Creating glowing volumentric projectiles with idtech4 ?

Started by oneofthe8devilz, May 25, 2015, 06:32:10 PM

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Hey folks,

I started to wonder how to efficiently create volumetric glowing projectiles within idtech4 that then can be used as tracers or plasma projectiles ingame...

The default Doom3 tracers are "deform tube" shaders which start to look bad once the projectile approaches or leaves the observer from frontal/back views...

And while "deform sprite" shaders work great for spherical projectiles they are not really usable for "elongated" projectile shapes...

I found a good example of what I am trying to achieve in the game "Star Wars Battlefront" which was released in the same year (2004) as Doom3 was...

Notice how the "SW Battlefront Laser Projectiles" become more spherical the more they directly approach/leave the observer from front/back and how they become more "elongated" the more they are observed from the side and all this while keeping their initial glow shading intact which from any point of view remains bright in the center while loosing intensity the more it expands towards the outer boundaries of the projectile...

So I would be open and appreciative for ideas how to efficiently achieve this within idtech4...
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Looks like the same approach as in Doom 3 and pretty much any other game - an oriented plane with glowing texture.


maybe controlled blooming? you could have a model for the projectiles wich could be a cylinder (a triangluar cylinder) if you create a render target just for the projectiles, and add a zbuffer info in it, and stencil out the 3d models of the lasers, with the info on how far are them, you could increase the blur per pixel of the "laser", and have it display different blooming amounts given their distance

I don't know how to do it, but maybe the code of the weapon (that is a 3d model separated from the rest of the world) might inspire the making of this?

hmm maybe this could be used in order to replace the polygonal blur in d3, if you had just the part of a "flare" texture visible to the camera, you could use it's entity info to control a 2D blur which would never cross any other world geometry as it currently happens in d3 flares when they are too big.


When I was building my Battlestar Galactica mod, that got nixed, I replaced the tracer model with a long thin model with a beam_red texture on it and that worked out somewhat, than added sounds. you can maybe try that.