We can see Glow effect in almost every game now. Indeed it really improves the visual result to the next level~ In this demo, I used some simply ways to implement the glow effect. Of course the first thing was to render the scene into a texture since its another post-processing rendering. So I rendered the scene with specular on and saved it to my texture and used it for my glow texture creation.
In order to produce that blurry effect, I first copied the scene texture to another small size one. This not only decreased the shader calculation but also created the basic blurry effect =P. After that I made the texture to multiply itself several time to make the bright color brighter and the dark color darker. And then I used Gaussian Blur to blur the result and Yea! a glow texture was done. Finally I added it with the original scene texture and its done~ ^_^
The result was like this~