Vertex Declaration for Irrlicht

[Megel]

this if my method how to add vertex declaration to Irrlicht

IMeshBuffer:

Code: Select all

enum VertexType
{
Position, Normal, TexCoord ....
}

struct VertexChannel
{
     int Stride;
     char* VertexPointer;
     VertexType Type;
}

class IVertexDeclaration
{
    public:
    virtual int getStride();
    virtual int ElementOffset(VertexType type);
}

class MeshBuffer
{
    int indexCount;
    int vertexCount;
    IVertexDeclaration* Declaration;

    void* Indices;
    array<VertexChannel*> Channels;
public:

    template<typename VertexType>
    VertexType* GetVertexChannel(VertexType type)
    {         
         for(int i = 0; i < Channles.size(); i++)
              if(Channels[i]->Type == type)
                 return (VertexType*)Channles[i]->VertexPointer;
        
         VertexChannel* channel = VertexChannel();
         channel->Type = type;
         channel->Stride = sizeof(VertexType);
         channel->VertexPointer = new VertexType[vertexCount];
         Channels->Add(channel);
    }

}

Writing VertexData:

Code: Select all

char* lockData;

//for each channels
VertexChannel* channel = ...

for(int i = 0; i < vertexCount; i++)
{
    int offset = Declaration->ElementOffset(channel->Type);
    memcpy(lockData +  i * Declaration->getStride() + offset,
        channel->VertexPointer + i * channel->Stride, channel->Stride);
}

Creating Mesh:

Code: Select all

vector3df* position =  mesh->GetVertexChannel(VertexType::Position);
vector3df* normals = mesh->GetVertexChannel(VertexType::Normal);

// Filling data

P.S.
sorry for my english

[sudi]

Ok...i don't get it there are some parts in your code that does not make any sense at all. for example:

Code: Select all

VertexChannel* channel = VertexChannel();
         channel->Type = type;
         channel->Stride = sizeof(VertexType);
         channel->VertexPointer = new VertexType[vertexCount];
         Channels->Add(channel); 

first u init a pointer wrong and then the vertexpointer is just filled with enums? huh?

[Megel]

Code: Select all

  template<typename T> 
    T* GetVertexChannel(VertexType type) 
    {          
         for(int i = 0; i < Channles.size(); i++) 
              if(Channels[i]->Type == type) 
                 return (T*)Channles[i]->VertexPointer; 
        
         VertexChannel* channel = VertexChannel(); 
         channel->Type = type; 
         channel->Stride = sizeof(VertexType); 
         channel->VertexPointer = new T[vertexCount]; 
         Channels->Add(channel); 
    }

this is xna style declaration. (MeshBuilder)

[Seven]

maybe working code would be easier to debug

[Megel]

i tryed to use this declaration in my engine and is works fine.
i can insert this declaration in engine if someone will be interested.
but in will take a lot of time

[vitek]

You do not allocate your vertex channel correctly, and what you have is not allowed by the C++ language. You'd need to write...

Code: Select all

VertexChannel* channel = new VertexChannel();

Your code has an implicit conversion from T* to char*, which is not allowed by the C++ language. You need an explicit cast.

Code: Select all

channel->VertexPointer = (char*)new T[vertexCount]; 

Your function falls of the end without returning the vertex data if it isn't found. You need to add the following to avoid undefined behavior.

Code: Select all

return (T*)channel->VertexPointer;

Travis