【Unity3d】将Particle转成UGUI_粒子转化为canvasrenderer

在unity官方论坛看到的一个解决方案，可以将Particle直接转换成CanvasRenderer元素显示。
新建一个UIParticleSystem.cs脚本，将以下代码复制进去：

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;

[ExecuteInEditMode]
[RequireComponent(typeof(CanvasRenderer))]
[RequireComponent(typeof(ParticleSystem))]
public class UIParticleSystem : MaskableGraphic
{

    public Texture particleTexture;
    public Sprite particleSprite;

    private Transform _transform;
    private ParticleSystem _particleSystem;
    private ParticleSystem.Particle[] _particles;
    private UIVertex[] _quad = new UIVertex[4];
    private Vector4 _uv = Vector4.zero;
    private ParticleSystem.TextureSheetAnimationModule _textureSheetAnimation;
    private int _textureSheetAnimationFrames;
    private Vector2 _textureSheedAnimationFrameSize;

    public override Texture mainTexture
    {
        get
        {
            if (particleTexture)
            {
                return particleTexture;
            }

            if (particleSprite)
            {
                return particleSprite.texture;
            }

            return null;
        }
    }

    protected bool Initialize()
    {
        // initialize members
        if (_transform == null)
        {
            _transform = transform;
        }

        // prepare particle system
        ParticleSystemRenderer renderer = GetComponent<ParticleSystemRenderer>();
        bool setParticleSystemMaterial = false;

        if (_particleSystem == null)
        {
            _particleSystem = GetComponent<ParticleSystem>();

            if (_particleSystem == null)
            {
                return false;
            }

            // get current particle texture
            if (renderer == null)
            {
                renderer = _particleSystem.gameObject.AddComponent<ParticleSystemRenderer>();
            }
            Material currentMaterial = renderer.sharedMaterial;
            if (currentMaterial && currentMaterial.HasProperty("_MainTex"))
            {
                particleTexture = currentMaterial.mainTexture;
            }

            // automatically set scaling
            _particleSystem.scalingMode = ParticleSystemScalingMode.Local;

            _particles = null;
            setParticleSystemMaterial = true;
        }
        else
        {
            if (Application.isPlaying)
            {
                setParticleSystemMaterial = (renderer.material == null);
            }
#if UNITY_EDITOR
            else
            {
                setParticleSystemMaterial = (renderer.sharedMaterial == null);
            }
#endif
        }

        // automatically set material to UI/Particles/Hidden shader, and get previous texture
        if (setParticleSystemMaterial)
        {
            Material material = new Material(Shader.Find("UI/Particles/Hidden"));
            if (Application.isPlaying)
            {
                renderer.material = material;
            }
#if UNITY_EDITOR
            else
            {
                material.hideFlags = HideFlags.DontSave;
                renderer.sharedMaterial = material;
            }
#endif
        }

        // prepare particles array
        if (_particles == null)
        {
            _particles = new ParticleSystem.Particle[_particleSystem.maxParticles];
        }

        // prepare uvs
        if (particleTexture)
        {
            _uv = new Vector4(0, 0, 1, 1);
        }
        else if (particleSprite)
        {
            _uv = UnityEngine.Sprites.DataUtility.GetOuterUV(particleSprite);
        }

        // prepare texture sheet animation
        _textureSheetAnimation = _particleSystem.textureSheetAnimation;
        _textureSheetAnimationFrames = 0;
        _textureSheedAnimationFrameSize = Vector2.zero;
        if (_textureSheetAnimation.enabled)
        {
            _textureSheetAnimationFrames = _textureSheetAnimation.numTilesX * _textureSheetAnimation.numTilesY;
            _textureSheedAnimationFrameSize = new Vector2(1f / _textureSheetAnimation.numTilesX, 1f / _textureSheetAnimation.numTilesY);
        }

        return true;
    }

    protected override void Awake()
    {
        base.Awake();

        if (!Initialize())
        {
            enabled = false;
        }
    }

    protected override void OnPopulateMesh(VertexHelper vh)
    {
#if UNITY_EDITOR
        if (!Application.isPlaying)
        {
            if (!Initialize())
            {
                return;
            }
        }
#endif

        // prepare vertices
        vh.Clear();

        if (!gameObject.activeInHierarchy)
        {
            return;
        }

        // iterate through current particles
        int count = _particleSystem.GetParticles(_particles);

        for (int i = 0; i < count; ++i)
        {
            ParticleSystem.Particle particle = _particles[i];

            // get particle properties
            Vector2 position = (_particleSystem.simulationSpace == ParticleSystemSimulationSpace.Local ? particle.position : _transform.InverseTransformPoint(particle.position));
            float rotation = -particle.rotation * Mathf.Deg2Rad;
            float rotation90 = rotation + Mathf.PI / 2;
            Color32 color = particle.GetCurrentColor(_particleSystem);
            float size = particle.GetCurrentSize(_particleSystem) * 0.5f;

            // apply scale
            if (_particleSystem.scalingMode == ParticleSystemScalingMode.Shape)
            {
                position /= canvas.scaleFactor;
            }

            // apply texture sheet animation
            Vector4 particleUV = _uv;
            if (_textureSheetAnimation.enabled)
            {
                float frameProgress = 1 - (particle.lifetime / particle.startLifetime);
                //                float frameProgress = textureSheetAnimation.frameOverTime.curveMin.Evaluate(1 - (particle.lifetime / particle.startLifetime)); // TODO - once Unity allows MinMaxCurve reading
                frameProgress = Mathf.Repeat(frameProgress * _textureSheetAnimation.cycleCount, 1);
                int frame = 0;

                switch (_textureSheetAnimation.animation)
                {

                    case ParticleSystemAnimationType.WholeSheet:
                        frame = Mathf.FloorToInt(frameProgress * _textureSheetAnimationFrames);
                        break;

                    case ParticleSystemAnimationType.SingleRow:
                        frame = Mathf.FloorToInt(frameProgress * _textureSheetAnimation.numTilesX);

                        int row = _textureSheetAnimation.rowIndex;
                        //                    if (textureSheetAnimation.useRandomRow) { // FIXME - is this handled internally by rowIndex?
                        //                        row = Random.Range(0, textureSheetAnimation.numTilesY, using: particle.randomSeed);
                        //                    }
                        frame += row * _textureSheetAnimation.numTilesX;
                        break;

                }

                frame %= _textureSheetAnimationFrames;

                particleUV.x = (frame % _textureSheetAnimation.numTilesX) * _textureSheedAnimationFrameSize.x;
                particleUV.y = Mathf.FloorToInt(frame / _textureSheetAnimation.numTilesX) * _textureSheedAnimationFrameSize.y;
                particleUV.z = particleUV.x + _textureSheedAnimationFrameSize.x;
                particleUV.w = particleUV.y + _textureSheedAnimationFrameSize.y;
            }

            _quad[0] = UIVertex.simpleVert;
            _quad[0].color = color;
            _quad[0].uv0 = new Vector2(particleUV.x, particleUV.y);

            _quad[1] = UIVertex.simpleVert;
            _quad[1].color = color;
            _quad[1].uv0 = new Vector2(particleUV.x, particleUV.w);

            _quad[2] = UIVertex.simpleVert;
            _quad[2].color = color;
            _quad[2].uv0 = new Vector2(particleUV.z, particleUV.w);

            _quad[3] = UIVertex.simpleVert;
            _quad[3].color = color;
            _quad[3].uv0 = new Vector2(particleUV.z, particleUV.y);

            if (rotation == 0)
            {
                // no rotation
                Vector2 corner1 = new Vector2(position.x - size, position.y - size);
                Vector2 corner2 = new Vector2(position.x + size, position.y + size);

                _quad[0].position = new Vector2(corner1.x, corner1.y);
                _quad[1].position = new Vector2(corner1.x, corner2.y);
                _quad[2].position = new Vector2(corner2.x, corner2.y);
                _quad[3].position = new Vector2(corner2.x, corner1.y);
            }
            else
            {
                // apply rotation
                Vector2 right = new Vector2(Mathf.Cos(rotation), Mathf.Sin(rotation)) * size;
                Vector2 up = new Vector2(Mathf.Cos(rotation90), Mathf.Sin(rotation90)) * size;

                _quad[0].position = position - right - up;
                _quad[1].position = position - right + up;
                _quad[2].position = position + right + up;
                _quad[3].position = position + right - up;
            }

            vh.AddUIVertexQuad(_quad);
        }
    }

    void Update()
    {
        if (Application.isPlaying)
        {
            // unscaled animation within UI
            _particleSystem.Simulate(Time.unscaledDeltaTime, false, false);

            SetAllDirty();
        }
    }

#if UNITY_EDITOR
    void LateUpdate()
    {
        if (!Application.isPlaying)
        {
            SetAllDirty();
        }
    }
#endif

}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289

脚本依赖ParticleSystem控件，只能挂载在Paricle物体上。新建一个ParticleSystem将脚本拖上去就能用了！

By：蒋志杰