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Rendering with GL_TRIANGLE_STRIP (.3ds model data)

Started by TheEfffigy Apr 13, 2012 at 12:52 AM 1 replies 1.8k views
Original Post
TheEfffigy
TheEfffigy
Hi there,

I've just written a .3ds format model loader which seems to be working very well - but I'm am having an issue rendering the model objects. It seems to me that the issue is with the order that I am rendering the vertices and most likely is a very simple and silly mistake perhaps someone here can point out for me.

As you can see in the screenshot below, the faces for the left and right hand side of the cube aren't rendering correctly.

<img src='http://www.acentuo.com/static/images/render-fail.png' alt='render-fail.png'>

And this is my relevant chunk of rendering code:

void Model::render() const {
glColor3f(1.0, 1.0, 1.0);
std::for_each(i_->objects.begin(), i_->objects.end(),
[](const i::Object& obj) {
glBegin(GL_TRIANGLE_STRIP);
std::for_each(obj.faces.begin(), obj.faces.end(),
[&obj](const i::Object::Face& f) {
const Vector3& v1 = obj.vertices[f.x];
glVertex3f(v1.x, v1.y, v1.z);
const Vector3& v2 = obj.vertices[f.y];
glVertex3f(v2.x, v2.y, v2.z);
const Vector3& v3 = obj.vertices[f.z];
glVertex3f(v3.x, v3.y, v3.z);
});
glEnd();
});
}

I've gone over the model loading code and I'm quite certain it follows the format specification correctly, and my hex editor agrees with what I've loaded.
TheEfffigy
TheEfffigy
May be worth noting that a simple plane, and a slightly more complex plane with an edge extruded 90 degrees render just fine... but as the polygons and depth increase things become a bit crazy.
TheEfffigy
TheEfffigy
Ah, problem solved! I went over a few other loaders I found on the net and it turns out that you have to swap the ordering of the face vertices.

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