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cae-tools/slicer/slice.c

271 lines
4.6 KiB
C

/*
* slice.c - Generate slices
*
* Written 2015 by Werner Almesberger
* Copyright 2015 by Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <stdbool.h>
#include <math.h>
#include <glib.h>
#include "util.h"
#include "stl.h"
#include "slice.h"
struct facet {
struct v a, b, c;
struct facet *next;
};
struct z {
float z;
};
static GTree *tree;
static struct facet *facets = NULL;
/* ----- Bounding box ------------------------------------------------------ */
static bool first = 1;
static float min_x, max_x, min_y, max_y;
static void bbox(float x, float y)
{
if (first) {
min_x = max_x = x;
min_y = max_y = y;
first = 0;
} else {
if (x < min_x)
min_x = x;
if (y < min_y)
min_y = y;
if (x > max_x)
max_x = x;
if (y > max_y)
max_y = y;
}
}
/* ----- Data collection --------------------------------------------------- */
static inline bool eq(float a, float b)
{
return fabsf(a - b) < 1e-5;
}
static void mark_z(float z)
{
struct z *e;
e = g_tree_lookup(tree, &z);
if (e)
return;
e = alloc_type(struct z);
e->z = z;
g_tree_insert(tree, &e->z, e);
}
static void add(const struct v *a, const struct v *b, const struct v *c)
{
float cross;
struct facet *f;
cross = (b->x - a->x) * (c->y - a->y) - (b->y - a->y) * (c->x - a->x);
if (!eq(cross, 0)) {
fprintf(stderr,
"inclined facet\n\t%f %f %f\n\t%f %f %f\n\t%f %f %f\n",
a->x, a->y, a->z, b->x, b->y, b->z, c->x, c->y, c->z);
exit(1);
}
bbox(a->x, a->y);
bbox(b->x, b->y);
bbox(c->x, c->y);
f = alloc_type(struct facet);
f->a = *a;
f->b = *b;
f->c = *c;
f->next = facets;
facets = f;
}
void slice(struct v f[3])
{
bool ab = eq(f[0].z, f[1].z);
bool bc = eq(f[1].z, f[2].z);
if (ab && bc) {
mark_z(f[0].z);
return;
}
add(f + 0, f + 1, f + 2);
}
/* ----- Insert intermediate layers ---------------------------------------- */
struct ctx {
float z_step;
bool first;
float z0; /* only defined if !first */
bool more; /* returned due to having made changes */
};
static gboolean check_z(gpointer key, gpointer value, gpointer data)
{
const struct z *z = value;
struct ctx *ctx = data;
float d;
int n, i;
if (ctx->first) {
ctx->first = 0;
ctx->z0 = z->z;
return 0;
}
d = z->z - ctx->z0;
if (d <= ctx->z_step) {
ctx->z0 = z->z;
return 0;
}
n = (d / ctx->z_step) + 1;
for (i = 1; i < n; i++)
mark_z(ctx->z0 + d / n * i);
ctx->more = 1;
return 1;
}
void slice_intermediate(float z_step)
{
struct ctx ctx = {
.z_step = z_step,
};
do {
ctx.first = 1;
ctx.more = 0;
g_tree_foreach(tree, check_z, &ctx);
}
while (ctx.more);
}
/* ----- Dumping ----------------------------------------------------------- */
static bool cut(const struct v *a, const struct v *b, float z, struct v *res)
{
float dx, dy, dz;
float f;
if (a->z > b->z)
return cut(b, a, z, res);
if (eq(a->z, b->z))
return 0;
if (a->z > z || b->z < z || eq(b->z, z))
return 0;
dx = b->x - a->x;
dy = b->y - a->y;
dz = b->z - a->z;
f = (z - a->z) / dz;
res->x = f * dx + a->x;
res->y = f * dy + a->y;
res->z = z;
return 1;
}
static gboolean dump_layer(gpointer key, gpointer value, gpointer data)
{
const struct z *z = value;
const struct facet *f;
struct v p1, p2;
for (f = facets; f; f = f->next) {
if (cut(&f->a, &f->b, z->z, &p1)) {
if (!cut(&f->a, &f->c, z->z, &p2) &&
!cut(&f->b, &f->c, z->z, &p2))
continue;
} else if (!cut(&f->a, &f->c, z->z, &p1) ||
!cut(&f->b, &f->c, z->z, &p2)) {
continue;
}
printf("%f %f %f\n%f %f %f\n\n\n",
p1.x, p1.y, z->z, p2.x, p2.y, z->z);
}
return 0;
}
static gboolean dump_box(gpointer key, gpointer value, gpointer data)
{
const struct z *z = value;
float box = *(float *) data;
printf("%f %f %f\n%f %f %f\n%f %f %f\n%f %f %f\n%f %f %f\n\n\n",
min_x - box, min_y - box, z->z,
max_x + box, min_y - box, z->z,
max_x + box, max_y + box, z->z,
min_x - box, max_y + box, z->z,
min_x - box, min_y - box, z->z);
return 0;
}
void slice_dump(float box)
{
g_tree_foreach(tree, dump_layer, NULL);
if (box && !first)
g_tree_foreach(tree, dump_box, &box);
}
/* ----- Initialization ---------------------------------------------------- */
static gint comp(gconstpointer a, gconstpointer b)
{
const float *za = a;
const float *zb = b;
return eq(*za, *zb) ? 0 : *za < *zb ? -1 : 1;
}
void slice_init(void)
{
tree = g_tree_new(comp);
}