PS
本篇持续上一篇的内容，咱们来对Native EGL环境实现的各个步骤进行具体解析
EGL Native层的实现
上一篇文章Android OpenGL ES - EGL源码解析以及C++实现
咱们还是先来回顾一下流程图
以及代码
//(1) 将线程附加到虚拟机，并获取env if (that->m_jvm_for_thread->AttachCurrentThread(&env, NULL) != JNI_OK) { LOGE(that->TAG, "线程初始化异样"); return; } // (2) 初始化 EGL if (!that->InitEGL()) { //解除线程和jvm关联 that->m_jvm_for_thread->DetachCurrentThread(); return; } //进入循环 while (true) { //依据OpenGL渲染状态进入不同的解决 switch (that->m_state) { //刷新Surface，从里面设置Surface后m_state置为该状态，阐明曾经从内部(java层)取得Surface的对象了 case FRESH_SURFACE: LOGI(that->TAG, "Loop Render FRESH_SURFACE") // (3) 初始化Window that->InitDspWindow(env); // (4) 创立EglSurface that->CreateSurface(); // m_state置为RENDERING状态进入渲染 that->m_state = RENDERING; break; case RENDERING: LOGI(that->TAG, "Loop Render RENDERING") // (5) 渲染 that->Render(); break; case STOP: LOGI(that->TAG, "Loop Render STOP") //(6) 解除线程和jvm关联 that->ReleaseRender(); that->m_jvm_for_thread->DetachCurrentThread(); return; case SURFACE_DESTROY: LOGI(that->TAG, "Loop Render SURFACE_DESTROY") //(7) 开释资源 that->DestroySurface(); that->m_state = NO_SURFACE; break; case NO_SURFACE: default: break; } usleep(20000); }}首先第(1)步将线程附加到虚拟机，并获取env,这一步简单明了，咱们从第(2)步开始
EGL封装筹备
咱们在上一篇就晓得了EGL的一些基础知识，EGLDiaplay,EGLConfig,EGLSurface,EGLContext，咱们须要把这些根底类进行封装，那么如何进行封装呢，咱们先看一下对于咱们上篇文章中自定义的GLRender类须要什么
gl_render.h
//Surface援用，必须要应用援用，否则无奈在线程中操作jobject m_surface_ref = NULL;//本地屏幕ANativeWindow *m_native_window = NULL;//EGL显示外表 留神这里是咱们自定义的EglSurface包装类而不是零碎提供的EGLSurface哦EglSurface *m_egl_surface = NULL;对于gl_render来说输出的是内部的Surface对象，咱们这里的是jobject m_surface_ref,那么输入须要的是ANativeWindow,EglSurface
对于ANativeWindow能够查看官网文档ANativeWindow那么EglSurface呢，
egl_surface.h
class EglSurface {private: const char *TAG = "EglSurface"; //本地屏幕 ANativeWindow *m_native_window = NULL; //封装了EGLDisplay EGLConfig EGLContext的自定义类 EglCore *m_core; //EGL API提供的 EGLSurface EGLSurface m_surface;}能够看到咱们下面的定义的思维也是V(View)和C(Controller)进行了拆散。
egl_core.h
class EglCore {private: const char *TAG = "EglCore"; //EGL显示窗口 EGLDisplay m_egl_dsp = EGL_NO_DISPLAY; //EGL上下文 EGLContext m_egl_context = EGL_NO_CONTEXT; //EGL配置 EGLConfig m_egl_config;}有了下面的筹备工作后，咱们就跟着流程图的步骤来一步步走
(2)初始化EGL
gl_render.cpp
bool GLRender::InitEGL() { //创立EglSurface对象 m_egl_surface = new EglSurface(); //调用EglSurface的init办法 return m_egl_surface->Init();}egl_surface.cpp
PS
咱们下面也说了EGL的初始化次要是对EGLDisplay EGLConfig EGLContext的操作，所以当初是对EGLCore的操作
EglSurface::EglSurface() { //创立EGLCore m_core = new EglCore();}bool EglSurface::Init() { //调用EGLCore的init办法 return m_core->Init(NULL);}egl_core.cpp
EglCore::EglCore() {}bool EglCore::Init(EGLContext share_ctx) { if (m_egl_dsp != EGL_NO_DISPLAY) { LOGE(TAG, "EGL already set up") return true; } if (share_ctx == NULL) { share_ctx = EGL_NO_CONTEXT; } //获取Dispaly m_egl_dsp = eglGetDisplay(EGL_DEFAULT_DISPLAY); if (m_egl_dsp == EGL_NO_DISPLAY || eglGetError() != EGL_SUCCESS) { LOGE(TAG, "EGL init display fail") return false; } EGLint major_ver, minor_ver; //初始化egl EGLBoolean success = eglInitialize(m_egl_dsp, &major_ver, &minor_ver); if (success != EGL_TRUE || eglGetError() != EGL_SUCCESS) { LOGE(TAG, "EGL init fail") return false; } LOGI(TAG, "EGL version: %d.%d", major_ver, minor_ver) //获取EGLConfig m_egl_config = GetEGLConfig(); const EGLint attr[] = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE}; //创立EGLContext m_egl_context = eglCreateContext(m_egl_dsp, m_egl_config, share_ctx, attr); if (m_egl_context == EGL_NO_CONTEXT) { LOGE(TAG, "EGL create fail, error is %x", eglGetError()); return false; } EGLint egl_format; success = eglGetConfigAttrib(m_egl_dsp, m_egl_config, EGL_NATIVE_VISUAL_ID, &egl_format); if (success != EGL_TRUE || eglGetError() != EGL_SUCCESS) { LOGE(TAG, "EGL get config fail, error is %x", eglGetError()) return false; } LOGI(TAG, "EGL init success") return true;}EGLConfig EglCore::GetEGLConfig() { EGLint numConfigs; EGLConfig config; //心愿的最小配置， static const EGLint CONFIG_ATTRIBS[] = { EGL_BUFFER_SIZE, EGL_DONT_CARE, EGL_RED_SIZE, 8,//R 位数 EGL_GREEN_SIZE, 8,//G 位数 EGL_BLUE_SIZE, 8,//B 位数 EGL_ALPHA_SIZE, 8,//A 位数 EGL_DEPTH_SIZE, 16,//深度 EGL_STENCIL_SIZE, EGL_DONT_CARE, EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT, EGL_SURFACE_TYPE, EGL_WINDOW_BIT, EGL_NONE // the end 完结标记 }; //依据你所设定的最小配置零碎会抉择一个满足你最低要求的配置，这个真正的配置往往要比你冀望的属性更多 EGLBoolean success = eglChooseConfig(m_egl_dsp, CONFIG_ATTRIBS, &config, 1, &numConfigs); if (!success || eglGetError() != EGL_SUCCESS) { LOGE(TAG, "EGL config fail") return NULL; } return config;}（3）创立Window
gl_render.cpp
void GLRender::InitDspWindow(JNIEnv *env) { //传进来的Surface对象的援用 if (m_surface_ref != NULL) { // 初始化窗口 m_native_window = ANativeWindow_fromSurface(env, m_surface_ref); // 绘制区域的宽高 m_window_width = ANativeWindow_getWidth(m_native_window); m_window_height = ANativeWindow_getHeight(m_native_window); //设置宽高限度缓冲区中的像素数量 ANativeWindow_setBuffersGeometry(m_native_window, m_window_width, m_window_height, WINDOW_FORMAT_RGBA_8888); LOGD(TAG, "View Port width: %d, height: %d", m_window_width, m_window_height) }}(4)创立EglSurface并绑定到线程
gl_render.cpp
void GLRender::CreateSurface() { m_egl_surface->CreateEglSurface(m_native_window, m_window_width, m_window_height); glViewport(0, 0, m_window_width, m_window_height);}egl_surface.cpp
/** * * @param native_window 传入上一步创立的ANativeWindow * @param width * @param height */void EglSurface::CreateEglSurface(ANativeWindow *native_window, int width, int height) { if (native_window != NULL) { this->m_native_window = native_window; m_surface = m_core->CreateWindSurface(m_native_window); } else { m_surface = m_core->CreateOffScreenSurface(width, height); } if (m_surface == NULL) { LOGE(TAG, "EGL create window surface fail") Release(); } MakeCurrent();}void EglSurface::MakeCurrent() { m_core->MakeCurrent(m_surface);}egl_core.cpp
EGLSurface EglCore::CreateWindSurface(ANativeWindow *window) { //调用EGL Native API创立Window Surface EGLSurface surface = eglCreateWindowSurface(m_egl_dsp, m_egl_config, window, 0); if (eglGetError() != EGL_SUCCESS) { LOGI(TAG, "EGL create window surface fail") return NULL; } return surface;}void EglCore::MakeCurrent(EGLSurface egl_surface) { //调用EGL Native API 绑定渲染环境到以后线程 if (!eglMakeCurrent(m_egl_dsp, egl_surface, egl_surface, m_egl_context)) { LOGE(TAG, "EGL make current fail"); }}(5)渲染
gl_render.cpp
void GLRender::Render() { if (RENDERING == m_state) { pImageRender->DoDraw();//画画画.... m_egl_surface->SwapBuffers(); }}egl_surface.cpp
void EglSurface::SwapBuffers() { m_core->SwapBuffer(m_surface);}egl_core.cpp
void EglCore::SwapBuffer(EGLSurface egl_surface) { //调用EGL Native API eglSwapBuffers(m_egl_dsp, egl_surface);}前面的进行与销毁就交给读者自行钻研了。
代码
EGLDemoActivity.java
EGL Native