In my implementation I have this structure as the Particle structure
struct ParticleVertex{ D3DXVECTOR3 initialpos; float U,V; D3DXVECTOR3 initialVelocity; float initialSize; float initialTime; float lifeTime; float mass; D3DCOLOR beginColor;};
Where initalpos is supposed to be the center of the quad and my VertexBuffer is Created once as a dynamic one with size equal numberofParticles* 4 (as each particle has 4 vertices). and pass the system to the VS to do the integration on the position.
What I'm missing is how I can update the buffer afterwards based on the new position (I mean updating the 4 vertices of each quad, based on the new center resulting from the integration)