make backface and coplanar optional
This commit is contained in:
Trammell hudson
parent
f2fe56eb86
commit
5d9e0b3673
2
camera.c
2
camera.c
|
|
@ -90,7 +90,7 @@ camera_project(
|
|||
// is this rotating?
|
||||
float px = p.p[1] / p.p[2];
|
||||
float py = p.p[0] / p.p[2];
|
||||
float pz = p.p[2];
|
||||
float pz = p.p[2] / c->zoom;
|
||||
|
||||
// return it to the caller
|
||||
v_out->p[0] = px * c->zoom;
|
||||
|
|
|
|||
121
hiddenwire.c
121
hiddenwire.c
|
|
@ -835,6 +835,7 @@ if(0) fprintf(stderr, "%p: %f,%f inside %f,%f %f,%f %f,%f\n",
|
|||
}
|
||||
|
||||
|
||||
|
||||
tri_t *
|
||||
tri_new(
|
||||
const v3_t * p
|
||||
|
|
@ -844,14 +845,13 @@ tri_new(
|
|||
if (!t)
|
||||
return NULL;
|
||||
for(int i = 0 ; i < 3 ; i++)
|
||||
for(int j = 0 ; j < 3 ; j++)
|
||||
t->p[i].p[j] = p[i].p[j];
|
||||
t->p[i] = p[i];
|
||||
|
||||
// precompute the normal
|
||||
t->normal = v3_cross(
|
||||
t->normal = v3_norm(v3_cross(
|
||||
v3_sub(t->p[1], t->p[0]),
|
||||
v3_sub(t->p[2], t->p[1])
|
||||
);
|
||||
));
|
||||
|
||||
|
||||
// compute the bounding box for the triangle
|
||||
|
|
@ -963,6 +963,52 @@ tri_print(
|
|||
);
|
||||
}
|
||||
|
||||
|
||||
/* Check if two triangles are coplanar and share an edge.
|
||||
*
|
||||
* Returns -1 if not coplanar, 0-2 for the edge in t0 that they share.
|
||||
*/
|
||||
int
|
||||
tri_coplanar(
|
||||
const tri_t * const t0,
|
||||
const tri_t * const t1,
|
||||
const float coplanar_eps
|
||||
)
|
||||
{
|
||||
// the two normals must be parallel-enough
|
||||
const float angle = v3_mag(v3_sub(t0->normal, t1->normal));
|
||||
if (angle < -coplanar_eps || +coplanar_eps < angle)
|
||||
return -1;
|
||||
|
||||
// find if there are two points shared
|
||||
unsigned matches = 0;
|
||||
for(int i = 0 ; i < 3 ; i++)
|
||||
{
|
||||
for(int j = 0 ; j < 3 ; j++)
|
||||
{
|
||||
if (!v3_eq(&t0->p[i], &t1->p[j]))
|
||||
continue;
|
||||
matches |= 1 << i;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
switch(matches)
|
||||
{
|
||||
case 0x3: return 0;
|
||||
case 0x6: return 1;
|
||||
case 0x5: return 2;
|
||||
case 0x7:
|
||||
fprintf(stderr, "uh, three points match?\n");
|
||||
tri_print(t0);
|
||||
tri_print(t1);
|
||||
return -1;
|
||||
default:
|
||||
// no shared edge
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
/** Find the Z point of a given xy point along the segment from p0 to p1.
|
||||
*
|
||||
* Returns -1 if there is no known Z point.
|
||||
|
|
@ -1337,6 +1383,11 @@ int main(
|
|||
const stl_face_t * const stl_faces = (const void*)(hdr+1);
|
||||
const int num_triangles = hdr->num_triangles;
|
||||
|
||||
int backface = 1;
|
||||
int coplanar = 1;
|
||||
int hidden = 1;
|
||||
float coplanar_eps = 0.01;
|
||||
|
||||
if(debug)
|
||||
{
|
||||
fprintf(stderr, "header: '%s'\n", hdr->header);
|
||||
|
|
@ -1351,7 +1402,7 @@ int main(
|
|||
printf("<svg xmlns=\"http://www.w3.org/2000/svg\">\n");
|
||||
|
||||
float off_x = 500;
|
||||
float off_y = 1200;
|
||||
float off_y = 500;
|
||||
printf("<g transform=\"translate(%f %f)\">\n", off_x, off_y);
|
||||
|
||||
int rejected = 0;
|
||||
|
|
@ -1372,6 +1423,14 @@ int main(
|
|||
for(int j = 0 ; j < 3 ; j++)
|
||||
camera_project(cam, &stl->p[j], &s[j]);
|
||||
|
||||
fprintf(stderr, "%.3f,%.3f,%.3f -> %.0f,%.0f\n",
|
||||
stl->p[0].p[0],
|
||||
stl->p[0].p[1],
|
||||
stl->p[0].p[2],
|
||||
s[0].p[0],
|
||||
s[0].p[1]
|
||||
);
|
||||
|
||||
tri_t * const tri = tri_new(s);
|
||||
|
||||
// reject this face if any of the vertices are behind us
|
||||
|
|
@ -1381,7 +1440,7 @@ int main(
|
|||
// do a back-face cull to determine if this triangle
|
||||
// is not facing us. we have to determine the orientation
|
||||
// from the winding of the new projection
|
||||
if (tri->normal.p[2] <= 0)
|
||||
if (backface && tri->normal.p[2] <= 0)
|
||||
goto reject;
|
||||
|
||||
retained++;
|
||||
|
|
@ -1389,15 +1448,6 @@ int main(
|
|||
// it passes the first tests, so insert the triangle
|
||||
// into the list and the three line segments
|
||||
tri_insert(&zlist, tri);
|
||||
|
||||
for(int j = 0 ; j < 3 ; j++)
|
||||
{
|
||||
seg_t * s = seg_new(tri->p[j], tri->p[(j+1) % 3]);
|
||||
s->next = slist;
|
||||
slist = s;
|
||||
}
|
||||
|
||||
|
||||
continue;
|
||||
|
||||
reject:
|
||||
|
|
@ -1408,10 +1458,48 @@ reject:
|
|||
if (debug)
|
||||
fprintf(stderr, "Retained %d, rejected %d triangles\n", retained, rejected);
|
||||
|
||||
|
||||
// generate a list of segments, dropping any coplanar ones
|
||||
rejected = 0;
|
||||
for(tri_t * t = zlist ; t ; t = t->next)
|
||||
{
|
||||
unsigned matches = 0;
|
||||
|
||||
if(coplanar)
|
||||
for(tri_t * t2 = zlist ; t2 ; t2 = t2->next)
|
||||
{
|
||||
if (t == t2)
|
||||
continue;
|
||||
|
||||
const int edge = tri_coplanar(t, t2, coplanar_eps);
|
||||
if (edge < 0)
|
||||
continue;
|
||||
matches |= 1 << edge;
|
||||
}
|
||||
|
||||
for(int j = 0 ; j < 3 ; j++)
|
||||
{
|
||||
// drop any that are coplanar
|
||||
if (matches & (1 << j))
|
||||
{
|
||||
rejected++;
|
||||
continue;
|
||||
}
|
||||
|
||||
seg_t * s = seg_new(t->p[j], t->p[(j+1) % 3]);
|
||||
s->next = slist;
|
||||
slist = s;
|
||||
}
|
||||
}
|
||||
|
||||
if (debug)
|
||||
fprintf(stderr, "Rejected %d coplanar segments\n", rejected);
|
||||
|
||||
|
||||
// we now have a z-sorted list of triangles
|
||||
rejected = 0;
|
||||
|
||||
if(1)
|
||||
if(hidden)
|
||||
{
|
||||
// work on each segment, intersecting it with all of the triangles
|
||||
while(slist)
|
||||
|
|
@ -1420,7 +1508,6 @@ reject:
|
|||
slist = s->next;
|
||||
|
||||
tri_seg_intersect(zlist, s, &slist_visible);
|
||||
|
||||
}
|
||||
} else {
|
||||
// don't do any intersection tests
|
||||
|
|
|
|||
Loading…
Reference in New Issue