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fix triangulation of complex polygons:

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find coordinates inside hole non-convex holes
This commit is contained in:
Hannes Janetzek 2013-01-04 19:49:51 +01:00
parent 3484110e08
commit 45b19d6a91
1 changed files with 54 additions and 35 deletions
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61
jni/TriangleJni.c
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@ -3,6 +3,7 @@
#include <string.h> #include <string.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <math.h>
#include "triangle.h" #include "triangle.h"
static void mylog(const char *msg) static void mylog(const char *msg)
@ -51,8 +52,8 @@ jint Java_org_quake_triangle_TriangleJNI_triangulate(JNIEnv *env, jclass c,
rings = (int*) malloc(num_rings * sizeof(int)); rings = (int*) malloc(num_rings * sizeof(int));
} }
int n = 0; int seg = 0;
int h = 0; int hole = 0;
int ring; int ring;
int point; int point;
@ -65,32 +66,50 @@ jint Java_org_quake_triangle_TriangleJNI_triangulate(JNIEnv *env, jclass c,
if (rings) if (rings)
rings[ring] = num_points; rings[ring] = num_points;
// add holes, fixme: works only for convex // add holes: we need a point inside the hole...
// if ring is clockwise one could take the center of // this is just a heuristic, assuming that two
// the first 'triangle' of a convex arc? // 'parallel' lines have a distance of at least
// 1 unit.
if (ring > 0) if (ring > 0)
{ {
int k; int k = point * 2;
float cx = 0;
float cy = 0;
for (k = point, len = k + num_points; k < len; k++) float cx = in.pointlist[k+0];
{ float cy = in.pointlist[k+1];
cx += in.pointlist[k*2];
cy += in.pointlist[k*2+1];
}
in.holelist[h++] = cx / num_points; float nx = in.pointlist[k+2];
in.holelist[h++] = cy / num_points; float ny = in.pointlist[k+3];
float vx = nx - cx;
float vy = ny - cy;
float a = sqrt(vx*vx + vy*vy);
// fixme: need to check a == 0?
//if (a > 0.00001 || a < -0.0001)
float ux = -vy / a;
float uy = vx / a;
float centerx = cx + vx / 2 - ux;
float centery = cy + vy / 2 - uy;
snprintf(buf, 128, "a: %f in:(%.2f %.2f) "
"cur:(%.2f %.2f), next:(%.2f %.2f)\n",
a, centerx, centery, cx, cy, nx,ny);
mylog(buf);
in.holelist[hole++] = centerx;
in.holelist[hole++] = centery;
} }
in.segmentlist[n++] = point + (num_points - 1); in.segmentlist[seg++] = point + (num_points - 1);
in.segmentlist[n++] = point; in.segmentlist[seg++] = point;
for (len = point + num_points - 1; point < len; point++) for (len = point + num_points - 1; point < len; point++)
{ {
in.segmentlist[n++] = point; in.segmentlist[seg++] = point;
in.segmentlist[n++] = point + 1; in.segmentlist[seg++] = point + 1;
} }
} }
#ifdef TESTING #ifdef TESTING
@ -132,9 +151,10 @@ jint Java_org_quake_triangle_TriangleJNI_triangulate(JNIEnv *env, jclass c,
} }
#endif #endif
// ----------- fix addresses to vertex buffer indices ------------- // ----------- fix offset to vertex buffer indices -------------
// scale to stride // scale to stride
short stride = 2; short stride = 2;
int n, m;
for (i = 0, n = out.numberoftriangles * 3; i < n; i++) for (i = 0, n = out.numberoftriangles * 3; i < n; i++)
out.trianglelist[i] *= stride; out.trianglelist[i] *= stride;
@ -150,7 +170,6 @@ jint Java_org_quake_triangle_TriangleJNI_triangulate(JNIEnv *env, jclass c,
short off = offset; short off = offset;
int add = 0; int add = 0;
int start = 0; int start = 0;
int m;
for (j = 0, m = in.numberofholes; j < m; j++) for (j = 0, m = in.numberofholes; j < m; j++)
{ {