PointSprite in DirectX9

Question

I was trying to implement a particle system using PointSprites. Draw calls return D3D_OK but I don't see any particle on the screen. I'm not using Vertex Buffer for the particles, but I use two vectors of vertices and I call the DrawPrimitiveUP function. This is my code:

            CreatePntVertices();

            pD3DD -> SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
            pD3DD -> SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
            pD3DD -> SetRenderState(D3DRS_DESTBLEND, D3DBLEND_ONE);

            pD3DD -> SetRenderState(D3DRS_ZWRITEENABLE, FALSE);
            pD3DD -> SetRenderState(D3DRS_ZENABLE, FALSE);

            pD3DD -> SetRenderState(D3DRS_LIGHTING, FALSE);

            pD3DD -> SetFVF(FVF_PNTVERTEX);
            pD3DD -> SetTexture(0, pTex[TEX_POINT]);

            pD3DD -> SetRenderState(D3DRS_POINTSPRITEENABLE, TRUE);
            pD3DD -> SetRenderState(D3DRS_POINTSCALEENABLE, TRUE);

            pD3DD -> SetRenderState(D3DRS_POINTSCALE_A, 0.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSCALE_B, 0.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSCALE_C, 1.0f);

            pD3DD -> SetRenderState(D3DRS_POINTSIZE, 20.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSIZE_MIN, 3.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSIZE_MAX, 50.0f);

            D3DXMatrixIdentity(&mWorld);
            pD3DD -> SetTransform(D3DTS_WORLD, &mWorld);

            pD3DD -> DrawPrimitiveUP(D3DPT_POINTLIST, pntPlanets.size(), (PVOID)pntPlanets.data(), sizeof(PNTVERTEX));

            pD3DD -> SetRenderState(D3DRS_POINTSIZE, 40.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSIZE_MIN, 9.0f);
            pD3DD -> SetRenderState(D3DRS_POINTSIZE_MAX, 70.0f);

            pD3DD -> DrawPrimitiveUP(D3DPT_POINTLIST, pntStars.size(), (PVOID)pntStars.data(), sizeof(PNTVERTEX));

            pD3DD -> SetRenderState(D3DRS_ALPHABLENDENABLE, FALSE);

            pD3DD -> SetRenderState(D3DRS_ZWRITEENABLE, TRUE);
            pD3DD -> SetRenderState(D3DRS_POINTSPRITEENABLE, FALSE);
            pD3DD -> SetRenderState(D3DRS_POINTSCALEENABLE, FALSE);

CreatePntVertices() is a function that set the position of objects and their color into two vectors of PNTVERTEX (pntStars and pntPlanets). pTex is an array of textures. mWorld is a D3DXMATRIX. pD3DD is the Device. FVF_PNTVERTEX is set as (D3DFVF_XYZ | D3DFVF_DIFFUSE). I really don't know why it doesn't work, I tried everything to make it work. Maybe, should I use a dynamic vertex buffer instead?

Answer 1

I found out the source of the problem. After days and days, I understood (at last) that with SetRenderState (in DirectX9), floats have to be converted into DWORDs in this way:

*((DWORD*)&f)

where f is the floating point. I already used this method for fog, but I forgot it and it took me other weeks to learn it again. I hope this answer will help other guys with the same problem!