Thread: Using D3DFVF_XYZRHW flag for a Vertex Buffer

  1. #1

    Using D3DFVF_XYZRHW flag for a Vertex Buffer

    I'm hoping i can pick someones brain for this without having to post a whole whack of code.

    I've got a 3D enviroment set up and i can display billboards and Meshs to it just fine. The textures come out exactly right. But i have need to display certain things on screen-relative coords (like my mouse cursor) so i used these flags D3DFVF_XYZRHW | D3DFVF_TEX1 when creating my vertex buffer, which looks like this:

    struct vertex
       float x, y, z, rhw;
       float u, v;
    vertex target[4];
    IDirect3DVertexBuffer8 * g_VBuffer;
    //displayed like this:
    //lock up VBuffer and memcopy it on in
    unsigned char *vb_vertices;
    if (FAILED( g_VBuffer->Lock(0, 0, &vb_vertices, 0) ))
       MessageBox(hWnd, "Lock() failed!", "Function Error", MB_OK);
       return E_FAIL;
    memcpy(vb_vertices, target, sizeof(target));
    g_pDevice->SetStreamSource(0, g_VBuffer, sizeof(vertex));
    g_pDevice->SetTexture(0, pTexture);
    g_pDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);

    The Buffer appears exactly wher it should and the texture is also displayed... but! Its all grey (which is the colour of my text incidentally). I know the texture is there because i alpha blended out the background colours on it and they disapeared leaving only a grey mouse-cursor shape without any of the textures colours on it.

    Oh, in case its relevant i've got the following RenderStates set:

    	//*** DISPLAY TYPE STUFF ***
    	//Z-Level? Yes. Of course.
        g_pDevice->SetRenderState( D3DRS_ZENABLE, TRUE );
    	//Noramlize Normals?
        g_pDevice->SetRenderState( D3DRS_NORMALIZENORMALS, TRUE );
    	//Cull Counter-Clockwise
        g_pDevice->SetRenderState( D3DRS_CULLMODE, D3DCULL_CCW );
    	//*** LIGHTING ***
    	//Set lighting OFF
    	g_pDevice->SetRenderState( D3DRS_LIGHTING, FALSE );
    	//*** TEXTURE HANDLING ***
    	//Texture stretching filter types (Option for D3DTEXF_LINEAR???)
        g_pDevice->SetTextureStageState( 0, D3DTSS_MAGFILTER, D3DTEXF_POINT );
        g_pDevice->SetTextureStageState( 0, D3DTSS_MINFILTER, D3DTEXF_POINT );
    	//Dither textures?
        g_pDevice->SetRenderState( D3DRS_DITHERENABLE, TRUE );
    	//Turned off because we dont use Coloured Vertexs
        g_pDevice->SetRenderState( D3DRS_COLORVERTEX, FALSE );
    	//Alpha Blending used in some textures for CVertexBuffer calls
    	g_pDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );
    	//*** PIXEL HANDLING ***
    	//Defines the method of determining pixel color
    	g_pDevice->SetTextureStageState( 0, D3DTSS_COLOROP,	  D3DTOP_SELECTARG1 );
    	//Take color only from texture instead of vertex colors (or which we have none)
    	g_pDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
    	//Defines the method of determining pixel alpha
    	g_pDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP,	  D3DTOP_SELECTARG1 );
    	//Alpha value for each pixel comes from the textures alpha value
    	g_pDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE );
    	//Source/Destination blending
    	g_pDevice->SetRenderState( D3DRS_SRCBLEND,	D3DBLEND_SRCALPHA );
    	g_pDevice->SetRenderState( D3DRS_DESTBLEND,	D3DBLEND_INVSRCALPHA );
    "There's always another way"
    -lightatdawn (

  2. #2
    Registered User Coder's Avatar
    Join Date
    Aug 2001
    Cairo, Egypt

    Just a note

    Just a sidenote (I don't think it has anything to do with the problem) : Why don't you disable the Z buffer test when you're rendering 2D stuff? Since you want it to be on top of everything

    By the way, if everybody fails to help you. Consider posting the code/url/attachment so that people'd try it on their PC's
    Last edited by Coder; 09-06-2001 at 03:38 PM.
    Muhammad Haggag

  3. #3
    Registered User
    Join Date
    Sep 2001
    check your e-mail.
    astride a storied past, thats everywhere you are

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