134 lines
4.2 KiB
C++
134 lines
4.2 KiB
C++
#include "b2d_decompose.h"
|
|
#include "b2Polygon.h"
|
|
|
|
namespace b2ConvexDecomp {
|
|
|
|
|
|
void add_to_res(Vector< Vector<Vector2> >& res,const b2Polygon& p_poly) {
|
|
|
|
Vector<Vector2> arr;
|
|
for(int i=0;i<p_poly.nVertices;i++) {
|
|
|
|
arr.push_back(Vector2(p_poly.x[i],p_poly.y[i]));
|
|
}
|
|
|
|
res.push_back(arr);
|
|
|
|
}
|
|
|
|
static Vector< Vector<Vector2> > _b2d_decompose(const Vector<Vector2>& p_polygon) {
|
|
|
|
|
|
Vector< Vector<Vector2> > res;
|
|
if (p_polygon.size()<3)
|
|
return res;
|
|
|
|
b2Vec2 *polys = memnew_arr(b2Vec2,p_polygon.size());
|
|
for(int i=0;i<p_polygon.size();i++)
|
|
polys[i]=b2Vec2(p_polygon[i].x,p_polygon[i].y);
|
|
|
|
|
|
b2Polygon *p = new b2Polygon(polys,p_polygon.size());
|
|
b2Polygon* decomposed = new b2Polygon[p->nVertices - 2]; //maximum number of polys
|
|
|
|
memdelete_arr(polys);
|
|
|
|
int32 nPolys = DecomposeConvex(p, decomposed, p->nVertices - 2);
|
|
//int32 extra = 0;
|
|
for (int32 i = 0; i < nPolys; ++i) {
|
|
// b2FixtureDef* toAdd = &pdarray[i+extra];
|
|
// *toAdd = *prototype;
|
|
//Hmm, shouldn't have to do all this...
|
|
b2Polygon curr = decomposed[i];
|
|
//TODO ewjordan: move this triangle handling to a better place so that
|
|
//it happens even if this convenience function is not called.
|
|
if (curr.nVertices == 3){
|
|
//Check here for near-parallel edges, since we can't
|
|
//handle this in merge routine
|
|
for (int j=0; j<3; ++j){
|
|
int32 lower = (j == 0) ? (curr.nVertices - 1) : (j - 1);
|
|
int32 middle = j;
|
|
int32 upper = (j == curr.nVertices - 1) ? (0) : (j + 1);
|
|
float32 dx0 = curr.x[middle] - curr.x[lower]; float32 dy0 = curr.y[middle] - curr.y[lower];
|
|
float32 dx1 = curr.x[upper] - curr.x[middle]; float32 dy1 = curr.y[upper] - curr.y[middle];
|
|
float32 norm0 = sqrtf(dx0*dx0+dy0*dy0); float32 norm1 = sqrtf(dx1*dx1+dy1*dy1);
|
|
if ( !(norm0 > 0.0f && norm1 > 0.0f) ) {
|
|
//Identical points, don't do anything!
|
|
goto Skip;
|
|
}
|
|
dx0 /= norm0; dy0 /= norm0;
|
|
dx1 /= norm1; dy1 /= norm1;
|
|
float32 cross = dx0 * dy1 - dx1 * dy0;
|
|
float32 dot = dx0*dx1 + dy0*dy1;
|
|
if (fabs(cross) < b2_angularSlop && dot > 0) {
|
|
//Angle too close, split the triangle across from this point.
|
|
//This is guaranteed to result in two triangles that satify
|
|
//the tolerance (one of the angles is 90 degrees)
|
|
float32 dx2 = curr.x[lower] - curr.x[upper]; float32 dy2 = curr.y[lower] - curr.y[upper];
|
|
float32 norm2 = sqrtf(dx2*dx2+dy2*dy2);
|
|
if (norm2 == 0.0f) {
|
|
goto Skip;
|
|
}
|
|
dx2 /= norm2; dy2 /= norm2;
|
|
float32 thisArea = curr.GetArea();
|
|
float32 thisHeight = 2.0f * thisArea / norm2;
|
|
float32 buffer2 = dx2;
|
|
dx2 = dy2; dy2 = -buffer2;
|
|
//Make two new polygons
|
|
//printf("dx2: %f, dy2: %f, thisHeight: %f, middle: %d\n",dx2,dy2,thisHeight,middle);
|
|
float32 newX1[3] = { curr.x[middle]+dx2*thisHeight, curr.x[lower], curr.x[middle] };
|
|
float32 newY1[3] = { curr.y[middle]+dy2*thisHeight, curr.y[lower], curr.y[middle] };
|
|
float32 newX2[3] = { newX1[0], curr.x[middle], curr.x[upper] };
|
|
float32 newY2[3] = { newY1[0], curr.y[middle], curr.y[upper] };
|
|
b2Polygon p1(newX1,newY1,3);
|
|
b2Polygon p2(newX2,newY2,3);
|
|
if (p1.IsUsable()){
|
|
add_to_res(res,p1);
|
|
//++extra;
|
|
} else if (B2_POLYGON_REPORT_ERRORS){
|
|
printf("Didn't add unusable polygon. Dumping vertices:\n");
|
|
p1.print();
|
|
}
|
|
if (p2.IsUsable()){
|
|
add_to_res(res,p2);
|
|
|
|
//p2.AddTo(pdarray[i+extra]);
|
|
|
|
//bd->CreateFixture(toAdd);
|
|
} else if (B2_POLYGON_REPORT_ERRORS){
|
|
printf("Didn't add unusable polygon. Dumping vertices:\n");
|
|
p2.print();
|
|
}
|
|
goto Skip;
|
|
}
|
|
}
|
|
|
|
}
|
|
if (decomposed[i].IsUsable()){
|
|
add_to_res(res,decomposed[i]);
|
|
|
|
//decomposed[i].AddTo(*toAdd);
|
|
//bd->CreateFixture((const b2FixtureDef*)toAdd);
|
|
} else if (B2_POLYGON_REPORT_ERRORS){
|
|
printf("Didn't add unusable polygon. Dumping vertices:\n");
|
|
decomposed[i].print();
|
|
}
|
|
Skip:
|
|
;
|
|
}
|
|
// delete[] pdarray;
|
|
delete[] decomposed;
|
|
delete p;
|
|
return res;// pdarray; //needs to be deleted after body is created
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
Vector< Vector<Vector2> > b2d_decompose(const Vector<Vector2>& p_polygon) {
|
|
|
|
return b2ConvexDecomp::_b2d_decompose(p_polygon);
|
|
|
|
|
|
}
|