organicmaps/libtess2
13
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity Actions

Merge branch 'pr/7'

Browse source
This commit is contained in:
Mikko Mononen 2018-04-16 09:57:43 +03:00
commit 344b315726
9 changed files with 358 additions and 68 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

81
Example/example.c
View file

@ -56,6 +56,7 @@ void poolFree( void* userData, void* ptr )
int run = 1;
int cdt = 0;
static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
{
@ -65,6 +66,8 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
glfwSetWindowShouldClose(window, GL_TRUE);
if (key == GLFW_KEY_SPACE && action == GLFW_PRESS)
run = !run;
if (key == GLFW_KEY_C && action == GLFW_PRESS)
cdt = !cdt;
}
int main(int argc, char *argv[])
@ -79,14 +82,15 @@ int main(int argc, char *argv[])
float t = 0.0f, pt = 0.0f;
TESSalloc ma;
TESStesselator* tess = 0;
const int nvp = 6;
const int nvp = 3;
unsigned char* vflags = 0;
int nvflags = 0;
#ifdef USE_POOL
struct MemPool pool;
unsigned char mem[1024*1024];
int nvflags = 0;
#else
int allocated = 0;
double t0 = 0, t1 = 0;
#endif
TESS_NOTUSED(argc);
TESS_NOTUSED(argv);
@ -104,7 +108,7 @@ int main(int argc, char *argv[])
if (!fg) return -1;
printf("go...\n");
// Flip y
for (it = bg; it != NULL; it = it->next)
for (i = 0; i < it->npts; ++i)
@ -138,7 +142,7 @@ int main(int argc, char *argv[])
it->pts[i*2+1] -= cy;
}
}
// Find BG bounds.
bounds[0] = bounds[2] = bg->pts[0];
bounds[1] = bounds[3] = bg->pts[1];
@ -154,7 +158,7 @@ int main(int argc, char *argv[])
if (y > bounds[3]) bounds[3] = y;
}
}
#ifdef USE_POOL
pool.size = 0;
@ -168,6 +172,8 @@ int main(int argc, char *argv[])
#else
t0 = glfwGetTime();
memset(&ma, 0, sizeof(ma));
ma.memalloc = stdAlloc;
ma.memfree = stdFree;
@ -178,6 +184,8 @@ int main(int argc, char *argv[])
if (!tess)
return -1;
tessSetOption(tess, TESS_CONSTRAINED_DELAUNAY_TRIANGULATION, 1);
// Offset the foreground shape to center of the bg.
offx = (bounds[2]+bounds[0])/2;
offy = (bounds[3]+bounds[1])/2;
@ -189,7 +197,7 @@ int main(int argc, char *argv[])
it->pts[i*2+1] += offy;
}
}
// Add contours.
for (it = bg; it != NULL; it = it->next)
tessAddContour(tess, 2, it->pts, sizeof(float)*2, it->npts);
@ -197,10 +205,14 @@ int main(int argc, char *argv[])
tessAddContour(tess, 2, it->pts, sizeof(float)*2, it->npts);
if (!tessTesselate(tess, TESS_WINDING_POSITIVE, TESS_POLYGONS, nvp, 2, 0))
return -1;
t1 = glfwGetTime();
printf("Time: %.3f ms\n", (t1 - t0) * 1000.0f);
printf("Memory used: %.1f kB\n", allocated/1024.0f);
#endif
mode = glfwGetVideoMode(glfwGetPrimaryMonitor());
width = mode->width - 40;
height = mode->height - 80;
@ -221,17 +233,27 @@ int main(int argc, char *argv[])
view[2] = cx + w*1.2f;
view[1] = cy - w*1.2f*(float)height/(float)width;
view[3] = cy + w*1.2f*(float)height/(float)width;
glfwSetTime(0);
while (!glfwWindowShouldClose(window))
{
float ct = (float)glfwGetTime();
int winWidth, winHeight;
int fbWidth, fbHeight;
float pxr, ct;
glfwGetWindowSize(window, &winWidth, &winHeight);
glfwGetFramebufferSize(window, &fbWidth, &fbHeight);
// Calculate pixel ration for hi-dpi devices.
pxr = (float)fbWidth / (float)winWidth;
ct = (float)glfwGetTime();
if (run) t += ct - pt;
pt = ct;
// Update and render
glViewport(0, 0, width, height);
glViewport(0, 0, fbWidth, fbHeight);
glClearColor(0.3f, 0.3f, 0.32f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glEnable(GL_BLEND);
@ -251,9 +273,11 @@ int main(int argc, char *argv[])
tess = tessNewTess(&ma);
if (tess)
{
tessSetOption(tess, TESS_CONSTRAINED_DELAUNAY_TRIANGULATION, cdt);
offx = (view[2]+view[0])/2 + sinf(t) * (view[2]-view[0])/2;
offy = (view[3]+view[1])/2 + cosf(t*3.13f) * (view[3]-view[1])/6;
for (it = fg; it != NULL; it = it->next)
{
for (i = 0; i < it->npts; ++i)
@ -293,7 +317,7 @@ int main(int argc, char *argv[])
nvflags = nverts;
vflags = (unsigned char*)malloc(sizeof(unsigned char)*nvflags);
}
if (vflags)
{
// Vertex indices describe the order the indices were added and can be used
@ -303,7 +327,7 @@ int main(int argc, char *argv[])
for (i = 0; i < nverts; ++i)
vflags[i] = vinds[i] == TESS_UNDEF ? 1 : 0;
}
for (i = 0; i < nelems; ++i)
{
int b = elems[i*2];
@ -314,9 +338,9 @@ int main(int argc, char *argv[])
tess = 0;
}
else
tess = 0;
tess = 0;
}
#endif
#endif
// Draw tesselated pieces.
if (tess)
@ -326,7 +350,7 @@ int main(int argc, char *argv[])
const int* elems = tessGetElements(tess);
const int nverts = tessGetVertexCount(tess);
const int nelems = tessGetElementCount(tess);
// Draw polygons.
glColor4ub(255,255,255,128);
for (i = 0; i < nelems; ++i)
@ -337,7 +361,10 @@ int main(int argc, char *argv[])
glVertex2f(verts[p[j]*2], verts[p[j]*2+1]);
glEnd();
}
glLineWidth(1.0f * pxr);
glPointSize(3.0f * pxr);
glColor4ub(0,0,0,16);
for (i = 0; i < nelems; ++i)
{
@ -347,9 +374,8 @@ int main(int argc, char *argv[])
glVertex2f(verts[p[j]*2], verts[p[j]*2+1]);
glEnd();
}
glColor4ub(0,0,0,128);
glPointSize(3.0f);
glBegin(GL_POINTS);
for (i = 0; i < nverts; ++i)
{
@ -360,21 +386,22 @@ int main(int argc, char *argv[])
glVertex2f(verts[i*2], verts[i*2+1]);
}
glEnd();
glPointSize(1.0f);
}
glEnable(GL_DEPTH_TEST);
glfwSwapBuffers(window);
glfwPollEvents();
}
if (tess) tessDeleteTess(tess);
if (vflags)
free(vflags);
svgDelete(bg);
svgDelete(fg);
svgDelete(bg);
svgDelete(fg);
glfwTerminate();
return 0;

32
Include/tesselator.h
View file

@ -1,5 +1,5 @@
/*
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
** All Rights Reserved.
**
@ -9,10 +9,10 @@
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
** of the Software, and to permit persons to whom the Software is furnished to do so,
** subject to the following conditions:
**
**
** The above copyright notice including the dates of first publication and either this
** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
** included in all copies or substantial portions of the Software.
** 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
@ -20,7 +20,7 @@
** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
** OR OTHER DEALINGS IN THE SOFTWARE.
**
**
** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
** be used in advertising or otherwise to promote the sale, use or other dealings in
** this Software without prior written authorization from Silicon Graphics, Inc.
@ -106,7 +106,7 @@ enum TessWindingRule
// }
// glEnd();
// }
//
enum TessElementType
{
TESS_POLYGONS,
@ -114,6 +114,16 @@ enum TessElementType
TESS_BOUNDARY_CONTOURS,
};
// TESS_CONSTRAINED_DELAUNAY_TRIANGULATION
// If enabled, the initial triagulation is improved with non-robust Constrained Delayney triangulation.
// Disable by default.
enum TessOption
{
TESS_CONSTRAINED_DELAUNAY_TRIANGULATION,
};
typedef float TESSreal;
typedef int TESSindex;
typedef struct TESStesselator TESStesselator;
@ -133,12 +143,12 @@ typedef struct TESSalloc TESSalloc;
// how often to allocate memory from the system versus how much extra space the system
// should allocate. Reasonable defaults are show in commects below, they will be used if
// the bucket sizes are zero.
//
//
// The use may left the memrealloc to be null. In that case, the tesselator will not try to
// dynamically grow int's internal arrays. The tesselator only needs the reallocation when it
// has found intersecting segments and needs to add new vertex. This defency can be cured by
// allocating some extra vertices beforehand. The 'extraVertices' variable allows to specify
// number of expected extra vertices.
// number of expected extra vertices.
struct TESSalloc
{
void *(*memalloc)( void *userData, unsigned int size );
@ -184,6 +194,12 @@ void tessDeleteTess( TESStesselator *tess );
// count - number of vertices in contour.
void tessAddContour( TESStesselator *tess, int size, const void* pointer, int stride, int count );
// tessSetOption() - Toggles optional tessellation parameters
// Parameters:
// option - one of TessOption
// value - 1 if enabled, 0 if disabled.
void tessSetOption( TESStesselator *tess, int option, int value );
// tessTesselate() - tesselate contours.
// Parameters:
// tess - pointer to tesselator object.
@ -207,7 +223,7 @@ const TESSreal* tessGetVertices( TESStesselator *tess );
// Every point added using tessAddContour() will get a new index starting at 0.
// New vertices generated at the intersections of segments are assigned value TESS_UNDEF.
const TESSindex* tessGetVertexIndices( TESStesselator *tess );
// tessGetElementCount() - Returns number of elements in the the tesselated output.
int tessGetElementCount( TESStesselator *tess );

36
Source/geom.c
View file

@ -1,5 +1,5 @@
/*
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
** All Rights Reserved.
**
@ -9,10 +9,10 @@
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
** of the Software, and to permit persons to whom the Software is furnished to do so,
** subject to the following conditions:
**
**
** The above copyright notice including the dates of first publication and either this
** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
** included in all copies or substantial portions of the Software.
** 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
@ -20,7 +20,7 @@
** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
** OR OTHER DEALINGS IN THE SOFTWARE.
**
**
** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
** be used in advertising or otherwise to promote the sale, use or other dealings in
** this Software without prior written authorization from Silicon Graphics, Inc.
@ -33,6 +33,7 @@
#include <assert.h>
#include "mesh.h"
#include "geom.h"
#include <math.h>
int tesvertLeq( TESSvertex *u, TESSvertex *v )
{
@ -259,3 +260,30 @@ void tesedgeIntersect( TESSvertex *o1, TESSvertex *d1,
v->t = Interpolate( z1, o2->t, z2, d2->t );
}
}
/*
Calculate the angle between v1-v2 and v1-v0
*/
TESSreal calcAngle( TESSvertex *v0, TESSvertex *v1, TESSvertex *v2 )
{
TESSreal num, den, ax, ay, bx, by;
ax = v2->s - v1->s;
ay = v2->t - v1->t;
bx = v0->s - v1->s;
by = v0->t - v1->t;
num = ax * bx + ay * by;
den = sqrt( ax * ax + ay * ay ) * sqrt( bx * bx + by * by );
if ( den > 0.0 ) num /= den;
if ( num < -1.0 ) num = -1.0;
if ( num > 1.0 ) num = 1.0;
return acos( num );
}
/*
Returns 1 is edge is locally delaunay
*/
int tesedgeIsLocallyDelaunay( TESShalfEdge *e )
{
return (calcAngle(e->Lnext->Org, e->Lnext->Lnext->Org, e->Org) +
calcAngle(e->Sym->Lnext->Org, e->Sym->Lnext->Lnext->Org, e->Sym->Org)) < (M_PI + 0.01);
}

2
Source/geom.h
View file

@ -59,6 +59,7 @@
#define EdgeGoesLeft(e) VertLeq( (e)->Dst, (e)->Org )
#define EdgeGoesRight(e) VertLeq( (e)->Org, (e)->Dst )
#define EdgeIsInternal(e) e->Rface && e->Rface->inside
#define ABS(x) ((x) < 0 ? -(x) : (x))
#define VertL1dist(u,v) (ABS(u->s - v->s) + ABS(u->t - v->t))
@ -72,5 +73,6 @@ TESSreal testransEval( TESSvertex *u, TESSvertex *v, TESSvertex *w );
TESSreal testransSign( TESSvertex *u, TESSvertex *v, TESSvertex *w );
int tesvertCCW( TESSvertex *u, TESSvertex *v, TESSvertex *w );
void tesedgeIntersect( TESSvertex *o1, TESSvertex *d1, TESSvertex *o2, TESSvertex *d2, TESSvertex *v );
int tesedgeIsLocallyDelaunay( TESShalfEdge *e );
#endif

79
Source/mesh.c
View file

@ -80,6 +80,7 @@ static TESShalfEdge *MakeEdge( TESSmesh* mesh, TESShalfEdge *eNext )
e->Lface = NULL;
e->winding = 0;
e->activeRegion = NULL;
e->mark = 0;
eSym->Sym = e;
eSym->Onext = eSym;
@ -88,6 +89,7 @@ static TESShalfEdge *MakeEdge( TESSmesh* mesh, TESShalfEdge *eNext )
eSym->Lface = NULL;
eSym->winding = 0;
eSym->activeRegion = NULL;
eSym->mark = 0;
return e;
}
@ -748,6 +750,83 @@ int tessMeshMergeConvexFaces( TESSmesh *mesh, int maxVertsPerFace )
return 1;
}
void tessMeshFlipEdge( TESSmesh *mesh, TESShalfEdge *edge )
{
TESShalfEdge *a0 = edge;
TESShalfEdge *a1 = a0->Lnext;
TESShalfEdge *a2 = a1->Lnext;
TESShalfEdge *b0 = edge->Sym;
TESShalfEdge *b1 = b0->Lnext;
TESShalfEdge *b2 = b1->Lnext;
TESSvertex *aOrg = a0->Org;
TESSvertex *aOpp = a2->Org;
TESSvertex *bOrg = b0->Org;
TESSvertex *bOpp = b2->Org;
TESSface *fa = a0->Lface;
TESSface *fb = b0->Lface;
assert(EdgeIsInternal(edge));
assert(a2->Lnext == a0);
assert(b2->Lnext == b0);
a0->Org = bOpp;
a0->Onext = b1->Sym;
b0->Org = aOpp;
b0->Onext = a1->Sym;
a2->Onext = b0;
b2->Onext = a0;
b1->Onext = a2->Sym;
a1->Onext = b2->Sym;
a0->Lnext = a2;
a2->Lnext = b1;
b1->Lnext = a0;
b0->Lnext = b2;
b2->Lnext = a1;
a1->Lnext = b0;
a1->Lface = fb;
b1->Lface = fa;
fa->anEdge = a0;
fb->anEdge = b0;
if (aOrg->anEdge == a0) aOrg->anEdge = b1;
if (bOrg->anEdge == b0) bOrg->anEdge = a1;
assert( a0->Lnext->Onext->Sym == a0 );
assert( a0->Onext->Sym->Lnext == a0 );
assert( a0->Org->anEdge->Org == a0->Org );
assert( a1->Lnext->Onext->Sym == a1 );
assert( a1->Onext->Sym->Lnext == a1 );
assert( a1->Org->anEdge->Org == a1->Org );
assert( a2->Lnext->Onext->Sym == a2 );
assert( a2->Onext->Sym->Lnext == a2 );
assert( a2->Org->anEdge->Org == a2->Org );
assert( b0->Lnext->Onext->Sym == b0 );
assert( b0->Onext->Sym->Lnext == b0 );
assert( b0->Org->anEdge->Org == b0->Org );
assert( b1->Lnext->Onext->Sym == b1 );
assert( b1->Onext->Sym->Lnext == b1 );
assert( b1->Org->anEdge->Org == b1->Org );
assert( b2->Lnext->Onext->Sym == b2 );
assert( b2->Onext->Sym->Lnext == b2 );
assert( b2->Org->anEdge->Org == b2->Org );
assert(aOrg->anEdge->Org == aOrg);
assert(bOrg->anEdge->Org == bOrg);
assert(a0->Oprev->Onext->Org == a0->Org);
}
#ifdef DELETE_BY_ZAPPING

4
Source/mesh.h
View file

@ -143,6 +143,7 @@ struct TESShalfEdge {
ActiveRegion *activeRegion; /* a region with this upper edge (sweep.c) */
int winding; /* change in winding number when crossing
from the right face to the left face */
int mark; /* Used by the Edge Flip algorithm */
};
#define Rface Sym->Lface
@ -155,7 +156,6 @@ struct TESShalfEdge {
#define Dnext Rprev->Sym /* 3 pointers */
#define Rnext Oprev->Sym /* 3 pointers */
struct TESSmesh {
TESSvertex vHead; /* dummy header for vertex list */
TESSface fHead; /* dummy header for face list */
@ -258,6 +258,8 @@ int tessMeshMergeConvexFaces( TESSmesh *mesh, int maxVertsPerFace );
void tessMeshDeleteMesh( TESSalloc* alloc, TESSmesh *mesh );
void tessMeshZapFace( TESSmesh *mesh, TESSface *fZap );
void tessMeshFlipEdge( TESSmesh *mesh, TESShalfEdge *edge );
#ifdef NDEBUG
#define tessMeshCheckMesh( mesh )
#else

170
Source/tess.c
View file

@ -1,5 +1,5 @@
/*
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
** All Rights Reserved.
**
@ -9,10 +9,10 @@
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
** of the Software, and to permit persons to whom the Software is furnished to do so,
** subject to the following conditions:
**
**
** The above copyright notice including the dates of first publication and either this
** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
** included in all copies or substantial portions of the Software.
** 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
@ -20,7 +20,7 @@
** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
** OR OTHER DEALINGS IN THE SOFTWARE.
**
**
** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
** be used in advertising or otherwise to promote the sale, use or other dealings in
** this Software without prior written authorization from Silicon Graphics, Inc.
@ -186,7 +186,7 @@ extern int RandomSweep;
#define S_UNIT_X (RandomSweep ? (2*drand48()-1) : 1.0)
#define S_UNIT_Y (RandomSweep ? (2*drand48()-1) : 0.0)
#else
#if defined(SLANTED_SWEEP)
#if defined(SLANTED_SWEEP)
/* The "feature merging" is not intended to be complete. There are
* special cases where edges are nearly parallel to the sweep line
* which are not implemented. The algorithm should still behave
@ -295,7 +295,7 @@ void tessProjectPolygon( TESStesselator *tess )
* (what else would it do??) The region must consist of a single
* loop of half-edges (see mesh.h) oriented CCW. "Monotone" in this
* case means that any vertical line intersects the interior of the
* region in a single interval.
* region in a single interval.
*
* Tessellation consists of adding interior edges (actually pairs of
* half-edges), to split the region into non-overlapping triangles.
@ -374,7 +374,6 @@ int tessMeshTessellateMonoRegion( TESSmesh *mesh, TESSface *face )
return 1;
}
/* tessMeshTessellateInterior( mesh ) tessellates each region of
* the mesh which is marked "inside" the polygon. Each such region
* must be monotone.
@ -391,11 +390,125 @@ int tessMeshTessellateInterior( TESSmesh *mesh )
if ( !tessMeshTessellateMonoRegion( mesh, f ) ) return 0;
}
}
return 1;
}
typedef struct EdgeStackNode EdgeStackNode;
typedef struct EdgeStack EdgeStack;
struct EdgeStackNode {
TESShalfEdge *edge;
EdgeStackNode *next;
};
struct EdgeStack {
EdgeStackNode *top;
struct BucketAlloc *nodeBucket;
};
int stackInit( EdgeStack *stack, TESSalloc *alloc )
{
stack->top = NULL;
stack->nodeBucket = createBucketAlloc( alloc, "CDT nodes", sizeof(EdgeStackNode), 512 );
return stack->nodeBucket != NULL;
}
void stackDelete( EdgeStack *stack )
{
deleteBucketAlloc( stack->nodeBucket );
}
int stackEmpty( EdgeStack *stack )
{
return stack->top == NULL;
}
void stackPush( EdgeStack *stack, TESShalfEdge *e )
{
EdgeStackNode *node = (EdgeStackNode *)bucketAlloc( stack->nodeBucket );
if ( ! node ) return;
node->edge = e;
node->next = stack->top;
stack->top = node;
}
TESShalfEdge *stackPop( EdgeStack *stack )
{
TESShalfEdge *e = NULL;
EdgeStackNode *node = stack->top;
if (node) {
stack->top = node->next;
e = node->edge;
bucketFree( stack->nodeBucket, node );
}
return e;
}
// Starting with a valid triangulation, uses the Edge Flip algorithm to
// refine the triangulation into a Constrained Delaunay Triangulation.
void tessMeshRefineDelaunay( TESSmesh *mesh, TESSalloc *alloc )
{
// At this point, we have a valid, but not optimal, triangulation.
// We refine the triangulation using the Edge Flip algorithm
//
// 1) Find all internal edges
// 2) Mark all dual edges
// 3) insert all dual edges into a queue
TESSface *f;
EdgeStack stack;
TESShalfEdge *e;
int maxFaces = 0, maxIter = 0, iter = 0;
stackInit(&stack, alloc);
for( f = mesh->fHead.next; f != &mesh->fHead; f = f->next ) {
if ( f->inside) {
e = f->anEdge;
do {
e->mark = EdgeIsInternal(e); // Mark internal edges
if (e->mark && !e->Sym->mark) stackPush(&stack, e); // Insert into queue
e = e->Lnext;
} while (e != f->anEdge);
maxFaces++;
}
}
// The algorithm should converge on O(n^2), since the predicate is not robust,
// we'll save guard against infinite loop.
maxIter = maxFaces * maxFaces;
// Pop stack until we find a reversed edge
// Flip the reversed edge, and insert any of the four opposite edges
// which are internal and not already in the stack (!marked)
while (!stackEmpty(&stack) && iter < maxIter) {
e = stackPop(&stack);
e->mark = e->Sym->mark = 0;
if (!tesedgeIsLocallyDelaunay(e)) {
TESShalfEdge *edges[4];
int i;
tessMeshFlipEdge(mesh, e);
// for each opposite edge
edges[0] = e->Lnext;
edges[1] = e->Lprev;
edges[2] = e->Sym->Lnext;
edges[3] = e->Sym->Lprev;
for (i = 0; i < 4; i++) {
if (!edges[i]->mark && EdgeIsInternal(edges[i])) {
edges[i]->mark = edges[i]->Sym->mark = 1;
stackPush(&stack, edges[i]);
}
}
}
iter++;
}
stackDelete(&stack);
}
/* tessMeshDiscardExterior( mesh ) zaps (ie. sets to NULL) all faces
* which are not marked "inside" the polygon. Since further mesh operations
* on NULL faces are not allowed, the main purpose is to clean up the
@ -485,7 +598,7 @@ TESStesselator* tessNewTess( TESSalloc* alloc )
if (alloc == NULL)
alloc = &defaulAlloc;
/* Only initialize fields which can be changed by the api. Other fields
* are initialized where they are used.
*/
@ -506,7 +619,7 @@ TESStesselator* tessNewTess( TESSalloc* alloc )
tess->alloc.dictNodeBucketSize = 512;
if (tess->alloc.regionBucketSize == 0)
tess->alloc.regionBucketSize = 256;
tess->normal[0] = 0;
tess->normal[1] = 0;
tess->normal[2] = 0;
@ -530,7 +643,7 @@ TESStesselator* tessNewTess( TESSalloc* alloc )
tess->outOfMemory = 0;
tess->vertexIndexCounter = 0;
tess->vertices = 0;
tess->vertexIndices = 0;
tess->vertexCount = 0;
@ -542,9 +655,9 @@ TESStesselator* tessNewTess( TESSalloc* alloc )
void tessDeleteTess( TESStesselator *tess )
{
struct TESSalloc alloc = tess->alloc;
deleteBucketAlloc( tess->regionPool );
if( tess->mesh != NULL ) {
@ -623,7 +736,7 @@ void OutputPolymesh( TESStesselator *tess, TESSmesh *mesh, int elementType, int
edge = edge->Lnext;
}
while (edge != f->anEdge);
assert( faceVerts <= polySize );
f->n = maxFaceCount;
@ -640,7 +753,7 @@ void OutputPolymesh( TESStesselator *tess, TESSmesh *mesh, int elementType, int
tess->outOfMemory = 1;
return;
}
tess->vertexCount = maxVertexCount;
tess->vertices = (TESSreal*)tess->alloc.memalloc( tess->alloc.userData,
sizeof(TESSreal) * tess->vertexCount * vertexSize );
@ -657,7 +770,7 @@ void OutputPolymesh( TESStesselator *tess, TESSmesh *mesh, int elementType, int
tess->outOfMemory = 1;
return;
}
// Output vertices.
for ( v = mesh->vHead.next; v != &mesh->vHead; v = v->next )
{
@ -679,7 +792,7 @@ void OutputPolymesh( TESStesselator *tess, TESSmesh *mesh, int elementType, int
for ( f = mesh->fHead.next; f != &mesh->fHead; f = f->next )
{
if ( !f->inside ) continue;
// Store polygon
edge = f->anEdge;
faceVerts = 0;
@ -748,7 +861,7 @@ void OutputContours( TESStesselator *tess, TESSmesh *mesh, int vertexSize )
tess->outOfMemory = 1;
return;
}
tess->vertices = (TESSreal*)tess->alloc.memalloc( tess->alloc.userData,
sizeof(TESSreal) * tess->vertexCount * vertexSize );
if (!tess->vertices)
@ -764,7 +877,7 @@ void OutputContours( TESStesselator *tess, TESSmesh *mesh, int vertexSize )
tess->outOfMemory = 1;
return;
}
verts = tess->vertices;
elements = tess->elements;
vertInds = tess->vertexIndices;
@ -865,6 +978,17 @@ void tessAddContour( TESStesselator *tess, int size, const void* vertices,
}
}
void tessSetOption( TESStesselator *tess, int option, int value )
{
switch(option)
{
case TESS_CONSTRAINED_DELAUNAY_TRIANGULATION:
tess->processCDT = value > 0 ? 1 : 0;
break;
}
}
int tessTesselate( TESStesselator *tess, int windingRule, int elementType,
int polySize, int vertexSize, const TESSreal* normal )
{
@ -885,7 +1009,7 @@ int tessTesselate( TESStesselator *tess, int windingRule, int elementType,
}
tess->vertexIndexCounter = 0;
if (normal)
{
tess->normal[0] = normal[0];
@ -900,7 +1024,7 @@ int tessTesselate( TESStesselator *tess, int windingRule, int elementType,
if (vertexSize > 3)
vertexSize = 3;
if (setjmp(tess->env) != 0) {
if (setjmp(tess->env) != 0) {
/* come back here if out of memory */
return 0;
}
@ -934,7 +1058,9 @@ int tessTesselate( TESStesselator *tess, int windingRule, int elementType,
if (elementType == TESS_BOUNDARY_CONTOURS) {
rc = tessMeshSetWindingNumber( mesh, 1, TRUE );
} else {
rc = tessMeshTessellateInterior( mesh );
rc = tessMeshTessellateInterior( mesh );
if (rc != 0 && tess->processCDT != 0)
tessMeshRefineDelaunay( mesh, &tess->alloc );
}
if (rc == 0) longjmp(tess->env,1); /* could've used a label */

14
Source/tess.h
View file

@ -1,5 +1,5 @@
/*
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
** All Rights Reserved.
**
@ -9,10 +9,10 @@
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
** of the Software, and to permit persons to whom the Software is furnished to do so,
** subject to the following conditions:
**
**
** The above copyright notice including the dates of first publication and either this
** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
** included in all copies or substantial portions of the Software.
** 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
@ -20,7 +20,7 @@
** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
** OR OTHER DEALINGS IN THE SOFTWARE.
**
**
** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
** be used in advertising or otherwise to promote the sale, use or other dealings in
** this Software without prior written authorization from Silicon Graphics, Inc.
@ -61,6 +61,8 @@ struct TESStesselator {
TESSreal bmin[2];
TESSreal bmax[2];
int processCDT; /* option to run Constrained Delayney pass. */
/*** state needed for the line sweep ***/
int windingRule; /* rule for determining polygon interior */
@ -71,7 +73,7 @@ struct TESStesselator {
struct BucketAlloc* regionPool;
TESSindex vertexIndexCounter;
TESSreal *vertices;
TESSindex *vertexIndices;
int vertexCount;
@ -79,7 +81,7 @@ struct TESStesselator {
int elementCount;
TESSalloc alloc;
jmp_buf env; /* place to jump to when memAllocs fail */
};

8
alg_outline.md
View file

@ -223,3 +223,11 @@ triangles into fans and strips. We do this using a greedy approach.
The triangulation itself is not optimized to reduce the number of
primitives; we just try to get a reasonable decomposition of the
computed triangulation.
Optionally, it's possible to output a Constrained Delaunay Triangulation.
This is done by doing a delaunay refinement with the normal triangulation as
a basis. The Edge Flip algorithm is used, which is guaranteed to terminate in O(n^2).
Note: We don't use robust predicates to check if edges are locally
delaunay, but currently us a naive epsilon of 0.01 radians to ensure
termination.