# What are Glow Textures?

So i'm not quite sure exactly what "glow textures" are. For my implementation of a "lightning" effect, according to the comments on the article; http://drilian.com/2009/02/25/lightning-bolts/

They guy uses "glow textures". To achieve the really cool effects on his beams. I'm trying to-do the same thing, except that i'm not 100% sure what a glow texture is, currently the texture i'm using produces this output *I'm also using a simple shader to adjust the color value the lightning is rendered at; http://www.youtube.com/watch?v=dQNRYD8bJJo

Which isn't very good, it has the shape of the lightning but it doesn't have the sorta "flare" of it. This is a screenshot of my current texture that i'm using: http://dl.dropbox.com/u/13874083/screenshots/screen120417-105326.png

So essentially what i'd like to ask is mainly what is a glow texture? And perhaps to see an example of one would be really appreicated.

Edit: Taking the advice of kaoD, i'm now rendering the using Additive Blending, I've also got the Max Blending working, yet, still the bolt's do not produce the required effect that i'd like. Here's another video of them in action with the current code; http://www.youtube.com/watch?v=T0OEBobHqks

And here's specifically how i'm rendering them;

        spriteBatch.Begin(SpriteSortMode.Immediate, new BlendState
{
ColorSourceBlend = Blend.One,
ColorDestinationBlend = Blend.One,
ColorBlendFunction = BlendFunction.Max
}, null, null, null, effect);

//Set Brightness of The First Bolt
effect.Parameters["brightness"].SetValue(firstBoltBrightness);

spriteBatch.Draw(firstBoltTarget, Vector2.Zero, Color.White);

//Set Brightness of the Seconded Bolt
effect.Parameters["brightness"].SetValue(secondBoltBrightness);

spriteBatch.Draw(secondBoltTarget, Vector2.Zero, Color.White);