在上一文我们对Unity实时更新纹理数据做了一些研究，但是最后有一步骤，texture.Apply()依然需要在渲染线程中执行，这个函数其实也是非常耗时的，依然会影响到应用的FPS。
这篇文章用了另外一条思路，就是开一个线程，主要处理纹理更新的线程，主要是参考了Unity 的NativeRenderingPlugin插件来写的，搞一个Unity单独更新纹理的插件。
1、EGL在Android平台上，EGL是OpenGL ES与本地窗口系统（本机窗口系统）之间的通信接口，其主要功能：
与设备的原生窗口系统通信；
查询绘图曲面的可用类型和配置；
创建图形曲面；
保持OpenGL ES和其他图形渲染API之间的同步渲染；
管理渲染资源，如纹理贴图。
OpenGL ES它在EGL实现的帮助下，EGL屏蔽了不同平台之间的差异（苹果提供您自己的EGL API Of iOS实现，声称是EAGL）。
本地窗口相关API提供对本地窗口系统接口的访问，EGL您可以创建渲染曲面EGLSurface，同时，它提供图形渲染上下文EGLContext，用于状态管理，下一个OpenGL ES您可以在此渲染曲面上绘制。
2、共享上下文时，哪些资源可以跨线程共享？可共享的资源：
texture ;
shader;
program Shader program ;
buffer Class object , Such as VBO、 EBO、 RBO etc. .
无法共享的资源：
FBO Framebuffer object （ Do not belong to buffer class ）;
VAO Vertex array object （ Do not belong to buffer class ）.
这里的解释是，在无法共享的资源中，FBO和VAO它是一个资源管理对象，FBO负责管理多个缓冲区，它不占用资源，VAO负责管理VBO或EBO，它不占用资源。
在我们开发实时更新纹理的过程中，我们就使用到了EGL这个库，以及共享上下文的特性。
第一步，我们需要写一个Unity Native Plugins来做渲染事情，可以参考GitHub - Unity-Technologies/NativeRenderingPlugin: C++ Rendering Plugin example for Unityhttps://github.com/Unity-Technologies/NativeRenderingPlugin
第二步，我们在Plugins中，加入我们多线程的一个处理方法。
总体的Plugin代码如下：
// Example low level rendering Unity plugin #include "PlatformBase.h" #include "RenderAPI.h" #include "TextureRender.h" #include "SafeQueue.h" #include#include #include #include #include #include #include #include static float g_Time; static void *g_TextureHandle = NULL; static int g_TextureWidth = 0; static int g_TextureHeight = 0; SafeQueue texDatas; EGLContext mainContext = NULL; EGLContext mainDisplay = NULL; EGLSurface pBufferSurface = NULL; EGLContext pBufferContext = NULL; pthread_t secondThread = -1; bool exitThread = false; GLsync mainThreadSyncObj = NULL; GLuint64 timeout = GL_TIMEOUT_IGNORED; // -------------------------------------------------------------------------- // UnitySetInterfaces static void UNITY_INTERFACE_API OnGraphicsDeviceEvent(UnityGfxDeviceEventType eventType); static IUnityInterfaces *s_UnityInterfaces = NULL; static IUnityGraphics *s_Graphics = NULL; extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginLoad(IUnityInterfaces *unityInterfaces) { s_UnityInterfaces = unityInterfaces; s_Graphics = s_UnityInterfaces->Get (); s_Graphics->RegisterDeviceEventCallback(OnGraphicsDeviceEvent); #if SUPPORT_VULKAN if (s_Graphics->GetRenderer() == kUnityGfxRendererNull) { extern void RenderAPI_Vulkan_OnPluginLoad(IUnityInterfaces *); RenderAPI_Vulkan_OnPluginLoad(unityInterfaces); } #endif // SUPPORT_VULKAN // Run OnGraphicsDeviceEvent(initialize) manually on plugin load OnGraphicsDeviceEvent(kUnityGfxDeviceEventInitialize); } extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginUnload() { s_Graphics->UnregisterDeviceEventCallback(OnGraphicsDeviceEvent); } #if UNITY_WEBGL typedef void (UNITY_INTERFACE_API * PluginLoadFunc)(IUnityInterfaces* unityInterfaces); typedef void (UNITY_INTERFACE_API * PluginUnloadFunc)(); extern "C" void UnityRegisterRenderingPlugin(PluginLoadFunc loadPlugin, PluginUnloadFunc unloadPlugin); extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API RegisterPlugin() { UnityRegisterRenderingPlugin(UnityPluginLoad, UnityPluginUnload); } #endif // -------------------------------------------------------------------------- // GraphicsDeviceEvent static RenderAPI *s_CurrentAPI = NULL; static UnityGfxRenderer s_DeviceType = kUnityGfxRendererNull; static void UNITY_INTERFACE_API OnGraphicsDeviceEvent(UnityGfxDeviceEventType eventType) { // Create graphics API implementation upon initialization if (eventType == kUnityGfxDeviceEventInitialize) { assert(s_CurrentAPI == NULL); s_DeviceType = s_Graphics->GetRenderer(); s_CurrentAPI = CreateRenderAPI(s_DeviceType); } // Let the implementation process the device related events if (s_CurrentAPI) { s_CurrentAPI->ProcessDeviceEvent(eventType, s_UnityInterfaces); } // Cleanup graphics API implementation upon shutdown if (eventType == kUnityGfxDeviceEventShutdown) { delete s_CurrentAPI; s_CurrentAPI = NULL; s_DeviceType = kUnityGfxRendererNull; } } static void ModifyTexturePixels(void *data) { void *textureHandle = g_TextureHandle; int width = g_TextureWidth; int height = g_TextureHeight; if (!textureHandle) return; if (!data) return; s_CurrentAPI->EndModifyTexture(textureHandle, width, height, 0, data); } void* animateTexture() { int textureRowPitch; void* textureDataPtr = s_CurrentAPI->BeginModifyTexture(g_TextureHandle, g_TextureWidth, g_TextureHeight, &textureRowPitch); if (!textureDataPtr) return NULL; const float t = g_Time * 4.0f; unsigned char* dst = (unsigned char*)textureDataPtr; for (int y = 0; y < g_TextureHeight; ++y) { unsigned char* ptr = dst; for (int x = 0; x < g_TextureWidth; ++x) { // Simple "plasma effect": several combined sine waves int vv = int( (127.0f + (127.0f * sinf(x / 7.0f + t))) + (127.0f + (127.0f * sinf(y / 5.0f - t))) + (127.0f + (127.0f * sinf((x + y) / 6.0f - t))) + (127.0f + (127.0f * sinf(sqrtf(float(x*x + y*y)) / 4.0f - t))) ) / 4; // Write the texture pixel ptr[0] = vv; ptr[1] = vv; ptr[2] = vv; ptr[3] = vv; // To next pixel (our pixels are 4 bpp) ptr += 4; } // To next image row dst += textureRowPitch; } return textureDataPtr; } static void *workingFunction(void *arg) { EGLConfig config = findConfig(mainDisplay, true, true); pBufferSurface = eglCreatePbufferSurface(mainDisplay, config, pBufferAttributes); if (pBufferSurface == EGL_NO_SURFACE) { EGLint error = eglGetError(); LOGE("eglGetError(): %i (0x%.4x)n", (int) error, (int) error); LOGE("Failed to create EGL pixel buffer surface at %s:%in", __FILE__, __LINE__); exit(1); } LOGI("PBuffer surface created successfully.n"); eglBindAPI(EGL_OPENGL_ES_API); pBufferContext = eglCreateContext(mainDisplay, config, mainContext, contextAttributes); if (pBufferContext == EGL_NO_CONTEXT) { EGLint error = eglGetError(); LOGE("eglGetError(): %i (0x%.4x)n", (int) error, (int) error); LOGE("Failed to create EGL pBufferContext at %s:%in", __FILE__, __LINE__); exit(1); } LOGI("PBuffer context created successfully sharing GLES objects with the main context.n"); eglMakeCurrent(mainDisplay, pBufferSurface, pBufferSurface, pBufferContext); LOGI("PBuffer context made current successfully.n"); GLbitfield flags = 0; GLenum condition = GL_SYNC_GPU_COMMANDS_COMPLETE; while (!exitThread) { if (mainThreadSyncObj != NULL) { glWaitSync(mainThreadSyncObj, flags, timeout); } else { LOGI("mainThreadSyncObj is null"); continue; } TextureDataInfo tempData; if (texDatas.Consume(tempData)) { ModifyTexturePixels(tempData.data); free(tempData.data); }else { void * data = animateTexture(); if(data == NULL) continue; ModifyTexturePixels(data); free(data); } } LOGI("Exiting secondary thread.n"); return NULL; } void createTextureThread(void) { pthread_create(&secondThread, NULL, &workingFunction, NULL); } void startTextureRender() { if (secondThread != -1) { LOGD("thread is started!"); return; } mainContext = eglGetCurrentContext(); if (mainContext == EGL_NO_CONTEXT) { LOGE("initCL: eglGetCurrentContext() returned 'EGL_NO_CONTEXT', error = %x", eglGetError()); return; } mainDisplay = eglGetCurrentDisplay(); if(mainDisplay == EGL_NO_DISPLAY) { LOGE("initCL: eglGetCurrentDisplay() returned 'EGL_NO_DISPLAY', error = %x", eglGetError()); return; } createTextureThread(); exitThread = false; } void stopTextureRender() { exitThread = true; TextureDataInfo tempData; while (texDatas.Consume(tempData)) { free(tempData.data); } secondThread = -1; } void addTextureData(TextureDataInfo dataInfo) { if (texDatas.Size() > 20) { LOGD("texDatas is large"); TextureDataInfo tempData; if (texDatas.Consume(tempData)) { free(tempData.data); } } texDatas.Produce(std::move(dataInfo)); } void renderFrame() { GLbitfield flags = 0; GLenum condition = GL_SYNC_GPU_COMMANDS_COMPLETE; mainThreadSyncObj = glFenceSync(condition, flags); } static void UNITY_INTERFACE_API OnRenderEvent(int eventID) { // Unknown / unsupported graphics device type? Do nothing if (s_CurrentAPI == NULL) return; renderFrame(); } extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API SetTimeFromUnity (float t) { g_Time = t; } extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API StartTextureRender(void *textureHandle, int w, int h) { // A script calls this at initialization time; just remember the texture pointer here. // Will update texture pixels each frame from the plugin rendering event (texture update // needs to happen on the rendering thread). g_TextureHandle = textureHandle; g_TextureWidth = w; g_TextureHeight = h; LOGI("texture width: %d, height: %d", w, h); startTextureRender(); } extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API StopTextureRender() { stopTextureRender(); } // -------------------------------------------------------------------------- // GetRenderEventFunc, an example function we export which is used to get a rendering event callback function. extern "C" UnityRenderingEvent UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API GetRenderEventFunc() { return OnRenderEvent; } extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UpdateTextureDataPtr(void *data, int len) { void *tempData = new unsigned char[len]; if (tempData == NULL) return; memcpy(tempData, data, len); TextureDataInfo dataInfo; dataInfo.data = tempData; dataInfo.len = len; addTextureData(dataInfo); }
Unity中使用方法：
using System;
using System.Runtime.InteropServices;
using UnityEngine;
public class MutilTextureRenderer : MonoBehaviour
{
[SerializeField]
private MeshRenderer imageRenderer;
[SerializeField, Tooltip("Frequency of sharing screens")]
private int frequency = 10;
private const string mainTexPropertyName = "_MainTex";
private Texture2D imageTexture;
private int imageWidth = 1920;
private int imageHeight = 1080;
public void OnDestroy()
{
NDKAPI.StopTextureRender();
if (imageTexture != null)
DestroyImmediate(imageTexture);
}
// Start is called before the first frame update
void Start()
{
if (imageTexture == null)
{
imageTexture = new Texture2D(imageWidth, imageHeight, TextureFormat.RGBA32, false, true);
imageTexture.wrapMode = TextureWrapMode.Clamp;
imageRenderer.material.SetTexture(mainTexPropertyName, imageTexture);
// Pass texture pointer to the plugin
NDKAPI.StartTextureRender(imageTexture.GetNativeTexturePtr(), imageTexture.width, imageTexture.height);
}
}
// Update is called once per frame
private void Update()
{
NDKAPI.SetTimeFromUnity(Time.timeSinceLevelLoad);
GL.IssuePluginEvent(NDKAPI.GetRenderEventFunc(), 1);
}
public struct NDKAPI
{
#if (UNITY_IOS || UNITY_TVOS || UNITY_WEBGL) && !UNITY_EDITOR
[DllImport ("__Internal")]
#else
[DllImport("RenderingPlugin")]
#endif
public static extern IntPtr GetRenderEventFunc();
#if (UNITY_IOS || UNITY_TVOS || UNITY_WEBGL) && !UNITY_EDITOR
[DllImport ("__Internal")]
#else
[DllImport("RenderingPlugin")]
#endif
public static extern void StartTextureRender(System.IntPtr texture, int w, int h);
#if (UNITY_IOS || UNITY_TVOS || UNITY_WEBGL) && !UNITY_EDITOR
[DllImport ("__Internal")]
#else
[DllImport("RenderingPlugin")]
#endif
public static extern void StopTextureRender();
#if (UNITY_IOS || UNITY_TVOS || UNITY_WEBGL) && !UNITY_EDITOR
[DllImport ("__Internal")]
#else
[DllImport("RenderingPlugin")]
#endif
public static extern void UpdateTextureDataPtr(System.IntPtr data, int len);
#if (UNITY_IOS || UNITY_TVOS || UNITY_WEBGL) && !UNITY_EDITOR
[DllImport ("__Internal")]
#else
[DllImport("RenderingPlugin")]
#endif
public static extern void SetTimeFromUnity(float t);
}
}
总体效果
常见问题
出现如下错误：
2022/05/06 14:23:17.861 22872 22917 Error libNative initCL: eglGetCurrentContext() returned 'EGL_NO_CONTEXT', error = 3000
需要在Unity中把Graphics APIS中的Vulkan去掉，以及勾选掉Multithreaded Rendering勾选掉。
我的demo代码下载地址：Unity多线程实时更新纹理数据（Android平台）-Android文档类资源-CSDN下载我们需要实时更新纹理数据，如果在主线程中更新，会影响帧率。当前我们在Unity中搞了一个Naitv更多下载资源、学习资料请访问CSDN下载频道.https://download.csdn.net/download/grace_yi/85301879 参考文献GitHub - Unity-Technologies/NativeRenderingPlugin: C++ Rendering Plugin example for UnityC++ Rendering Plugin example for Unity. Contribute to Unity-Technologies/NativeRenderingPlugin development by creating an account on GitHub.https://github.com/Unity-Technologies/NativeRenderingPlugin
https://github.com/ARM-software/opengl-es-sdk-for-android/blob/4ca9fdb10bcd721bb9af19ccd9bdd95bdf34a07b/samples/advanced_samples/ThreadSync/jni/ThreadSync.cpphttps://github.com/ARM-software/opengl-es-sdk-for-android/blob/4ca9fdb10bcd721bb9af19ccd9bdd95bdf34a07b/samples/advanced_samples/ThreadSync/jni/ThreadSync.cppMultithreading rendering with OpenGL es shared context - 文章整合https://chowdera.com/2021/06/20210619181834707p.html
