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Eric Sartre
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4 files changed

+451
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‎geometry.c

+203
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include "geometry.h"
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static vertex_t *vertices = NULL;
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static face_t *faces = NULL;
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static unsigned capacity_vertices;
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static unsigned capacity_faces;
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static unsigned num_vertices;
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static unsigned num_faces;
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void init_geometry()
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{
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num_vertices = num_faces = 0;
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capacity_vertices = INIT_BUFSIZE_VERTICES;
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capacity_faces = INIT_BUFSIZE_FACES;
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if((vertices = malloc(capacity_vertices * sizeof(vertex_t))) == NULL) {
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error_printf("out of memory(faces)\n");
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exit(EXIT_FAILURE);
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}
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if((faces = malloc(capacity_faces * sizeof(face_t))) == NULL) {
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error_printf("out of memory(vertices)\n");
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FREE(vertices);
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exit(EXIT_FAILURE);
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}
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}
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void finalize_geometry()
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{
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FREE(vertices);
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FREE(faces);
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}
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bool is_valid_id(const vertex_id id)
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{
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if(id > num_vertices) {
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error_printf("invalid vertex_id %d\n", id);
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return false;
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} else {
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return true;
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}
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}
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vertex_id new_vertex(const double x, const double y, const double z)
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{
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// initialized check
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if(vertices == NULL) {
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error_printf("not initialized\n");
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exit(EXIT_FAILURE);
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}
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// expand vertices buffer
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if(num_vertices >= capacity_vertices) {
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capacity_vertices *= 2;
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vertices = realloc(vertices, capacity_vertices * sizeof(vertex_t));
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if(vertices == NULL) {
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error_printf("failed to expand buffer(vertices)\n");
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FREE(faces);
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exit(EXIT_FAILURE);
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}
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}
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// put on record
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vertices[num_vertices].x = x;
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vertices[num_vertices].y = y;
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vertices[num_vertices].z = z;
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num_vertices++;
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return num_vertices - 1;
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}
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vertex_id copy_vertex(const vertex_id v)
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{
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if(!is_valid_id(v)) return ERROR_VERTEX;
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return new_vertex(vertices[v].x, vertices[v].y, vertices[v].z);
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}
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void new_face(const vertex_id v1, const vertex_id v2, const vertex_id v3)
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{
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// initialized check
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if(faces == NULL) {
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error_printf("not initialized\n");
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exit(EXIT_FAILURE);
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}
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// expand faces buffer
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if(num_faces >= capacity_faces) {
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capacity_faces *= 2;
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faces = realloc(faces, capacity_faces * sizeof(face_t));
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if(faces == NULL) {
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error_printf("failed to expand buffer(faces)\n");
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FREE(vertices);
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exit(EXIT_FAILURE);
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}
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}
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// put on record
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faces[num_faces].v1 = v1;
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faces[num_faces].v2 = v2;
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faces[num_faces].v3 = v3;
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num_faces++;
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}
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double get_x(const vertex_id v)
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{
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return vertices[v].x;
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}
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double get_y(const vertex_id v)
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{
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return vertices[v].y;
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}
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double get_z(const vertex_id v)
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{
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return vertices[v].z;
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}
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vertex_t get_point(const vertex_id v)
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{
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return vertices[v];
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}
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bool flushOBJ(FILE *fp)
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{
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// initialized check
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if(vertices == NULL || faces == NULL) {
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error_printf("not initialized\n");
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exit(EXIT_FAILURE);
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}
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// flush vertices
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for(unsigned i = 0; i < num_vertices; ++i) {
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vertex_t *v = &vertices[i];
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if(fprintf(fp, "v %f %f %f\n", v->x, v->y, v->z) < 0) {
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error_printf("failed to write file\n");
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goto ON_ERROR;
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}
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}
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// flush faces
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for(unsigned i = 0; i < num_faces; ++i) {
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face_t *f = &faces[i];
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if(fprintf(fp, "f %d %d %d\n", f->v1 + 1, f->v2 + 1, f->v3 + 1) < 0) {
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error_printf("failed to write file\n");
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goto ON_ERROR;
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}
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}
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return true;
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ON_ERROR:
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FREE(vertices);
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FREE(faces);
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fclose(fp);
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return false;
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}
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static inline vertex_t *vp(const vertex_id id)
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{
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return &vertices[id];
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}
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bool vertex_translate(const vertex_id *vs, const unsigned len,
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const double x, const double y, const double z)
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{
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for(unsigned i = 0; i < len; ++i) {
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if(!is_valid_id(vs[i])) return false;
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vertex_t *v = vp(vs[i]);
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v->x += x;
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v->y += y;
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v->z += z;
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}
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return true;
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}
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bool vertex_scale(const vertex_id *vs, const unsigned len,
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const double x, const double y, const double z)
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{
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for(unsigned i = 0; i < len; ++i) {
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if(!is_valid_id(vs[i])) return false;
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vertex_t *v = vp(vs[i]);
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v->x *= x;
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v->y *= y;
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v->z *= z;
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}
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return true;
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}
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bool vertex_rotate(const vertex_id *vs,
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const unsigned len, const double degree,
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const double nx, const double ny, const double nz)
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{
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const double rad = M_PI * degree / 180.0 / 2.0;
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const double x = nx * sin(rad);
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const double y = ny * sin(rad);
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const double z = nz * sin(rad);
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const double w = cos(rad / 2.0);
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const double m[3][3] = {
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{1-2*(y*y+z*z), 2*(x*y-z*w) , 2*(x*z+y*w) },
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{2*(x*y+z*w) , 1-2*(z*z+x*x), 2*(y*z-x*w) },
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{2*(x*y-y*w) , 2*(y*z+x*w) , 1-2*(x*x+y*y)},
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};
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for(unsigned i = 0; i < len; ++i) {
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if(!is_valid_id(vs[i])) return false;
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vertex_t *v = vp(vs[i]);
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const vertex_t t = {v->x, v->y, v->z};
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v->x = t.x * m[0][0] + t.y * m[0][1] + t.z * m[0][2];
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v->y = t.x * m[1][0] + t.y * m[1][1] + t.z * m[1][2];
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v->z = t.x * m[2][0] + t.y * m[2][1] + t.z * m[2][2];
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}
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return true;
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}
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‎geometry.h

+60
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#ifndef GEOMETRY_H_
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#define GEOMETRY_H_
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#include <stdio.h>
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#include <stdbool.h>
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#include <limits.h>
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#define INIT_BUFSIZE_VERTICES 1024
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#define INIT_BUFSIZE_FACES 1024
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#define ERROR_VERTEX UINT_MAX
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// Utility
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#define FREE(P) do { if(P) free(P); P = NULL; } while(0)
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#define error_printf(...) do {\
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fprintf(stderr, "ERROR(%s) : ", __func__);\
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fprintf(stderr, __VA_ARGS__);\
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} while(0)
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typedef struct {
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double x;
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double y;
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double z;
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} vertex_t;
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typedef unsigned vertex_id;
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typedef struct {
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vertex_id v1;
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vertex_id v2;
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vertex_id v3;
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} face_t;
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void init_geometry();
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void finalize_geometry();
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bool is_valid_id(const vertex_id id);
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// Constructors
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vertex_id new_vertex(const double x, const double y, const double z);
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vertex_id copy_vertex(const vertex_id v);
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void new_face(const vertex_id v1, const vertex_id v2, const vertex_id v3);
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// Accessor
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double get_x(const vertex_id v);
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double get_y(const vertex_id v);
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double get_z(const vertex_id v);
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vertex_t get_point(const vertex_id v);
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// Affine transformations
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bool vertex_translate(const vertex_id *vs, const unsigned len,
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const double x, const double y, const double z);
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bool vertex_scale(const vertex_id *vs, const unsigned len,
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const double x, const double y, const double z);
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bool vertex_rotate(const vertex_id *vs,
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const unsigned len, const double degree,
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const double nx, const double ny, const double nz);
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// Flush as Wavefront OBJ file format
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bool flushOBJ(FILE *fp);
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#endif
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