D3DXLoadMeshFromX(MESH_FILE,0,D3DDev,NULL,NULL,NULL,NULL,&D3DMesh)
access to the vertex data
Author
Hi.
I use DirectX 9.
My problem is: how can I access to the data (position, normal, ...) of each vertex ?
The 3D object mesh is loaded from the DirectX file (*.x), with the function "D3DXLoadMeshFromX":
How can I access to the data of each vertex from the this ?
Someone know the solution ?
Thanls for all.
You have to lock the vertex buffer, which provides you with a pointer to the raw vertex data. With ID3DXMesh, you can just call LockVertexBuffer rather than calling Lock directly on the vertex buffer.
Author
Quote:Original post by MJP
LockVertexBuffer
So, I have to use "LockVertexBuffer" for locking and access to the vertex data. Then I can manipolate the position of the vertex and then unlock.
Is this the correct procedure ?
Author
Quote:Original post by MJP
Yes, that is correct.
One question:
if I use the follow:
D3DMesh->LockVertexBuffer(D3DLOCK_DISCARD, ppData)"ppData" just contain the vertex data (position, normal, ... ) ?
Quote:Original post by ClaudioNo - because D3DLOCK_DISCARD means "Throw away the contents of the buffer and give me a new one" (more or less).Quote:Original post by MJP
Yes, that is correct.
One question:
if I use the follow:
*** Source Snippet Removed ***
"ppData" just contain the vertex data (position, normal, ... ) ?
You want to lock with either 0 or D3DLOCK_READONLY.
Author
Quote:Original post by Evil SteveQuote:Original post by ClaudioNo - because D3DLOCK_DISCARD means "Throw away the contents of the buffer and give me a new one" (more or less).
One question:
if I use the follow:
*** Source Snippet Removed ***
"ppData" just contain the vertex data (position, normal, ... ) ?
You want to lock with either 0 or D3DLOCK_READONLY.
So, if I use "0" or "D3DLOCK_READONLY":
D3DMesh->LockVertexBuffer(0, ppData) the vertex data (position, ...) are in "ppData" ?
But if I want to modifiy te position of the vertex,the flag has to be "0" and not "D3DLOCK_READONLY" ?
Yes, it will be a pointer to a buffer of data that has the layout specified in your vertex declaration. So if your VB has a position, texture coordinate, and normal, then each vertex will have a total 8 float's.
If you create a struct whose layout exactly matches your vertex layout, you can just treat the buffer pointer as a pointer to an array of this struct type. So for instance with the layout I just mentioned, you would have this:
Then when you lock...
If you create a struct whose layout exactly matches your vertex layout, you can just treat the buffer pointer as a pointer to an array of this struct type. So for instance with the layout I just mentioned, you would have this:
struct VertexPositionTextureNormal{ D3DXVECTOR3 Position; D3DXVECTOR2 TexCoord; D3DXVECTOR3 Normal;}Then when you lock...
VertexPostionTextureNormal* verts = NULL;D3DMesh->LockVertexBuffer(D3DLOCK_DISCARD, (VOID**)&verts);DWORD numVerts = D3DMesh->GetNumVertices();for (int i = 0; i < numVerts; i++){ // Access verts as an array to access the vertex data}
Author
While if I want to use the vertex buffer "D3DVB" ?
Is correct ?
Appear error about "access violation to..."
Thanks for all.
struct VERTEX3D{ D3DXVECTOR3 position; D3DXVECTOR3 normal; DWORD color; };VERTEX3D * vertex = NULL;D3DVB->Lock(0, 0, (VOID**) &vertex, D3DLOCK_READONLY); // lockDWORD numVerts = D3DMesh()->GetNumVertices(); // total number of verticesfor(int i=0; i < numVerts; i + +){ // access to: vertex.position, vertex.normal, vertex.color}D3DVB->Unlock(); // unlock Is correct ?
Appear error about "access violation to..."
Thanks for all.
Quote:Original post by ClaudioYes.
While if I want to use the vertex buffer "D3DVB" ?
*** Source Snippet Removed ***
Is correct ?
Quote:Original post by ClaudioBecause you're not checking return values. What do the Debug Runtimes say?
Appear error about "access violation to..."
This topic is closed to new replies.
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