getVertexCount() Is Not Returning the amount of vertexes

[trollger]

I have tried to get the amount of vertexes in a mesh but I am having a problem with it. This is the code that I am using:

Code: Select all

 std::cout << "The Mesh Has: " << CUBE->getMesh()->getMeshBuffer(0)->getVertexCount() << " Vertices";

I have a cube and obviously a cube has 8 vertexes but this function keeps returning 12

I'm stumped.

[Radikalizm]

A cube doesn't necessarily have to have 8 vertices; to be able to do correct UVW-mapping for the cube it needs 12 vertices, otherwise not all faces would display their textures correctly

[trollger]

hmm... Thats Interesting. So How Would I count the vertexes so as to arrive at 8?

[Radikalizm]

hmm... Thats Interesting. So How Would I count the vertexes so as to arrive at 8?

You could always create a mesh scenenode which holds a cube with only 8 vertices (you'd need to write an implementation to generate such a cube yourself, but this isn't hard) as long as you keep in mind that your textures won't display correctly

Otherwise there's no way around the fact that your vertex count will be higher than 8

[HerrAlmanack]

hmm... Thats Interesting. So How Would I count the vertexes so as to arrive at 8?

I suggest you read up on some general 3d graphics tutorials. you need to understand the concepts of unwrapped vertices, their normals, etc etc. it's not a simple matter of the "apparent" number of vertices.

[Radikalizm]

I suggest you read up on some general 3d graphics tutorials. you need to understand the concepts of unwrapped vertices, their normals, etc etc. it's not a simple matter of the "apparent" number of vertices.

I can understand his confusion about the subject, in computer graphics the word vertex has a slightly different meaning than in standard geometry

In geometry a vertex is just a point which represents a corner or intersection of geometric shapes, this means that 2 vertices should never be in the same location since this would make absolutely no sense
In CG a vertex is an element which describes certain properties of a mesh at a certain position, and since a single point can have multiples of the same property (like UV-coordinates), 2 vertices can be placed at the same position

[trollger]

hmm... Thats Interesting. So How Would I count the vertexes so as to arrive at 8?

I suggest you read up on some general 3d graphics tutorials. you need to understand the concepts of unwrapped vertices, their normals, etc etc. it's not a simple matter of the "apparent" number of vertices.

I Would be willing to do some reading on the subject if you have any suggestions.

By the way I have used blender a lot and I have unwrapped UV coordinates but the idea of 2 (or more) vertexes in one position is new to me.

[HerrAlmanack]

blender sets more than one vertex per position when unwrapping, it's just that blender makes it more user friendly by providing a nice graphical interface; it does all the back-end stuff for you.

btw I use blender too I started out with game programming with python and the blender game engine.

[hybrid]

If your question in your first reply was how to find the really distinct vertices, you have to go through all vertices and sort out those which are quite close to each other. Definition of 'quite close' is up to you, and can differ from mesh to mesh. That's the only thing you can do. If you can lend Irrlicht some memory temporarily, you can also create a mesh with distinct vertices with the geometry manipulator. Calling getVertexCount would result in the correct number then.