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Rendering vertex buffer - nothing displayed

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Hi all, I am working on my graphics engine. Have skybox, meshes displaying properly. Currently working on the particle engine. I have completed coding it and feel it should work. No errors, but nothing displayed. I adapted this from an example from a book, and it looks solid. Don't know why it's not rendering the vertex buffer. Anyone see anything? I feel it's something small I'm forgetting. I've only included the primary methods, any q's plz ask.
void cParticleCollection::PreRender()
//TODO: move some of these one-time settings to constructor.. not sure which ones

//general settings
Graphics->p_device->SetRenderState(D3DRS_LIGHTING, false);
Graphics->p_device->SetRenderState(D3DRS_POINTSPRITEENABLE, true);
Graphics->p_device->SetRenderState(D3DRS_POINTSCALEENABLE, true);
Graphics->p_device->SetRenderState(D3DRS_POINTSIZE, FloatToDWORD(2.5f) );
Graphics->p_device->SetRenderState(D3DRS_POINTSIZE_MIN, FloatToDWORD(0.1f) );

//set the size of the particle relative to distance
Graphics->p_device->SetRenderState(D3DRS_POINTSCALE_A, FloatToDWORD(0.0f) );
Graphics->p_device->SetRenderState(D3DRS_POINTSCALE_B, FloatToDWORD(0.0f) );
Graphics->p_device->SetRenderState(D3DRS_POINTSCALE_C, FloatToDWORD(1.0f) );

//use alpha from texture
Graphics->p_device->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
Graphics->p_device->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_SELECTARG1);

Graphics->p_device->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
Graphics->p_device->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
Graphics->p_device->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

//set vertex format
Graphics->p_device->SetFVF(D3DFVF_XYZ | D3DFVF_DIFFUSE | D3DFVF_PSIZE);
//set stream source
Graphics->p_device->SetStreamSource(0, ParticleBuffer, 0, sizeof(cVertex));

void cParticleCollection::PostRender()
Graphics->p_device->SetRenderState(D3DRS_LIGHTING, true);
Graphics->p_device->SetRenderState(D3DRS_POINTSPRITEENABLE, false);
Graphics->p_device->SetRenderState(D3DRS_POINTSCALEENABLE, false);
Graphics->p_device->SetRenderState(D3DRS_ALPHABLENDENABLE, false);
void cParticleCollection::Render()
	if (Particles.size() > 0) //if there are entries
	PreRender();				//prepare to render

	//render collection:
	cVertex *v = 0;
	int iCurrentVertex = 0;

		//counter number of particles that are on
		for (int i = 0; i <= Particles.size(); i++) 	//loop thru all
			if (Particles.fLifeTime > 0)				//if on

				//lock a slot
				ParticleBuffer->Lock(iCurrentVertex * sizeof(cVertex),							//beginning of lock
									 sizeof(cVertex),											//size of lock range
									 (void**)&v,												//address of vertex
									 iCurrentVertex ? D3DLOCK_NOOVERWRITE : D3DLOCK_DISCARD);	//flags
				//fill info
				v->d3dColor = d3d::GREEN;						//sould ba var
				v->fSize	= 50.0f;								//should be a var
				v->vPos		= Particles.vPos;
				//set texture
				Graphics->p_device->SetTexture(0, Graphics->Textures[10]); //30 should be a variable
				//unlock and render
				//move to next slot
					if ( iCurrentVertex > iVBsize-1 ) { iCurrentVertex = 0; }


	PostRender();			//reset after render
void cParticleCollection::Init()
	r = Graphics->p_device->CreateVertexBuffer(iVBsize * sizeof(cVertex),
												D3DFVF_XYZ | D3DFVF_DIFFUSE,

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CreateVertexBuffer is not getting the correct FVF. You are leaving off the D3DFVF_PSIZE.

If that doesn't fix the problem, check your vertex structure. The data should be 3 floats for position, 1 float for point size, and 1 DWORD for color (so says your FVF). A common bug is the ordering. Make sure position is first, then point size, then color. More details.

Hope that helps.

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