编辑“︁StendhalScripting/Lua”︁（章节）

== Adding Entities ==

=== Signs ===

Signs can be created with <code>entities:createSign</code> and <code>entities:createShopSign</code>:

<pre>
local zone = "0_semos_city"
if game:setZone(zone) then
	-- create the sign instance
	local sign = entities:createSign()
	sign:setEntityClass("signpost")
	sign:setPosition(12, 55)
	sign:setText("Meet Lua!")

	-- Add it to the world
	game:add(sign)
else
	logger:error("Could not set zone: " .. zone)
end
</pre>

=== NPCs ===

Use the <code>entities:createSpeakerNPC</code> method to create an interactive NPC:

<pre>
local zone = "0_semos_city"
if game:setZone(zone) then
	-- Use helper object to create a new NPC
	local npc = entities:createSpeakerNPC("Lua")
	npc:setEntityClass("littlegirlnpc")
	npc:setPosition(10, 55)
	npc:setBaseSpeed(0.1)
	npc:setCollisionAction(CollisionAction.STOP)

	local nodes = {
		{10, 55},
		{11, 55},
		{11, 56},
		{10, 56},
	}

	npc:setPath(nodes)

	-- Dialogue
	npc:addJob("Actually, I am jobless.")
	npc:addGoodbye();

	-- Add to the world
	game:add(npc)
else
	logger:error("Could not set zone: " .. zone)
end
</pre>

==== Adding Transitions ====

A simple example of adding a chat transition can be done without any special functionality:
<pre>
local frank = entities:createSpeakerNPC("Frank")
frank:add(ConversationStates.IDLE,
	ConversationPhrases.GREETING_MESSAGES,
	nil,
	ConversationStates.ATTENDING,
	"Hello.",
	nil)
</pre>

This simply adds a response to saying "hello" & sets the NPC to attend to the player (equivalent of <code>frank:addGreeting("Hello")</code>).

For more complicated behavior, we need to use some helper methods. If we want to check a condition we use the <code>conditions:create</code> method. The first parameter is the string name of the ChatCondition we want to instantiate. The second parameter is a table that contains the values that should be passed to the ChatCondition constructor.

Example:
<pre>
frank:add(ConversationStates.IDLE,
	ConversationPhrases.GREETING_MESSAGES,
	conditions:create("PlayerHasItemWithHimCondition", {"money"}),
	ConversationStates.ATTENDING,
	"Hello.",
	nil)
</pre>

In this scenario, the NPC will only respond if the player is carrying <item>money</item>.

A NotCondition instance can be created with the <code>actions:notCondition</code> method:

Example usage:
<pre>
local condition = conditions.notCondition(conditions:create("PlayerHasItemWithHimCondition", {"money"})
</pre>

To add a ChatAction, we use the <code>actions:create</code> method. Its usage is identical to <code>conditions:create</code>.

Example:
<pre>
frank:add(ConversationStates.IDLE,
	ConversationPhrases.GREETING_MESSAGES,
	conditions:create("PlayerHasItemWithHimCondition", {"money"}),
	ConversationStates.ATTENDING,
	"Hello.",
	actions:create("NPCEmoteAction", {"looks greedily at your pouch of money.", false}))
</pre>

Lua tables can be used to add multiple conditions or actions:
<pre>
frank:add(ConversationStates.IDLE,
	ConversationPhrases.GREETING_MESSAGES,
	{
		conditions:create("PlayerHasItemWithHimCondition", {"money"}),
		conditions:notCondition(conditions:create("NakedCondition")),
	},
	ConversationStates.ATTENDING,
	nil,
	{
		actions:create("SayTextAction", {"Hello."}),
		actions:create("NPCEmoteAction", {"looks greedily at your pouch of money.", false}),
	})
</pre>

In this scenario, the NPC will respond if the player has money & is not naked.

Nested tables are supported as well:
<pre>
local conditions = {
	conditions:create("PlayerHasItemWithHimCondition", {"money"}),
	{
		conditions:notCondition(conditions:create("NakedCondition")),
	},
}

frank:add(ConversationStates.IDLE,
	ConversationPhrases.GREETING_MESSAGES,
	conditions,
	ConversationStates.ATTENDING,
	nil,
	{
		actions:create("SayTextAction", {"Hello."}),
		actions:create("NPCEmoteAction", {"looks greedily at your pouch of money.", false}),
	})
</pre>

==== Adding Merchant Behavior ====

The <code>merchants</code> object is used for adding merchant behavior (buying/selling) to an NPC.

Example of adding seller behavior to an NPC:
<pre>
if game:setZone("0_semos_city") then
	local frank = entities.createSpeakerNPC("Frank")
	merchants:addSeller(frank, merchants.shops:get("shopname"), true)

	game:add(frank)
end
</pre>

To create a custom shop list, you can use a Lua table (there are multiple ways to add elements to a Lua table):

Method 1:
<pre>
local priceList = {
	meat = 50,
	["ham"] = 70,
}
</pre>

Method 2:
<pre>
local priceList = {}
priceList.meat = 50
priceList["ham"] = 70
</pre>

The helper methods have special handling for underscore characters as well (the following are all the same):
<pre>
local priceList = {
	smoked_ham = 100,
	["smoked ham"] = 100,
}
priceList.smoked_ham = 100
priceList["smoked ham"] = 100
</pre>

Then add the seller behavior using the custom list:
<pre>
merchants:addSeller(frank, priceList, true)
</pre>