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rework to collect things into polygons

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This commit is contained in:
Trammell Hudson 2014-12-14 22:18:34 -05:00
parent 5f7c406716
commit d4454c67bd
1 changed files with 191 additions and 163 deletions
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354
unfold.c
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@ -8,13 +8,13 @@
#include <unistd.h> #include <unistd.h>
#include <math.h> #include <math.h>
#include <err.h> #include <err.h>
#include <assert.h>
#include "v3.h"
#ifndef M_PI #ifndef M_PI
#define M_PI 3.1415926535897932384 #define M_PI 3.1415926535897932384
#endif #endif
#define EPS 0.0001
typedef struct typedef struct
{ {
char header[80]; char header[80];
@ -22,10 +22,6 @@ typedef struct
} __attribute__((__packed__)) } __attribute__((__packed__))
stl_header_t; stl_header_t;
typedef struct
{
float p[3];
} v3_t;
typedef struct typedef struct
{ {
@ -37,6 +33,7 @@ stl_face_t;
typedef struct face face_t; typedef struct face face_t;
typedef struct poly poly_t;
struct face struct face
{ {
@ -47,54 +44,25 @@ struct face
int used; int used;
}; };
// once this triangle has been used, it will be placed
static int // in a polygon group and fixed in a position relative to that group
v3_eq( struct poly
const v3_t * v1,
const v3_t * v2
)
{ {
float dx = v1->p[0] - v2->p[0]; int start_edge;
float dy = v1->p[1] - v2->p[1]; int printed;
float dz = v1->p[2] - v2->p[2];
if (-EPS < dx && dx < EPS // local coordinates of the triangle vertices
&& -EPS < dy && dy < EPS float a;
&& -EPS < dz && dz < EPS) float x2;
return 1; float y2;
float rot;
return 0; // absolute coordintes of the triangle vertices
} float p[3][2];
face_t * face;
static int poly_t * next[3];
edge_eq( };
const stl_face_t * const t0,
const stl_face_t * const t1,
int e0,
int e1
)
{
const v3_t * const v0 = &t0->p[e0];
const v3_t * const v1 = &t0->p[e1];
if (v3_eq(v0, &t1->p[0]) && v3_eq(v1, &t1->p[1]))
return 1;
if (v3_eq(v0, &t1->p[1]) && v3_eq(v1, &t1->p[0]))
return 1;
if (v3_eq(v0, &t1->p[0]) && v3_eq(v1, &t1->p[2]))
return 1;
if (v3_eq(v0, &t1->p[2]) && v3_eq(v1, &t1->p[0]))
return 1;
if (v3_eq(v0, &t1->p[1]) && v3_eq(v1, &t1->p[2]))
return 1;
if (v3_eq(v0, &t1->p[2]) && v3_eq(v1, &t1->p[1]))
return 1;
return 0;
}
/* Compare two edges in two triangles. /* Compare two edges in two triangles.
@ -124,157 +92,185 @@ edge_eq2(
} }
double
v3_len(
const v3_t * const v0,
const v3_t * const v1
)
{
float dx = v0->p[0] - v1->p[0];
float dy = v0->p[1] - v1->p[1];
float dz = v0->p[2] - v1->p[2];
return sqrt(dx*dx + dy*dy + dz*dz);
}
void void
svg_line( svg_line(
float x1, const char * color,
float y1, float * p1,
float x2, float * p2
float y2
) )
{ {
printf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" style=\"stroke:rgb(255,255,0);\"/>\n", printf("<line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" stroke=\"%s\"/>\n",
x1, p1[0],
y1, p1[1],
x2, p2[0],
y2 p2[1],
color
); );
} }
/** recursively try to fix up the triangles. void
* rotate(
* returns 0 if this should be unwound, 1 if was successful float * p,
*/ float a,
int float x,
recurse( float y
face_t * const f,
int start_edge
) )
{ {
static int depth; p[0] = cos(a) * x - sin(a) * y;
p[1] = sin(a) * x + cos(a) * y;
}
depth++;
// flag that we are looking into this one /* Rotate and translate a triangle */
f->used = 1; void
poly_position(
poly_t * const g,
float trans_x,
float trans_y,
float rot
)
{
face_t * const f = g->face;
const int start_edge = g->start_edge;
// print out a svg group for this triangle, starting with
// the incoming edge
float a = f->sides[(start_edge + 0) % 3]; float a = f->sides[(start_edge + 0) % 3];
float c = f->sides[(start_edge + 1) % 3]; float c = f->sides[(start_edge + 1) % 3];
float b = f->sides[(start_edge + 2) % 3]; float b = f->sides[(start_edge + 2) % 3];
float x2 = (a*a + b*b - c*c) / (2*a); float x2 = (a*a + b*b - c*c) / (2*a);
float y2 = sqrt(b*b - x2*x2); float y2 = sqrt(b*b - x2*x2);
// before drawing the triangle, check to see if any of the g->rot = rot;
// edges are coplanar and if so, don't draw the edge g->a = a;
if (!f->coplanar[(0+start_edge) % 3]) g->x2 = x2;
svg_line(0, 0, a, 0); g->y2 = y2;
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]); rotate(g->p[0], rot, trans_x + 0, trans_y + 0);
rotate(g->p[1], rot, trans_x + a, trans_y + 0);
rotate(g->p[2], rot, trans_x + x2, trans_y + y2);
}
/** 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;
fprintf(stderr, "%p: adding to poly\n", f);
for(int pass = 0 ; pass < 2 ; pass++) for(int pass = 0 ; pass < 2 ; pass++)
{ {
// for each edge, find the triangle that matches // for each edge, find the triangle that matches
for (int edge = 0 ; edge < 3 ; edge++) for (int i = 0 ; i < 3 ; i++)
{ {
face_t * const f2 = f->next[(edge+start_edge) % 3]; const int edge = (i + start_edge) % 3;
face_t * const f2 = f->next[edge];
assert(f2 != NULL);
if (f2->used) if (f2->used)
continue; continue;
if (pass == 0 && !f->coplanar[(edge+start_edge) % 3]) if (pass == 0 && !f->coplanar[edge])
continue; continue;
// create a group that translates and rotates // create a group that translates and rotates
// such that it lines up with this edge // such that it lines up with this edge
float trans_x, trans_y, rotate; float trans_x, trans_y, rotate;
if (edge == 0) if (i == 0)
{ {
trans_x = a; trans_x = g->a;
trans_y = 0; trans_y = 0;
rotate = 180; rotate = 180;
} else } else
if (edge == 1) if (i == 1)
{ {
trans_x = x2; trans_x = g->x2;
trans_y = y2; trans_y = g->y2;
rotate = -atan2(y2, a-x2) * 180 / M_PI; rotate = -atan2(g->y2, g->a - g->x2);
} else } else
if (edge == 2) if (i == 2)
{ {
trans_x = 0; trans_x = 0;
trans_y = 0; trans_y = 0;
rotate = atan2(y2, x2) * 180 / M_PI; rotate = atan2(g->y2, g->x2);
} else { } else {
errx(EXIT_FAILURE, "edge %d invalid?\n", edge); errx(EXIT_FAILURE, "edge %d invalid?\n", i);
} }
printf("<!-- edge %d --><g transform=\"translate(%f,%f) rotate(%f)\">\n", // position this one translated and rotated
edge, poly_t * const g2 = calloc(1, sizeof(*g2));
trans_x, g2->face = f2;
trans_y, g2->start_edge = f->next_edge[edge];
rotate g->next[edge] = g2;
g2->next[g2->start_edge] = g;
poly_position(
g2,
g->rot + rotate,
g->p[0][0] + trans_x,
g->p[0][1] + trans_y
); );
recurse(f2, f->next_edge[(edge+start_edge) % 3]); // \todo: CHECK FOR OVERLAP!
printf("</g>\n"); poly_build(g2);
} }
} }
// no success
return 0; return 0;
} }
v3_t v3_sub(v3_t a, v3_t b) void
poly_print(
poly_t * const g
)
{ {
v3_t c = { .p = { face_t * const f = g->face;
a.p[0] - b.p[0], const int start_edge = g->start_edge;
a.p[1] - b.p[1],
a.p[2] - b.p[2],
} };
return c;
}
float v3_dot(v3_t a, v3_t b) g->printed = 1;
{
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) // draw this triangle;
{ // if the edge is an outside, which means that the group
float u1 = u.p[0]; // has no next element, draw a cut line. If there is an
float u2 = u.p[1]; // adjacent neighbor and it is not coplanar, draw a score line
float u3 = u.p[2]; printf("<g>\n");
for (int i = 0 ; i < 3 ; i++)
{
poly_t * const next = g->next[i];
float v1 = v.p[0]; if (!next)
float v2 = v.p[1]; {
float v3 = v.p[2]; // draw a cut line
svg_line("#FF0000", g->p[i], g->p[(i+1) % 3]);
continue;
}
v3_t c = { .p = { //if (next->printed)
u2*v3 - u3*v2, //continue;
u3*v1 - u1*v3,
u1*v2 - u2*v1,
}};
return c; if (!f->coplanar[(0+start_edge) % 3])
{
// draw a score line since they are not coplanar
svg_line("#00FF00", g->p[i], g->p[(i+1) % 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);
}
} }
@ -315,23 +311,17 @@ coplanar_check(
} }
/** Translate a list of STL triangles into a connected graph of faces.
int main(void) *
* 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
)
{ {
const size_t max_len = 1 << 20;
uint8_t * const buf = calloc(max_len, 1);
ssize_t rc = read(0, buf, max_len);
if (rc == -1)
return EXIT_FAILURE;
const stl_header_t * const hdr = (const void*) buf;
const stl_face_t * const stl_faces = (const void*)(hdr+1);
const int num_triangles = hdr->num_triangles;
fprintf(stderr, "header: '%s'\n", hdr->header);
fprintf(stderr, "num: %d\n", num_triangles);
face_t * const faces = calloc(num_triangles, sizeof(*faces)); face_t * const faces = calloc(num_triangles, sizeof(*faces));
// convert the stl triangles into faces // convert the stl triangles into faces
@ -387,15 +377,53 @@ int main(void)
// all three edges should be matched // all three edges should be matched
if (f->next[0] && f->next[1] && f->next[2]) if (f->next[0] && f->next[1] && f->next[2])
continue; continue;
errx(EXIT_FAILURE, "%d missing edges?\n", i); fprintf(stderr, "%d missing edges?\n", i);
free(faces);
return NULL;
} }
// we now have a graph that shows the connection between return faces;
// all of the faces and their sizes. start converting them }
int main(void)
{
const size_t max_len = 1 << 20;
uint8_t * const buf = calloc(max_len, 1);
ssize_t rc = read(0, buf, max_len);
if (rc == -1)
return EXIT_FAILURE;
const stl_header_t * const hdr = (const void*) buf;
const stl_face_t * const stl_faces = (const void*)(hdr+1);
const int num_triangles = hdr->num_triangles;
fprintf(stderr, "header: '%s'\n", hdr->header);
fprintf(stderr, "num: %d\n", num_triangles);
face_t * const faces = stl2faces(stl_faces, num_triangles);
// we now have a graph that shows the connection between
// all of the faces and their sizes. start trying to build
// non-overlapping groups of them
printf("<svg xmlns=\"http://www.w3.org/2000/svg\">\n"); printf("<svg xmlns=\"http://www.w3.org/2000/svg\">\n");
//for (int i = 0 ; i < num_triangles ; i++) for (int i = 0 ; i < num_triangles ; i++)
recurse(&faces[0], 0); {
face_t * const f = &faces[i];
if (f->used)
continue;
poly_t g;
g.face = f;
poly_position(&g, 0, 0, 0);
poly_build(&g);
printf("<g>\n");
poly_print(&g);
printf("</g>\n");
}
printf("</svg>\n"); printf("</svg>\n");