Move half-edge assembler to separate .c file

This commit is contained in:
hasufell 2014-05-16 20:10:43 +02:00
parent dfd978f714
commit cd864fa1ba
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GPG Key ID: 220CD1C5BDEED020
4 changed files with 506 additions and 467 deletions

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@ -2,7 +2,7 @@ include ../common.mk
TARGET = drow-engine
HEADERS = err.h common.h print.h filereader.h gl_draw.h vector.h half_edge.h
OBJECTS = print.o filereader.o gl_draw.o vector.o half_edge.o
OBJECTS = print.o filereader.o gl_draw.o vector.o half_edge.o half_edge_AS.o
INCS = -I.
CFLAGS += $(shell $(PKG_CONFIG) --cflags gl glu glib-2.0)

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@ -34,7 +34,6 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/**
@ -56,24 +55,7 @@
static bool get_all_emanating_edges(HE_vert const * const vert,
HE_edge ***edge_array_out,
uint32_t *ec_out);
static int32_t get_row_count(int32_t const **array);
static int32_t get_face_count(FACES const faces);
static int32_t get_edge_count(FACES const faces);
static double **parse_2d_array(char const * const obj_string,
char *item);
static FACES parse_face_array(char const * const obj_string);
static void assemble_HE_stage1(VERTICES obj_v,
HE_vert *vertices,
int32_t *vc);
static void assemble_HE_stage2(FACES obj_f,
HE_vert *vertices,
HE_face *faces,
HE_edge *edges,
int32_t *fc,
int32_t *ec);
static void assemble_HE_stage3(HE_edge *edges,
int32_t *ec,
int32_t *dec);
/**
* Get all edges that emanate from vertice and return a pointer
@ -116,376 +98,6 @@ static bool get_all_emanating_edges(HE_vert const * const vert,
return true;
}
/**
* Get the row count of the 2d array.
*
* @param array the 2 dimensional array
* @return the row count
*/
static int32_t get_row_count(int32_t const **array)
{
uint32_t rc = 0;
if (!array)
return -1;
while (array[rc])
rc++;
return rc;
}
/**
* Get the amount of faces as they are in the
* .obj file.
*
* @param faces the faces array
* @return the count of faces, -1 on failure
*/
static int32_t get_face_count(FACES const faces)
{
if (!faces)
return 0;
return get_row_count((int32_t const**)faces);
}
/**
* Get the amount of edges.
*
* @param faces the faces array which will be used
* to calculate the amount of edges
* @return the count of edges, -1 on failure
*/
static int32_t get_edge_count(FACES const faces)
{
uint32_t ec = 0;
uint32_t fc;
if (!faces)
return -1;
fc = get_face_count(faces);
for (uint32_t i = 0; i < fc; i++)
ec += faces[i][0];
return ec;
}
/**
* Parse a string which supposedly is a 2-dimensional
* array in the .obj file, describing all faces, all vertices
* and such. The parsing depends on the item string, such as "f"
* or "v".
*
* @param obj_string the string that is in obj format
* @param item the item to look for, such as "f" or "v"
* @return a newly allocated 2-dimensional array, NULL on failure
*/
static double **parse_2d_array(char const * const obj_string,
char *item)
{
uint32_t lc = 0;
char *string,
*str_ptr_space = NULL, /* for strtok */
*str_ptr_newline = NULL, /* for strtok */
*str_tmp_ptr = NULL; /* for strtok */
double **arr = NULL;
if (!obj_string || !item)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
str_tmp_ptr = strtok_r(string, "\n", &str_ptr_newline);
while (str_tmp_ptr && *str_tmp_ptr) {
str_tmp_ptr = strtok_r(str_tmp_ptr, " ", &str_ptr_space);
if (!strcmp(str_tmp_ptr, item)) {
char *myint = NULL;
uint8_t i = 1;
REALLOC(arr, sizeof(double*) * (lc + 2));
arr[lc] = NULL;
while ((myint = strtok_r(NULL, " ", &str_ptr_space))) {
i++;
REALLOC(arr[lc],
sizeof(double**) * (i + 1));
arr[lc][i - 1] = atof(myint);
}
arr[lc][0] = i - 1; /* save length at first position */
lc++;
arr[lc] = NULL; /* trailing NULL pointer */
}
str_tmp_ptr = strtok_r(NULL, "\n", &str_ptr_newline);
}
free(string);
return arr;
}
/**
* Parses the face arrays. Since these contain slashes, such as
* "f 1/4/3 8/4/4 9/8/3" we cannot use parse_2d_array() since
* we need extra logic.
*
* @param obj_string the string that is in obj format
* @return a newly allocated FACES array, NULL on failure
*/
static FACES parse_face_array(char const * const obj_string)
{
uint32_t lc = 0;
char *string,
*str_ptr_space = NULL, /* for strtok */
*str_ptr_newline = NULL, /* for strtok */
*str_tmp_ptr = NULL; /* for strtok */
FACES arr = NULL;
if (!obj_string)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
str_tmp_ptr = strtok_r(string, "\n", &str_ptr_newline);
while (str_tmp_ptr && *str_tmp_ptr) {
str_tmp_ptr = strtok_r(str_tmp_ptr, " ", &str_ptr_space);
if (!strcmp(str_tmp_ptr, "f")) {
char *myint = NULL;
uint8_t i = 1;
REALLOC(arr, sizeof(uint32_t*) * (lc + 2));
arr[lc] = NULL;
while ((myint = strtok_r(NULL, " ", &str_ptr_space))) {
i++;
REALLOC(arr[lc],
sizeof(uint32_t**) * (i + 1));
arr[lc][i - 1] = atoi(myint);
}
arr[lc][0] = i - 1; /* save length at first position */
lc++;
arr[lc] = NULL; /* trailing NULL pointer */
}
str_tmp_ptr = strtok_r(NULL, "\n", &str_ptr_newline);
}
free(string);
return arr;
}
/**
* First stage of assembling the half-edge data structure.
* Here we allocate vertices and fill their coordinates
* with the information we have from parsing the obj file.
* All other yet unknown members such as edge are set to
* NULL. This function isn't really modular, but makes
* reading parse_obj() a bit less painful.
*
* @param obj_v the vertices in the raw form after they are
* parsed from the obj file
* @param vertices pointer the actual half-edge vertices
* @param vc pointer to the vertice count
*/
static void assemble_HE_stage1(VERTICES obj_v,
HE_vert *vertices,
int32_t *vc)
{
uint8_t const xpos = 1;
uint8_t const ypos = 2;
uint8_t const zpos = 3;
int8_t const default_col = -1;
*vc = 0;
while (obj_v[*vc]) {
vector *tmp_vec;
if (obj_v[*vc][0] > 3)
ABORT("Failure in parse_obj(),\n"
"malformed vertice, exceeds 3 dimensions!\n");
tmp_vec = malloc(sizeof(vector));
CHECK_PTR_VAL(tmp_vec);
tmp_vec->x = obj_v[*vc][xpos];
tmp_vec->y = obj_v[*vc][ypos];
tmp_vec->z = obj_v[*vc][zpos];
vertices[*vc].vec = tmp_vec;
/* set unused/unknown values to NULL */
vertices[*vc].edge = NULL;
vertices[*vc].edge_array = NULL;
vertices[*vc].eac = 0;
vertices[*vc].dc = 0;
/* allocate color struct and set preliminary colors */
vertices[*vc].col = malloc(sizeof(color));
vertices[*vc].col->red = default_col;
vertices[*vc].col->green = default_col;
vertices[*vc].col->blue = default_col;
(*vc)++;
}
}
/**
* Second stage of assembling the half-edge data structure.
* Here we start creating the HE_edges and HE_faces and also
* fill some missing information to the HE_verts along with it.
* The edge pairs are still unknown, as well as some other
* acceleration-structure related members like vertice->dummys.
* This function isn't really modular, but makes
* reading parse_obj() a bit less painful.
*
* @param obj_f the raw faces as they are after parsing the obj file
* @param vertices the half-edge vertices
* @param faces the half-edge faces
* @param edges the half-edge edges
* @param fc the count of half-edge faces
* @param ec the count of half-edge edges
*/
static void assemble_HE_stage2(FACES obj_f,
HE_vert *vertices,
HE_face *faces,
HE_edge *edges,
int32_t *fc,
int32_t *ec)
{
*ec = 0;
/* create HE_edges and real HE_faces */
for (uint32_t i = 0; i < (uint32_t)(*fc); i++) { /* for all faces */
/* for all vertices of the face */
for (uint32_t j = 0; j < (uint32_t)obj_f[i][0]; j++) {
uint32_t obj_f_pos = j + 1; /* first pos is reserved for length */
uint32_t fv_arr_id =
obj_f[i][obj_f_pos] - 1; /* fv_id starts at 1 */
edges[*ec].vert = &(vertices[fv_arr_id]);
edges[*ec].face = &(faces[i]);
edges[*ec].pair = NULL; /* preliminary */
vertices[fv_arr_id].edge = &(edges[*ec]); /* last one wins */
vertices[fv_arr_id].dummys = NULL; /* preliminary */
/* Skip j == 0 here, so we don't underrun the arrays,
* since we always look one edge back. The first edge
* element is taken care of below as well. */
if (j > 0) {
uint32_t *eac = &(edges[*ec].vert->eac);
/* connect previous edge to current edge */
edges[*ec - 1].next = &(edges[*ec]);
/* Acceleration struct:
* add previous edge to edge_array of current vertice */
REALLOC(edges[*ec].vert->edge_array,
sizeof(HE_edge*) * (*eac + 1));
edges[*ec].vert->edge_array[*eac] = &(edges[*ec - 1]);
(*eac)++;
if (obj_f_pos == (uint32_t)obj_f[i][0]) { /* no vertice left */
uint32_t *eac;
/* connect last edge to first edge */
edges[*ec].next = &(edges[*ec - j]);
eac = &(edges[*ec].next->vert->eac);
/* Acceleration struct:
* add last edge to edge_array element of first vertice */
REALLOC(edges[*ec].next->vert->edge_array,
sizeof(HE_edge*) * (*eac + 1));
edges[*ec].next->vert->edge_array[*eac] = &(edges[*ec]);
(*eac)++;
}
}
(*ec)++;
}
faces[i].edge = &(edges[*ec - 1]); /* "last" edge */
}
}
/**
* Third stage of assembling the half-edge data structure.
* Here we find the pairs of edges and also account for the
* possibility of border-edges, where we have to set up
* dummy edges and connect them properly.
*
* @param edges the half-edge edges
* @param ec the half-edge edges count
* @param dec the dummy edges count
*/
static void assemble_HE_stage3(HE_edge *edges,
int32_t *ec,
int32_t *dec)
{
/* find pairs */
for (uint32_t i = 0; i < (uint32_t)(*ec); i++) { /* for all edges */
uint32_t eac = edges[i].vert->eac;
bool pair_found = false;
for (uint32_t j = 0; j < eac; j++) { /* for all potential pairs */
if (edges[i].vert->edge_array[j] &&
(edges[i].next->vert ==
edges[i].vert->edge_array[j]->vert)) {
edges[i].pair = edges[i].vert->edge_array[j];
edges[i].vert->edge_array[j] = NULL;
pair_found = true;
break;
}
}
/* create dummy pair edge if we have a border edge */
if (!pair_found) {
uint32_t *vert_dc = &(edges[i].next->vert->dc);
REALLOC(edges[i].next->vert->dummys,
sizeof(HE_edge*) * (*vert_dc + 1));
/* NULL-face indicates border-edge */
edges[*ec + *dec].face = NULL;
/* we don't know this one yet */
edges[*ec + *dec].next = NULL;
/* set both pairs */
edges[*ec + *dec].pair = &(edges[i]);
edges[i].pair = &(edges[*ec + *dec]);
/* set vertex */
edges[*ec + *dec].vert = edges[i].next->vert;
/* add the dummy edge to the dummys array of the vertex */
edges[*ec + *dec].vert->dummys[*vert_dc] = &(edges[*ec + *dec]);
(*vert_dc)++;
(*dec)++;
}
}
/* now we have to connect the dummy edges together */
for (uint32_t i = 0; i < (uint32_t) (*dec); i++) { /* for all dummy edges */
/* vertex the dummy edge points to */
HE_vert *vert = edges[*ec + i].pair->vert;
/* iterate over the dummy array */
for (uint32_t j = 0; j < vert->dc; j++) {
if (vert == vert->dummys[j]->vert)
edges[*ec + i].next = vert->dummys[j];
j++;
}
}
}
/**
* Calculate the normal of a face that corresponds
@ -651,81 +263,6 @@ bool normalize_object(HE_obj *obj)
return true;
}
/**
* Parse an .obj string and return a HE_obj
* that represents the whole object.
*
* @param obj_string the whole string from the .obj file
* @return the HE_face array that represents the object, NULL
* on failure
*/
HE_obj *parse_obj(char const * const obj_string)
{
int32_t vc = 0, /* vertices count */
fc = 0, /* face count */
ec = 0, /* edge count */
dec = 0; /* dummy edge count */
char *string = NULL;
HE_vert *vertices = NULL;
HE_edge *edges = NULL;
HE_face *faces = NULL;
HE_obj *obj = NULL;
FACES obj_f = NULL;
/* V_TEXTURES obj_vt = NULL; */
VERTICES obj_v = NULL;
if (!obj_string || !*obj_string)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
obj_v = parse_2d_array(string, "v");
/* obj_vt = parse_2d_array(obj_string, "vt"); */
obj_f = parse_face_array(string);
if ((ec = get_edge_count(obj_f)) == -1)
ABORT("Invalid edge count!\n");
if ((fc = get_face_count(obj_f)) == -1)
ABORT("Invalid face count!\n");
vertices = malloc(sizeof(HE_vert) *
get_row_count((int32_t const**)obj_v) + 1);
CHECK_PTR_VAL(vertices);
faces = (HE_face*) malloc(sizeof(HE_face) * fc);
CHECK_PTR_VAL(faces);
/* hold enough space for possible dummy edges */
edges = (HE_edge*) malloc(sizeof(HE_edge) * ec * 2);
CHECK_PTR_VAL(edges);
assemble_HE_stage1(obj_v, vertices, &vc);
assemble_HE_stage2(obj_f, vertices, faces, edges, &fc, &ec);
assemble_HE_stage3(edges, &ec, &dec);
obj = (HE_obj*) malloc(sizeof(HE_obj));
CHECK_PTR_VAL(obj);
obj->edges = edges;
obj->vertices = vertices;
obj->faces = faces;
obj->ec = ec;
obj->vc = vc;
obj->fc = fc;
/* cleanup */
for (uint32_t i = 0; i < (uint32_t)fc; i++)
free(obj_f[i]);
free(obj_f);
for (uint32_t i = 0; i < (uint32_t)vc; i++) {
free(vertices[i].dummys);
free(vertices[i].edge_array);
free(obj_v[i]);
}
free(obj_v);
free(string);
return obj;
}
/**
* Free the inner structures of an object.
*

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@ -18,10 +18,11 @@
/**
* @file half_edge.h
* Header for the external API of half_edge.c,
* Header for the external API of half_edge.c
* and half_edge_AS.c,
* primarily holding the common half-edge data
* structures.
* @brief header of half_edge.c
* @brief header of half_edge related functions
*/
#ifndef _DROW_ENGINE_HE_OPERATIONS_H

501
src/half_edge_AS.c Normal file
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@ -0,0 +1,501 @@
/*
* Copyright 2011-2014 hasufell
*
* This file is part of a hasufell project.
*
* 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 version 2 of the License only.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file half_edge.c
* This files only purpose is to assemble the half-edge
* data structure from an obj string.
* @brief half-edge assembler
*/
#include "common.h"
#include "err.h"
#include "filereader.h"
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static int32_t get_row_count(int32_t const **array);
static int32_t get_face_count(FACES const faces);
static int32_t get_edge_count(FACES const faces);
static double **parse_2d_array(char const * const obj_string,
char *item);
static FACES parse_face_array(char const * const obj_string);
static void assemble_HE_stage1(VERTICES obj_v,
HE_vert *vertices,
int32_t *vc);
static void assemble_HE_stage2(FACES obj_f,
HE_vert *vertices,
HE_face *faces,
HE_edge *edges,
int32_t *fc,
int32_t *ec);
static void assemble_HE_stage3(HE_edge *edges,
int32_t *ec,
int32_t *dec);
/**
* Get the row count of the 2d array.
*
* @param array the 2 dimensional array
* @return the row count
*/
static int32_t get_row_count(int32_t const **array)
{
uint32_t rc = 0;
if (!array)
return -1;
while (array[rc])
rc++;
return rc;
}
/**
* Get the amount of faces as they are in the
* .obj file.
*
* @param faces the faces array
* @return the count of faces, -1 on failure
*/
static int32_t get_face_count(FACES const faces)
{
if (!faces)
return 0;
return get_row_count((int32_t const**)faces);
}
/**
* Get the amount of edges.
*
* @param faces the faces array which will be used
* to calculate the amount of edges
* @return the count of edges, -1 on failure
*/
static int32_t get_edge_count(FACES const faces)
{
uint32_t ec = 0;
uint32_t fc;
if (!faces)
return -1;
fc = get_face_count(faces);
for (uint32_t i = 0; i < fc; i++)
ec += faces[i][0];
return ec;
}
/**
* Parse a string which supposedly is a 2-dimensional
* array in the .obj file, describing all faces, all vertices
* and such. The parsing depends on the item string, such as "f"
* or "v".
*
* @param obj_string the string that is in obj format
* @param item the item to look for, such as "f" or "v"
* @return a newly allocated 2-dimensional array, NULL on failure
*/
static double **parse_2d_array(char const * const obj_string,
char *item)
{
uint32_t lc = 0;
char *string,
*str_ptr_space = NULL, /* for strtok */
*str_ptr_newline = NULL, /* for strtok */
*str_tmp_ptr = NULL; /* for strtok */
double **arr = NULL;
if (!obj_string || !item)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
str_tmp_ptr = strtok_r(string, "\n", &str_ptr_newline);
while (str_tmp_ptr && *str_tmp_ptr) {
str_tmp_ptr = strtok_r(str_tmp_ptr, " ", &str_ptr_space);
if (!strcmp(str_tmp_ptr, item)) {
char *myint = NULL;
uint8_t i = 1;
REALLOC(arr, sizeof(double*) * (lc + 2));
arr[lc] = NULL;
while ((myint = strtok_r(NULL, " ", &str_ptr_space))) {
i++;
REALLOC(arr[lc],
sizeof(double**) * (i + 1));
arr[lc][i - 1] = atof(myint);
}
arr[lc][0] = i - 1; /* save length at first position */
lc++;
arr[lc] = NULL; /* trailing NULL pointer */
}
str_tmp_ptr = strtok_r(NULL, "\n", &str_ptr_newline);
}
free(string);
return arr;
}
/**
* Parses the face arrays. Since these contain slashes, such as
* "f 1/4/3 8/4/4 9/8/3" we cannot use parse_2d_array() since
* we need extra logic.
*
* @param obj_string the string that is in obj format
* @return a newly allocated FACES array, NULL on failure
*/
static FACES parse_face_array(char const * const obj_string)
{
uint32_t lc = 0;
char *string,
*str_ptr_space = NULL, /* for strtok */
*str_ptr_newline = NULL, /* for strtok */
*str_tmp_ptr = NULL; /* for strtok */
FACES arr = NULL;
if (!obj_string)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
str_tmp_ptr = strtok_r(string, "\n", &str_ptr_newline);
while (str_tmp_ptr && *str_tmp_ptr) {
str_tmp_ptr = strtok_r(str_tmp_ptr, " ", &str_ptr_space);
if (!strcmp(str_tmp_ptr, "f")) {
char *myint = NULL;
uint8_t i = 1;
REALLOC(arr, sizeof(uint32_t*) * (lc + 2));
arr[lc] = NULL;
while ((myint = strtok_r(NULL, " ", &str_ptr_space))) {
i++;
REALLOC(arr[lc],
sizeof(uint32_t**) * (i + 1));
arr[lc][i - 1] = atoi(myint);
}
arr[lc][0] = i - 1; /* save length at first position */
lc++;
arr[lc] = NULL; /* trailing NULL pointer */
}
str_tmp_ptr = strtok_r(NULL, "\n", &str_ptr_newline);
}
free(string);
return arr;
}
/**
* First stage of assembling the half-edge data structure.
* Here we allocate vertices and fill their coordinates
* with the information we have from parsing the obj file.
* All other yet unknown members such as edge are set to
* NULL. This function isn't really modular, but makes
* reading parse_obj() a bit less painful.
*
* @param obj_v the vertices in the raw form after they are
* parsed from the obj file
* @param vertices pointer the actual half-edge vertices
* @param vc pointer to the vertice count
*/
static void assemble_HE_stage1(VERTICES obj_v,
HE_vert *vertices,
int32_t *vc)
{
uint8_t const xpos = 1;
uint8_t const ypos = 2;
uint8_t const zpos = 3;
int8_t const default_col = -1;
*vc = 0;
while (obj_v[*vc]) {
vector *tmp_vec;
if (obj_v[*vc][0] > 3)
ABORT("Failure in parse_obj(),\n"
"malformed vertice, exceeds 3 dimensions!\n");
tmp_vec = malloc(sizeof(vector));
CHECK_PTR_VAL(tmp_vec);
tmp_vec->x = obj_v[*vc][xpos];
tmp_vec->y = obj_v[*vc][ypos];
tmp_vec->z = obj_v[*vc][zpos];
vertices[*vc].vec = tmp_vec;
/* set unused/unknown values to NULL */
vertices[*vc].edge = NULL;
vertices[*vc].edge_array = NULL;
vertices[*vc].eac = 0;
vertices[*vc].dc = 0;
/* allocate color struct and set preliminary colors */
vertices[*vc].col = malloc(sizeof(color));
vertices[*vc].col->red = default_col;
vertices[*vc].col->green = default_col;
vertices[*vc].col->blue = default_col;
(*vc)++;
}
}
/**
* Second stage of assembling the half-edge data structure.
* Here we start creating the HE_edges and HE_faces and also
* fill some missing information to the HE_verts along with it.
* The edge pairs are still unknown, as well as some other
* acceleration-structure related members like vertice->dummys.
* This function isn't really modular, but makes
* reading parse_obj() a bit less painful.
*
* @param obj_f the raw faces as they are after parsing the obj file
* @param vertices the half-edge vertices
* @param faces the half-edge faces
* @param edges the half-edge edges
* @param fc the count of half-edge faces
* @param ec the count of half-edge edges
*/
static void assemble_HE_stage2(FACES obj_f,
HE_vert *vertices,
HE_face *faces,
HE_edge *edges,
int32_t *fc,
int32_t *ec)
{
*ec = 0;
/* create HE_edges and real HE_faces */
for (uint32_t i = 0; i < (uint32_t)(*fc); i++) { /* for all faces */
/* for all vertices of the face */
for (uint32_t j = 0; j < (uint32_t)obj_f[i][0]; j++) {
uint32_t obj_f_pos = j + 1; /* first pos is reserved for length */
uint32_t fv_arr_id =
obj_f[i][obj_f_pos] - 1; /* fv_id starts at 1 */
edges[*ec].vert = &(vertices[fv_arr_id]);
edges[*ec].face = &(faces[i]);
edges[*ec].pair = NULL; /* preliminary */
vertices[fv_arr_id].edge = &(edges[*ec]); /* last one wins */
vertices[fv_arr_id].dummys = NULL; /* preliminary */
/* Skip j == 0 here, so we don't underrun the arrays,
* since we always look one edge back. The first edge
* element is taken care of below as well. */
if (j > 0) {
uint32_t *eac = &(edges[*ec].vert->eac);
/* connect previous edge to current edge */
edges[*ec - 1].next = &(edges[*ec]);
/* Acceleration struct:
* add previous edge to edge_array of current vertice */
REALLOC(edges[*ec].vert->edge_array,
sizeof(HE_edge*) * (*eac + 1));
edges[*ec].vert->edge_array[*eac] = &(edges[*ec - 1]);
(*eac)++;
if (obj_f_pos == (uint32_t)obj_f[i][0]) { /* no vertice left */
uint32_t *eac;
/* connect last edge to first edge */
edges[*ec].next = &(edges[*ec - j]);
eac = &(edges[*ec].next->vert->eac);
/* Acceleration struct:
* add last edge to edge_array element of first vertice */
REALLOC(edges[*ec].next->vert->edge_array,
sizeof(HE_edge*) * (*eac + 1));
edges[*ec].next->vert->edge_array[*eac] = &(edges[*ec]);
(*eac)++;
}
}
(*ec)++;
}
faces[i].edge = &(edges[*ec - 1]); /* "last" edge */
}
}
/**
* Third stage of assembling the half-edge data structure.
* Here we find the pairs of edges and also account for the
* possibility of border-edges, where we have to set up
* dummy edges and connect them properly.
*
* @param edges the half-edge edges
* @param ec the half-edge edges count
* @param dec the dummy edges count
*/
static void assemble_HE_stage3(HE_edge *edges,
int32_t *ec,
int32_t *dec)
{
/* find pairs */
for (uint32_t i = 0; i < (uint32_t)(*ec); i++) { /* for all edges */
uint32_t eac = edges[i].vert->eac;
bool pair_found = false;
for (uint32_t j = 0; j < eac; j++) { /* for all potential pairs */
if (edges[i].vert->edge_array[j] &&
(edges[i].next->vert ==
edges[i].vert->edge_array[j]->vert)) {
edges[i].pair = edges[i].vert->edge_array[j];
edges[i].vert->edge_array[j] = NULL;
pair_found = true;
break;
}
}
/* create dummy pair edge if we have a border edge */
if (!pair_found) {
uint32_t *vert_dc = &(edges[i].next->vert->dc);
REALLOC(edges[i].next->vert->dummys,
sizeof(HE_edge*) * (*vert_dc + 1));
/* NULL-face indicates border-edge */
edges[*ec + *dec].face = NULL;
/* we don't know this one yet */
edges[*ec + *dec].next = NULL;
/* set both pairs */
edges[*ec + *dec].pair = &(edges[i]);
edges[i].pair = &(edges[*ec + *dec]);
/* set vertex */
edges[*ec + *dec].vert = edges[i].next->vert;
/* add the dummy edge to the dummys array of the vertex */
edges[*ec + *dec].vert->dummys[*vert_dc] = &(edges[*ec + *dec]);
(*vert_dc)++;
(*dec)++;
}
}
/* now we have to connect the dummy edges together */
for (uint32_t i = 0; i < (uint32_t) (*dec); i++) { /* for all dummy edges */
/* vertex the dummy edge points to */
HE_vert *vert = edges[*ec + i].pair->vert;
/* iterate over the dummy array */
for (uint32_t j = 0; j < vert->dc; j++) {
if (vert == vert->dummys[j]->vert)
edges[*ec + i].next = vert->dummys[j];
j++;
}
}
}
/**
* Parse an .obj string and return a HE_obj
* that represents the whole object.
*
* @param obj_string the whole string from the .obj file
* @return the HE_face array that represents the object, NULL
* on failure
*/
HE_obj *parse_obj(char const * const obj_string)
{
int32_t vc = 0, /* vertices count */
fc = 0, /* face count */
ec = 0, /* edge count */
dec = 0; /* dummy edge count */
char *string = NULL;
HE_vert *vertices = NULL;
HE_edge *edges = NULL;
HE_face *faces = NULL;
HE_obj *obj = NULL;
FACES obj_f = NULL;
/* V_TEXTURES obj_vt = NULL; */
VERTICES obj_v = NULL;
if (!obj_string || !*obj_string)
return NULL;
string = malloc(sizeof(char) * strlen(obj_string) + 1);
strcpy(string, obj_string);
obj_v = parse_2d_array(string, "v");
/* obj_vt = parse_2d_array(obj_string, "vt"); */
obj_f = parse_face_array(string);
if ((ec = get_edge_count(obj_f)) == -1)
ABORT("Invalid edge count!\n");
if ((fc = get_face_count(obj_f)) == -1)
ABORT("Invalid face count!\n");
vertices = malloc(sizeof(HE_vert) *
get_row_count((int32_t const**)obj_v) + 1);
CHECK_PTR_VAL(vertices);
faces = (HE_face*) malloc(sizeof(HE_face) * fc);
CHECK_PTR_VAL(faces);
/* hold enough space for possible dummy edges */
edges = (HE_edge*) malloc(sizeof(HE_edge) * ec * 2);
CHECK_PTR_VAL(edges);
assemble_HE_stage1(obj_v, vertices, &vc);
assemble_HE_stage2(obj_f, vertices, faces, edges, &fc, &ec);
assemble_HE_stage3(edges, &ec, &dec);
obj = (HE_obj*) malloc(sizeof(HE_obj));
CHECK_PTR_VAL(obj);
obj->edges = edges;
obj->vertices = vertices;
obj->faces = faces;
obj->ec = ec;
obj->vc = vc;
obj->fc = fc;
/* cleanup */
for (uint32_t i = 0; i < (uint32_t)fc; i++)
free(obj_f[i]);
free(obj_f);
for (uint32_t i = 0; i < (uint32_t)vc; i++) {
free(vertices[i].dummys);
free(vertices[i].edge_array);
free(obj_v[i]);
}
free(obj_v);
free(string);
return obj;
}