main.c

#include <allegro.h>
#include <stdio.h>
#include <string.h>

typedef int face[3];
typedef char texture[64];
typedef struct mesh
{
	V3D *verts;
	V3D_f *verts_f;
	texture *textures;
	int num_verts, num_faces, num_textures;
	face *faces;
} mesh;

void unpack_faces(face *uv_faces, face *pos_faces, int num_faces, V3D_f *uv_verts, V3D_f *pos_verts, face *out_faces, V3D_f **out_verts, int *num_verts_out)
{
	int vuv[99999], vpos[99999];
	int i, j, k;
	
	*num_verts_out = 0;
	
	for(i = 0; i < num_faces; i++)
	{
		for(j = 0; j < 3; j++)
		{
			for(k = 0; k < *num_verts_out; k++)
			{
				if(uv_faces[i][j] == vuv[k] && pos_faces[i][j] == vpos[k])
				{
					out_faces[i][j] = k;
					break;
				}
			}
			if(k == *num_verts_out)
			{
				vuv[*num_verts_out] = uv_faces[i][j];
				vpos[*num_verts_out] = pos_faces[i][j];
				out_faces[i][j] = *num_verts_out;
				(*num_verts_out)++;
			}
		}
	}
	
	*out_verts = malloc(sizeof(V3D_f) * *num_verts_out);
	for(k = 0; k < *num_verts_out; k++)
	{
		(*out_verts)[k].x = pos_verts[vpos[k]].x;
		(*out_verts)[k].y = pos_verts[vpos[k]].y;
		(*out_verts)[k].z = pos_verts[vpos[k]].z;
		(*out_verts)[k].u = uv_verts[vuv[k]].u;
		(*out_verts)[k].v = uv_verts[vuv[k]].v;
	}
}

#define VPICK(a,b) ((b) == 0 ? (&a.x) : (b) == 1 ? (&a.y) : (&a.z))
#define VTPICK(a,b) ((b) == 0 ? (&a.u) : (&a.v))

mesh load_obj(const char *fn)
{
	char lin[1024];
	char *tok;
	FILE *obj = fopen(fn, "r");
	int n_v, n_vt, n_f, n_mtl;
	int i;
	int pass;
	mesh m;
	V3D_f *uv_verts, *pos_verts;
	int n_faces;
	face *uv_faces, *pos_faces;
	
	for(pass = 0; pass < 2; pass++, fseek(obj, 0, SEEK_SET))
	{
		if(pass)
		{
			uv_verts = malloc(sizeof(V3D_f) * n_vt);
			pos_verts = malloc(sizeof(V3D_f) * n_v);
			
			uv_faces = malloc(sizeof(face) * n_f);
			pos_faces = malloc(sizeof(face) * n_f);
			m.faces = malloc(sizeof(face) * n_f);
			n_faces = n_f;
			m.num_faces = n_f;
			
			m.num_textures = n_mtl;
			m.textures = malloc(sizeof(texture) * n_mtl);
		}
		n_v = 0; n_vt = 0; n_f = 0; n_mtl = 0;
		while(fgets(lin, 1024, obj))
		{
			int cmd = 0;
			if(!strlen(lin)) continue;
			
			for(tok = strtok(lin, " "); tok; tok = strtok(0, " "))
			{
				if(cmd && !pass) break;
				switch(cmd)
				{
					case 0:
						if(!strcmp(tok, "#")) goto nxl;
						if(!strcmp(tok, "v"))
						{
							cmd = 1;
							n_v++;
							i = 0;
						}
						if(!strcmp(tok, "vt"))
						{
							cmd = 2;
							n_vt++;
							i = 0;
						}
						if(!strcmp(tok, "vn")) cmd = 3;
						if(!strcmp(tok, "f"))
						{
							cmd = 4;
							n_f++;
							i = 0;
						}
						if(!strcmp(tok, "g")) cmd = 5;
						if(!strcmp(tok, "usemtl"))
						{
							cmd = 6;
							n_mtl++;
						}
						if(!strcmp(tok, "s")) cmd = 7;
						if(!cmd) goto nxl;
						break;
					case 1:
						*VPICK(pos_verts[n_v - 1], i) = atof(tok);
						i++;
						break;
					case 2:
						*VTPICK(uv_verts[n_vt - 1], i) = atof(tok);
						i++;
						break;
					case 4:
						*strchr(tok, '/') = 0;
						pos_faces[n_f - 1][i] = atoi(tok);
						tok[strlen(tok)] = '/';
						uv_faces[n_f - 1][i] = atoi(strchr(tok, '/') + 1);
						i++;
						break;
					case 6:
						strcpy(m.textures[n_mtl - 1], tok);
						break;
				}
			}
			nxl:
			continue;
		}
	}
	
	unpack_faces(uv_faces, pos_faces, n_faces, uv_verts, pos_verts, m.faces, &m.verts_f, &m.num_verts);
	free(uv_verts);
	free(pos_verts);
	free(uv_faces);
	free(pos_faces);
	
	return m;
}

int main()
{
	allegro_init();
	set_color_depth(32);
	set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);
	install_keyboard();
	install_mouse();
	
	mesh m = load_obj("data/level.obj");
	
	while(!key[KEY_ESC])
	{
		vsync();
	}
	
	return 0;
}
END_OF_MAIN()