往期推文全新看点（文中附带全新鸿蒙5.0全栈学习笔录）
✏️ 鸿蒙（HarmonyOS）北向开发知识点记录~
✏️ 鸿蒙（OpenHarmony）南向开发保姆级知识点汇总~
✏️ 鸿蒙应用开发与鸿蒙系统开发哪个更有前景？
✏️ 嵌入式开发适不适合做鸿蒙南向开发？看完这篇你就了解了~
✏️ 对于大前端开发来说，转鸿蒙开发究竟是福还是祸？
✏️ 鸿蒙岗位需求突增！移动端、PC端、IoT到底该怎么选？
✏️ 记录一场鸿蒙开发岗位面试经历~
✏️ 持续更新中......
场景描述
在直播场景中，会有礼物、魔法等表情临时出现在画面，需要获取视频画面帧进行纹理更新后再渲染
通过OpenGL渲染视频画面帧。
⦁ 在ArkTS侧调用createAVPlayer()创建AVPlayer实例，初始化进入idle状态。设置业务需要的监听事件，设置资源：设置属性url，AVPlayer进入initialized状态。
⦁ 设置窗口：获取并设置属性SurfaceID，该surfaceId是native侧nativeImage的surfaceID，调用play方法开始播放。
⦁ 添加XComponent组件，在native侧通过OH_NativeXComponent_RegisterCallback注册XComponent回调。
⦁ 在napi 接口init的时候在Xcomponent的OnSurfaceCreatedCB回调中初始化渲染线程，通过OH_NativeImage_Create创建nativeImage。
⦁ 通过OH_NativeImage_GetSurfaceId获取surfaceID并传递到arkts侧。
⦁ 通过OH_NativeImage_SetOnFrameAvailableListener设置帧可用回调，通过NativeVsync接收系统信号，控制渲染。
⦁ 通过OH_NativeImage_UpdateSurfaceImage获取最新帧更新相关联的OpenGL ES纹理，通过eglSwapBuffers将纹理渲染上屏。
核心代码
创建nativeImage，获取nativeImage的id，设置帧可用回调。
bool RenderThread::CreateNativeImage()
{
nativeImage_ = OH_NativeImage_Create(-1, GL_TEXTURE_EXTERNAL_OES);
if (nativeImage_ == nullptr) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread", "OH_NativeImage_Create failed.");
return false;
}
int ret = 0;
{
std::lock_guard<std::mutex> lock(nativeImageSurfaceIdMutex_);
ret = OH_NativeImage_GetSurfaceId(nativeImage_, &nativeImageSurfaceId_);
}
if (ret != 0) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread",
"OH_NativeImage_GetSurfaceId failed, ret is %{public}d.", ret);
return false;
}
nativeImageFrameAvailableListener_.context = this;
nativeImageFrameAvailableListener_.onFrameAvailable = &RenderThread::OnNativeImageFrameAvailable;
ret = OH_NativeImage_SetOnFrameAvailableListener(nativeImage_, nativeImageFrameAvailableListener_);
if (ret != 0) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread",
"OH_NativeImage_SetOnFrameAvailableListener failed, ret is %{public}d.", ret);
return false;
}
return true;
}
void RenderThread::OnNativeImageFrameAvailable(void *data)
{
OH_LOG_Print(LOG_APP, LOG_DEBUG, LOG_PRINT_DOMAIN, "RenderThread", "OnNativeImageFrameAvailable.");
auto renderThread = reinterpret_cast<RenderThread *>(data);
if (renderThread == nullptr) {
return;
}
renderThread->availableFrameCnt_++;
renderThread->wakeUpCond_.notify_one();
}
NativeVsync接收系统发送的Vsync信号，控制渲染节奏。
bool RenderThread::InitNativeVsync()
{
nativeVsync_ = OH_NativeVSync_Create(DEMO_NAME, strlen(DEMO_NAME));
if (nativeVsync_ == nullptr) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread", "Create NativeVSync failed.");
return false;
}
(void)OH_NativeVSync_RequestFrame(nativeVsync_, &RenderThread::OnVsync, this);
return true;
}
void RenderThread::OnVsync(long long timestamp, void *data)
{
OH_LOG_Print(LOG_APP, LOG_DEBUG, LOG_PRINT_DOMAIN, "RenderThread", "OnVsync %{public}llu.", timestamp);
auto renderThread = reinterpret_cast<RenderThread *>(data);
if (renderThread == nullptr) {
return;
}
renderThread->vSyncCnt_++;
renderThread->wakeUpCond_.notify_one();
}在渲染线程中更新画面帧数据到OpenGL纹理，并做对应的opengl处理后，通过SwapBuffers()方法上屏。
void RenderThread::DrawImage()
{
if(nativeImageTexId_ == 9999) {
glGenTextures(1, &nativeImageTexId_);
glBindTexture(GL_TEXTURE_EXTERNAL_OES, nativeImageTexId_);
// set the texture wrapping parameters
glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}
OH_LOG_Print(LOG_APP, LOG_DEBUG, LOG_PRINT_DOMAIN, "RenderThread", "DrawImage.");
if (eglSurface_ == EGL_NO_SURFACE) {
OH_LOG_Print(LOG_APP, LOG_WARN, LOG_PRINT_DOMAIN, "RenderThread", "eglSurface_ is EGL_NO_SURFACE");
return;
}
OH_NativeImage_AttachContext(nativeImage_, nativeImageTexId_);
renderContext_->MakeCurrent(eglSurface_);
int32_t ret = OH_NativeImage_UpdateSurfaceImage(nativeImage_);
if (ret != 0) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread",
"OH_NativeImage_UpdateSurfaceImage failed, ret: %{public}d, texId: %{public}d",
ret, nativeImageTexId_);
return;
}
OH_LOG_Print(LOG_APP, LOG_DEBUG, LOG_PRINT_DOMAIN, "RenderThread", "OH_NativeImage_UpdateSurfaceImage succeed.");
float matrix[16];
ret = OH_NativeImage_GetTransformMatrix(nativeImage_, matrix);
if (ret != 0) {
OH_LOG_Print(LOG_APP, LOG_ERROR, LOG_PRINT_DOMAIN, "RenderThread",
"OH_NativeImage_GetTransformMatrix failed, ret: %{public}d", ret);
return;
}
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
shaderProgram_->Use();
shaderProgram_->SetInt("texture", 0);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_EXTERNAL_OES, nativeImageTexId_);
shaderProgram_->SetMatrix4v("matTransform", matrix, 16, false);
glBindVertexArray(vertexArrayObject_);
glEnable(GL_DEPTH_TEST);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, Detail::indices);
renderContext_->SwapBuffers(eglSurface_);
}