用Unity模仿CSGO里的火焰效果
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CSGO里的火焰效果和真实的情况比较像,能沿着遮挡物前进,如下是模仿效果。
思路比较简单,开始想的是一圈一圈发出去,但是前圈与后圈的联系不好做,换种思路,每个方向发射一条线,这样根据上一个位置的方位先向前进,如果前面有遮挡,则计算好新的位置与方向,反之前面没有遮挡,选择合适的位置,并从这个方向的上面向下检测,检测这个方向的垂直位置有没遮挡,如果有遮挡,计算新的方向与位置,没有,则表明延展不下去。如下图所示.
相关主要代码:
//根据一条线的上一个节点,确定这个节点如何定位 bool forward(ref Vector3 pos, ref Quaternion quat) { var forward = quat * Vector3.forward; var up = quat * Vector3.up; var nextPos = pos + forward * radius; RaycastHit hit; //前面有没挡住 //Debug.DrawRay(nextPos, forward, Color.red, 100); var hitForward = Physics.Raycast(nextPos, forward, out hit, radius * 2); var hitDown = false; //如果前面没有挡住,检查垂直位置 if (!hitForward) { //height用来控制垂直扩展的高度 var upPos = pos + 2 * forward * radius + up * height * 2; //Debug.DrawRay(upPos, -up, Color.green, 100); hitDown = Physics.Raycast(upPos, -up, out hit, height * 4); } if (hitForward || hitDown) { //新的位置 pos = hit.point + hit.normal * prefabHeight; //Debug.DrawRay(pos, hit.normal, Color.blue, 100); quat = Quaternion.FromToRotation(up, hit.normal) * quat; return true; } return false; }
如上代码每句都加上了注释,我们添加了一个radius参数,用来表示每次前进的步子大小,radius越小,则越密集,然后添加一个height参数用来表示垂直方向升降能力,可以看下图。
确定一条线上显示后,我们只要考虑沿着周围全部扩展就行,在这我们用level表示扩展多少层,层数越多,我们每条线的相隔的角度也应该越小,如下效果。
相关代码:
//分成多条线向外扩散 public void extend() { //分成多条线 count = (int)(2 * level * Mathf.PI); //每条偏移角度 angle = 360.0f / count; var up = transform.rotation * Vector3.up; for (int i = 0; i < count; i++) { var curAngle = angle * i; var curQuat = Quaternion.AngleAxis(curAngle, up); var quat = curQuat * transform.rotation; //forward(transform.position, quat, level, i); StartCoroutine(forward(transform.position, quat, level, i)); } } //每条线向前扩展,自动翻越遮挡 public IEnumerator forward(Vector3 pos, Quaternion quat, int level, int place) { var npos = pos; var nquat = quat; int curLevel = 1; var prePos = npos; while (curLevel <= level && forward(ref npos, ref nquat)) { //Debug.DrawLine(prePos, npos, Color.blue, 100f, true); if (bCreate(curLevel, place)) { var offset = offsetPos(nquat, 1); var obj = Instantiate(getPrefab(curLevel), npos + offset, nquat); //Debug.DrawLine(prePos, npos, Color.blue, 100f, true); var duration = getDuration(curLevel); Destroy(obj, duration); } yield return new WaitForSeconds(deltaTime); curLevel++; prePos = npos; } }
这些蓝线确定了火焰沿线步局,但是现在最中心会比较密集,我们需要有选择的是否生成,如下图:
相关代码:
//确定当前层上的某个位置是否需要生成 bool bCreate(int level, int place) { //当前需要显示的个数 var levelCount = (int)(2 * level * Mathf.PI); var levelLength = Mathf.RoundToInt((float)count / levelCount); //每层起点偏移一点位置 var offset = place + level; return offset % levelLength == 0; }
这样就能简单在每层生成合适的个数,其中最上面有个prefabHeight,用来控制模型中心与下边的高度,用来控制生成的模型贴着遮挡物,如图:
如下是完整代码:
using UnityEngine; using System.Collections; public class FireMove : MonoBehaviour { public GameObject[] particlePrefabs; [Tooltip("半径越小,模型越密集")] public float radius = 0.5f; [Tooltip("高度越大,模型能越过更高的遮挡物")] public float height = 0.5f; [Tooltip("层级越多,向外扩展的导数越多")] public int level = 10; [Tooltip("每层间隔生成时间")] public float deltaTime = 0.1f; [Tooltip("控制火焰显示时间")] public float duration = 5.0f; [Tooltip("水平偏移")] public float offsetHeight = 0.1f; [Tooltip("高度偏移")] public float offsetPanel = 0.2f; [Tooltip("模型与地面的距离")] public float prefabHeight = 0.01f; private int count; private float angle; #if UNITY_EDITOR public void Update() { if (Input.GetKeyDown(KeyCode.K)) { extend(); } } #endif public void attack(int level) { this.level = level; extend(); } //分成多条线向外扩散 public void extend() { //分成多条线 count = (int)(2 * level * Mathf.PI); //每条偏移角度 angle = 360.0f / count; var up = transform.rotation * Vector3.up; for (int i = 0; i < count; i++) { var curAngle = angle * i; var curQuat = Quaternion.AngleAxis(curAngle, up); var quat = curQuat * transform.rotation; //forward(transform.position, quat, level, i); StartCoroutine(forward(transform.position, quat, level, i)); } } //每条线向前扩展,自动翻越遮挡 public IEnumerator forward(Vector3 pos, Quaternion quat, int level, int place) { var npos = pos; var nquat = quat; int curLevel = 1; var prePos = npos; while (curLevel <= level && forward(ref npos, ref nquat)) { //Debug.DrawLine(prePos, npos, Color.blue, 100f, true); if (bCreate(curLevel, place)) { var offset = offsetPos(nquat, 1); var obj = Instantiate(getPrefab(curLevel), npos + offset, nquat); //Debug.DrawLine(prePos, npos, Color.blue, 100f, true); var duration = getDuration(curLevel); Destroy(obj, duration); } yield return new WaitForSeconds(deltaTime); curLevel++; prePos = npos; } } //确定当前层上的某个位置是否需要生成 bool bCreate(int level, int place) { //当前需要显示的个数 var levelCount = (int)(2 * level * Mathf.PI); var levelLength = Mathf.RoundToInt((float)count / levelCount); //每层起点偏移一点位置 var offset = place + level; return offset % levelLength == 0; } public GameObject getPrefab(int curLevel) { var prfabCount = particlePrefabs.Length; //var t = Mathf.RoundToInt(prfabCount * (curLevel - 1) / level); var index = Random.Range(0, prfabCount); return particlePrefabs[index]; } //加上偏移 public Vector3 offsetPos(Quaternion quat, int level) { var xAxis = quat * Vector3.right * Random.Range(-offsetPanel, offsetPanel) * level; var zAxis = quat * Vector3.forward * Random.Range(-offsetPanel, offsetPanel) * level; var yAxis = quat * Vector3.up * Random.Range(-offsetHeight, offsetHeight) * level; return xAxis + zAxis + yAxis; } //每层的生命周期 float getDuration(int level) { var levelDuration = duration - 2 * level * deltaTime; return levelDuration; } //根据一条线的上一个节点,确定这个节点如何定位 bool forward(ref Vector3 pos, ref Quaternion quat) { var forward = quat * Vector3.forward; var up = quat * Vector3.up; var nextPos = pos + forward * radius; RaycastHit hit; //前面有没挡住 //Debug.DrawRay(nextPos, forward, Color.red, 100); var hitForward = Physics.Raycast(nextPos, forward, out hit, radius * 2); var hitDown = false; //如果前面没有挡住,检查垂直位置 if (!hitForward) { //height用来控制垂直扩展的高度 var upPos = pos + 2 * forward * radius + up * height * 2; //Debug.DrawRay(upPos, -up, Color.green, 100); hitDown = Physics.Raycast(upPos, -up, out hit, height * 4); } if (hitForward || hitDown) { //新的位置 pos = hit.point + hit.normal * prefabHeight; //Debug.DrawRay(pos, hit.normal, Color.blue, 100); quat = Quaternion.FromToRotation(up, hit.normal) * quat; return true; } return false; } }
直接放到一个物体上就可以了,其中radius设为相应的火焰半径大小就可,如果要密一些,降低一些就行,相应offset参数用来设定水平与垂直上的偏移,免的给人太规律了,代码上都有详细注释,可以自己改动。
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