android搭建opengles 的egl环境之前使用java已经写过，但是一般实际开发opengles的相关代码都在native层，因为native的话效率会比java高很多，步骤都是一致的，只是换一种语言写而已。之前使用java写的opengles egl环境搭建点击下面链接:
https://www.jianshu.com/p/ce3496ab9e02
本文demo下载地址:
https://github.com/ChinaZeng/NativeEglDemo
步骤都是一样的：
1、得到Egl实例
2、得到默认的显示设备（就是窗口）
3、初始化默认显示设备
4、设置显示设备的属性
5、从系统中获取对应属性的配置
6、创建EglContext
7、创建渲染的Surface
8、绑定EglContext和Surface到显示设备中
9、刷新数据，显示渲染场景
代码目录:
首先配置android ndk开发环境，我使用的是cmake
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16cmake_minimum_required(VERSION 3.4.1)
add_library( # Sets the name of the library.
native-lib
SHARED
native-lib.cpp
egl/EglHelper.cpp
)
target_link_libraries(
native-lib
EGL
GLESv2
android
log
)书写EglHelper，这个类主要负责egl的环境初始化，绘制和销毁
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100//环境搭建初始化
int EglHelper::initEgl(EGLNativeWindowType window) {
//1.得到默认的显示设备（就是窗口） -- eglGetDisplay
mEglDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
if (mEglDisplay == EGL_NO_DISPLAY) {
LOGE("eglGetDisplay error");
return -1;
}
//2. 初始化默认显示设备 -- eglInitialize
EGLint *version = new EGLint[2];
if (!eglInitialize(mEglDisplay, &version[0], &version[1])) {
LOGE("eglInitialize error");
return -1;
}
//3. 设置显示设备的属性
const EGLint attrib_config_list[] = {
EGL_RED_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_BLUE_SIZE, 8,
EGL_ALPHA_SIZE, 8,
EGL_DEPTH_SIZE, 8,
EGL_STENCIL_SIZE, 8,// 眼睛屏幕的距离
EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,//版本号
EGL_NONE
};
//3.1 根据所需的参数获取符合该参数的config_size，主要是解决有些手机eglChooseConfig失败的兼容性问题
EGLint num_config;
if (!eglChooseConfig(mEglDisplay, attrib_config_list, NULL, 1, &num_config)) {
LOGE("eglChooseConfig error");
return -1;
}
//3.2 根据获取到的config_size得到eglConfig
EGLConfig eglConfig;
if (!eglChooseConfig(mEglDisplay, attrib_config_list, &eglConfig, num_config, &num_config)) {
LOGE("eglChooseConfig error");
return -1;
}
//4. 创建egl上下文 eglCreateContext
const EGLint attrib_ctx_list[] = {
EGL_CONTEXT_CLIENT_VERSION, 2,
EGL_NONE
};
mEglContext = eglCreateContext(mEglDisplay, eglConfig, NULL, attrib_ctx_list);
if (mEglContext == EGL_NO_CONTEXT) {
LOGE("eglCreateContext error");
return -1;
}
//5.创建渲染的surface
mEglSurface = eglCreateWindowSurface(mEglDisplay, eglConfig, window, NULL);
if (mEglSurface == EGL_NO_SURFACE) {
LOGE("eglCreateWindowSurface error");
return -1;
}
//6. 绑定eglContext和surface到display
if (!eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
LOGE("eglMakeCurrent error");
return -1;
}
//7. 刷新数据，显示渲染场景 -- eglSwapBuffers
return 0;
}
//交换缓冲 绘制
int EglHelper::swapBuffers() {
if (mEglDisplay != EGL_NO_DISPLAY && mEglSurface != EGL_NO_SURFACE &&
eglSwapBuffers(mEglDisplay, mEglSurface)) {
return 0;
}
return -1;
}
//销毁
void EglHelper::destroyEgl() {
if (mEglDisplay != EGL_NO_DISPLAY) {
//解绑display上的eglContext和surface
eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
//销毁surface 和 eglContext
if (mEglSurface != EGL_NO_SURFACE) {
eglDestroySurface(mEglDisplay, mEglSurface);
mEglSurface = EGL_NO_SURFACE;
}
if (mEglContext != EGL_NO_CONTEXT) {
eglDestroyContext(mEglDisplay, mEglContext);
mEglContext = EGL_NO_CONTEXT;
}
if (mEglDisplay != EGL_NO_DISPLAY) {
eglTerminate(mEglDisplay);
mEglDisplay = EGL_NO_DISPLAY;
}
}
}
书写EglThread，顾名思义，这个类主要负责开启一个线程然后根据外部的生命周期调用EglHelper完成egl的环境搭建，并且和外部交互。
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- 书写java层和native层交互，对应生命周期回调即可
NationOpenGL.java1
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13public class NationOpenGL {
static {
System.loadLibrary("native-lib");
}
public native void nativeSurfaceCreate(Surface surface);
public native void nativeSurfaceChanged(int width, int height);
public native void nativeSurfaceDestroyed();
}
NativeGLSurfaceView.java1
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32public class NativeGLSurfaceView extends SurfaceView implements SurfaceHolder.Callback {
private NationOpenGL mNationOpenGL;
public NativeGLSurfaceView(Context context) {
this(context, null);
}
public NativeGLSurfaceView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public NativeGLSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mNationOpenGL = new NationOpenGL();
getHolder().addCallback(this);
}
public void surfaceCreated(SurfaceHolder holder) {
mNationOpenGL.nativeSurfaceCreate(holder.getSurface());
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
mNationOpenGL.nativeSurfaceChanged(width, height);
}
public void surfaceDestroyed(SurfaceHolder holder) {
mNationOpenGL.nativeSurfaceDestroyed();
}
}
native-lib.cpp1
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56EglThread *eglThread = NULL;
void callBackOnCreate() {
LOGE("callBackOnCreate");
}
void callBackOnChange(int width, int height) {
glViewport(0, 0, width, height);
LOGE("callBackOnChange");
}
void callBackOnDraw() {
glClearColor(0.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
LOGE("callBackOnDraw");
}
extern "C"
JNIEXPORT void JNICALL
Java_com_zzw_nativeopnegldemo_opengl_NationOpenGL_nativeSurfaceCreate(JNIEnv *env, jobject instance,
jobject surface) {
eglThread = new EglThread();
eglThread->callBackOnCreate(callBackOnCreate);
eglThread->callBackOnChange(callBackOnChange);
eglThread->callBackOnDraw(callBackOnDraw);
eglThread->setRenderModule(RENDER_MODULE_MANUAL);
ANativeWindow *nativeWindow = ANativeWindow_fromSurface(env, surface);
eglThread->onSurfaceCreate(nativeWindow);
}
extern "C"
JNIEXPORT void JNICALL
Java_com_zzw_nativeopnegldemo_opengl_NationOpenGL_nativeSurfaceChanged(JNIEnv *env,
jobject instance, jint width,
jint height) {
if (eglThread) {
eglThread->onSurfaceChange(width, height);
}
}
extern "C"
JNIEXPORT void JNICALL
Java_com_zzw_nativeopnegldemo_opengl_NationOpenGL_nativeSurfaceDestroyed(JNIEnv *env,
jobject instance) {
if (eglThread) {
eglThread->isExit = true;
delete (eglThread);
eglThread = NULL;
}
}