Jump to content
  • Advertisement
Sign in to follow this  
necreia

DrawIndexedPrimitive help please

This topic is 4777 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Ok, I've been banging my head on the wall for 2 days on this one... here is the code:
// Render a face while the stream is open
HRESULT CMeshStream::RenderMesh(CVertex *Vertices, short *Indices,
unsigned short NumVerts, unsigned short NumIndices,int TESTNUM)
{
	// if the stream is not open, open it
	if(!m_bLoaded)
		Open();

	// fail out if the values passed do not work
	if(Vertices == NULL)
		return E_FAIL;
	if(Indices == NULL)
		return E_FAIL;

	HRESULT r = 0;		// error holding value

	// create the index buffer
	g_pDevice->CreateIndexBuffer(sizeof(short)*NumIndices,
             D3DUSAGE_WRITEONLY,D3DFMT_INDEX16, D3DPOOL_DEFAULT, &m_pIB);
	if(FAILED(r))
	{
		ErrorMessage.Show("Could not create the index buffer");
		return E_FAIL;
	}

	// create the vertex buffer
	r = g_pDevice->CreateVertexBuffer(sizeof(CVertex)*NumVerts,
             D3DUSAGE_WRITEONLY,VERTEX_TYPE, D3DPOOL_DEFAULT, &m_pVB);
	if(FAILED(r))
	{
		ErrorMessage.Show("Could not create the vertex buffer");
		return E_FAIL;
	}

	BYTE* pData;	    // vertex buffer data
	BYTE* pIndexData;   // index buffer data

	r = m_pVB->Lock(0, 0, &pData, 0);  // lock the vertex buffer
	if(FAILED(r))
	{
		ErrorMessage.Show("Could not lock the vertex buffer");
		m_pVB->Release();
		return E_FAIL;
	}
	
	r = m_pIB->Lock(0, 0, &pIndexData, 0);  // lock the index buffer
	if(FAILED(r))
	{
		ErrorMessage.Show("Could not lock the index buffer");
		m_pVB->Release();
		return E_FAIL;
	}	

	// copy the indices into the index buffer
	CopyMemory(pIndexData, Indices, sizeof(short)*NumIndices);
	m_pIB->Unlock(); // unlock the index buffer			

	// copy the vertices to the vertex buffer
	CopyMemory(pData, Vertices, sizeof(CVertex)*NumVerts);
	m_pVB->Unlock(); // unlock the vertex buffer

	// connect the vertex buffer to a rendering stream
	g_pDevice->SetStreamSource(0, m_pVB, sizeof(CVertex));
	// tell direct3d about the index buffer
	g_pDevice->SetIndices(m_pIB, 0);

	// draw the mesh
	g_pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,NumIndices,
           0,(NumIndices/3));

	m_pVB->Release();
	m_pIB->Release();
	
	return S_OK;
}

The problem is, at the part: g_pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,NumIndices,0,(NumIndices/3)); The program fails. Now if I pass the parameters: g_pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,21,0,7); or lower, it doesn't fail... and just renders those ones. This has lead me to beleive there is a bug in my indices and vertex streams, so I parced them and found nothing that is out of place. What I did do that WORKS however, is set up an if loop and cycle through the indices 3 at a time, pull out those vertices, and render the faces individually with g_pDevice->DrawPrimitive(D3DPT_TRIANGLELIST,0,1); This is grossly underproductive, anyone have any idea why my program might be crashing with the above source snipit? (or anything I should look into). The error message is the general (report the error to microsoft?) The debugger says "Unhandled exception in Kelic Saga.exe (D3D8.DLL): 0xC0000005; Access Violation." Thanks in Advanced

Share this post


Link to post
Share on other sites
Advertisement
I only glanced at the code, but it doesn't look like you provided the mappings for what index references what vertex. If you have an index that references a vertex which is out of bounds, you'll get an error.

Share this post


Link to post
Share on other sites
Quote:
Original post by QuadMV
I only glanced at the code, but it doesn't look like you provided the mappings for what index references what vertex. If you have an index that references a vertex which is out of bounds, you'll get an error.


I'm afraid I don't understand what you mean. If you are referring to the ID's in the index, and their values compared to the array-location of the vertex in the datastream, they (at least when I did teasting) should be pointing to valid data.

Share this post


Link to post
Share on other sites
In this part:
g_pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,NumIndices,
0,(NumIndices/3));

Shouldn't NumIndices be actually the number of vertices? And is (NumIndices/3) actually the primitive count? Again, I think it would rather be (NumVertices/3).

Share this post


Link to post
Share on other sites
Quote:
Original post by Specchum
In this part:
g_pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,NumIndices,
0,(NumIndices/3));

Shouldn't NumIndices be actually the number of vertices? And is (NumIndices/3) actually the primitive count? Again, I think it would rather be (NumVertices/3).


Ah hah, you were half right. NumIndices should have been NumVertices, however the primitive count is the indicies number divided by 3 (triangles)

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!