blog4.cs

while (window.Exists)
{
    InputSnapshot snapshot = window.GetInputSnapshot(); // Process window events.
    rc.ClearBuffer(); // Clear the screen.

    rc.SetViewport(0, 0, window.Width, window.Height); // Ensure the viewport covers the whole window, in case it was resized.
    float timeFactor = Environment.TickCount / 1000f; // Get a rough time estimate.
    viewProjection.Data =
        // Create a rotated camera matrix based on the current time.
        Matrix4x4.CreateLookAt(
            new Vector3(2 * (float)Math.Sin(timeFactor), (float)Math.Sin(timeFactor), 2 * (float)Math.Cos(timeFactor)),
            Vector3.Zero, // Always look at the world origin.
            Vector3.UnitY)
        // And combine it with a perspective projection matrix.
        * Matrix4x4.CreatePerspectiveFieldOfView(1.05f, (float)window.Width / window.Height, .5f, 10f);
    rc.SetVertexBuffer(vb); // Attach the cube vertex buffer.
    rc.SetIndexBuffer(ib); // Attach the cube index buffer.
    rc.SetMaterial(material); // Attach the material.
    rc.DrawIndexedPrimitives(Cube.Indices.Length); // Draw the cube.

    rc.SwapBuffers(); // Swap the back-buffer and present the scene to the window.
}