Lachlan's misadventures in games programming

Friday, 16 September 2011

Ancient CRT Emulation

9/16/2011 03:21:00 pm Posted by Lachlan No comments
I was playing around with some idea's today about making stuff look early CRT era old. I was partially inspired by playing wee bits of fallout 2, and this article on SNES emulation - and making it work accurately rather then conveniently.

I tried to make a couple of screenshot mockups to see what could happen - not with anything I'll make (at the moment), but to see what kind of styles we could go for. I came up with these:

Completely original - except letters used from http://www.zee-3.com/pickfordbros/archive/bitmapfonts.php 
The infamous Doom title screen. Zoom in (click) for the detail
The first of these was just an idea for a piece of tiny art that I brought to fruition. The details are similar to the Doom one, which I'll explain more fully. The Doom one was me seeing what I could do to make something look old. I recommend zooming in.

What I did (all in Gimp)
- Started with the 320x240 resolution picture of the Doom title screen
- Resized it with no interpolation (ie. just making to blocks bigger) to 1280x960
- Colourised it to Amber
- Changed the colour curve to make it almost (but not quite) 4 colour - this works because the analogue screen I'm trying to emulate does have some transition between the 4 colours (but still actually 4 colours - just slightly more... antialiased) ... or something like that
- Duplicated the layer
- Blurred the top layer (lightly)
- Blurred the bottom layer more
- Added the lines at 40% opacity with a fill tool with a pattern on the top layer
- Merged layers
- Applied the lens distortion effect

It still could do with a few things to make it look more real - the colour still isn't quite right, the scanlines are in reality partially horizontal as well as vertical, there are little grey dots near the corners I couldn't be bothered with fixing and there could be some reflection on the screen, and maybe a little darker towards the edges.

I'd be fascinated to see if I could get this to run in real-time - though, I doubt it would be even remotely possible without lots of pixel shaders. It'd be fantastic to do though for a retro styled game. It's ironic it requires so much clockpower to make something look so old.


Lachlan

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