Creating Looped Automatic Portals

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This tutorial will show step-by-step instructions on how to create linked portals similar to the ones seen in Test Chamber 01, in which the blue portals are seen switching on and off in a specific order. Following along with this tutorial will require some knowledge of how to use logic and math entities.

Construction

Step 1: Portal Frame

File:File:AutoPortals Step1.JPG

The layout of the auto portal frames.

To start, select the entity tool, and create a prop_static for each portal you intend to have in your map. Set the model to models/props/autoportal_frame/autoportal_frame.mdl for each one. The models should be placed and arranged at the locations the portals themselves will be.

Step 2: Creating the Portals

File:File:AutoPortals Step2.JPG

Example of how the prop_portal should be positioned.

Next, create a prop_portal for each of your portals, one for your red portal, and then any additional ones for your blue portals. For the sake of this tutorial, we will be creating 3 blue portals.

These prop_portals need to be positioned in the center of each portal frame, similar to the screenshot provided. They will also need to be rotated to be facing outward from the wall.

Note: Rotating the prop_portal will make the portal look like it is in the same position in the Hammer Editor, you will have to rely on which direction the origin (yellow line in 2D view) is facing.

Name your red portal “portal_red01”, and name the three blue portals “portal_blue01”, “portal_blue02”, and “portal_blue03”.

For the red portal, change its properties to the following settings:

Property Name	Value
Start Activated	Inactive
Portal Number	2

For the blue portals, change their properties to the following settings:

Property Name	Value
Start Activated	Inactive
Portal Number	1

Step 3: Creating the Logic Relays

File:File:AutoPortals Step3.JPG

Diagram of how the logic_relays will work.

In order to make our sequential auto portals work, we will be employing the use of several logic and math entities. The one we will begin with is logic_relay.

To start, we are going to want to create four logic_relay entities for our blue portals:

• 2 relays for the first blue portal. The first relay will be used to initialize the portal opening/closing sequence, while the second relay will open the first portal after the last portal has fizzled.
• 1 relay for each of the remaining portals in the sequence.

For first portal’s initial relay, name it “relay_blue01_int”, and give it the following I/O:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnTrigger	portal_blue01	SetActivatedState	1	0.00	No

For the remaining relays, you will want to add an additional I/O to fizzle the previous blue portal as well. Name these relays “relay_blue02”, “relay_blue03”, and “relay_blue04” respectively.

The I/Os for these should look like this: relay_blue02

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnTrigger	portal_blue02	SetActivatedState		0.00	No
	OnTrigger	portal_blue01	Fizzle		0.00	No

relay_blue03

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnTrigger	portal_blue03	SetActivatedState		0.00	No
	OnTrigger	portal_blue02	Fizzle		0.00	No

relay_blue04

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnTrigger	portal_blue01	SetActivatedState		0.00	No
	OnTrigger	portal_blue03	Fizzle		0.00	No

Step 4: Create the Logic_Case Entity

File:File:AutoPortals Step4.JPG

The logic entities to be used.

Now that we have our relays set up, we can move onto adding the remaining logic entities we’ll need to make this work. The entities in question are:

• logic_timer
• logic_case
• math_counter

The first one we’ll create is the logic_case. This entity will be responsible for triggering the relays on each portal. Create the logic_case entity, and give it the following parameters:

Property Name	Value
Name	portals_case
Case 01	1
Case 02	2
Case 03	3
Case 04	4

Next, you will need to give it the following I/Os:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnCase01	relay_blue01_int	Trigger		0.00	No
	OnCase02	relay_blue02	Trigger		0.00	No
	OnCase03	relay_blue03	Trigger		0.00	No
	OnCase04	relay_blue01	Trigger		0.00	No

Step 5: Create the Logic_Timer Entity

Next, we will make the logic_timer entity. Place one in your map, and give it the following parameters:

Property Name	Value
Name	portals_timer
Start Disabled	Yes
Use Random Time	No
Refire Interval	5

Then, give it the following I/O:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnTimer	portals_counter	Add	1	0.00	No

Step 6: Create the Math_Counter Entity

Finally, we add a math_counter entity, which will allow our setup cycle through the portals every time it has a value added to it (via the logic_timer).

Place one in your map, and give it the following parameters:

Property Name	Value
Name	portals_counter
Start Disabled	No
Initial Value	0
Minimum Legal Value	0
Maximum Legal Value	5

The reason we set the maximum value to five is to allow a looping point in the portal opening/closing sequence.

• A value of 1 triggers the initial relay for the first blue portal.
• A value of 2 triggers the relay for the second blue portal.
• A value of 3 triggers the relay for the third blue portal.
• A value of 4 trigger the second relay for the first blue portal.
• Finally, value of 5 triggers a self-reset of the counter, with the rest value being set to 2.

To sum up, you will want to set the “Maximum Legal Value” to how many relays you have set up, +1 to act as a looping point. This sequence will be kept running thanks to our logic_timer entity.

Add the following I/Os to the math_counter entity:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnHitMax	!self	SetValue	2	0.00	No
	OutValue	portals_case	InValue		0.00	No

Implementation

Assuming that you have your auto-portals in their places (and have their entities set up), you can now make a trigger the player will walk into to start the sequence.

Trigger the Auto-Portal Sequence

File:File:AutoPortals Step7.JPG

The trigger_once that is used to activate the red portal and logic_timer.

Create a brush textured with tools/toolstrigger, and press Ctrl + T to turn it into a brush entity. Change this entity into a trigger_once, and give it the following I/Os:

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnStartTouch	portal_red01	SetActivatedState	1	0.00	No
	OnStartTouch	portals_timer	Enable		0.00	No

When the player walks into the trigger’s volume, it will activate the red portal first, then after 5 seconds, the blue portals will open and close in a looped sequence.