How would YOU do tracer fire?

#1 For my tracer I used a normal projectile which was 2 intersecting planes with a third square section near the front to give it some "width" when it was coming towards the player/camera. The material is double sided and set to "emissive" so that it's not affected by lights or shadows.

Check out the video on this blog of mine linky.

#2 I've debated about doing a "billboard" style sprite, but I'm not sure how to do the calculations :P

#3 What about using the built in light description on the projectile datablock?

#4 Like Steve said, but with some glow added to the material too :)

#5 offtopic but hey ...

Guy, is that flashlight an actual mounted light or are you doing something funky? Also spam this youTube Torque dev thread

#6 @Steve, yeah, it's just a spotlight mounted to a node out in front of the player.

#7 Which way should I modify the light Description? Adding a sprite?

#8 From the code comments:
A helper datablock used by classes (such as shapebase) that submit lights to the scene but do not use actual "LightBase" objects.
This datablock stores the properties of that light as fields that can be initialized from script.

Example:

// Declare a light description to be used on a rocket launcher projectile
datablock LightDescription(RocketLauncherLightDesc)
{
   range = 4.0;
   color = "1 1 0";
   brightness = 5.0;
   animationType = PulseLightAnim;
   animationPeriod = 0.25;
};

// Declare a ProjectileDatablock which uses the light description
datablock ProjectileData(RocketLauncherProjectile)
{
   lightDesc = RocketLauncherLightDesc;
   projectileShapeName = "art/shapes/weapons/SwarmGun/rocket.dts";
   directDamage = 30;
   radiusDamage = 30;
   damageRadius = 5;
   areaImpulse = 2500;
   // ... remaining ProjectileData fields not listed for this example
};

Basically it allows you to define a light that will move with the projectile. Not sure of the performance of this versus adding a glow to the material of the projectile. But try it both ways and see if one performs better than the other.

#9 I found the light description, but I meant to add a visible tracer to the projectile, which is why I referenced particles. I don't really want to use a light itself as a tracer, I want something that is similar to what Guy showed (which is a great idea btw), but something that will also work for people who can't run glow shaders. I might even use something like that added onto what I use for a tracer.

Basically something similar to what Steve referenced attached to the projectile. I just want to know other ways of achieving it, or if someone knows how to code a "billboard" style sprite that would be aligned to the direction of the projectile.

#10 "emissive" - like glow but not fancy, just shows your sprite up as you coloured it, so colour it as a bright orange line and that's what you'll get.

#11 Thanks Steve. I just wanna know how I'd go about attaching said sprite with it also being a billboard.

I really do appreciate the replies guys. :)

#12 A billboard would only work if it was circular (eg: it had not front and back). Billboards are just a mesh with a _BB at the end of the name.

For a long, thin, line of tracer you'd have to have the normal pointing to the camera - which would require source code changes (I believe this is how MaxGaming did their "ribbons" effects on missiles in some space sim game they made).

I cheated with the billboard idea and made the cross section bullet out of overlapping, doublesided polys.

#13 Ok. I see. Simply put I'll probably be doing it your style. If there are other ideas I'll still check those out in case anyone knows a better way.

Thank you all very much.

#14 Why not just wrap a cylinder around the projectile (non-colliding) with a transparency and a glow/emissive effect? A 4-5 sided cylinder shouldn't be too taxing on resources.

#15 That's a nice idea for a alternate for those who can run it. I'm looking at having less framerate intensive stuff as well, so I can use 2 types of tracers.

It is a nice idea Dustin. :)