Bloom Pixel Shader for bsnes

I did some digging around online and came across some bloom filters written in GLSL. The one on this site looked the best to my eyes, so I converted it to work with bsnes and tweaked the settings a bit to achieve the desired effects.

What I found while playing around with it is:

1. Turning on 'Smooth video' seems to amplify the bloom effect.

2. The same amount of bloom looks different on each game, depending on the overall dark/light-ness of the game.

3. Combining excessive bloom with bsnes' scanline filters can make a pretty decent approximation of a CRT. While this is in no way as accurate or as nice looking as cgwg's CRT shaders, it may be an option for the many people whose video cards don't have enough horsepower to handle that complex shader.

First, I made a simple, fairly subtle (as far as bloom is concerned...) shader, which looks like this:

Looks pretty nice, eh? Unfortunately, the exact same shader settings look awful in Super Mario World:

One big flare-out... All I need is some brown and lens flare and I'll have next-gen graphics.

However, if you add in a scanline filter, things can really get evened out. In fact, you can use the different scanline intensity filters on a game-to-game basis to attenuate the inconsistency of the bloom effect. For example, here's a shot of Super Mario World with even more bloom added and 'smooth video' checked, but with 100% scanlines to chill things out a bit:

As you can see, it kinda gives it a plasticy, oversaturated look, but it's sort of charming, if you ask me.

In contrast, those exact same settings in Chrono Trigger--an altogether darker game--produce a really nice CRT-style effect, like this:

As you can see, even the bright parts don't suffer from excessive flare-out and the color bleed into the scanlines from the bloom provides an effect that is reminiscent of the phosphor glow on a CRT display.

One more shot of Chrono Trigger, this time using heavy bloom, 25% scanlines and smooth video:

I have asked WhateverMan if he would release his shader code under a permissive license. If he does, I will post my simplebloom and heavybloom versions here for download.

Update (1/19/11): WhateverMan was nice enough to allow his work to be distributed/modified under the GPL, so you can download the heavybloom shader here and the simplebloom shader here.

Update (2/2/11):

I also made a simple scanline shader that works with or without video smoothing:

For best results, use it along with a scale factor of 4x. Otherwise, the pixels won't line up with the scanlines correctly.

UPDATE (2/28/11): I made a scanline shader that works with a 3x scale factor, as well. You can download it (and the other GLSL shaders) here.