Getting Started with AGS - Part 3

Adding some interaction

Ok, so we now have a working room. The player can walk around it as much as they like. However, our game so far is pretty boring - the player can't actually do anything of value yet!

AGS provides you with three types of things that the player can interact with - hotspots, objects and characters:

A hotspot is an area of the background image that the player can look at, interact with, and so forth. Hotspots are generally used for parts of the screen such as a tree or the grass, which won't change as the game progresses.
An object is an item in the room that can move around the screen, and be switched on and off at will. Objects must stay within the room that they are created in.
A character is like an object, except that it can move between rooms and therefore appear all over the game. Characters also have special properties such as talking animations and so forth, which means you will usually use one to represent each NPC (non-player character) in the game.

Hotspots

The easiest thing to start off with is hotspots. Go to the "Areas" pane under the Room Editor, and select "Hotspots" from the drop-down list box.

Hotspots are drawn in exactly the same way as walk-behind and walkable areas. This time though, the different colours that are available for drawing, with each representing a different hotspot. That is, if the player clicks a dark blue area of the screen (Hotspot 1), then Hotspot 1's interactions will be triggered. If they click a green area, a different response will happen, and so forth.

You can use the same colour in two different areas of the screen if they represent the same thing - for example, you could use colour 1 for two different trees, as long as you want a common response for clicking on both of them.

I've drawn four types of hotspot onto my screen

Once you've drawn a hotspot, there are two other fields to set:

The hotspot's name. This sets a player-friendly name for the hotspot, which is vital if you are going to use a Lucasarts-style interface where the player can move the mouse over the screen to see what's where. If you're using a Sierra-style interface then this name will never be displayed to the player, but it's useful to fill it in anyway for your own benefit.
The Script O-Name: This is a name by which the hotspot can be referred to from the room script. This name cannot have any spaces or special characters -- just the letters a to z. You'll notice that an "h" is automatically prepended to the start of the name, so if you call it "Door" then in the script it will be available as "hDoor" (The h means "hotspot").

In the Areas editor, all the hotspots except the currently selected one are drawn in grey. This is to emphasise which hotspot you have selected to edit.

Interactions

Right, now it's time to make something happen! Make sure the first hotspot is selected (it should read "Editing: 1"), and click the "Interaction..." button. You should be presented with a window that looks like this:

The interaction editor

This is the Interaction Editor, and you will become very familiar with this window during your AGS development.

You should see a list of events, from "Player stands on hotspot" at the top down to "Usermode2 hotspot" at the bottom. The events are represented by flag icons.

These events show you all the possible things that can happen to this hotspot during the game. At the moment, nothing is set to happen in response to any of the events, so whatever the player does to the hotspot, they will get no reply.

Right, let's start with something simple. When the player looks at my hotspot, I want to display a message telling them what they can see. So, double-click the "Look at hotspot" event, and a new window should pop-up:

The action editor

You'll see that this new window is quite plain and empty at the moment. The most important thing is the large drop-down list box near the top of the window, which currently says "Do nothing". This box is where you set what you want the game to do when the player looks at the hotspot.

Open up the combobox, and you'll see quite an extensive list of options - but don't worry, they're in alphabetical order! Scroll down and select "Game - Display a message". The rest of the window is updated with information related to this command:

The action editor with "Display message" selected

The text "Message number: 0" is a parameter for the command. Different commands have various parameters, and they let you set specific information for this use of the command. Here, we are being asked which message we want to display. Click the "Change" button if you need to change it, but since this will be our first message, number 0 will be fine.

Messages

Each room in the game has its own set of messages. A message is simply a string of text that can be displayed during the game. To bring up the room message editor, there are two options - either click the "Edit message" button in the action editor (like we have here), or at other times you can use the "Edit messages" button in the Room Settings pane.

The room message editor

Click the "New message" button in the bottom left. A new item should be added to the left hand list box, and the cursor is placed in the text box on the right.

Simply type your message into the text box. The "Display message as" box allows you to have one of the characters saying the text if you want, otherwise leave it as "Normal text" to use the standard message box.

Once you're done typing the message in, press OK.

You should be back at the Action Editor now. We've set it all up correctly to display the message when the player looks at the hotspot, so click OK to exit this dialog box. You should notice that a new tree node "Game - Display a message (0)" has appeared in the main interaction editor under Look at Hotspot. The (0) shows you at a glance the values of the parameters to the command.

You can add as many commands as you like to be run when an event happens. But now, since double-clicking collapses the tree, you need to right-click on "Look at hotspot" and select "New action" instead. However, let's not worry about that for now. Click "Close" to exit the interaction editor.

Walk-to points

Ok, since we're back at the Areas screen, let me quickly explain the "Set walk-to point" button. This allows you to set a position for each hotspot where the character will walk to whenever the player interacts with the hotspot - just like the way the Lucasarts games like Monkey Island (tm) worked.

If you set a walk-to point, then whenever the player clicks interact or talk on the hotspot, the main character will first walk to that point before the relevant event is triggered. If you want, the man can also walk there when the LOOK mode is used - this option is configurable in the game General Settings pane.

To remove a walk-to point, select the appropriate hotspot and click the "Remove walk-to point" button.

Edges revisited

Ok, so we've covered the basics of creating a room. However, there's one thing that we did way back in the tutorial that we need to clear up - yes, the edges.

Go to the "Settings" mode under the Room Editor. If you select the "Interactions" option from the Room menu, the Interaction Editor will appear, but this time with a different set of events.

Among the events listed, you'll see "Walk off left edge", "Walk off right edge", and so on. These use the edges we defined back in part 2. A common command to use in response to these events is the "Player - Go to a different room" command.

Now, save the room and the game, then choose File, Test Game to test out your room like we did before.

Go to part 4: Objects and inventory