February 15, 2019
Tower Defense Tutorial
Episode 15 – Laser Beamer
Youtube – How to make a Tower Defense Game (E15 LASER EFFECTS) – Unity Tutorial
By: Brackeys
Ep. 15
This tutorial will focus on creating extra effects for our laser. We’re adding a LaserImpact particle system, starting as a duplicate of the BulletImpact particles.
We started by making it a new material, LaserImpact material, and making this green with some emission. As many other particle effect parameters, this is setup differently in newer versions of unity. The intensity is in the color selector palette after turning on “Emission” for the material. Since we have so many particle systems now, we’re narrowing down what they collide with. We put all the nodes and ground planes on an “Environment” layer and made sure the particle system only collided with that.
Instead of making this particle effect its own prefab like the others, we attached it as a child to the Laser Beamer object. This would then just be an object we enable/disable when needed. For the particle system, we actually use Play() and Stop(), instead of enable/disable. This makes sure you aren’t creating multiple instances of the particle effect, and also makes it so that when you turn off the particle system, it doesn’t immediately go away. The residual particles will still do their thing.
To position the particle system, we just started by making its position that of the target. This however puts it directly in the middle of the target, where we would prefer having it on the surface where the object is hit. To do this, we created a vector that is the difference between our turret’s firepoint and the target to get the direction. Then we rotated the particle system to match this direction, and added/subtracted a small amount from the target position to place it slightly closer to our turret (so hopefully closer to the surface of the object). There might be a cleaner and more consistent way to do this with rays.
We wanted to add more effects to this laser, so we added a child particle system to this original laser ImpactEffect. Play()/Stop() will also apply to any children particle systems of an object. The material they used for this wanted to use the shader Particles -> Additive, which is only a Legacy option now. The new Particles -> Standard Surface shader has a rendering mode blending option that has an additive option, so I tried to see if that was similar. It seemed to give a similar effect, as long as I put the material (we were using the default particle material) in the Albedo map.
We gave the particle a blinking effect by editing the “Color Over Lifetime” to have 0 alpha at the end. So as it would loop, it basically faded in and out very quickly. Finally we added a green light to this particle system as an extra glowing effect. This however, would leave the light at its last position when an object got out of range.
When we went to fix the light (enable/disable it), they mention we could use animations instead to control all of these particle system events as opposed to scripting all of them. The light was just another reference in the Turret script that we enabled/disabled with all the other laser effects.
SUMMARY
- I really need to look into tutorials for the new particle system editor to help find equivalent options for these older tutorials
- Use Play(), Stop() with particle effects instead of enable = true or false for normal use
- Create blinking effect in particle system with looping, short lifetime, and setting “Color over lifetime” final alpha value to 0