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prefer coplanar sections

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This commit is contained in:
Trammell Hudson 2014-12-14 13:36:42 -05:00
parent d1c03c3700
commit 78e2a3ce3f
1 changed files with 93 additions and 7 deletions
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100
unfold.c
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@ -137,6 +137,23 @@ v3_len(
}
void
svg_line(
float x1,
float y1,
float x2,
float y2
)
{
printf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" style=\"stroke:rgb(255,255,0);\"/>\n",
x1,
y1,
x2,
y2
);
}
/** recursively try to fix up the triangles.
*
* returns 0 if this should be unwound, 1 if was successful
@ -162,19 +179,27 @@ recurse(
float x2 = (a*a + b*b - c*c) / (2*a);
float y2 = sqrt(b*b - x2*x2);
printf("<polyline points=\"0,0 %f,0 %f,%f\ 0,0\" fill=\"none\" stroke=\"#FF0000\" />\n",
a,
x2,
y2
);
// before drawing the triangle, check to see if any of the
// edges are coplanar and if so, don't draw the edge
if (!f->coplanar[(0+start_edge) % 3])
svg_line(0, 0, a, 0);
if (!f->coplanar[(1+start_edge) % 3])
svg_line(a, 0, x2, y2);
if (!f->coplanar[(2+start_edge) % 3])
svg_line(x2, y2, 0, 0);
//printf("%p %d %f %f %f\n", f, start_edge, f->sides[0], f->sides[1], f->sides[2]);
for(int pass = 0 ; pass < 2 ; pass++)
{
// for each edge, find the triangle that matches
for (int edge = 0 ; edge < 3 ; edge++)
{
face_t * const f2 = f->next[(edge+start_edge) % 3];
if (f2->used)
continue;
if (pass == 0 && !f->coplanar[(edge+start_edge) % 3])
continue;
// create a group that translates and rotates
// such that it lines up with this edge
@ -209,11 +234,46 @@ recurse(
printf("</g>\n");
}
}
// no success
return 0;
}
v3_t v3_sub(v3_t a, v3_t b)
{
v3_t c = { .p = {
a.p[0] - b.p[0],
a.p[1] - b.p[1],
a.p[2] - b.p[2],
} };
return c;
}
float v3_dot(v3_t a, v3_t b)
{
return a.p[0]*b.p[0] + a.p[1]*b.p[1] + a.p[2]*b.p[2];
}
v3_t v3_cross(v3_t u, v3_t v)
{
float u1 = u.p[0];
float u2 = u.p[1];
float u3 = u.p[2];
float v1 = v.p[0];
float v2 = v.p[1];
float v3 = v.p[2];
v3_t c = { .p = {
u2*v3 - u3*v2,
u3*v1 - u1*v3,
u1*v2 - u2*v1,
}};
return c;
}
int
coplanar_check(
@ -221,8 +281,34 @@ coplanar_check(
const stl_face_t * const f2
)
{
// no, for now
return 0;
// 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;
//fprintf( stderr, "%p %p %s\n", f1, f2, check ? "yes" : "no");
return check;
}