Fade out a model

[tjheldna]

Hi All,

 

I need a little direction on how to fade out a model over time, is this done via a shader? or is there some other method? (don't know a whole lot about shaders as of yet).

 

This would be great for fading out dead characters etc instead of just deleting them as I am doing currently.

 

Cheers!

[Rick]

This is one of the things I hate about the forward renderer. The model has to be in another world. If you are using the framework there is a transparency world created for you already. You have to switch to that world, load your object, then you can switch back.

 

The thing to remember is that this other world won't care the same lighting unless you make it the same as your main world. Also if you load multiple instances of the same model all in the same world, fading 1 will fade all. All in all it's a mess I think. If there were a way to do this with a shader it would be 100% better, but I'm not sure of the challenges in that alone.

[Naughty Alien]

..shader is best way to do it..not just with transparency, but make character disappear in to 'ash', or erode, and so on..other way is to control color value, and gradually cut it down to '0'. That however depending on your renderer setup so i cant say for sure..

[Benton]

Right, because deferred renderer handles transparency differently...

[tjheldna]

Thanks for the advice guys, i'll give it a crack with a shader. I may need a little more help, but I'll see how I go first.

 

Cheers!

[shadmar]

You still have to have the mesh in the transparency world when using shaders.

So assuming you are using fw, it should go someting like this (not tested)

 

SetWorld(fw.transparency.world)
model = LoadMesh("abstract::model.gmf")
SetWorld(fw.main.world);

myfade=0;
material=LoadMaterial("abstract::"))
shader=GetMaterialShader(material)

 

In your run loop :

 

myfade=myfade+0.001
SetShaderFloat(shader,"myfade",myfade)

 

In mat file have

 

blend=alpha

 

In your shader (frag file)

 

add before main():

uniform float myfade=0.0;

 

find : gl_FragData[0] = diffuse;

 

Add below

 

gl_FragData[0].a-=clamp(myfade,0,1);

 

 

It should now alpha fade by 0.001 per flip() (in theory)

[tjheldna]

Thanks shadmar. The community project has kept me too busy to check this out, but I will. That looks to me like it will work.

 

Many Thanks!!