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merging two meshes

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I have two mesh: SourceMesh and MergeMesh, both have Position, Normal and Text1, both have identical Position and Normals, but has diferent texture coordinates I like to create another one, having all the data in the SourceMesh, plus another texture channel which I have from the second. This is what I had done:
        public struct myVertex
            public Vector3 Position;
            public Vector3 Normal;
            public Vector2 Text1;
            public Vector2 Text2;

VertexElement[] elements = new VertexElement[]
    new VertexElement(0, 0, DeclarationType.Float3, DeclarationMethod.Default, DeclarationUsage.Position, 0),
    new VertexElement(0, 12, DeclarationType.Float3, DeclarationMethod.Default, DeclarationUsage.Normal, 0),                                        
    new VertexElement(0, 24, DeclarationType.Float2, DeclarationMethod.Default, DeclarationUsage.TextureCoordinate, 0),
    new VertexElement(0, 32, DeclarationType.Float2, DeclarationMethod.Default, DeclarationUsage.TextureCoordinate, 1),                                        

Mesh NewMesh = new Mesh(SourceMesh.NumberFaces, SourceMesh.NumberFaces * 3, SourceMesh.Options.Value, elements, Form_Main.Form.device);

// Set the indices into the NewMesh
short[] aIndices = (short[])SourceMesh.LockIndexBuffer(typeof(short), LockFlags.ReadOnly, SourceMesh.NumberFaces * 3);
NewMesh.SetIndexBufferData(aIndices, LockFlags.None);

// Create 3 vertices per face
myVertex[] NewVertex = new myVertex[NewMesh.NumberFaces * 3];

    CustomVertex.PositionNormalTextured[] SourceVertex = (CustomVertex.PositionNormalTextured[])SourceMesh.LockVertexBuffer(typeof(CustomVertex.PositionNormalTextured), LockFlags.ReadOnly, SourceMesh.NumberVertices);
    CustomVertex.PositionNormalTextured[] MergeVertex = (CustomVertex.PositionNormalTextured[])MergeMesh.LockVertexBuffer(typeof(CustomVertex.PositionNormalTextured), LockFlags.ReadOnly, MergeMesh.NumberVertices);

        // Copy the info
        foreach (short Index in aIndices)
            NewVertex[Index].Position = SourceVertex[aIndices[Index]].Position;
            NewVertex[Index].Normal   = SourceVertex[aIndices[Index]].Normal;
            NewVertex[Index].Text1 = new Vector2(SourceVertex[aIndices[Index]].Tu, SourceVertex[aIndices[Index]].Tv);
            NewVertex[Index].Text2 = new Vector2(MergeVertex[aIndices[Index]].Tu, MergeVertex[aIndices[Index]].Tv);

        // Set the vertices into NewMesh
        NewMesh.SetVertexBufferData(NewVertex, LockFlags.None);



// Copy attributes
int[] SourceAttributes = SourceMesh.LockAttributeBufferArray(LockFlags.None);
int[] NewAttributes = NewMesh.LockAttributeBufferArray(LockFlags.None);
    SourceAttributes.CopyTo(NewAttributes, 0);


The problem is that in fact it create another mesh, but when I render the new one, there are some faces which are ok, but there are others that take random vertices in the mesh. So it looks like a bunch of random triangles with the form of the source mesh. Any tip why this code doesn't work?

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I don't have time to step through your code, but you might want to check out the D3DXConcatenateMeshes() function since you are already using meshes.

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what the D3DXConcatenateMeshes() does is to attash to meshes
(newfaces = sourceFaces + mergeFaces),
what I want to do is to keep the original sourceFaces and add a second texture channel from the mergeMesh.

I fix a bit the code and now it generate the correct positions. The problem was that the vertex ordering of the newMesh is not same of the sourceMesh since I expand the vertices into 3 unique vertices per face, and so I have to generate new indices, not just copying the original index buffer from the source.

But now arrice another problem, I what to keep the attributes. So I have to copy the source attribute buffer to the newBuffer and this is what I do:

int[] FromAttributes = SourceMesh.LockAttributeBufferArray(LockFlags.None);
int[] ToAttributes = NewMesh.LockAttributeBufferArray(LockFlags.None);

// Copy the complete array
FromAttributes.CopyTo(ToAttributes, 0);


That code should copy the attributes from the source mesh to the newMesh. But inmediatly after that I did this just to check:

int[] Attributess = NewMesh.LockAttributeBufferArray(LockFlags.None);

and Attributess returns an array with the correct length but filled of ceros.

Whats the problem? Why the buffer is not copying? Am I missing something? Maybe some flag?

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