graph building works
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Trammell Hudson
parent
a304573a45
commit
2881e65d18
188
unfold.c
188
unfold.c
@ -1,3 +1,7 @@
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/** \file
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* Unfold an STL file into a set of laser-cutable polygons.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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@ -27,13 +31,16 @@ typedef struct
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stl_face_t;
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#define MAX_POINTS 24
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typedef struct face face_t;
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typedef struct
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struct face
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{
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int n;
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int p[MAX_POINTS];
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} poly_t;
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float sides[3];
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face_t * next[3];
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int next_edge[3];
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int coplanar[3];
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int used;
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};
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static int
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@ -85,6 +92,33 @@ edge_eq(
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}
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/* Compare two edges in two triangles.
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*
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* note that if the windings are all the same, the edges will
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* compare in the opposite order (for example, the edge from 0 to 1
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* compares to the edge from 2 to 1 in the other triangle).
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*/
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static int
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edge_eq2(
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const stl_face_t * const t0,
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const stl_face_t * const t1,
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int e0,
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int e1
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)
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{
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const v3_t * const v00 = &t0->p[e0];
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const v3_t * const v01 = &t0->p[(e0+1) % 3];
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const v3_t * const v10 = &t1->p[e1];
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const v3_t * const v11 = &t1->p[(e1+1) % 3];
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if (v3_eq(v00, v11) && v3_eq(v01, v10))
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return 1;
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return 0;
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}
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double
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v3_len(
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const v3_t * const v0,
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@ -98,30 +132,6 @@ v3_len(
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return sqrt(dx*dx + dy*dy + dz*dz);
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}
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typedef struct
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{
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float v[2][2];
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v3_t p[2];
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} rotate_t;
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typedef {
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float p[3][2];
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} project_t;
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void
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project(
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const stl_face_t * const t,
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const rotate_t * const r,
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project * const p
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)
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{
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double d0 = v3_len(&t->p[0], &t->p[1]);
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double d1 = v3_len(&t->p[1], &t->p[2]);
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double d2 = v3_len(&t->p[1], &t->p[2]);
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}
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/** recursively try to fix up the triangles.
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*
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@ -129,47 +139,29 @@ project(
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*/
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int
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recurse(
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const stl_face_t * const faces,
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int start,
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const int num_faces,
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int * const used,
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rotate_t * r
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face_t * const f,
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int start_edge
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)
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{
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static int depth;
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depth++;
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const stl_face_t * const t = &faces[start];
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// flag that we are looking into this one
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used[start] = 1;
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f->used = 1;
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// start with the first triangle, find the ones that connect
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project(t, r);
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// print out a svg group for this triangle, starting with
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// the incoming edge
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printf("%p %d %f %f %f\n", f, start_edge, f->sides[0], f->sides[1], f->sides[2]);
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// for each edge, find the triangle that matches
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for (int j = 0 ; j < num_faces ; j++)
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for (int edge = 0 ; edge < 3 ; edge++)
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{
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if (used[j])
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face_t * const f2 = f->next[edge];
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if (f2->used)
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continue;
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const stl_face_t * const t2 = &faces[j];
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if (edge_eq(t, t2, 0, 1))
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{
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fprintf(stderr, "%d.0 -> %d\n", start, j);
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recurse(faces, j, num_faces, used);
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}
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if (edge_eq(t, t2, 0, 2))
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{
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fprintf(stderr, "%d.1 -> %d\n", start, j);
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recurse(faces, j, num_faces, used);
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}
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if (edge_eq(t, t2, 1, 2))
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{
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fprintf(stderr, "%d.2 -> %d\n", start, j);
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recurse(faces, j, num_faces, used);
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}
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recurse(f2, f->next_edge[edge]);
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}
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// no success
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@ -177,6 +169,17 @@ recurse(
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}
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int
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coplanar_check(
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const stl_face_t * const f1,
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const stl_face_t * const f2
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)
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{
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// no, for now
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return 0;
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}
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int main(void)
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{
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@ -188,22 +191,75 @@ int main(void)
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return EXIT_FAILURE;
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const stl_header_t * const hdr = (const void*) buf;
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const stl_face_t * const faces = (const void*)(hdr+1);
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const stl_face_t * const stl_faces = (const void*)(hdr+1);
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const int num_triangles = hdr->num_triangles;
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fprintf(stderr, "header: '%s'\n", hdr->header);
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fprintf(stderr, "num: %d\n", num_triangles);
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int * const used = calloc(num_triangles, sizeof(*used));
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face_t * const faces = calloc(num_triangles, sizeof(*faces));
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rotate_t r = {
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.x = 0,
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.y = 0,
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.p0 = faces[0].p[0],
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.p1 = faces[0].p[1]
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};
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// convert the stl triangles into faces
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for (int i = 0 ; i < num_triangles ; i++)
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{
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const stl_face_t * const stl = &stl_faces[i];
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face_t * const f = &faces[i];
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recurse(faces, 0, num_triangles, used, &r);
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f->sides[0] = v3_len(&stl->p[0], &stl->p[1]);
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f->sides[1] = v3_len(&stl->p[1], &stl->p[2]);
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f->sides[2] = v3_len(&stl->p[2], &stl->p[0]);
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}
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// look to see if there is a matching point
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// in the faces that we've already built
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for (int i = 0 ; i < num_triangles ; i++)
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{
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const stl_face_t * const stl = &stl_faces[i];
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face_t * const f = &faces[i];
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for (int j = 0 ; j < num_triangles ; j++)
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{
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if (i == j)
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continue;
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const stl_face_t * const stl2 = &stl_faces[j];
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face_t * const f2 = &faces[j];
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for (int edge = 0 ; edge < 3 ; edge++)
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{
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if (f->next[edge])
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continue;
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for (int edge2 = 0 ; edge2 < 3 ; edge2++)
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{
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if (f2->next[edge2])
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continue;
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if (!edge_eq2(stl, stl2, edge, edge2))
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continue;
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f->next[edge] = f2;
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f->next_edge[edge] = edge2;
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f2->next[edge2] = f;
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f2->next_edge[edge2] = edge;
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f->coplanar[edge] =
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f2->coplanar[edge2] = coplanar_check(stl, stl2);
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}
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}
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}
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// all three edges should be matched
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if (f->next[0] && f->next[1] && f->next[2])
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continue;
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fprintf(stderr, "%d: missing edges?\n", i);
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}
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// we now have a graph that shows the connection between
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// all of the faces and their sizes. start converting them
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//for (int i = 0 ; i < num_triangles ; i++)
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recurse(&faces[0], 0);
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#if 0
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// worst case -- all separate polygons
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