Using deform sprite (material global keyword)

[SteveL]

I've been testing deform sprite this afternoon. I couldn't find useful info in the forum or the wiki or modwiki, so I'll share my notes here and put it somewhere on the wiki after figuring out the unanswered bits.

 

First up, if what you want to do can be done with particles, I believe you don't need to use deform sprite in the material def: you can use Orientation > View in the particle editor (but I've not tested particles yet).

 

Notes from testing deform sprite:

• The material won't receive lighting. If you just add "deform sprite" to an existing material def, it'll show up pure black in game. You can fake the lighting by using an opaque or alpha blend and adjust rgb to an appropriate lighting level.
  
• Only works with a four-sided surface made of 2 tris. Applying a deform sprite texture to any other surface will result in your "deform sprite" instruction being ignored and an error message every frame in your console.
  
• The surface always renders as a square, so use a flat square patch and don't fix subdivisions in the patch inspector. That way it'll look similar in game and in DR. Using a quadrilateral brush face also works, but I can;t think of any situations where that'd be useful... the sprite face becomes detached from the rest of the brush in order to face the player.
  
• Rotating the patch in DR has no effect. Stretching it affects the size of the resulting square sprite.
  
• Scaling and translating the texture in DR don't affect the output (always renders a square with texture fit 1:1), but you can do those things in the material shader and it works, so I hope you can do it dynamically with shaderparms or globals.
  

Things I'm not sure about:

• Should the rgb level be adjustable to ambient light level using the global0/1/2 keywords? I tried that just once but I got a black result, meaning the globals were set to 0 in my test map. How is it done?
  
• I guess you might as well delete any bumpmap and specular stages from a material you adapt for a sprite, because there's no lighting so they'll not show up. Is that right?
  

[grayman]

What would you use this for?

[SteveL]

Umm.. can't really answer that except in PM without a spoiler. My use case seems so obvious (to me) that a hint would be a giveaway!

[grayman]

Umm.. can't really answer that except in PM without a spoiler. My use case seems so obvious (to me) that a hint would be a giveaway!

 

Heh!

[stumpy]

shaderparms are used to adjust globals in material definitions.

 

http://wiki.thedarkmod.com/index.php?title=List_of_shaderParm_variables