nzacl0

04-05-2011, 08:52 PM

Folks

Being a newbie to OpenGL (and not yet into shaders), I wonder if anyone can tell me if my thinking on VBO's and the use of welded (shared) vertices vs unwelded vertices in models is correct.

If I use welded vertices with VBOs, then the advantages are:

1/ Less memory space is used on the card.

2/ Vertex array normals for shared vertices are algorithmically easier to compute.

The disadvantages are:

1/ Textures are harder to render correctly because texture coordinates are shared by vertices.

And a general comment...

1/ There is no speed advantage using welded vertices since the number of vertices drawn is the same whether vertices are welded or unwelded.

So...if the above is fairly correct then I should use unwelded models where I'm using textures.

Being a newbie to OpenGL (and not yet into shaders), I wonder if anyone can tell me if my thinking on VBO's and the use of welded (shared) vertices vs unwelded vertices in models is correct.

If I use welded vertices with VBOs, then the advantages are:

1/ Less memory space is used on the card.

2/ Vertex array normals for shared vertices are algorithmically easier to compute.

The disadvantages are:

1/ Textures are harder to render correctly because texture coordinates are shared by vertices.

And a general comment...

1/ There is no speed advantage using welded vertices since the number of vertices drawn is the same whether vertices are welded or unwelded.

So...if the above is fairly correct then I should use unwelded models where I'm using textures.