B站视频：【Creator3】好玩的编队代码 魔性排列停不下来 附源码及出处

这次带来一个有趣的编队代码，简单的算法得到令人惊叹的编队队形，叹为观止，前几天刷视频的时候看到一个有趣的展示，来自youtube大神：Tarodev的队形计算展示《 Fun with Formations - Game Dev Adventure》

他的是Unity实现的，我用最新发布的Creator 3.3版本制作了一个，视频如下：

参考资料：https://www.youtube.com/watch?v=NEFxWkTRVCc 

开发工具 CocosCreator 3.3.0

BGM： Jazzy Frenchy form bensound

 Creator3以后的引擎，对于3D方面的计算基本上和Unity很像了，转译C#代码并不难，原版代码在这里：GitHub - Matthew-J-Spencer/Formations: Some simple scripts to create formations in Unity 

CocosCreator中的关键代码如下：

/** 编队的基类 */
import { _decorator, Component, Node, Vec3, v3 } from 'cc';
const { ccclass, property } = _decorator;
@ccclass('BaseFormation')
export class BaseFormation extends Component {
    @property
    noise: number = 0;
    @property
    Spread: number = 1;
    offsetPos:Vec3 = v3();
    EvaluatePoints(): Vec3[] {
        return null;
    }
    GetNoise(pos: Vec3): Vec3 {
        const noise = this.noise;
        const x = pos.x + Math.random() * noise - noise / 2;
        const z = pos.z + Math.random() * noise - noise / 2;
        pos.x = x;
        pos.z = z;
        return pos;
    }
}

/** 方形编队组件脚本代码 */
import { _decorator, Component, Node, Vec3, v3 } from 'cc';
import { BaseFormation } from './BaseFormation';
const { ccclass, property } = _decorator;
@ccclass('BoxFormation')
export class BoxFormation extends BaseFormation {
    @property
    unitWidth: number = 5;
    @property
    unitDepth: number = 5;
    @property
    hollow: boolean = false;
    @property
    nthOffset: number = 0;
    EvaluatePoints(): Vec3[] {
        const ret: Vec3[] = [];
        const middleOffset = v3((this.unitWidth - 1) * 0.5, 0, (this.unitDepth - 1) * 0.5);
        for (let x = 0; x < this.unitWidth; x++) {
            for (let z = 0; z < this.unitDepth; z++) {
                if (this.hollow && x != 0 && x != this.unitWidth - 1 && z != 0 && z != this.unitDepth - 1) continue;
                let pos = v3(x + (z % 2 == 0 ? 0 : this.nthOffset), 0, z);

                pos = pos.subtract(middleOffset);

                pos = this.GetNoise(pos);

                pos = pos.multiplyScalar(this.Spread);
                pos.add(this.offsetPos);
                ret.push(pos);
            }
        }
        return ret;
    }
}

/** 放射编队组件脚本代码 */
import { _decorator, Component, Node, Vec3, v3 } from 'cc';
import { BaseFormation } from './BaseFormation';
const { ccclass, property } = _decorator;
@ccclass('RadialFormation')
export class RadialFormation extends BaseFormation {
    @property
    amount: number = 10;
    @property
    radius: number = 1;
    @property
    radiusGrowthMultiplier: number = 0;
    @property
    rotations: number = 1;
    @property
    rings: number = 1;
    @property
    ringOffset: number = 1;
    @property
    nthOffset: number = 1;
    EvaluatePoints(): Vec3[] {
        const ret: Vec3[] = [];
        let amountPerRing = this.amount / this.rings;
        let ringOffset = 0;
        for (var i = 0; i < this.rings; i++) {
            for (var j = 0; j < amountPerRing; j++) {
                let angle = j * Math.PI * (2 * this.rotations) / amountPerRing + (i % 2 != 0 ? this.nthOffset : 0);

                let radius = this.radius + ringOffset + j * this.radiusGrowthMultiplier;
                let x = Math.cos(angle) * radius;
                let z = Math.sin(angle) * radius;

                let pos = new Vec3(x, 0, z);

                pos = this.GetNoise(pos);

                pos = pos.multiplyScalar(this.Spread);

                pos.add(this.offsetPos);
                ret.push(pos);
            }
            ringOffset += this.ringOffset;
        }
        return ret;
    }
}

以上便是CocosCreator3版本的核心计算代码了，可以自行贴在编队节点上，人物控制应该是由特定的渲染代码完成。

编队展示处理代码

/**
 * 编队渲染展示的代码，挂在到你想展示的节点容器上，配合对应的Formation组件
 * 请自行构建Actor角色组件用于处理人物逻辑，实现removeSelf和moveTo
 * 在合适的时机处理编队的刷新，比如编队参数变化、队伍移动的时候
 */
import { _decorator, Component, Node, Prefab, instantiate, director } from 'cc';
import { Actor } from '../actors/Actor';
import { BaseFormation } from '../formations/BaseFormation';
const { ccclass, property } = _decorator;
 
@ccclass('FormationShow')
export class FormationShow extends Component {
    @property(Prefab)
    actor: Prefab = null;
    start() {
        this.FormationUpdate();
    }
    FormationUpdate(prop?: string, value?: number) {
        const formation = this.getComponent(BaseFormation);
        if (formation) {
            if (prop) {
                const old = formation[prop];
                formation[prop] = value;
                if (old == formation[prop]) {
                    return;
                }
            }
            const points = formation.EvaluatePoints();
            for (let i = this.node.children.length - 1; i >= points.length; i--) {
                this.node.children[i].getComponent(Actor).removeSelf();
            }
            const len = this.node.children.length;
            for (let i = 0; i < points.length; i++) {
                if (i < points.length && i >= len) {
                    let actor = null;
                    if (len > 0) {
                        actor = this.node.children[len - 1];
                    } else {
                        actor = this.actor;
                    }
                    const a = instantiate(actor);
                    this.node.addChild(a);
                }
                this.node.children[i].getComponent(Actor).moveTo(points[i]);
            }
        }
    }
}

结语

视频中的源码工程已经发布到Cocos的官方商店，有需要的自取
https://store.cocos.com/app/detail/3210