.OBJ OpenGL wrong render

Question

anybody knows, why it happen? A try to render OBJ file with Opengl.

  // (0 - индекс вершины / 1 - индекс текстурной координаты / 2 - индекс нормали)
  for i := 0 to length(faces) - 1 do
  begin
    glBegin(faces[i].mode);
    Count := length(faces[i].data);
    for k := 0 to Count - 1 do
    begin
      glNormal3fv(@normals[faces[i].data[k].normalIndex]);
      glTexCoord2fv(@texcoords[faces[i].data[k].texCoodIndex]);
      glVertex3fv(@vertexes[faces[i].data[k].vIndex]);
    end;
    glEnd();

already answered but see [How do I sort the texture positions based on the texture indices given in a Wavefront (.obj) file?](https://stackoverflow.com/a/51722009/2521214) for some more info — Spektre, Jan 29 '20 at 08:59

score 4 · Accepted Answer · answered Jan 26 '20 at 20:43

4

Wavefront OBJ start at 1. So you have to subtract 1 from each index:

glNormal3fv(@normals[faces[i].data[k].normalIndex - 1]);
glTexCoord2fv(@texcoords[faces[i].data[k].texCoodIndex - 1]);
glVertex3fv(@vertexes[faces[i].data[k].vIndex - 1]);

answered Jan 26 '20 at 20:43

Rabbid76

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Surprising that the code that parses the obj file doesn't make that adjustment – David Heffernan Jan 27 '20 at 08:05
@DavidHeffernan That's a common issue in many different wavefront parser in many languages. – Rabbid76 Jan 27 '20 at 08:13
2

It's almost as if the author of the parser never even bothered to write code to render the model! – David Heffernan Jan 27 '20 at 08:37

.OBJ OpenGL wrong render

1 Answers1