Alpha Channel for Sprite System?

[clonewar12345]

I am trying to use sprites to render a fire effect. I have some fire animations for the sprites. Is there a way to make them partly transparent with an alpha channel? I have an alpha channel for them but i cant figure how to load that into the sprite system. Any help would be appreciated. Thanks

[Paul Forwood]

If the images used by the sprite emitters have an alpha channel, (they are 32bit Targas or Png files), then they should render just like a cookie-cut image. I haven't tested PNG images in a sprite emitter but I think that they should work.

 

On top of that you can adjust the opacity through the sprite system and sprite emitter properties.

[johnl3d]

If the fire animation has a alpha channel then you should have no trouble using it as a sprite just choose the animation as the sprite image. Or you can use the animation as a layer and animate the layer.

 

 

I did that here

 

http://migrate.hash.com/forums/index.php?s...re+extinguisher

 

images here

http://migrate.hash.com/forums/index.php?s...re+extinguisher

[clonewar12345]

If i have a quicktime mov file how would i make a layer emmited as a sprite? I have the alpha channel in the form of annother quicktime file.

[johnl3d]

the layer would not be a sprite ..you would animated the layer size and position to act as a sprite/emitter...sorry if I am confusing you. or not understanding....I'm old. If you want to use your qt just choose it as the sprite image.

[clonewar12345]

Yea, but is there any way to key it so the black portion is transparent?

[johnl3d]

To get a quicktime to work it cannot be compressed.

 

I did a qt using "animation" as the non compressed codec using the explosion material on a small model with the alpha buffer so the size is large

 

spritely.mov

 

 

I used this qt as the image for a sprite material here

 

spritemov.mov

 

It does not show the black

 

The trouble with animated sprites is they all show the same frame whether or not its just starting to emit or has emitted 15 frames ago as the frames are rendered.

[johnl3d]

THe solution is to use layers and animate them you have control of the animation

 

 

layer.mov

 

 

If you use the large qt above here is the project file

 

 

layers.zip

 

 

Post whatever you get