本文为大家分享了Unity实现粒子光效导出成png序列帧的具体代码，供大家参考，具体内容如下
这个功能并不是很实用，不过美术同学有这样的需求，那么就花了一点时间研究了下。
我们没有使用Unity的引擎，但是做特效的同学找了一批Unity的粒子特效，希望导出成png序列帧的形式，然后我们的游戏来使用。这个就相当于拿Unity做了特效编辑器的工作。这个并不是很“邪门”，因为用幻影粒子，或者3dmax，差不多也是这个思路，只不过那些软件提供了正规的导出功能，而Unity则没有。
先上代码
using UnityEngine;
using UnityEditor;
using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
public class ParticleExporter : MonoBehaviour
{
// Default folder name where you want the animations to be output
public string folder = "PNG_Animations";
// Framerate at which you want to play the animation
public int frameRate = 25; // export frame rate 导出帧率，设置Time.captureFramerate会忽略真实时间，直接使用此帧率
public float frameCount = 100; // export frame count 导出帧的数目，100帧则相当于导出5秒钟的光效时间。由于导出每一帧的时间很长，所以导出时间会远远长于直观的光效播放时间
public int screenWidth = 960; // not use 暂时没用，希望可以直接设置屏幕的大小（即光效画布的大小）
public int screenHeight = 640;
public Vector3 cameraPosition = Vector3.zero;
public Vector3 cameraRotation = Vector3.zero;
private string realFolder = ""; // real folder where the output files will be
private float originaltimescaleTime; // track the original time scale so we can freeze the animation between frames
private float currentTime = 0;
private bool over = false;
private int currentIndex = 0;
private Camera exportCamera; // camera for export 导出光效的摄像机，使用RenderTexture
public void Start()
{
// set frame rate
Time.captureFramerate = frameRate;
// Create a folder that doesn't exist yet. Append number if necessary.
realFolder = Path.Combine(folder, name);
// Create the folder
if (!Directory.Exists(realFolder)) {
Directory.CreateDirectory(realFolder);
}
originaltimescaleTime = Time.timeScale;
GameObject goCamera = Camera.main.gameObject;
if (cameraPosition != Vector3.zero) {
goCamera.transform.position = cameraPosition;
}
if (cameraRotation != Vector3.zero) {
goCamera.transform.rotation = Quaternion.Euler(cameraRotation);
}
GameObject go = Instantiate(goCamera) as GameObject;
exportCamera = go.GetComponent();
currentTime = 0;
}
void Update()
{
currentTime += Time.deltaTime;
if (!over && currentIndex >= frameCount) {
over = true;
Cleanup();
Debug.Log("Finish");
return;
}
// 每帧截屏
StartCoroutine(CaptureFrame());
}
void Cleanup()
{
DestroyImmediate(exportCamera);
DestroyImmediate(gameObject);
}
IEnumerator CaptureFrame()
{
// Stop time
Time.timeScale = 0;
// Yield to next frame and then start the rendering
// this is important, otherwise will have error
yield return new WaitForEndOfFrame();
string filename = String.Format("{0}/{1:D04}.png", realFolder, ++currentIndex);
Debug.Log(filename);
int width = Screen.width;
int height = Screen.height;
//Initialize and render textures
RenderTexture blackCamRenderTexture = new RenderTexture(width, height, 24, RenderTextureFormat.ARGB32);
RenderTexture whiteCamRenderTexture = new RenderTexture(width, height, 24, RenderTextureFormat.ARGB32);
exportCamera.targetTexture = blackCamRenderTexture;
exportCamera.backgroundColor = Color.black;
exportCamera.Render();
RenderTexture.active = blackCamRenderTexture;
Texture2D texb = GetTex2D();
//Now do it for Alpha Camera
exportCamera.targetTexture = whiteCamRenderTexture;
exportCamera.backgroundColor = Color.white;
exportCamera.Render();
RenderTexture.active = whiteCamRenderTexture;
Texture2D texw = GetTex2D();
// If we have both textures then create final output texture
if (texw && texb) {
Texture2D outputtex = new Texture2D(width, height, TextureFormat.ARGB32, false);
// we need to check alpha ourselves,because particle use additive shader
// Create Alpha from the difference between black and white camera renders
for (int y = 0; y < outputtex.height; ++y) { // each row
for (int x = 0; x < outputtex.width; ++x) { // each column
float alpha;
alpha = texw.GetPixel(x, y).r - texb.GetPixel(x, y).r;
alpha = 1.0f - alpha;
Color color;
if (alpha == 0) {
color = Color.clear;
} else {
color = texb.GetPixel(x, y);
}
color.a = alpha;
outputtex.SetPixel(x, y, color);
}
}
// Encode the resulting output texture to a byte array then write to the file
byte[] pngShot = outputtex.EncodeToPNG();
File.WriteAllBytes(filename, pngShot);
// cleanup, otherwise will memory leak
pngShot = null;
RenderTexture.active = null;
DestroyImmediate(outputtex);
outputtex = null;
DestroyImmediate(blackCamRenderTexture);
blackCamRenderTexture = null;
DestroyImmediate(whiteCamRenderTexture);
whiteCamRenderTexture = null;
DestroyImmediate(texb);
texb = null;
DestroyImmediate(texw);
texb = null;
System.GC.Collect();
// Reset the time scale, then move on to the next frame.
Time.timeScale = originaltimescaleTime;
}
}
// Get the texture from the screen, render all or only half of the camera
private Texture2D GetTex2D()
{
// Create a texture the size of the screen, RGB24 format
int width = Screen.width;
int height = Screen.height;
Texture2D tex = new Texture2D(width, height, TextureFormat.ARGB32, false);
// Read screen contents into the texture
tex.ReadPixels(new Rect(0, 0, width, height), 0, 0);
tex.Apply();
return tex;
}
}
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