I have a terrain class that renders fine and I'm trying to add point sprites above each patch ( diamond) of the terrain. I have it set up so the terrain is rendered first using a mesh, then I set the stream to the vertex buffer containing the point sprites. The program compiles fine, but when I run it it crashes and the debugger points me to the line where I'm assigning the point sprite VB to the device stream. Here's the function that's supposed to draw the point sprites:

void Terrain::drawNodes()
{
	_device->SetRenderState(D3DRS_LIGHTING, false);
	_device->SetRenderState(D3DRS_POINTSPRITEENABLE, true);
	_device->SetRenderState(D3DRS_POINTSCALEENABLE, true); 
	_device->SetRenderState(D3DRS_POINTSIZE, d3d::FtoDw(0.25f));
	_device->SetRenderState(D3DRS_POINTSIZE_MIN, d3d::FtoDw(0.0f));

	_device->SetRenderState(D3DRS_POINTSCALE_A, d3d::FtoDw(0.0f));
	_device->SetRenderState(D3DRS_POINTSCALE_B, d3d::FtoDw(0.0f));
	_device->SetRenderState(D3DRS_POINTSCALE_C, d3d::FtoDw(1.0f));

	_device->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
	_device->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);

	_device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
	_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
    _device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
	///////////////////////////////////////////////////////////////////////


	_device->SetTexture(0, _point);
	_device->SetFVF(TerrainNode::FVF);
	_device->SetStreamSource(0, _vb, 0, sizeof(TerrainNode)); //this causes runtime error


	_device->DrawPrimitive( D3DPT_POINTLIST, 0, _numNodes );

	///////////////////////////////////////////////////////////////////////

	_device->SetRenderState(D3DRS_LIGHTING,          true);
	_device->SetRenderState(D3DRS_POINTSPRITEENABLE, false);
	_device->SetRenderState(D3DRS_POINTSCALEENABLE,  false);
	_device->SetRenderState(D3DRS_ALPHABLENDENABLE,  false);

}

[edited by - Silex on January 18, 2004 4:46:43 PM]

This is where I fill and declare the buffer:

HRESULT hr = 0;	hr = _device->CreateVertexBuffer( _numNodes * sizeof(TerrainNode),									D3DUSAGE_WRITEONLY | D3DUSAGE_POINTS,									TerrainNode::FVF,									D3DPOOL_MANAGED,									&_vb,									0 );	if ( FAILED(hr) )		return false;	// coordinates to start generating vertices at	int startX = -_width / 2 + _cellSpacing / 2;	int startZ =  _depth / 2 - _cellSpacing / 2;	// coordinates to end generating vertices at	int endX =  _width / 2 - _cellSpacing / 2;	int endZ = -_depth / 2 + _cellSpacing / 2;	TerrainNode* n;	_vb->Lock( 0, 0, (void**)&n, 0 );	int i = 0;	for(int z = startZ; z >= endZ; z -= _cellSpacing)	{		int j = 0;		for(int x = startX; x <= endX; x += _cellSpacing)		{			int index = i * _numCellsPerRow + j;			n[index] = TerrainNode(				(float)x,				getHeight(x, z),				(float)z,				d3d::LIGHTGREEN );			j++; // next column		}		i++; // next row	}	_vb->Unlock();}

And this is the TerrainNode definition:

struct TerrainNode	{		TerrainNode(){}		TerrainNode( float x, float y, float z, D3DCOLOR color )		{			_position.x = x; _position.y = y; _position.z = z; _color = color;		}		D3DXVECTOR3 _position;		D3DCOLOR _color;		static const DWORD FVF;	};

With the FVF defined as D3DFVF_XYZ | D3DFVF_DIFFUSE.

i got it.