525 lines
17 KiB
Markdown
525 lines
17 KiB
Markdown
---
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front: https://nie.res.netease.com/r/pic/20211104/69055361-2e7a-452f-8b1a-f23e1262a03a.jpg
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hard: 高级
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time: 25分钟
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---
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# 联动生物事件与行为
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最后，我们来探索生物的触发器组件。在本节中，我们欲通过**触发器**（**Trigger**）来做到一个松鼠的“避难”机制。
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## 事件和触发器
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通过之前的章节，我们已经了解到**事件**是实体定义文件中一种非常重要的机制。我们可以通过定义不同的事件来触发不同的效果、添加或移除组件组。而事件的触发机制也是多种多样的。不过，除了内置事件的硬编码触发以外，最多的触发手段应该当属**触发器**组件了。
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触发器组件也是一种实体行为包组件。不同于其他类型的组件，触发器组件主要用于触发一个事件。换句话说，触发器组件就是为了事件而生的。触发器的原理与模组SDK中的事件监听类似，都是通过监听一定的系统事件，然后在特定的时机执行指定的内容。只不过，在实体定义文件这种数据驱动文件中，事件响应执行的内容往往是有限的。在这里，触发器只能用于触发另一个定义在实体行为包定义文件中的事件。
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实体的触发器组件也有很多类型。我们这里想制作一个松鼠受伤后就会逃跑的机制，于是我们需要用到与受伤有关的触发器。在掠夺者的组件定义中，我们便可以发现类似的触发器。
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```json
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"minecraft:on_hurt": {
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"event": "minecraft:ranged_mode",
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"target": "self"
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},
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"minecraft:on_hurt_by_player": {
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"event": "minecraft:ranged_mode",
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"target": "self"
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},
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"minecraft:on_target_escape": {
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"event": "minecraft:calm",
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"target": "self"
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}
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```
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这里，`minecraft:on_hurt`是实体受到伤害时触发，`minecraft:on_hurt_by_player`是实体受到玩家伤害时触发，而`minecraft:on_target_escape`是该实体的目标消失后（即不再将某个实体视为目标后）触发。
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我们可以使用`minecraft:on_hurt`和`minecraft:on_target_escape`来设计一个逃跑机制。
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## 为松鼠设计逃跑机制
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我们知道，要想使松鼠逃跑，我们应该需要使用一种可以用来规避生物的AI意向。通过对原版机制的了解，我们知道苦力怕会规避“猫科”生物。我们利用这一点到苦力怕的行为文件中寻找相关AI意向。不出所料，我们找到了规避特定生物的AI意向`minecraft:behavior.avoid_mob_type`，这是他在苦力怕文件中的表达：
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```json
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"minecraft:behavior.avoid_mob_type": {
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"priority": 3,
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"entity_types": [
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{
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"filters": {
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"any_of": [
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{ "test" : "is_family", "subject" : "other", "value" : "ocelot"},
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{ "test" : "is_family", "subject" : "other", "value" : "cat"}
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]
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},
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"max_dist": 6,
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"walk_speed_multiplier": 1,
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"sprint_speed_multiplier": 1.2
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}
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]
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}
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```
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我们便可以使用这个AI意向来作为松鼠规避对它造成伤害的生物的意向。为了改造成我们需要的这种功能，我们需要先了解这个AI意向中使用的一种我的世界机制——**过滤器**（**Filter**）。
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上面这段代码中的`filters`字段便是用于指定过滤器的字段。我们可以看到原版的苦力怕指定了两个过滤器，并且使用`any_of`逻辑，意为只要两者出现其一满足，便可以触发该AI意向。这里原版使用了`is_family`过滤器。该过滤器是一个字符串测试，这里原版分别测试了对立实体是否为豹猫或猫，一旦满足便执行规避的AI意向。
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我们期望我们的实体规避对其造成伤害的实体。而我们知道我们已经有了`minecraft:behavior.hurt_by_target`AI意向，任意对其造成伤害的实体都会被其标记为目标。因此我们只需要`has_target`过滤器，该过滤器是一个布尔测试。我们只需要测试对立实体是否为我们实体的目标即可。
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我们改造后的组件如下：
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```json
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"minecraft:behavior.avoid_mob_type": {
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"priority": 3,
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"entity_types": [
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{
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"filters": {
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"test": "is_target",
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"subject": "other",
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"value": true
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},
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"max_dist": 6,
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"walk_speed_multiplier": 1,
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"sprint_speed_multiplier": 1.2
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}
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]
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}
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```
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这样，只要对立实体是其目标，我们的松鼠便会自动规避至与其距离6米远之外。
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当然，这里我们意图通过触发器来做到这一点。虽然由于过滤器的存在，再使用触发器便没有必要了，但是我们依旧设计了一个使用触发器触发的松鼠。设计完毕的实体定义文件如下：
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```json
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{
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"format_version": "1.12.0",
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"minecraft:entity": {
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"description": {
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"identifier": "tutorial_demo:squirrel",
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"is_experimental": false,
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"is_spawnable": true,
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"is_summonable": true
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},
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"component_groups": {
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"tutorial_demo:color_red": {
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"minecraft:variant": {
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"value": 0
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}
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},
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"tutorial_demo:color_gray": {
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"minecraft:variant": {
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"value": 1
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}
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},
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"tutorial_demo:escaping": {
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"minecraft:behavior.avoid_mob_type": {
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"priority": 3,
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"entity_types": [
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{
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"filters": {
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"test": "is_target",
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"subject": "other",
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"value": true
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},
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"max_dist": 6,
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"walk_speed_multiplier": 1,
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"sprint_speed_multiplier": 1.2
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}
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]
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}
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}
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},
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"components": {
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// ...
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"minecraft:behavior.hurt_by_target": {
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"priority": 1
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},
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"minecraft:behavior.delayed_attack": {
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"priority": 4,
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"reach_multiplier": 1.5,
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"attack_duration": 0.75,
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"hit_delay_pct": 0.25,
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"track_target": true,
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"sound_event": "attack.strong"
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},
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"minecraft:behavior.random_stroll": {
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"priority": 6,
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"xz_dist": 2,
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"y_dist": 1,
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"speed_multiplier": 0.8
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},
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"minecraft:behavior.random_look_around": {
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"priority": 9
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},
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"minecraft:behavior.look_at_player": {
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"priority": 11
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},
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// ...
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"minecraft:movement": {
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"value": 0.3
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},
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"minecraft:health": {
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"value": 30,
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"max": 30
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},
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"minecraft:on_hurt": {
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"event": "tutorial_demo:escape_started",
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"target": "self"
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},
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"minecraft:on_hurt_by_player": {
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"event": "tutorial_demo:escape_started",
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"target": "self"
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},
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"minecraft:on_target_escape": {
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"event": "tutorial_demo:escape_ended",
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"target": "self"
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}
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},
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"events": {
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"minecraft:entity_spawned": {
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// ...
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},
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"tutorial_demo:escape_started": {
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"add": {
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"component_groups": [
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"tutorial_demo:escaping"
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]
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}
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},
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"tutorial_demo:escape_ended": {
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"remove": {
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"component_groups": [
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"tutorial_demo:escaping"
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]
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}
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}
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}
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}
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}
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```
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这里我们添加了一个`tutorial_demo:escaping`组件组，用于`minecraft:behavior.avoid_mob_type`AI意向的动态增减。然后我们通过`tutorial_demo:escape_started`和`tutorial_demo:escape_ended`事件来进行组件组的增减。最后，我们通过`minecraft:on_hurt`、`minecraft:on_hurt_by_player`和`minecraft:on_target_escape`来实现两个事件的触发。这样，一个动态增删功能（这里是增删规避生物的AI意向）的实现就完成了。
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当然，如果我们的“脑补”能力比较强，我们可以发现这样的设计有个明显的缺点。那就是由于`minecraft:behavior.delayed_attack`的存在，虽然其优先级为4，低于优先级为3的`minecraft:behavior.avoid_mob_type`，但是`minecraft:behavior.avoid_mob_type`只会让实体规避至6米以外。当实体行走至6米以外时，`minecraft:behavior.avoid_mob_type`便会暂时被停用，此时`minecraft:behavior.delayed_attack`便会由于高优先级的AI意向被停用从而被激活，实体就会重新接近之前攻击它的目标。而接近到一定距离时，又会因为太近而重新激活`minecraft:behavior.avoid_mob_type`，同时`minecraft:behavior.delayed_attack`再次被停用。实体便会处于一会规避，一会接近的循环状态。我们也可以在电脑开发版中通过ImGui来直观地看到这一点。
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我们需要对此进行优化。
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### 优化数据
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我们意图通过改变`minecraft:behavior.delayed_attack`的存在性来解决这个问题。我们期望两种变体的松鼠的行为不一致，红色松鼠比较“勇”，只要有人打它就反击，而灰色松鼠比较“逊”，有人打它就逃跑。那么，我们如何实现这一机制呢？事实上，`minecraft:on_hurt`等触发器也是可以使用过滤器来进行条件触发的。我们可以以如下这种方式来写入一个过滤器：
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```json
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"minecraft:on_hurt": {
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"event": "tutorial_demo:escape_started",
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"filters":{
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"test": "is_variant",
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"value": 1
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},
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"target": "self"
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},
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"minecraft:on_hurt_by_player": {
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"event": "tutorial_demo:escape_started",
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"filters":{
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"test": "is_variant",
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"value": 1
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},
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"target": "self"
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},
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"minecraft:on_target_escape": {
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"event": "tutorial_demo:escape_ended",
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"target": "self"
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}
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```
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其中`is_variant`过滤器是用于检测变体的值的过滤器。灰色松鼠的变体值为1，因此，我们只有检测到变体值为1时我们才触发添加对应AI意向的事件。而红色松鼠则是直接在生成时也通过组件组的形式添加延迟攻击组件，这样，灰色松鼠就不会附带有这个组件。我们将`minecraft:behavior.delayed_attack`组件移动到红色松鼠的变体组件组中，如下：
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```json
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{
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"format_version": "1.12.0",
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"minecraft:entity": {
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"description": {
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"identifier": "tutorial_demo:squirrel",
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"is_experimental": false,
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"is_spawnable": true,
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"is_summonable": true
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},
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"component_groups": {
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"tutorial_demo:color_red": {
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"minecraft:behavior.delayed_attack": {
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"priority": 4,
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"reach_multiplier": 1.5,
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"attack_duration": 0.75,
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"hit_delay_pct": 0.25,
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"track_target": true,
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"sound_event": "attack.strong"
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},
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"minecraft:variant": {
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"value": 0
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}
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},
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"tutorial_demo:color_gray": {
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"minecraft:variant": {
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"value": 1
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}
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},
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"tutorial_demo:escaping": {
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"minecraft:behavior.avoid_mob_type": {
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"priority": 3,
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"entity_types": [
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{
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"filters": {
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"test": "is_target",
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"subject": "other",
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"value": true
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},
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"max_dist": 6,
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"walk_speed_multiplier": 1,
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"sprint_speed_multiplier": 1.2
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}
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]
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}
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}
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},
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"components": {
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// ...
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"minecraft:behavior.hurt_by_target": {
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"priority": 1
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},
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"minecraft:behavior.random_stroll": {
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"priority": 6,
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"xz_dist": 2,
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"y_dist": 1,
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"speed_multiplier": 0.8
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},
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"minecraft:behavior.random_look_around": {
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"priority": 9
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},
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"minecraft:behavior.look_at_player": {
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"priority": 11
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},
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// ...
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"minecraft:on_hurt": {
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"event": "tutorial_demo:escape_started",
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"filters":{
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"test": "is_variant",
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"value": 1
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},
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"target": "self"
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},
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"minecraft:on_hurt_by_player": {
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"event": "tutorial_demo:escape_started",
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"filters":{
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"test": "is_variant",
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"value": 1
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},
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"target": "self"
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},
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"minecraft:on_target_escape": {
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"event": "tutorial_demo:escape_ended",
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"target": "self"
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}
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},
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"events": {
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"minecraft:entity_spawned": {
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// ...
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},
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"tutorial_demo:escape_started": {
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// ...
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},
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"tutorial_demo:escape_ended": {
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// ...
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}
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}
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}
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}
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```
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这样，我们便实现了红灰两种松鼠的行为特异化，我们进入游戏来检测我们的内容。我们可以通过电脑开发版的ImGui直观地看到组件组的增删和AI意向的激活与停用。
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这样，我们便修复了我们的异常。下面，我们放出我们目前为止行为包定义文件中全部的内容，供各位开发者们参考：
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```json
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{
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"format_version": "1.12.0",
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"minecraft:entity": {
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"description": {
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"identifier": "tutorial_demo:squirrel",
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"is_experimental": false,
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"is_spawnable": true,
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"is_summonable": true
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},
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"component_groups": {
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"tutorial_demo:color_red": {
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"minecraft:behavior.delayed_attack": {
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"priority": 4,
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"reach_multiplier": 1.5,
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"attack_duration": 0.75,
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"hit_delay_pct": 0.25,
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"track_target": true,
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"sound_event": "attack.strong"
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},
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"minecraft:variant": {
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"value": 0
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}
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},
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"tutorial_demo:color_gray": {
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"minecraft:variant": {
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"value": 1
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}
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},
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"tutorial_demo:escaping": {
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"minecraft:behavior.avoid_mob_type": {
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"priority": 3,
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"entity_types": [
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{
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"filters": {
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"test": "is_target",
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"subject": "other",
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"value": true
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},
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"max_dist": 6,
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"walk_speed_multiplier": 1,
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"sprint_speed_multiplier": 1.2
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}
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]
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}
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}
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},
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"components": {
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"minecraft:hurt_on_condition": {
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"damage_conditions": [{
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"filters": {
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"test": "in_lava",
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"subject": "self",
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"operator": "==",
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"value": true
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},
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"cause": "lava",
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"damage_per_tick": 4
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}]
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},
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"minecraft:pushable": {
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"is_pushable": true,
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"is_pushable_by_piston": true
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},
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"minecraft:experience_reward": {
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"on_death": "query.last_hit_by_player ? Math.Random(0,1) : 0"
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},
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"minecraft:breathable": {
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"total_supply": 15,
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"suffocate_time": 0
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},
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"minecraft:physics": {},
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"minecraft:navigation.walk": {
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"can_path_over_water": true,
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"avoid_water": true
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},
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"minecraft:movement.skip": {},
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"minecraft:jump.static": {},
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"minecraft:behavior.float": {
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"priority": 0
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},
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"minecraft:behavior.hurt_by_target": {
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"priority": 1
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},
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"minecraft:behavior.random_stroll": {
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"priority": 6,
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"xz_dist": 2,
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"y_dist": 1,
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"speed_multiplier": 0.8
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},
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"minecraft:behavior.random_look_around": {
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"priority": 9
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},
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"minecraft:behavior.look_at_player": {
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"priority": 11
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},
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"minecraft:equipment": {
|
||
"table": "loot_tables/entities/squirrel_equipment.json"
|
||
},
|
||
"minecraft:type_family": {
|
||
"family":["squirrel", "mob"]
|
||
},
|
||
"minecraft:can_climb": {},
|
||
"minecraft:collision_box": {
|
||
"width": 0.7,
|
||
"height": 0.7
|
||
},
|
||
"minecraft:attack": {
|
||
"damage": 1.0
|
||
},
|
||
"minecraft:movement": {
|
||
"value": 0.3
|
||
},
|
||
"minecraft:health": {
|
||
"value": 30,
|
||
"max": 30
|
||
},
|
||
"minecraft:on_hurt": {
|
||
"event": "tutorial_demo:escape_started",
|
||
"filters":{
|
||
"test": "is_variant",
|
||
"value": 1
|
||
},
|
||
"target": "self"
|
||
},
|
||
"minecraft:on_hurt_by_player": {
|
||
"event": "tutorial_demo:escape_started",
|
||
"filters":{
|
||
"test": "is_variant",
|
||
"value": 1
|
||
},
|
||
"target": "self"
|
||
},
|
||
"minecraft:on_target_escape": {
|
||
"event": "tutorial_demo:escape_ended",
|
||
"target": "self"
|
||
}
|
||
},
|
||
"events": {
|
||
"minecraft:entity_spawned": {
|
||
"sequence": [
|
||
{
|
||
"randomize": [
|
||
{
|
||
"weight": 1,
|
||
"add": {
|
||
"component_groups": [
|
||
"tutorial_demo:color_red"
|
||
]
|
||
}
|
||
},
|
||
{
|
||
"weight": 1,
|
||
"add": {
|
||
"component_groups": [
|
||
"tutorial_demo:color_gray"
|
||
]
|
||
}
|
||
}
|
||
]
|
||
}
|
||
]
|
||
},
|
||
"tutorial_demo:escape_started": {
|
||
"add": {
|
||
"component_groups": [
|
||
"tutorial_demo:escaping"
|
||
]
|
||
}
|
||
},
|
||
"tutorial_demo:escape_ended": {
|
||
"remove": {
|
||
"component_groups": [
|
||
"tutorial_demo:escaping"
|
||
]
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
```
|
||
|