Reactor.PointParticleSystem.Draw C# (CSharp) Method

        public override void Draw(GameTime gameTime)
        {
            GraphicsDevice device = REngine.Instance._graphics.GraphicsDevice;

            // Restore the vertex buffer contents if the graphics device was lost.
            if (vertexBuffer.IsContentLost)
            {
                vertexBuffer.SetData(particles);
            }

            // If there are any particles waiting in the newly added queue,
            // we'd better upload them to the GPU ready for drawing.
            if (firstNewParticle != firstFreeParticle)
            {
                AddNewParticlesToVertexBuffer();
            }

            // If there are any active particles, draw them now!
            if (firstActiveParticle != firstFreeParticle)
            {

                // Set an effect parameter describing the viewport size. This is needed
                // to convert particle sizes into screen space point sprite sizes.
                effectViewportHeightParameter.SetValue(REngine.Instance.GetViewport().Height);
                effectViewParameter.SetValue(REngine.Instance._camera.viewMatrix);
                effectProjectionParameter.SetValue(REngine.Instance._camera.projMatrix);
                // Set an effect parameter describing the current time. All the vertex
                // shader particle animation is keyed off this value.
                effectTimeParameter.SetValue(currentTime);

                // Set the particle vertex buffer and vertex declaration.
                device.SetVertexBuffer(vertexBuffer);

                // Activate the particle effect.

                foreach (EffectPass pass in particleEffect.CurrentTechnique.Passes)
                {
                    pass.Apply();

                    if (firstActiveParticle < firstFreeParticle)
                    {
                        // If the active particles are all in one consecutive range,
                        // we can draw them all in a single call.
                        //device.DrawPrimitives(PrimitiveType.,
                        //                      firstActiveParticle,
                        //                      firstFreeParticle - firstActiveParticle);
                    }
                    else
                    {
                        // If the active particle range wraps past the end of the queue
                        // back to the start, we must split them over two draw calls.
                        //device.DrawPrimitives(PrimitiveType.PointList,
                        //                      firstActiveParticle,
                        //                      particles.Length - firstActiveParticle);

                        if (firstFreeParticle > 0)
                        {
                        //    device.DrawPrimitives(PrimitiveType.PointList,
                        //                          0,
                        //                          firstFreeParticle);
                        }
                    }

                }

            }

            drawCounter++;
        }