I am trying to write my own OBJ importer and renderer in OpenGL (yes, I know, reinventing the wheel) and I found a problem that I don't knwo how to handle.
In an OBJ file faces are defined by a list of indices that refers to the vertices IDs that belongs to that face (and the same for texture coordinates IDs), an example of a face could be:
f 2411/905 2414/906 2913/1463
which would mean that this face is created by vertices
2411, 2414, 3913 and texture coordinates IDs
905, 906, 1463. And this leads to different index buffers, if I am not mistaken...
Now the question is, having both a buffer of vertices and a buffer of texture coordinates, how can I use both "at the same time", if I am only able to bing one index buffer and the indices to be used for a particular face are different for vertices and texture coordinates? Is there any trick to bind two index buffers, one for vertices and another one for texture coordinates?
And finally, just to give some code of what I've tried and that obviously doesn't work because I am binding two different
GL_ELEMENT_ARRAY_BUFFER_ARB before drawing..., so it ends up with random texture coodinates.
// TEXTURE VBO glBindBufferARB(GL_ARRAY_BUFFER_ARB, texCoordBuffer); glTexCoordPointer(2, GL_FLOAT, 0, 0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, texIndicesBuffer); glIndexPointer(GL_INT, 0, 0); // GEOMETRY VBO glBindBufferARB(GL_ARRAY_BUFFER_ARB, vertexBuffer); glVertexPointer(3, GL_FLOAT, 0, 0); glEnableClientState(GL_VERTEX_ARRAY); glBindBufferARB(GL_ARRAY_BUFFER_ARB, normalBuffer); glNormalPointer(GL_FLOAT, 0, 0); glEnableClientState(GL_NORMAL_ARRAY); glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, indicesBuffer); glIndexPointer(GL_INT, 0, 0); // Bind texture and draw...