Back to opengl's tesselator for triangulation. I'll spend more time
writing mine later. [git-p4: depot-paths = "//depot/solvespace/": change = 1810]
This commit is contained in:
Jonathan Westhues
parent
9b008ad1cd
commit
a47a77c37c
2
dsc.h
2
dsc.h
@ -45,8 +45,6 @@ public:
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static Vector From(hParam x, hParam y, hParam z);
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static Vector AtIntersectionOfPlanes(Vector n1, double d1,
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Vector n2, double d2);
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static bool LinesIntersect(Vector a0, Vector da, Vector b0, Vector db,
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double *ta, double *tb);
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bool Equals(Vector v);
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Vector Plus(Vector b);
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268
polygon.cpp
268
polygon.cpp
@ -314,246 +314,62 @@ bool SPolygon::AllPointsInPlane(Vector *notCoplanarAt) {
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return true;
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}
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bool SPolygon::IntersectsPolygon(Vector ga, Vector gb) {
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int i, j;
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for(i = 0; i < l.n; i++) {
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SContour *sc = &(l.elem[i]);
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for(j = 0; j < sc->l.n; j++) {
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Vector pa = sc->l.elem[j].p,
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pb = sc->l.elem[WRAP(j+1, (sc->l.n - 1))].p;
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// So do the lines from (ga to gb) and (pa to pb) intersect?
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Vector dp = pb.Minus(pa), dg = gb.Minus(ga);
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double tp, tg;
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if(!Vector::LinesIntersect(pa, dp, ga, dg, &tp, &tg)) {
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continue;
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}
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// So check if the line segments intersect
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double lp = dp.Magnitude(), lg = dg.Magnitude();
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tp *= lp;
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tg *= lg;
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if(tg > LENGTH_EPS && tg < (lg - LENGTH_EPS) &&
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tp > LENGTH_EPS && tp < (lp - LENGTH_EPS))
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static int TriMode, TriVertexCount;
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static Vector Tri1, TriNMinus1, TriNMinus2;
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static Vector TriNormal;
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static SMesh *TriMesh;
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static STriMeta TriMeta;
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static void GLX_CALLBACK TriBegin(int mode)
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{
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return true;
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TriMode = mode;
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TriVertexCount = 0;
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}
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}
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}
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return false;
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}
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bool SPolygon::VisibleVertices(SContour *outer, SContour *inner,
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SEdgeList *extras, int *vo, int *vi)
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static void GLX_CALLBACK TriEnd(void)
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{
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int i, j, k;
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double lmin = 1e12;
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for(i = 0; i < outer->l.n; i++) {
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Vector op = outer->l.elem[i].p;
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for(j = 0; j < inner->l.n; j++) {
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Vector ip = inner->l.elem[j].p;
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if(IntersectsPolygon(op, ip)) goto dontuse;
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for(k = 0; k < extras->l.n; k++) {
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SEdge *se = &(extras->l.elem[k]);
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if(ip.Equals(se->a) || ip.Equals(se->b) ||
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op.Equals(se->a) || op.Equals(se->b))
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}
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static void GLX_CALLBACK TriVertex(Vector *triN)
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{
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goto dontuse;
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if(TriVertexCount == 0) {
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Tri1 = *triN;
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}
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if(TriMode == GL_TRIANGLES) {
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if((TriVertexCount % 3) == 2) {
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TriMesh->AddTriangle(
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TriMeta, TriNormal, TriNMinus2, TriNMinus1, *triN);
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}
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} else if(TriMode == GL_TRIANGLE_FAN) {
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if(TriVertexCount >= 2) {
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TriMesh->AddTriangle(
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TriMeta, TriNormal, Tri1, TriNMinus1, *triN);
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}
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} else if(TriMode == GL_TRIANGLE_STRIP) {
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if(TriVertexCount >= 2) {
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TriMesh->AddTriangle(
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TriMeta, TriNormal, TriNMinus2, TriNMinus1, *triN);
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}
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} else oops();
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Vector dt = ip.Minus(op), de = (se->b).Minus(se->a);
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double te, tt;
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if(!Vector::LinesIntersect(op, dt, se->a, de, &tt, &te))
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continue;
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double le = de.Magnitude(), lt = dt.Magnitude();
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tt *= lt;
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te *= le;
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if(tt > LENGTH_EPS && tt < (lt - LENGTH_EPS) &&
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te > LENGTH_EPS && te < (le - LENGTH_EPS))
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{
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goto dontuse;
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TriNMinus2 = TriNMinus1;
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TriNMinus1 = *triN;
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TriVertexCount++;
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}
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}
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if((op.Minus(ip)).Magnitude() < lmin) {
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lmin = (op.Minus(ip)).Magnitude();
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*vo = i;
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*vi = j;
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}
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dontuse:;
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}
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}
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if(lmin < 1e12) {
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return true;
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} else {
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return false;
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}
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}
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bool SContour::VertexIsEar(int v, Vector normal) {
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int va = WRAP(v-1, l.n), vb = WRAP(v , l.n), vc = WRAP(v+1, l.n);
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Vector a = l.elem[va].p, b = l.elem[vb].p, c = l.elem[vc].p;
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STriMeta meta;
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ZERO(&meta);
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STriangle tr = STriangle::From(meta, a, b, c);
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if(normal.Dot(tr.Normal()) > 0) return false;
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int i;
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for(i = 0; i < l.n; i++) {
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if(i == va) continue;
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if(i == vb) continue;
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if(i == vc) continue;
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Vector p = l.elem[i].p;
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if(p.Equals(tr.a)) continue;
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if(p.Equals(tr.b)) continue;
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if(p.Equals(tr.c)) continue;
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if(tr.ContainsPoint(p)) return false;
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}
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return true;
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}
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void SContour::TriangulateInto(SMesh *m, STriMeta meta, Vector normal) {
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int i;
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bool odd = false;
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while(l.n >= 3) {
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int start, end, incr;
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if(odd) {
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start = 0; end = l.n; incr = 1;
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} else {
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start = l.n - 1; end = -1; incr = -1;
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}
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for(i = start; i != end; i += incr) {
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if(VertexIsEar(i, normal)) {
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break;
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}
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}
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if(i == end) {
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dbp("couldn't find ear!");
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return;
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}
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Vector a = l.elem[WRAP(i-1, l.n)].p,
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b = l.elem[WRAP(i , l.n)].p,
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c = l.elem[WRAP(i+1, l.n)].p;
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m->AddTriangle(meta, c, b, a);
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l.ClearTags();
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l.elem[i].tag = 1;
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l.RemoveTagged();
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odd = !odd;
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}
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l.Clear();
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}
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void SPolygon::TriangulateInto(SMesh *m) {
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STriMeta meta;
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ZERO(&meta);
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TriangulateInto(m, meta);
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}
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void SPolygon::TriangulateInto(SMesh *m, STriMeta meta) {
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FixContourDirections();
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TriMesh = m;
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TriNormal = normal;
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TriMeta = meta;
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int i, j, k;
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bool *used = (bool *)AllocTemporary(l.n*sizeof(bool));
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int *winding = (int *)AllocTemporary(l.n*sizeof(int));
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bool **contained = (bool **)AllocTemporary(l.n*sizeof(bool *));
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for(i = 0; i < l.n; i++) {
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contained[i] = (bool *)AllocTemporary(l.n*sizeof(bool));
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GLUtesselator *gt = gluNewTess();
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gluTessCallback(gt, GLU_TESS_BEGIN, (glxCallbackFptr *)TriBegin);
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gluTessCallback(gt, GLU_TESS_END, (glxCallbackFptr *)TriEnd);
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gluTessCallback(gt, GLU_TESS_VERTEX, (glxCallbackFptr *)TriVertex);
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SContour *sci = &(l.elem[i]);
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if(sci->l.n < 1) continue;
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for(j = 0; j < l.n; j++) {
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SContour *scj = &(l.elem[j]);
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if(scj->l.n < 1) continue;
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if(i == j) {
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contained[i][j] = true;
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continue;
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}
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if(scj->ContainsPointProjdToNormal(normal, sci->l.elem[0].p)) {
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(winding[i])++;
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contained[i][j] = true;
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}
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}
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}
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for(;;) {
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for(i = 0; i < l.n; i++) {
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if(winding[i] == 0) break;
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}
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if(i >= l.n) {
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// No outer contours left, so we're done
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break;
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}
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SContour *outer = &(l.elem[i]);
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SContour merged;
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ZERO(&merged);
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SEdgeList extras;
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ZERO(&extras);
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for(j = 0; j < outer->l.n - 1; j++) {
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merged.AddPoint(outer->l.elem[j].p);
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}
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// If this polygon has holes, then we must merge them in.
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for(;;) {
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for(j = 0; j < l.n; j++) {
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if(used[j]) continue;
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if(winding[j] != winding[i] + 1) continue;
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if(!contained[j][i]) continue;
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SContour *inner = &(l.elem[j]);
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int vinner, vouter;
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if(VisibleVertices(&merged, inner, &extras, &vouter, &vinner)) {
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used[j] = true;
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SEdge se =
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{ 0, merged.l.elem[vouter].p, inner->l.elem[vinner].p };
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extras.l.Add(&se);
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SContour alt;
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ZERO(&alt);
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for(k = 0; k <= vouter; k++) {
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alt.AddPoint(merged.l.elem[k].p);
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}
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for(k = 0; k <= inner->l.n - 1; k++) {
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int v = WRAP(k + vinner, inner->l.n - 1);
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alt.AddPoint(inner->l.elem[v].p);
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}
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for(k = vouter; k < merged.l.n; k++) {
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alt.AddPoint(merged.l.elem[k].p);
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}
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merged.l.Clear();
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merged = alt;
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break;
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}
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}
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if(j >= l.n) {
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break;
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}
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}
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merged.TriangulateInto(m, meta, normal);
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merged.l.Clear();
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extras.Clear();
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for(j = 0; j < l.n; j++) {
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if(contained[j][i]) winding[j] -= 2;
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}
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used[i] = true;
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}
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glxTesselatePolygon(gt, this);
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gluDeleteTess(gt);
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}
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16
polygon.h
16
polygon.h
@ -78,20 +78,12 @@ public:
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Vector p;
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};
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typedef struct {
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DWORD face;
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int color;
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} STriMeta;
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class SContour {
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public:
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int tag;
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SList<SPoint> l;
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void AddPoint(Vector p);
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void MakeEdgesInto(SEdgeList *el);
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bool VertexIsEar(int v, Vector normal);
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void TriangulateInto(SMesh *m, STriMeta meta, Vector normal);
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void Reverse(void);
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Vector ComputeNormal(void);
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bool IsClockwiseProjdToNormal(Vector n);
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@ -99,6 +91,11 @@ public:
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bool AllPointsInPlane(Vector n, double d, Vector *notCoplanarAt);
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};
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typedef struct {
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DWORD face;
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int color;
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} STriMeta;
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class SPolygon {
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public:
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SList<SContour> l;
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@ -115,9 +112,6 @@ public:
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void Clear(void);
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bool AllPointsInPlane(Vector *notCoplanarAt);
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bool IsEmpty(void);
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bool IntersectsPolygon(Vector a, Vector b);
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bool VisibleVertices(SContour *outer, SContour *inner,
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SEdgeList *extras, int *vo, int *vi);
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Vector AnyPoint(void);
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};
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15
util.cpp
15
util.cpp
@ -500,21 +500,6 @@ Vector Vector::AtIntersectionOfPlanes(Vector n1, double d1,
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return (n1.ScaledBy(c1)).Plus(n2.ScaledBy(c2));
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}
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bool Vector::LinesIntersect(Vector a0, Vector da, Vector b0, Vector db,
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double *ta, double *tb)
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{
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Vector dn = da.Cross(db); // normal to both
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if(dn.Magnitude() < 1e-10) return false;
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Vector dna = dn.Cross(da); // normal to dp
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Vector dnb = dn.Cross(db); // normal to dg
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*tb = ((a0.Minus(b0)).Dot(dna))/(db.Dot(dna));
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*ta = -((a0.Minus(b0)).Dot(dnb))/(da.Dot(dnb));
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return true;
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}
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Point2d Point2d::Plus(Point2d b) {
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Point2d r;
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r.x = x + b.x;
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