Hi I have some problem with Point Sprites rendering and I am surprised it appeared in this place. I coded particie struci

struct Particle
{
D3DXVECTOR3 m_Pos;
D3DXVECTOR3 m_Velocity;
D3DCOLOR m_Color;
};

Also standard Vertex Struct needed for VertexBuffer During particle initialization I am setting m_Pos on (100.0f, 100.0f, 1.0f) and m_Velocity on (50.0f, 0.0f, 0.0f) Position of every particle is counted using this formula

particles.m_vPos += particles.m_vVel * (float)dElpasedFrameTime; 

So I am assuming that particle should go along X axis only, but there is something weird it looks like it goes along X- and Z-axis, even if m_Velocity.z=0.0f; I thought it has something with matrices but I set them orthographic.

D3DXMATRIX matrix;
D3DMatrixIdenity(&matrix)
d3dDevice->SetTransform( D3DTS_WORLD, &matrix);
d3dDevice->SetTransform( D3DTS_VIEW, &matrix);

D3DXMatrixOrthoOffCenterLH(&matrix, 0.0f, 1024.0f, 768.0f, 0.5f, 0.0f)
d3dDevice->SetTransform( D3DTS_PROJECTION, &matrix);

Her eis the code that renders the particie.

d3dDevice->SetRenderState( D3DRS_ZWRITEENABLE, FALSE );

    d3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );
    d3dDevice->SetRenderState( D3DRS_DESTBLEND, D3DBLEND_ONE );

	

d 3dDevice->SetRenderState( D3DRS_POINTSPRITEENABLE, TRUE );    
d3dDevice->SetRenderState( D3DRS_POINTSCALEENABLE,  TRUE); 
d3dDevice->SetRenderState( D3DRS_POINTSIZE,     FtoDW(1.0) );  
d3dDevice->SetRenderState( D3DRS_POINTSIZE_MIN, FtoDW(1.0f) );. 
d3dDevice->SetRenderState( D3DRS_POINTSCALE_A,  FtoDW(0.0f) ); 
d3dDevice->SetRenderState( D3DRS_POINTSCALE_B,  FtoDW(0.0f) ); 
d3dDevice->SetRenderState( D3DRS_POINTSCALE_C,  FtoDW(1.0f) ); 

	Vertex *pPointVertices;

	VertexBuffer->Lock( 0, MAX_PARTICLES * sizeof(Vertex),
		                   (void**)&pPointVertices, D3DLOCK_DISCARD );

for( int i = 0; i < MAX_PARTICLES; ++i )
    {
        pPointVertices->posit = particles.m_Pos;
        pPointVertices->color = particles.m_Color;
        pPointVertices++;
    }

    	VertexBuffer->Unlock();
	

d3dDevice->SetStreamSource( 0, VertexBuffer, 0, sizeof(Vertex) );
d3dDevice->SetFVF( Vertex::FVF_Flags );
d3dDevice->DrawPrimitive( D3DPT_POINTLIST, 0, MAX_PARTICLES );

	
    d3dDevice->SetRenderState( D3DRS_POINTSPRITEENABLE, FALSE );
   d3dDevice->SetRenderState( D3DRS_POINTSCALEENABLE,  FALSE );

    d3dDevice->SetRenderState( D3DRS_ZWRITEENABLE, TRUE );
   d3dDevice->SetRenderState( D3DRS_ALPHABLENDENABLE, FALSE );
}

I have no idea what is going on.

I didn't understand your question. Particles doesn't move on desired x axis, but on z axis too?

Also I have noticed few things. 50.0f for x velocity is too much. If you presume that you have i.e 30 FPS, your particle will move in one second 30*50= 1500 on one axis! Isn't that too much?

Also drawing always MAX_PARTICLES will hit your performance. Not all of particles are drawn every moment, you will need to optimize a little bit.

And in particles.m_vPos += particles.m_vVel * (float)dElpasedFrameTime;
I see "particles.m_vVel"
in
for( int i = 0; i < MAX_PARTICLES; ++i )
{
pPointVertices->posit = particles.m_Pos;
pPointVertices->color = particles.m_Color;
pPointVertices++;
}
you don't copy it. If you don't initialize vector you will have some dumb value in your velocity...
Does this:
for( int i = 0; i < MAX_PARTICLES; ++i )
{
pPointVertices->posit = particles.m_Pos;
pPointVertices->color = particles.m_Color;
pPointVertices->m_vVel= particles.m_Velocity;
pPointVertices++;
}
helps?