Anybody have any .obj file to ALLEGRO

Mark Oates

So I wrote a routine to load a blender .obj file into my program. This is just a simple cube:

{"name":"608542","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/f\/efc6caeda9d0a6762939e1e1b5eaec9b.png","w":644,"h":509,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/f\/efc6caeda9d0a6762939e1e1b5eaec9b"}

That exports like this:

# Blender v2.64 (sub 0) OBJ File: ''
# www.blender.org
o Cube
v 300.000000 -300.000000 -299.999969
v 300.000000 -300.000000 300.000000
v -300.000031 -300.000000 299.999939
v -299.999878 -300.000000 -300.000122
v 300.000153 300.000000 -299.999847
v 299.999817 300.000000 300.000183
v -300.000122 300.000000 299.999878
v -299.999969 300.000000 -300.000000
s off
f 1 2 3 4
f 5 8 7 6
f 1 5 6 2
f 2 6 7 3
f 3 7 8 4
f 5 1 4 8

And when displayed it looks like this:

{"name":"608541","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/c\/ec2f741c5e888f24a33d98427083e1f5.png","w":644,"h":509,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/c\/ec2f741c5e888f24a33d98427083e1f5"}

So obviously I'm getting something right. It looks like the coordinates are being imported correctly, but not being drawn correctly. I tried different ALLEGRO_PRIM_TYPEs because it seems like that might be what's causing it to not work, and they changed the way it displayed but never displayed correctly. I tried reversing the order of the vertexes, cause, who knows that might do something.

here's the import function:

#SelectExpand
  1class Model
  2{
  3public:
std::vector<std::vector<ALLEGRO_VERTEX>> face;
ALLEGRO_PRIM_TYPE prim_type;
ALLEGRO_BITMAP *texture;
//placement3d place;
  8
Model();
 10
void clear();
void scale(float x, float y, float z);
void move(float x, float y, float z);
void move_to(float x, float y, float z);

void set_texture(ALLEGRO_BITMAP *t);
 17
void load_obj(std::string filename, ALLEGRO_COLOR color);  // see below
 19
void draw();
 21};
 22
 23
 24
 25
 26void Model::load_obj(std::string filename, ALLEGRO_COLOR color=al_map_rgb_f(1, 1, 1))
 27{
clear();
 29
 30
std::ifstream in(filename, std::ios::in);
if (!in)
{
  std::cerr << "Cannot open " << filename << std::endl;
  //exit(1);
}
 37
//prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_LIST;
//prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_STRIP;
prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_FAN;
//ALLEGRO_PRIM_TRIANGLE_FAN;
 42
//vec3d vec;
//Face *current_face = face;
 45
std::string line;
std::vector<ALLEGRO_VERTEX> *current_face = NULL;
std::vector<ALLEGRO_VERTEX> dummy_face;
float x, y, z;
while (getline(in, line))
{
  if (line.substr(0,2) == "o ")
{
  face.push_back(dummy_face);
  current_face = &face.back();
}
  else if (line.substr(0,2) == "v ")
{
    std::istringstream s(line.substr(2));
  s >> x; s >> y; s >> z;
  current_face->push_back(build_vertex(x, y, z, color, 0, 0));
  }
else if (line.substr(0,2) == "f ")
{
  /*
    std::istringstream s(line.substr(2));
    GLushort a,b,c;
    s >> a; s >> b; s >> c;
    a--; b--; c--;
 70
    elements.push_back(a);
  elements.push_back(b);
  elements.push_back(c);
  */
  }
  else if (line[0] == '#') { /* ignoring this line */ }
  else { /* ignoring this line */ }
}
 79}

(I also have no idea how to get the texture applied/exported/imported.)

[edit:] After more poking, I think it has to do with the faces, I have an idea.

[edit 2:]
boohm! got it. 8-)
{"name":"608544","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/2\/c\/2c1537e594341a2fd814862e306a9752.png","w":629,"h":494,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/2\/c\/2c1537e594341a2fd814862e306a9752"}
{"name":"608543","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/9\/e96cda0491c652395dc651c31aedaad1.png","w":629,"h":494,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/e\/9\/e96cda0491c652395dc651c31aedaad1"}
(with random colors on the vertices.)

Edgar Reynaldo

Damn Oates! Nice work!

pkrcel

Mark, is the code in your post the latest one that loads correctly? I can't see how you handle vertex ordering in the faces.

Mark Oates

Now my loader takes in uv textures! 8-)

{"name":"608545","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/b\/8\/b895d2e258bd8b16efc906985ddd3da6.png","w":852,"h":682,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/b\/8\/b895d2e258bd8b16efc906985ddd3da6"}

It's all weird and half the coordinates are flipped and stuff, but who cares!! I can hack around that until I sort it out later! Celebration!!!

pkrcel said:

Mark, is the code in your post the latest one that loads correctly? I can't see how you handle vertex ordering in the faces.

Here's the code, now. It's nasty don't look at it :-X

#SelectExpand
   1
   2class Model
   3{
   4public:
   5
   6  std::vector<std::vector<ALLEGRO_VERTEX>> face;
   7
   8  std::vector<ALLEGRO_VERTEX> vertexes;
   9  std::vector<vec2d> uvs;
  10  std::vector<std::vector<int>> face_index_lists;
  11  std::vector<std::vector<int>> uv_index_lists;
  12  //std::vector<ModelFace> face_definitions;
  13
  14  ALLEGRO_PRIM_TYPE prim_type;
  15  ALLEGRO_BITMAP *texture;
  16  //placement3d place;
  17
  18  Model();
  19
  20  void clear();
  21  void scale(float x, float y, float z);
  22  void move(float x, float y, float z);
  23  void move_to(float x, float y, float z);
  24  
  25  void set_texture(ALLEGRO_BITMAP *t);
  26
  27  void load_obj(std::string filename, ALLEGRO_COLOR color);
  28
  29  void draw();
  30};
  31
  32
  33
  34
  35void Model::load_obj(std::string filename, ALLEGRO_COLOR color=al_map_rgb_f(1, 1, 1))
  36{
  37  clear();
  38
  39  texture = al_load_bitmap("data/bitmaps/pillar_texture-02.png");
  40
  41
  42  std::ifstream in(filename, std::ios::in);
  43  if (!in)
  44  {
  45    std::cerr << "Cannot open " << filename << std::endl;
  46    //exit(1);
  47  }
  48
  49  //prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_LIST;
  50  //prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_STRIP;
  51  prim_type = ALLEGRO_PRIM_TYPE::ALLEGRO_PRIM_TRIANGLE_FAN;
  52  //ALLEGRO_PRIM_TRIANGLE_FAN;
  53
  54  //vec3d vec;
  55  //Face *current_face = face;
  56
  57  //std::vector<ALLEGRO_VERTEX> *current_face = NULL;
  58  //std::vector<ALLEGRO_VERTEX> dummy_face;
  59
  60  std::string line;
  61  float x, y, z;
  62  std::vector<int> dummy_face_index;
  63  while (getline(in, line))
  64  {
  65    if (line.substr(0,2) == "o ")
  66  {
  67    //face.push_back(dummy_face);
  68    //current_face = &face.back();
  69  }
  70    else if (line.substr(0,2) == "v ")
  71  {
  72      std::istringstream s(line.substr(2));
  73    s >> x; s >> y; s >> z;
  74    vertexes.push_back(build_vertex(x, y, z, color::white, 0, 0));
  75    }
  76    else if (line.substr(0,3) == "vt ")
  77  {
  78      std::istringstream s(line.substr(3));
  79    s >> x; s >> y;
  80    uvs.push_back(vec2d(x, y));
  81    }
  82  else if (line.substr(0,2) == "f ")
  83  {
  84      std::istringstream s(line.substr(2));
  85
  86    face_index_lists.push_back(dummy_face_index);
  87    uv_index_lists.push_back(dummy_face_index);
  88    std::vector<std::string> tokens = php::explode(" ", line.substr(2));
  89    for (unsigned i=0; i<tokens.size(); i++)
  90    {
  91      std::vector<std::string> face_parts = php::explode("/", tokens[i]);
  92
  93      // get the face vertex
  94      if (face_parts.size() >= 1)
  95        face_index_lists.back().push_back(atoi(face_parts[0].c_str()) - 1);
  96
  97      // get the uv vertex
  98      if (face_parts.size() >= 2)
  99        uv_index_lists.back().push_back(atoi(face_parts[1].c_str()) - 1);
 100    }
 101    }
 102    else if (line[0] == '#') { /* ignoring this line */ }
 103    else { /* ignoring this line */ }
 104  }
 105
 106  std::cout << "Model Loaded" << std::endl;
 107  std::cout << "  uvs.size(): " << uvs.size();
 108}
 109
 110
 111
 112
 113
 114void Model::draw()
 115{
 116  //ALLEGRO_TRANSFORM transform;
 117  //al_identity_transform(&transform);
 118
 119  //place.start_transform();
 120
 121  if (!face.empty())
 122    for (unsigned f=0; f<face.size(); f++)
 123      al_draw_prim(&face[f][0], NULL, texture, 0, face[f].size(), prim_type);
 124  else if (!face_index_lists.empty() && !vertexes.empty())
 125  {
 126    for (unsigned i=0; i<face_index_lists.size(); i++)
 127    {
 128      // reset the uv coordinates
 129      for (unsigned j=0; j<face_index_lists[i].size(); j++)
 130      {
 131        ALLEGRO_VERTEX *this_vertex = &vertexes[face_index_lists[i][j]];
 132        //uv_index_lists[i][j];
 133        this_vertex->u = uvs[uv_index_lists[i][j]].x * al_get_bitmap_width(texture);
 134        this_vertex->v = -uvs[uv_index_lists[i][j]].y * al_get_bitmap_height(texture);
 135        //this_vertex->u = random_float(0, 1) * al_get_bitmap_width(texture);
 136        //this_vertex->v = random_float(0, 1) * al_get_bitmap_height(texture);
 137      }
 138      al_draw_indexed_prim(&vertexes[0], NULL, texture, &face_index_lists[i][0], face_index_lists[i].size(), prim_type);
 139    }
 140  }
 141
 142
 143
 144  //place.restore_transform();
 145}

AMCerasoli

pkrcel

Cool, I am not familiar with blender obj files.....has it any info about the texture embedded in it?

Nice job anyway Mark.....I still struggle a bit with how you handle vertex indexes but it is really really cool.

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