[OpenGL ES] 编写MyEglHelper

MyEglHelper 

package com.example.opengldemo;

import android.opengl.EGL14;
import android.view.Surface;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.egl.EGLSurface;

public class MyEglHelper {

    private EGL10 mEgl;
    private EGLDisplay mEglDisplay;
    private EGLContext mEglContext;
    private EGLSurface mEglSurface;


    public void initEgl(Surface surface, EGLContext eglContext) {

        //1
        mEgl = (EGL10) EGLContext.getEGL();

        //2 默认显示设备
        mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);

        if (mEglDisplay == EGL10.EGL_NO_DISPLAY) {
            throw new RuntimeException("eglGetDisplay failed");
        }
        //3 初始化设备  获取版本号
        int[] version = new int[2];
        if (!mEgl.eglInitialize(mEglDisplay, version)) {
            throw new RuntimeException("eglInitialize failed");
        }

        //4.
        int[] attrbutes = new int[]{
                EGL10.EGL_RED_SIZE, 8,
                EGL10.EGL_GREEN_SIZE, 8,
                EGL10.EGL_BLUE_SIZE, 8,
                EGL10.EGL_ALPHA_SIZE, 8,
                EGL10.EGL_DEPTH_SIZE, 8,
                EGL10.EGL_STENCIL_SIZE, 8,
                EGL10.EGL_RENDERABLE_TYPE, 4,
                EGL10.EGL_NONE};
        //
        int[] num_config = new int[1];
        //得到属性
        if (!mEgl.eglChooseConfig(mEglDisplay, attrbutes, null, 1, num_config)) {
            throw new IllegalArgumentException("eglChooseConfig failed");
        }
        int numConfig = num_config[0];

        if (numConfig < 0) {
            throw new IllegalArgumentException("No configs match configSpec");
        }
        //5.创建config
        EGLConfig[] configs = new EGLConfig[numConfig];
        if (!mEgl.eglChooseConfig(mEglDisplay, attrbutes, configs, numConfig, num_config)) {
            throw new IllegalArgumentException("eglChooseConfig#2 failed");
        }

        //6.初始化eglContext
        
        int [] attrib_list = {EGL14.EGL_CONTEXT_CLIENT_VERSION,2, EGL10.EGL_NONE};
        

        if (eglContext != null) {
            mEglContext = mEgl.eglCreateContext(mEglDisplay, configs[0], eglContext, attrib_list);
        } else {
            mEglContext = mEgl.eglCreateContext(mEglDisplay, configs[0], EGL10.EGL_NO_CONTEXT, attrib_list);
        }

        //7.
        mEglSurface = mEgl.eglCreateWindowSurface(mEglDisplay, configs[0], surface, null);

        //8.
        if (!mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
            throw new RuntimeException("eglMakeCurrent failed");
        }
    }

    public boolean swapBuffers() {
        if (mEgl != null) {
            return mEgl.eglSwapBuffers(mEglDisplay, mEglSurface);
        } else {
            throw new RuntimeException("egl is null");
        }
    }

    public EGLContext getmEglContext() {
        return mEglContext;
    }

    public void destoryEgl() {
        if (mEgl != null) {
            mEgl.eglMakeCurrent(mEglDisplay,
                    EGL10.EGL_NO_SURFACE,
                    EGL10.EGL_NO_SURFACE,
                    EGL10.EGL_NO_CONTEXT);
            mEgl.eglDestroySurface(mEglDisplay, mEglSurface);
            mEglSurface = null;

            mEgl.eglDestroyContext(mEglDisplay, mEglContext);
            mEglContext = null;

            mEgl.eglTerminate(mEglDisplay);
            mEglDisplay = null;
            mEgl = null;
        }
    }
}

MainActivity

package com.example.opengldemo;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.opengl.GLES20;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MainActivity extends AppCompatActivity {

    SurfaceView surfaceView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        surfaceView = findViewById(R.id.sv_main);
        surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(@NonNull SurfaceHolder surfaceHolder) {

            }

            @Override
            public void surfaceChanged(@NonNull final SurfaceHolder surfaceHolder, final int i, final int i1, int i2) {
                new Thread() {
                    @Override
                    public void run() {
                        super.run();
                        MyEglHelper myEglHelper = new MyEglHelper();
                        myEglHelper.initEgl(surfaceHolder.getSurface(), null);

                        while (true) {
                            GLES20.glViewport(0, 0, i, i1);
                            GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
                            GLES20.glClearColor(1.0f, 0.0f, 0.0f, 1.0f);

                            myEglHelper.swapBuffers();

                            try {
                                Thread.sleep(16);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }

                        }


                    }
                }.start();
            }

            @Override
            public void surfaceDestroyed(@NonNull SurfaceHolder surfaceHolder) {

            }
        });
    }
}

xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <SurfaceView
        android:id="@+id/sv_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>