Understanding Andos's Shadow Engine

**SergeantBiscuits** · 29th April 2012, 06:21 AM

Hey fellas, I've been trying to make heads or tails of Andos's "Shadow Engine" example and have been having a heck of a time with it. I don't understand the relationship between the 'LightSurface' object and 'Quick Backdrop 2'. How exactly is the LightSurface object masking it? And how does Quick Backdrop 2 not follow the frame? I'm very confused; there's some trickery here. Quick Backdrop 2 is no ordinary quick backdrop...

Could someone shed some light on this mystery?

(shadow engine is first on this page: http://www.andersriggelsen.dk/mmf2_examples.php )

Thank you!

**ChrisBurrows** · 29th April 2012, 09:46 AM

I don't have time to check it out, but setting the x and y scrolling coefficients to 0 will make all objects on that layer follow the frame...

**Fanotherpg** · 29th April 2012, 10:01 AM

Andos is using several instances of Surface Object (1 for each light source). And Surface object is doing all the magic. But his methodology maybe effective but is very CPU intensive and it won't be good in a real game AFAIK. But it's one of examples for me to improve in my 'career' and use in one of games

But it's 3rd on the list now AFAIR.

**SergeantBiscuits** · 29th April 2012, 10:38 PM

Aha, interesting... Thanks for the input fellas. I'm trying to port the light effect into one of my games; I don't need the shadow-casting, just the light glow that 'reveals' the playing area underneath it. I'll keep messin around with it...

**Fanotherpg** · 30th April 2012, 12:11 AM

LOL if only that then you need only Substract Shader. Nothing more.

Download LightsEg.mfa and LightsEg2.mfa from:

https://skydrive.live.com/?cid=b1e7e...4271BBDA%21482

**SergeantBiscuits** · 30th April 2012, 05:37 PM

Thanks, yeah, realized how simple it was when I realized I could make layers with blending effects! Never knew that, and I've been usin MMF for years... learn somethin new every day.

Ended up just havin a black object over the entire 'lighting' layer and putting active objects over my light sources that are just a radial gradient from white in the middle to black on the outside, all with 'add' effect, and the layer having 'multiply' effect. Works great! (See link below.)

http://i49.tinypic.com/2psk21k.png

A whole new world has opened up... Thanks fellas!