WiseLaser

This tutorial was originally created by wisemx. It was originally posted on SDKnuts.net.

In this tutorial, we will approach basic aspects of using lasers in level design.

Moving Laser

Moving laser

The image to the right shows a laser that travels back and forth from both ends of a tunnel, and will kill the player if touched. The height of the tunnel is big enough for the player to be able to jump over the laser. The player can not go under the laser at this height however.

There are several ways to create an effect like this, the settings and methods that is used in this tutorial can easily be changed to your liking. Notice the sprite placed on each side for a burning hot effect.

There's a secondary ambient effect used in this tutorial, not related to the laser: a water puddle was created on the floor, and it will make a splash sound.

An env_beam is used on each side of the tunnel to create the moving laser:

Class: env_beam
Keyvalues		Comments
Parent	Beam01train	Right side parent equals Beam02train
Brightness	75
Beam Color	255 0 0
Life	0	(Infinite)
Width of Beam	0.7
Noise	0
Sprite name	sprites/laserbeam.spr
Texture scroll rate	40
Damage	1000
Start Entity	Beam01	Beam02 for the right side
Ending Entity	Beam02	Beam01 for the right side
Touch Type	Not a tripwire

	Flag
		Start

Setup in Hammer

To the right there's a shot from Hammer of the left side env_sprite, env_beam, func_tracktrain and first path_track.

Note:The left and right sides are identical except for entity names.

Objects used

Transparent = func_tracktrain
Purple = env_beam
Green = env_sprite
Red = path_track

By looking at the image you can see the env_sprite is parented to the env_beam. The env_beam is parented to the invisible func_tracktrain. Our first path_track, the starting point, is nestled right in there with the other entities.

env_sprite

These are the settings for each env_sprite, which are only used for a slight effect.

Class: env_sprite
Keyvalues		Comments
Parent	Beam01	Beam02 for right side
Render FX	Normal
Render Mode	Additive
FX Amount	150
FX Color	255 0 0
Disable receiving shadows	Yes
Frame rate	10.0
Sprite name	materials/sprites/glow03.vmt
Scale	0.2
Size of Glow	2.0

	Flag
		Start

func_tracktrain

Settings for each func_tracktrain:

Class: func_tracktrain
Keyvalues		Comments
Name	Beam01train	Beam02train for the right side
Disable receiving shadows	Yes
Disable Shadows	Yes
First Stop Target	Beam01path01	Beam02path01 for the right side
Max speed	60
Initial Speed	60
Change Velocity	Instantaneously
Change Angles	Near path_tracks
Distance between the wheels	10
Height above the track	0
Bank angle on turns	0
Move sound	d3_citadel.weapon_zapper_beam_loop1	Left side only
Volume	2

	Flag
		No User Control
		Passable
		Fixed Orientation
		Is unblockable by Player

Setup in Hammer

path_track

Notice, in the image to the right, that there are only 4 path_track entities: two on each side, for each func_tracktrain.

On the left side the first path_track references the second path_track which in turn references the first path_track, which causes the lasers on each side to go in a loop, back and forth.

By adding more of these path_track's you could cause the laser to travel in a zigzag pattern. You could also attach multiple lasers to each side, for a double effect as an example. You are free to change the visual effect of the laser, its speed and the tiny sprite to your liking.

Tip:The reason an env_beam was used on each side rather than only on one side is that the laser effect appears to be much better. However, you can experiment with this.

Settings for first path_track on the left side:

Class: path_track
Keyvalues		Comments
Name	Beam01path01	Beam02path01 on the Right side
Name	Beam01path02	Beam02path02 on the Right side

Water puddle

Water Puddle

The water puddle effect is done with an info_overlay. One can place an env_cubemap over this, an ambient_generic for the sound and a trigger_multiple to play the sound when the player steps there.