# Resizing D3D Buffers within a frame

I have a particle system. So far it worked like this: I have a dynamic vertex buffer for a system, which is created with a size that can hold for example 100 000 particles. I map/unmap this and write the new data into it every frame.

But what if the particle count gets bigger than the buffer can hold? I thought of recreating the vertex buffer with the double of its previous capacity (then map/unmap into it). Is this the right direction for this or should I solve it in a different way?

A short example:

ID3D11VertexBuffer* buffer;
ID3D11Device*       graphicsDevice;
//...
D3D11_BUFFER_DESC desc;
buffer->GetDesc(&desc);
if(dataSize>(int)desc.ByteWidth){ //data can't fit, so destroy and recreate
buffer->Release();
desc.ByteWidth*=2;
graphicsDevice->CreateBuffer( &desc, nullptr, &buffer ); //returns S_OK
}


Update:

I want to use it for other things, not just particles but for example instanced meshes. If I spawn a couple of instances, I'd only like to resize a buffer, without creating an other one.