inside_count++;
}
result._regen_face_aabbs();
} break;
case OPERATION_SUBSTRACTION: {
int face_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (mesh_merge.faces[i].from_b && !mesh_merge.faces[i].inside)
continue;
if (!mesh_merge.faces[i].from_b && mesh_merge.faces[i].inside)
continue;
face_count++;
}
result.faces.resize(face_count);
face_count = 0;
for (int i = 0; i < mesh_merge.faces.size(); i++) {
if (mesh_merge.faces[i].from_b && !mesh_merge.faces[i].inside)
continue;
if (!mesh_merge.faces[i].from_b && mesh_merge.faces[i].inside)
continue;
for (int j = 0; j < 3; j++) {
result.faces.write[face_count].vertices[j] = mesh_merge.points[mesh_merge.faces[i].points[j]];
result.faces.write[face_count].uvs[j] = mesh_merge.faces[i].uvs[j];
}
if (mesh_merge.faces[i].from_b) {
//invert facing of insides of B
SWAP(result.faces.write[face_count].vertices[1], result.faces.write[face_count].vertices[2]);
SWAP(result.faces.write[face_count].uvs[1], result.faces.write[face_count].uvs[2]);
}
result.faces.write[face_count].smooth = mesh_merge.faces[i].smooth;
result.faces.write[face_count].invert = mesh_merge.faces[i].invert;
result.faces.write[face_count].material = mesh_merge.faces[i].material_idx;
face_count++;
}
result._regen_face_aabbs();
} break;
}
//updatelist of materials
result.materials.resize(mesh_merge.materials.size());
for (const Map<Ref<Material>, int>::Element *E = mesh_merge.materials.front(); E; E = E->next()) {
result.materials.write[E->get()] = E->key();
}
}