附录（二）EGL创建 以及绘制
2021-06-19 本文已影响0人
大旺旺的弟弟小旺旺
第三章比较详细的说了EGL的创建过程，在使用的过程中如果去使用呢。
- 先和窗口进行通信
- 得到句柄，然后进行初始化
- 自己遍历所有的属性选择，或者是让系统自己选择
- 使用属性创建窗口
- 创建GL上下文
- 使用当前上下文
- 进行绘制
- 更新交换区
和窗口进行通信
EGL10 egl10 = (EGL10) EGLContext.getEGL();
//获取表面
EGLDisplay eglDisplay = egl10.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
进行初始化
//初始化 成功打开之后就进行一个初始化
egl10.eglInitialize(eglDisplay, new int[2]);
自己选择属性
EGLConfig[] configs = new EGLConfig[1];
//要EGL选择匹配的EGLConfigs 自己指定 属性 返回configs
egl10.eglChooseConfig(eglDisplay,
new int[]{EGL10.EGL_DEPTH_SIZE, 16, EGL10.EGL_NONE},
configs,
1,
new int[1]);
创建窗口
EGLConfig eglEGLConfig = configs[0];
//创建屏幕渲染窗口
EGLSurface eglSurface = egl10.eglCreateWindowSurface(eglDisplay, eglEGLConfig,
EGLGLSurfaceView.this.getHolder(), null);
创建渲染上下文
//创建渲染上下文
EGLContext eglContext = egl10.eglCreateContext(eglDisplay, eglEGLConfig, EGL10.EGL_NO_CONTEXT, null);
使用当前
egl10.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext);
mGL10 = (GL10) eglContext.getGL();
绘制
while (isKeyFlag()) {
onDrawFrame(mGL10);
//交换缓存区
egl10.eglSwapBuffers(eglDisplay, eglSurface);
}
stop(egl10, eglDisplay, eglSurface, eglContext);
销毁
private void stop(EGL10 egl10, EGLDisplay eglDisplay, EGLSurface eglSurface, EGLContext eglContext) {
egl10.eglMakeCurrent(eglDisplay, EGL10.EGL_NO_SURFACE,
EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT);
egl10.eglDestroyContext(eglDisplay, eglContext);
egl10.eglDestroySurface(eglDisplay, eglSurface);
mGL10 = null;
}
这个仅仅是创建了EGL,然后清了一下屏幕，并没有其它操作。
完整代码：
public class EGLSurfaceViewDemo extends SurfaceView implements SurfaceHolder.Callback {
private GL10 mGL10;
public EGLSurfaceViewDemo(Context context) {
super(context);
//注册回调接口
getHolder().addCallback(this);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
//开启线程
startGLThreads();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// 关闭
stopGLThreads();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
private void onDrawFrame(GL10 gl) {
gl.glClearColor(1, 0, 0, 1.0f);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
}
private EGL_GLThread mEGL_GLThread;
public void startGLThreads() {
mEGL_GLThread = new EGL_GLThread();
mEGL_GLThread.drawFlag(true); //线程标志位为true
mEGL_GLThread.start();
}
public void stopGLThreads() {
mEGL_GLThread.drawFlag(false);
mEGL_GLThread = null;
}
//刷帧线程
private class EGL_GLThread extends Thread {
private boolean keyFlag = false;
@Override
public void run() {
EGL10 egl10 = (EGL10) EGLContext.getEGL();
EGLDisplay eglDisplay = egl10.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
egl10.eglInitialize(eglDisplay, new int[2]);
EGLConfig[] configs = new EGLConfig[1];
egl10.eglChooseConfig(eglDisplay,
new int[]{EGL10.EGL_DEPTH_SIZE, 16, EGL10.EGL_NONE},
configs,
1,
new int[1]);
EGLConfig eglEGLConfig = configs[0];
EGLSurface eglSurface = egl10.eglCreateWindowSurface(eglDisplay, eglEGLConfig,
EGLSurfaceViewDemo.this.getHolder(), null);
EGLContext eglContext = egl10.eglCreateContext(eglDisplay, eglEGLConfig,
EGL10.EGL_NO_CONTEXT, null);
egl10.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext);
mGL10 = (GL10) eglContext.getGL();
//绘制是一直执行的
while (isDrawing()) {
onDrawFrame(mGL10);
egl10.eglSwapBuffers(eglDisplay, eglSurface);
}
stop(egl10, eglDisplay, eglSurface, eglContext);
}
private void stop(EGL10 egl10, EGLDisplay eglDisplay, EGLSurface eglSurface, EGLContext eglContext) {
egl10.eglMakeCurrent(eglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE,
EGL10.EGL_NO_CONTEXT);
egl10.eglDestroyContext(eglDisplay, eglContext);
egl10.eglDestroySurface(eglDisplay, eglSurface);
mGL10 = null;
}
public void drawFlag(boolean keyFlag) {
this.keyFlag = keyFlag;
}
public boolean isDrawing() {
return keyFlag;
}
}
}
使用它绘制一个三角形
代码稍作整理：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<SurfaceView
android:id="@+id/surface_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
创建一个EGLRender,它是一个线程。
public class EGLRenderer extends HandlerThread {
private EGLConfig eglConfig = null;
private EGLDisplay eglDisplay = EGL14.EGL_NO_DISPLAY;
private EGLContext eglContext = EGL14.EGL_NO_CONTEXT;
private int program;
private int vPosition;
private int uColor;
private SurfaceHolder surfaceHolder;
public EGLRenderer(SurfaceHolder surfaceHolder) {
super("EGLRenderer");
this.surfaceHolder = surfaceHolder;
}
private void onCreate() {
eglDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
int[] version = new int[2];
if (!EGL14.eglInitialize(eglDisplay, version, 0, version, 1)) {
throw new RuntimeException("EGL error " + EGL14.eglGetError());
}
int[] configAttribs = {
EGL14.EGL_BUFFER_SIZE, 32,
EGL14.EGL_ALPHA_SIZE, 8,
EGL14.EGL_BLUE_SIZE, 8,
EGL14.EGL_GREEN_SIZE, 8,
EGL14.EGL_RED_SIZE, 8,
EGL14.EGL_RENDERABLE_TYPE, //renderable
EGL14.EGL_OPENGL_ES2_BIT,
EGL14.EGL_SURFACE_TYPE,
EGL14.EGL_WINDOW_BIT,
EGL14.EGL_NONE
};
int[] numConfigs = new int[1];
EGLConfig[] configs = new EGLConfig[1];
if (!EGL14.eglChooseConfig(eglDisplay,
configAttribs,
0,
configs,
0,
configs.length,
numConfigs,
0)) {
throw new RuntimeException("EGL error " + EGL14.eglGetError());
}
eglConfig = configs[0];
int[] contextAttribs = {
EGL14.EGL_CONTEXT_CLIENT_VERSION, 2,
EGL14.EGL_NONE
};
eglContext = EGL14.eglCreateContext(eglDisplay, eglConfig, EGL14.EGL_NO_CONTEXT, contextAttribs, 0);
if (eglContext == EGL14.EGL_NO_CONTEXT) {
throw new RuntimeException("EGL error " + EGL14.eglGetError());
}
}
private void onDestroy() {
EGL14.eglDestroyContext(eglDisplay, eglContext);
eglContext = EGL14.EGL_NO_CONTEXT;
eglDisplay = EGL14.EGL_NO_DISPLAY;
}
@Override
public synchronized void start() {
super.start();
new Handler(getLooper()).post(new Runnable() {
@Override
public void run() {
onCreate();
surfaceCreated(surfaceHolder);
while (true){
if(isDraw) {
onFrame();
}
}
}
});
}
public void onRelease() {
new Handler(getLooper()).post(new Runnable() {
@Override
public void run() {
onDestroy();
quit();
}
});
}
private int loadShader(int shaderType, String sourceCode) {
int shader = GLES20.glCreateShader(shaderType);
if (shader != 0) {
GLES20.glShaderSource(shader, sourceCode);
GLES20.glCompileShader(shader);
int[] compiled = new int[1];
GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
if (compiled[0] == 0) {
Log.e("ES20_ERROR", "Could not compile shader " + shaderType + ":");
Log.e("ES20_ERROR", GLES20.glGetShaderInfoLog(shader));
GLES20.glDeleteShader(shader);
shader = 0;
}
}
return shader;
}
EGLSurface eglSurface;
private static final String verticesShader
= "attribute vec2 vPosition; \n"
+ "void main(){ \n"
+ " gl_Position = vec4(vPosition,0,1);\n"
+ "}";
private static final String fragmentShader
= "precision mediump float; \n"
+ "uniform vec4 uColor; \n"
+ "void main(){ \n"
+ " gl_FragColor = uColor; \n"
+ "}";
private FloatBuffer getVertices() {
float vertices[] = {
0.0f, 0.5f,
-0.5f, -0.5f,
0.5f, -0.5f,
};
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
vbb.order(ByteOrder.nativeOrder());
FloatBuffer vertexBuf = vbb.asFloatBuffer();
vertexBuf.put(vertices);
vertexBuf.position(0);
return vertexBuf;
}
private int createProgram(String vertexSource, String fragmentSource) {
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
if (vertexShader == 0) {
return 0;
}
int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
if (pixelShader == 0) {
return 0;
}
int program = GLES20.glCreateProgram();
return program;
}
private boolean isDraw = false;
public void surfaceCreated(SurfaceHolder surface){
final int[] surfaceAttribs = { EGL14.EGL_NONE };
eglSurface = EGL14.eglCreateWindowSurface(eglDisplay, eglConfig, surface, surfaceAttribs, 0);
EGL14.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext);
program = createProgram(verticesShader, fragmentShader);
vPosition = GLES20.glGetAttribLocation(program, "vPosition");
uColor = GLES20.glGetUniformLocation(program, "uColor");
GLES20.glViewport(0,0,400,400);
GLES20.glClearColor(1.0f, 0, 0, 1.0f);
isDraw = true;
}
private void onFrame() {
System.out.println("绘制");
FloatBuffer vertices = getVertices();
GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glUseProgram(program);
GLES20.glVertexAttribPointer(vPosition, 2, GLES20.GL_FLOAT, false, 0, vertices);
GLES20.glEnableVertexAttribArray(vPosition);
GLES20.glUniform4f(uColor, 0.0f, 1.0f, 0.0f, 1.0f);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 3);
EGL14.eglSwapBuffers(eglDisplay, eglSurface);
EGL14.eglDestroySurface(eglDisplay, eglSurface);
}
}
Activity代码
setContentView(R.layout.activity_egl);
SurfaceView surfaceView = findViewById(R.id.surface_view);
surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
mGLRenderer = new EGLRenderer(surfaceHolder);
mGLRenderer.start();
}
@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
}
@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
}
});
