   How to use different opacity levels and alpha blending?
  Hi dudes!I'm doing a 2D engine where my polygons are just quads with a texture.If I add an alpha channel and I activate blendglEnable (GL_BLEND); glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);everything works as I expect, but now I would like to add a general opacity property in my meshes that I could change "on the fly".What should I do? Any suggestion?Thanks a lot for your time.   
  why not just play with the color alpha of the vertex?  with this blend function it should directly effect the opacity.   