title: Custom BlendState to avoid AlphaBlending artifacts
body: <p>I am essentially drawing a texture onto itself every frame, each time i draw it i want to decrement the alpha so that it eventually hits 0 so no artifacts are left.</p>
  
  <p>The basic equation is:</p>
  
  <pre><code>result = (source * sourceBlendFactor) blendFunction (destination * destinationBlendFactor)
  </code></pre>
  
  <p>And since my destination is Color.Transparent I figure i need:</p>
  
  <pre><code>result = 0 = (source * sourceBlendFactor); 
  </code></pre>
  
  <p>Im racking my brain going over the different BlendState components but I cant seem to acheive this...</p>
  
  <p>Is there any way to have the alpha decrement linearly?</p>