vmario/papercraft
0
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

both inside case fixes

Browse Source
This commit is contained in:
Trammell hudson 2017-10-07 14:29:37 -04:00
parent fd64a1947d
commit 8e82fb44c6
Failed to extract signature
1 changed files with 81 additions and 592 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

673
hiddenwire.c
View File

@ -58,186 +58,26 @@ struct _seg_t {
}; };
#if 0
typedef struct face face_t;
typedef struct poly poly_t;
struct face
{
float sides[3];
face_t * next[3];
int next_edge[3];
int coplanar[3];
int used;
};
// once this triangle has been used, it will be placed
// in a polygon group and fixed in a position relative to that group
struct poly
{
int start_edge;
int printed;
// local coordinates of the triangle vertices
float a;
float x2;
float y2;
float rot;
// absolute coordintes of the triangle vertices
float p[3][2];
// todo: make this const and add backtracking
face_t * face;
poly_t * next[3];
poly_t * work_next;
};
/* Compare two edges in two triangles.
*
* note that if the windings are all the same, the edges will
* compare in the opposite order (for example, the edge from 0 to 1
* compares to the edge from 2 to 1 in the other triangle).
*/
static int
edge_eq2(
const stl_face_t * const t0,
const stl_face_t * const t1,
int e0,
int e1
)
{
const v3_t * const v00 = &t0->p[e0];
const v3_t * const v01 = &t0->p[(e0+1) % 3];
const v3_t * const v10 = &t1->p[e1];
const v3_t * const v11 = &t1->p[(e1+1) % 3];
if (v3_eq(v00, v11) && v3_eq(v01, v10))
return 1;
return 0;
}
#endif
void void
svg_line( svg_line(
const char * color, const char * color,
const float * p1, const float * p1,
const float * p2, const float * p2,
int dash float thick
) )
{ {
if (!dash) printf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" stroke=\"%s\" stroke-width=\"%.1fpx\"/>\n",
{ p1[0],
printf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" stroke=\"%s\" stroke-width=\"0.5px\"/>\n", p1[1],
p1[0], p2[0],
p1[1], p2[1],
p2[0], color,
p2[1], thick
color );
);
return;
}
// dashed line, split in the middle
const float dx = p2[0] - p1[0];
const float dy = p2[1] - p1[1];
const float h1[] = {
p1[0] + dx*0.45,
p1[1] + dy*0.45,
};
const float h2[] = {
p1[0] + dx*0.55,
p1[1] + dy*0.55,
};
svg_line(color, p1, h1, 0);
svg_line(color, h2, p2, 0);
} }
#if 0
void
rotate(
float * p,
const float * origin,
float a,
float x,
float y
)
{
p[0] = cos(a) * x - sin(a) * y + origin[0];
p[1] = sin(a) * x + cos(a) * y + origin[1];
}
/* Rotate and translate a triangle */
void
poly_position(
poly_t * const g,
const poly_t * const g_src,
float rot,
float trans_x,
float trans_y
)
{
const face_t * const f = g->face;
const int start_edge = g->start_edge;
float a = f->sides[(start_edge + 0) % 3];
float c = f->sides[(start_edge + 1) % 3];
float b = f->sides[(start_edge + 2) % 3];
float x2 = (a*a + b*b - c*c) / (2*a);
float y2 = sqrt(b*b - x2*x2);
// translate by trans_x/trans_y in the original ref frame
// to get the origin point
float origin[2];
rotate(origin, g_src->p[0], g_src->rot, trans_x, trans_y);
g->rot = g_src->rot + rot;
g->a = a;
g->x2 = x2;
g->y2 = y2;
//fprintf(stderr, "%p %d %f %f %f %f => %f %f %f\n", f, start_edge, g->rot*180/M_PI, a, b, c, x2, y2, rot);
rotate(g->p[0], origin, g->rot, 0, 0);
rotate(g->p[1], origin, g->rot, a, 0);
rotate(g->p[2], origin, g->rot, x2, y2);
}
static void
enqueue(
poly_t * g,
poly_t * const new_g,
int at_head
)
{
if (at_head)
{
new_g->work_next = g->work_next;
g->work_next = new_g;
return;
}
// go to the end of the line
while (g->work_next)
g = g->work_next;
g->work_next = new_g;
}
static poly_t * poly_root;
static float poly_min[2], poly_max[2];
#endif
static inline int static inline int
v2_eq( v2_eq(
const float p0[], const float p0[],
@ -363,407 +203,6 @@ if(0) fprintf(stderr, "collision: %.0f,%.0f,%.0f->%.0f,%.0f,%.0f %.0f,%.0f,%.0f-
} }
#if 0
/** Check to see if two triangles overlap */
int
overlap_poly(
const poly_t * const g1,
const poly_t * const g2
)
{
if (intersect(g1->p[0], g1->p[1], g2->p[0], g2->p[1]))
return 1;
if (intersect(g1->p[0], g1->p[1], g2->p[1], g2->p[2]))
return 1;
if (intersect(g1->p[0], g1->p[1], g2->p[2], g2->p[0]))
return 1;
if (intersect(g1->p[1], g1->p[2], g2->p[0], g2->p[1]))
return 1;
if (intersect(g1->p[1], g1->p[2], g2->p[1], g2->p[2]))
return 1;
if (intersect(g1->p[1], g1->p[2], g2->p[2], g2->p[0]))
return 1;
if (intersect(g1->p[2], g1->p[0], g2->p[0], g2->p[1]))
return 1;
if (intersect(g1->p[2], g1->p[0], g2->p[1], g2->p[2]))
return 1;
if (intersect(g1->p[2], g1->p[0], g2->p[2], g2->p[0]))
return 1;
return 0;
}
/** Check to see if any triangles overlap */
int
overlap_check(
const poly_t * g,
const poly_t * const new_g
)
{
// special case -- if the root is the same as the one that we
// are checking, then it does not overlap
if (g == new_g)
return 0;
while (g)
{
if (overlap_poly(g, new_g))
return 1;
g = g->work_next;
}
return 0;
}
/** recursively try to fix up the triangles.
*
* returns the maximum number of triangles added
*/
int
poly_build(
poly_t * const g
)
{
face_t * const f = g->face;
const int start_edge = g->start_edge;
f->used = 1;
// update the group's bounding box
for (int i = 0 ; i < 3 ; i++)
{
const float px = g->p[i][0];
const float py = g->p[i][1];
if (px < poly_min[0]) poly_min[0] = px;
if (px > poly_max[0]) poly_max[0] = px;
if (py < poly_min[1]) poly_min[1] = py;
if (py > poly_max[1]) poly_max[1] = py;
}
if (debug) fprintf(stderr, "%p: adding to poly\n", f);
for(int pass = 0 ; pass < 2 ; pass++)
{
// for each edge, find the triangle that matches
for (int i = 0 ; i < 3 ; i++)
{
const int edge = (i + start_edge) % 3;
face_t * const f2 = f->next[edge];
assert(f2 != NULL);
if (f2->used)
continue;
if (pass == 0 && f->coplanar[edge] == 0)
continue;
// create a group that translates and rotates
// such that it lines up with this edge
float trans_x, trans_y, rotate;
if (i == 0)
{
trans_x = g->a;
trans_y = 0;
rotate = M_PI;
} else
if (i == 1)
{
trans_x = g->x2;
trans_y = g->y2;
rotate = -atan2(g->y2, g->a - g->x2);
} else
if (i == 2)
{
trans_x = 0;
trans_y = 0;
rotate = atan2(g->y2, g->x2);
} else {
errx(EXIT_FAILURE, "edge %d invalid?\n", i);
}
// position this one translated and rotated
poly_t * const g2 = calloc(1, sizeof(*g2));
g2->face = f2;
g2->start_edge = f->next_edge[edge];
poly_position(
g2,
g,
rotate,
trans_x,
trans_y
);
if (overlap_check(poly_root, g2))
{
free(g2);
continue;
}
// no overlap, add it to the current group
g->next[i] = g2;
g2->next[0] = g;
f2->used = 1;
// if g2 is a coplanar triangle, process it now rather than
// defering the work.
if (f->coplanar[edge] == 0)
enqueue(g, g2, 1);
else
enqueue(g, g2, 0);
}
}
return 0;
}
void
svg_text(
float x,
float y,
float angle,
const char * fmt,
...
)
{
printf("<g transform=\"translate(%f %f) rotate(%f)\">",
x,
y,
angle
);
printf("<text x=\"-2\" y=\"1.5\" style=\"font-size:1.5px;\">");
va_list ap;
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("</text></g>\n");
}
void
poly_print(
poly_t * const g
)
{
const face_t * const f = g->face;
const int start_edge = g->start_edge;
g->printed = 1;
// draw this triangle;
// if the edge is an outside, which means that the group
// has no next element, draw a cut line. If there is an
// adjacent neighbor and it is not coplanar, draw a score line
printf("<g><!-- %p %d %f %f->%p %f->%p %f->%p -->\n",
f,
g->start_edge, g->rot * 180/M_PI,
f->sides[0],
f->next[0],
f->sides[1],
f->next[1],
f->sides[2],
f->next[2]
);
int cut_lines = 0;
const uintptr_t a1 = (0x7FFFF & (uintptr_t) f) >> 3;
for (int i = 0 ; i < 3 ; i++)
{
const int edge = (start_edge + i) % 3;
poly_t * const next = g->next[i];
if (!next)
{
// draw a cut line
const float * const p1 = g->p[i];
const float * const p2 = g->p[(i+1) % 3];
const float cx = (p2[0] + p1[0]) / 2;
const float cy = (p2[1] + p1[1]) / 2;
const float dx = (p2[0] - p1[0]);
const float dy = (p2[1] - p1[1]);
const float angle = atan2(dy, dx) * 180 / M_PI;
svg_line("#FF0000", p1, p2, 0);
cut_lines++;
// use the lower address as the label
if (draw_labels)
{
uintptr_t a2 = (0x7FFFF & (uintptr_t) f->next[edge]) >> 3;
if (a2 > a1)
a2 = a1;
svg_text(cx, cy, angle, "%04x", a2);
}
continue;
}
if (next->printed)
continue;
if (f->coplanar[edge] < 0)
{
// draw a mountain score line since they are not coplanar
svg_line("#00FF00", g->p[i], g->p[(i+1) % 3], 1);
} else
if (f->coplanar[edge] > 0)
{
// draw a valley score line since they are not coplanar
svg_line("#00FF00", g->p[i], g->p[(i+1) % 3], 0);
} else {
// draw a shadow line since they are coplanar
//svg_line("#F0F0F0", g->p[i], g->p[(i+1) % 3]);
}
}
/*
// only draw labels if requested and if there are any cut-edges
// on this polygon.
const float tx = (g->p[0][0] + g->p[1][0] + g->p[2][0]) / 3.0;
const float ty = (g->p[0][1] + g->p[1][1] + g->p[2][1]) / 3.0;
if (draw_labels && cut_lines > 0)
svg_text(tx, ty, 0, "%04x",
(0x7FFFF & (uintptr_t) f) >> 3);
*/
printf("</g>\n");
for (int i = 0 ; i < 3 ; i++)
{
poly_t * const next = g->next[i];
if (!next || next->printed)
continue;
poly_print(next);
}
}
/* Returns the 0 for coplanar, negative for mountain, positive for valley.
* (approximates the angle between two triangles that share one edge).
*/
int
coplanar_check(
const stl_face_t * const f1,
const stl_face_t * const f2
)
{
// find the four distinct points
v3_t x1 = f1->p[0];
v3_t x2 = f1->p[1];
v3_t x3 = f1->p[2];
v3_t x4;
for (int i = 0 ; i < 3 ; i++)
{
x4 = f2->p[i];
if (v3_eq(&x1, &x4))
continue;
if (v3_eq(&x2, &x4))
continue;
if (v3_eq(&x3, &x4))
continue;
break;
}
// (x3-x1) . ((x2-x1) X (x4-x3)) == 0
v3_t dx31 = v3_sub(x3, x1);
v3_t dx21 = v3_sub(x2, x1);
v3_t dx43 = v3_sub(x4, x3);
v3_t cross = v3_cross(dx21, dx43);
float dot = v3_dot(dx31, cross);
int check = -EPS < dot && dot < +EPS;
if (debug) fprintf( stderr, "%p %p %s: %f\n", f1, f2, check ? "yes" : "no", dot);
return (int) dot;
}
/** Translate a list of STL triangles into a connected graph of faces.
*
* If there are any triangles that do not have three connected edges,
* the first error will be reported and NULL will be returned.
*/
face_t *
stl2faces(
const stl_face_t * const stl_faces,
const int num_triangles
)
{
face_t * const faces = calloc(num_triangles, sizeof(*faces));
// convert the stl triangles into faces
for (int i = 0 ; i < num_triangles ; i++)
{
const stl_face_t * const stl = &stl_faces[i];
face_t * const f = &faces[i];
f->sides[0] = v3_len(&stl->p[0], &stl->p[1]);
f->sides[1] = v3_len(&stl->p[1], &stl->p[2]);
f->sides[2] = v3_len(&stl->p[2], &stl->p[0]);
if (debug) fprintf(stderr, "%p %f %f %f\n",
f, f->sides[0], f->sides[1], f->sides[2]);
}
// look to see if there is a matching point
// in the faces that we've already built
for (int i = 0 ; i < num_triangles ; i++)
{
const stl_face_t * const stl = &stl_faces[i];
face_t * const f = &faces[i];
for (int j = 0 ; j < num_triangles ; j++)
{
if (i == j)
continue;
const stl_face_t * const stl2 = &stl_faces[j];
face_t * const f2 = &faces[j];
for (int edge = 0 ; edge < 3 ; edge++)
{
if (f->next[edge])
continue;
for (int edge2 = 0 ; edge2 < 3 ; edge2++)
{
if (f2->next[edge2])
continue;
if (!edge_eq2(stl, stl2, edge, edge2))
continue;
f->next[edge] = f2;
f->next_edge[edge] = edge2;
f2->next[edge2] = f;
f2->next_edge[edge2] = edge;
f->coplanar[edge] =
f2->coplanar[edge2] = coplanar_check(stl, stl2);
}
}
}
// all three edges should be matched
if (f->next[0] && f->next[1] && f->next[2])
continue;
fprintf(stderr, "%d missing edges?\n", i);
free(faces);
return NULL;
}
return faces;
}
#endif
int int
@ -787,9 +226,9 @@ tri_inside(
// compute the barycentric coordinates of p in triangle t // compute the barycentric coordinates of p in triangle t
const float a = (p1y - p2y)*(p0x - p2x) + (p2x - p1x)*(p0y - p2y); const float a = (p1y - p2y)*(p0x - p2x) + (p2x - p1x)*(p0y - p2y);
//fprintf(stderr, "a=%f\n", a); //fprintf(stderr, "a=%f\n", a);
if (-EPS < a && a < EPS) if (a < EPS)
{ {
// triangle is too small // triangle is too small or has negative area
return 0; return 0;
} }
@ -1057,23 +496,37 @@ find_z(
} }
/* /*
int * Find the Z point of an XY coordinate in a triangle.
tri_line_intersect( *
const tri_t * zlist, * p can be written as a combination of t01 and t02,
const tri_t * t * p - t0 = a * (t1 - t0) + b * (t2 - t0)
* setting t0 to 0, this becomes:
* p = a * t1 + b * t2
* which is two equations with two unknowns
*/
float
tri_find_z(
const tri_t * const t,
const v3_t * const p
) )
{ {
for( const tri_t * t2 = zlist ; t2 ; t2 = t2->next ) const float t1x = t->p[1].p[0] - t->p[0].p[0];
{ const float t1y = t->p[1].p[1] - t->p[0].p[1];
if (t2 == t) const float t1z = t->p[1].p[2] - t->p[0].p[2];
continue; const float t2x = t->p[2].p[0] - t->p[0].p[0];
for(int j = 0 ; j < 3 ; j++) const float t2y = t->p[2].p[1] - t->p[0].p[1];
{ const float t2z = t->p[2].p[2] - t->p[0].p[2];
const v3_t * const p0 = &t->p[j].p; const float px = p->p[0] - t->p[0].p[0];
const v3_t * const p1 = &t->p[(j+1) % 3].p; const float py = p->p[1] - t->p[0].p[1];
*/
const float a = (px * t2y - py * t2x) / (t1x * t2y - t2x * t1y);
const float b = (px * t1y - py * t1x) / (t2x * t1y - t1x * t2y);
const float z = t->p[0].p[2] + a * t1z + b * t2z;
return z;
}
/* /*
@ -1166,9 +619,17 @@ fprintf(stderr, "%d: processing segment ", recursive++); seg_print(s);
int inside0 = tri_inside(t, &s->p[0], &bary[0]); int inside0 = tri_inside(t, &s->p[0], &bary[0]);
int inside1 = tri_inside(t, &s->p[1], &bary[1]); int inside1 = tri_inside(t, &s->p[1], &bary[1]);
// if both are inside we discard this segment // if both are inside and the triangle is behind
// this segment, then we discard this segment
if (inside0 && inside1) if (inside0 && inside1)
{ {
float p0_tri_z = tri_find_z(t, &s->p[0]);
if (s->p[0].p[2] <= p0_tri_z)
continue;
fprintf(stderr, "z=%.3f ", p0_tri_z);
seg_print(s);
tri_print(t);
//svg_line("#0000FF", s->p[0].p, s->p[1].p, 0); //svg_line("#0000FF", s->p[0].p, s->p[1].p, 0);
//svg_line("#00FF00", t->p[0].p, t->p[1].p, 0); //svg_line("#00FF00", t->p[0].p, t->p[1].p, 0);
//svg_line("#00FF00", t->p[1].p, t->p[2].p, 0); //svg_line("#00FF00", t->p[1].p, t->p[2].p, 0);
@ -1180,6 +641,10 @@ seg_print(s);
fprintf(stderr, "bary0 %f,%f,%f\n", bary[0].p[0], bary[0].p[1], bary[0].p[2]); fprintf(stderr, "bary0 %f,%f,%f\n", bary[0].p[0], bary[0].p[1], bary[0].p[2]);
fprintf(stderr, "bary1 %f,%f,%f\n", bary[1].p[0], bary[1].p[1], bary[1].p[2]); fprintf(stderr, "bary1 %f,%f,%f\n", bary[1].p[0], bary[1].p[1], bary[1].p[2]);
} }
//svg_line("#00FF00", s->p[0].p, s->p[1].p, 10);
//svg_line("#0000FF", t->p[0].p, t->p[1].p, 2);
//svg_line("#0000FF", t->p[1].p, t->p[2].p, 2);
//svg_line("#0000FF", t->p[2].p, t->p[0].p, 2);
recursive--; recursive--;
return; return;
} }
@ -1228,7 +693,14 @@ fprintf(stderr, "bary1 %f,%f,%f\n", bary[1].p[0], bary[1].p[1], bary[1].p[2]);
//fprintf(stderr, "split %d %d inter %d\n", inside0 , inside1, intersections); //fprintf(stderr, "split %d %d inter %d\n", inside0 , inside1, intersections);
if (intersections == 3) if (intersections == 3)
{ {
// this likely means that the triangle is very, very
// small, so let's just throw away this line segment
/*
fprintf(stderr, "uh, three intersections?\n"); fprintf(stderr, "uh, three intersections?\n");
seg_print(s);
tri_print(t);
svg_line("#00FF00", s->p[0].p, s->p[1].p, 10);
*/
recursive--; recursive--;
return; return;
} }
@ -1316,20 +788,24 @@ seg_print(news);
if (is[0].p[2] <= it[0].p[2]) if (is[0].p[2] <= it[0].p[2])
continue; continue;
/*
// due to floating point issues, one of these might // due to floating point issues, one of these might
// be closer to the edge. re-check the barycentric // be closer to the edge. re-check the barycentric
// coordinates for "close enough" // coordinates for "close enough"
inside0 = bary[0].p[0] > -EPS && bary[0].p[1] > -EPS && bary[0].p[2] > -EPS; inside0 = bary[0].p[0] > -EPS && bary[0].p[1] > -EPS && bary[0].p[2] > -EPS;
inside1 = bary[1].p[0] > -EPS && bary[1].p[1] > -EPS && bary[1].p[2] > -EPS; inside1 = bary[1].p[0] > -EPS && bary[1].p[1] > -EPS && bary[1].p[2] > -EPS;
*/
// segment is behind the triangle, so it needs to be // segment is behind the triangle, so it needs to be
// cut into pieces // cut into pieces
if (v2_eq(s->p[0].p, is[0].p, 0.1) /*
|| v2_eq(s->p[1].p, is[0].p, 0.1)) if (v2_eq(s->p[0].p, is[0].p, 0.01)
|| v2_eq(s->p[1].p, is[0].p, 0.01))
{ {
// we're touching on one side, ignore it // we're touching on one side, ignore it
continue; continue;
} else } else
*/
if (inside0) if (inside0)
{ {
// shorten it on the 0 side // shorten it on the 0 side
@ -1344,6 +820,18 @@ seg_print(news);
//fprintf(stderr, "short seg 1: "); seg_print(s); //fprintf(stderr, "short seg 1: "); seg_print(s);
continue; continue;
} else { } else {
// both outside, but an intersection?
// split at that point and hope for the best
seg_t * const news = seg_new(s->p[0], is[0]);
news->src[0] = s->src[0];
news->src[1] = s->src[1];
s->p[0] = is[0];
tri_seg_intersect(zlist->next, news, slist_visible);
//fprintf(stderr, "%d -----\n", --recursive);
// continue splitting our current segment
continue;
/*
fprintf(stderr, "**** uh, both outside but one intersection? %.3f,%.3f\n", fprintf(stderr, "**** uh, both outside but one intersection? %.3f,%.3f\n",
is[0].p[0], is[0].p[0],
is[0].p[1] is[0].p[1]
@ -1352,8 +840,9 @@ seg_print(s);
tri_print(t); tri_print(t);
fprintf(stderr, "bary0 %f,%f,%f\n", bary[0].p[0], bary[0].p[1], bary[0].p[2]); fprintf(stderr, "bary0 %f,%f,%f\n", bary[0].p[0], bary[0].p[1], bary[0].p[2]);
fprintf(stderr, "bary1 %f,%f,%f\n", bary[1].p[0], bary[1].p[1], bary[1].p[2]); fprintf(stderr, "bary1 %f,%f,%f\n", bary[1].p[0], bary[1].p[1], bary[1].p[2]);
//svg_line("#00FF00", s->p[0].p, s->p[1].p, 0); svg_line("#00FF00", s->p[0].p, s->p[1].p, 10);
continue; continue;
*/
} }
} }
} }
@ -1399,7 +888,7 @@ int main(
int backface = 1; int backface = 1;
int coplanar = 1; int coplanar = 1;
int hidden = 1; int hidden = 1;
float coplanar_eps = 0.0001; float coplanar_eps = 0.001;
if(debug) if(debug)
{ {
@ -1533,7 +1022,7 @@ tri_print(t);
// display all of the visible segments // display all of the visible segments
for(seg_t * s = slist_visible ; s ; s = s->next) for(seg_t * s = slist_visible ; s ; s = s->next)
{ {
svg_line("#FF0000", s->p[0].p, s->p[1].p, 0); svg_line("#FF0000", s->p[0].p, s->p[1].p, 1);
} }
if (debug) if (debug)