Android OpenGLES + Camera1 相机预览

实现效果

一、GLSurfaceView

众所周知，GLSurfaceView提供了一个EGL环境，只需实现其中的Renderer，即可使用OpenGLES API进行绘制操作

Renderer

有三个方法，需要我们实现

• onSurfaceCreated(GL10 gl, EGLConfig config)

  此处进行一些初始化工作，比如加载着色器、加载纹理、初始化顶点和纹理坐标等

• onSurfaceChanged(GL10 gl, int width, int height)

  此处进行窗口大小的设置

• onDrawFrame(GL10 gl)

  此处进行一些渲染工作，比如绑定纹理、传入顶点和纹理坐标、矩阵等

这里只做个简单的介绍，笔者是默认您会OpenGLES基本渲染步骤，如果还不太了解，相关的介绍网络上有很多

二、EGLTextureView

既然有了GLSurfaceView，那么为什么还要自定义一个EGLTextureView呢？

因为需要EGLTextureView里面使用的是TextureView实现，可以满足Android View的一些特性，而GLSurfaceView是SurfaceView实现，对View的一些特性是不支持的

如何自定义EGLTextureView？

• 新建类EGLTextureView
• 复制GLSurfaceView的所有内容到EGLTextureView
• 修改继承的类的TextureView，并实现TextureView.SurfaceTextureListener接口
• 删除所有报错的地方
• 修改EGLHelper里createSurface里创建EGLSurface的地方

如果觉得麻烦，可以参考笔者定义的EGLTextureView

到此，我们将环境搭建好了，那么接下来Renderer就是关键，如果你看了笔者定义的EGLTextureView，你会发现Renderer有些不一样，这个是因为我觉得既然都自定义EGLTextureView了，那么Renderer自然弄简单一点，也好理解一点

public interface Renderer {
    void onCreate();

    void onChange(int width, int height);

    void onDraw();
}
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三、BaseRender

注意到，EGLTextureView里面，setRenderer方法只能调用一次，因为在调用setRenderer的时候，如果发现GLThread已经存在了，则直接抛出异常

private void checkRenderThreadState() {
    if (mGLThread != null) {
        throw new IllegalStateException(
                "setRenderer has already been called for this instance.");
    }
}
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也就是说，设置了Renderer后，就不能更换了，那么如果有需求：本来是渲染一个灰度滤镜的，当想变换其他滤镜的时候，又不能重新设置Renderer，此时应该如何

其实可以这样，Renderer可以只做一个调度者，Renderer里面可以写很多的滤镜，也可以变换滤镜，那么就可以满足我们的需求

那么接下来就先来定义一个基础滤镜

首先第一步，创建一个IRender

public interface IRender {
    /**
     * 创建
     */
    void onCreate();

    /**
     * 设置尺寸
     */
    void onChange(int width, int height);

    /**
     * 绘制
     */
    void onDraw(int textureId);

    /**
     * 释放资源
     */
    void onRelease();
}
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和Renderer有些许不同，修改和增加了一些方法

新建BaseRender，实现IRender接口

public class BaseRender implements IRender {
    /**
     * Context
     */
    private Context context;

    /**
     * 渲染数据
     */
    private BaseRenderBean renderBean;

    /**
     * 顶点坐标
     */
    private FloatBuffer vertexBuffer;

    /**
     * 纹理坐标
     */
    private FloatBuffer coordinateBuffer;

    /**
     * 顶点坐标维数（即x, y, z）
     */
    private int vertexSize = 2;

    /**
     * 纹理坐标维数（即x, y, z）
     */
    private int coordinateSize = 2;

    /**
     * 顶点坐标步长（即维数 * 字节数）
     */
    private int vertexStride = vertexSize * 4;

    /**
     * 纹理坐标步长（即维数 * 字节数）
     */
    private int coordinateStride = coordinateSize * 4;

    /**
     * 顶点个数
     */
    private int vertexCount = 4;

    /**
     * 纹理点个数
     */
    private int coordinateCount = 4;

    /**
     * vertex shader
     */
    private int vertexShader;

    /**
     * frag shader
     */
    private int fragShader;

    /**
     * program
     */
    private int program;

    /**
     * 纹理 id
     */
    private int textureId;

    /**
     * fbo纹理id
     */
    private int fboTextureId;

    /**
     * fbo id
     */
    private int fboId;

    /**
     * vbo id
     */
    private int vboId;

    /**
     * 顶点着色器代码路径
     */
    private String vertexFilename;

    /**
     * 片元着色器代码路径
     */
    private String fragFilename;

    /**
     * 尺寸
     */
    private int width;
    private int height;

    /**
     * 是否绑定Fbo
     */
    private boolean isBindFbo = false;

    /**
     * 着色器顶点坐标位置
     */
    private int aPosLocation;

    /**
     * 着色器纹理坐标位置
     */
    private int aCoordinateLocation;

    /**
     * 着色器纹理位置
     */
    private int uSamplerLocation;

    /**
     * 是否执行了onCreate
     */
    private boolean isCreate = false;

    /**
     * 是否执行了onChange
     */
    private boolean isChange = false;

    public BaseRender(Context context) {
        this(context, "render/base/base/vertex.frag", "render/base/base/frag.frag");
    }

    public BaseRender(Context context, String vertexFilename, String fragFilename) {
        this.context = context;
        this.vertexFilename = vertexFilename;
        this.fragFilename = fragFilename;
    }

    @Override
    public void onCreate() {
        if (isCreate) {
            return;
        }
        onCreatePre();
        onClearColor();
        onInitBlend();
        onInitVertexBuffer();
        onInitCoordinateBuffer();
        onInitVbo();
        onInitProgram();
        onCreateAfter();
        isCreate = true;
    }

    @Override
    public void onChange(int width, int height) {
        if (isChange) {
            return;
        }
        onChangePre();
        setWidth(width);
        setHeight(height);
        onViewport();
        onInitFbo();
        onChangeAfter();
        isChange = true;
    }

    @Override
    public void onDraw(int textureId) {
        if (!onReadyToDraw()) {
            return;
        }
        onDrawPre();
        onClear();
        onUseProgram();
        onInitLocation();
        onBindFbo();
        onBindVbo();
        onActiveTexture(textureId);
        onEnableVertexAttributeArray();
        onSetVertexData();
        onSetCoordinateData();
        onSetOtherData();
        onDraw();
        onDisableVertexAttributeArray();
        onUnBind();
        onDrawAfter();
    }

    @Override
    public void onRelease() {
        onDeleteProgram(program);
        onDeleteShader(vertexShader);
        onDeleteShader(fragShader);
        onDeleteTexture(textureId);
        onDeleteTexture(fboTextureId);
        onDeleteFbo(fboId);
        onDeleteVbo(vboId);
    }

    /**
     * 创建之前
     */
    public void onCreatePre() {

    }

    /**
     * 设置背景颜色
     */
    public void onClearColor() {
        GLES20.glClearColor(0, 0, 0, 1);
    }

    /**
     * 是否启用混色
     */
    public boolean onEnableBlend() {
        return false;
    }

    /**
     * 初始化混色
     */
    private void onInitBlend() {
        if (!onEnableBlend()) {
            return;
        }
        GLES20.glEnable(GLES20.GL_BLEND);
        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
    }

    /**
     * 初始化顶点坐标
     */
    public void onInitVertexBuffer() {
        vertexBuffer = OpenGLESUtils.getSquareVertexBuffer();
    }

    /**
     * 初始化纹理坐标
     */
    public void onInitCoordinateBuffer() {
        if (isBindFbo) {
            coordinateBuffer = OpenGLESUtils.getSquareCoordinateReverseBuffer();
        } else {
            coordinateBuffer = OpenGLESUtils.getSquareCoordinateBuffer();
        }
    }

    /**
     * 初始化Vbo
     */
    public void onInitVbo() {
        vboId = OpenGLESUtils.getVbo(vertexBuffer, coordinateBuffer);
    }

    /**
     * 初始化Program
     */
    public void onInitProgram() {
        String vertexShaderCode = OpenGLESUtils.getShaderCode(context, vertexFilename);
        String fragShaderCode = OpenGLESUtils.getShaderCode(context, fragFilename);

        vertexShader = OpenGLESUtils.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
        fragShader = OpenGLESUtils.loadShader(GLES20.GL_FRAGMENT_SHADER, fragShaderCode);

        program = OpenGLESUtils.linkProgram(vertexShader, fragShader);
    }

    /**
     * 创建之后
     */
    public void onCreateAfter() {

    }

    /**
     * 设置尺寸之前
     */
    public void onChangePre() {

    }

    /**
     * 设置窗口尺寸
     */
    public void onViewport() {
        GLES20.glViewport(0, 0, width, height);
    }

    /**
     * 初始化Fbo
     */
    public void onInitFbo() {
        if (!isBindFbo) {
            return;
        }
        int[] fboData = OpenGLESUtils.getFbo(width, height);
        fboId = fboData[0];
        fboTextureId = fboData[1];
    }

    /**
     * 设置尺寸之后
     */
    public void onChangeAfter() {

    }

    /**
     * 绘制之前的准备
     */
    public boolean onReadyToDraw() {
        return true;
    }

    /**
     * 绘制之前
     */
    public void onDrawPre() {

    }

    /**
     * 清屏
     */
    public void onClear() {
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
    }

    /**
     * 使用Program
     */
    public void onUseProgram() {
        GLES20.glUseProgram(program);
    }

    /**
     * 初始化着色器各个位置
     */
    public void onInitLocation() {
        aPosLocation = GLES20.glGetAttribLocation(program, "aPos");
        aCoordinateLocation = GLES20.glGetAttribLocation(program, "aCoordinate");
        uSamplerLocation = GLES20.glGetUniformLocation(program, "uSampler");
    }

    /**
     * 绑定Fbo
     */
    public void onBindFbo() {
        if (!isBindFbo) {
            return;
        }
        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, fboId);
        GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0,
                GLES20.GL_TEXTURE_2D, fboTextureId, 0);
        GLES20.glViewport(0, 0, width, height);
    }

    /**
     * 绑定Vbo
     */
    public void onBindVbo() {
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vboId);
    }

    /**
     * 激活并绑定纹理
     */
    public void onActiveTexture(int textureId) {
        this.textureId = textureId;
        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
        GLES20.glUniform1i(uSamplerLocation, 0);
    }

    /**
     * 启用顶点坐标
     */
    public void onEnableVertexAttributeArray() {
        GLES20.glEnableVertexAttribArray(aPosLocation);
        GLES20.glEnableVertexAttribArray(aCoordinateLocation);
    }

    /**
     * 设置顶点坐标
     */
    public void onSetVertexData() {
        GLES20.glVertexAttribPointer(aPosLocation, vertexSize, GLES20.GL_FLOAT, false, vertexStride, 0);
    }

    /**
     * 设置纹理坐标
     */
    public void onSetCoordinateData() {
        GLES20.glVertexAttribPointer(aCoordinateLocation, coordinateSize, GLES20.GL_FLOAT, false, coordinateStride, vertexBuffer.limit() * 4);
    }

    /**
     * 设置其他数据
     */
    public void onSetOtherData() {

    }

    /**
     * 绘制
     */
    public void onDraw() {
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, vertexCount);
    }

    /**
     * 禁用顶点坐标
     */
    public void onDisableVertexAttributeArray() {
        GLES20.glDisableVertexAttribArray(aPosLocation);
        GLES20.glDisableVertexAttribArray(aCoordinateLocation);
    }

    /**
     * 解除绑定
     */
    public void onUnBind() {
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
    }

    /**
     * 绘制之后
     */
    public void onDrawAfter() {

    }

    /**
     * 删除Program
     */
    public void onDeleteProgram(int program) {
        GLES20.glDeleteProgram(program);
    }

    /**
     * 删除Shader
     */
    public void onDeleteShader(int shader) {
        GLES20.glDeleteShader(shader);
    }

    /**
     * 删除纹理
     */
    public void onDeleteTexture(int textureId) {
        GLES20.glDeleteTextures(1, new int[]{textureId}, 0);
    }

    /**
     * 删除Fbo
     */
    public void onDeleteFbo(int fboId) {
        GLES20.glDeleteFramebuffers(1, new int[]{fboId}, 0);
    }

    /**
     * 删除Vbo
     */
    public void onDeleteVbo(int vboId) {
        GLES20.glDeleteBuffers(1, new int[]{vboId}, 0);
    }

    public Context getContext() {
        return context;
    }

    public void setContext(Context context) {
        this.context = context;
    }

    public FloatBuffer getVertexBuffer() {
        return vertexBuffer;
    }

    public void setVertexBuffer(FloatBuffer vertexBuffer) {
        this.vertexBuffer = vertexBuffer;
    }

    public FloatBuffer getCoordinateBuffer() {
        return coordinateBuffer;
    }

    public void setCoordinateBuffer(FloatBuffer coordinateBuffer) {
        this.coordinateBuffer = coordinateBuffer;
    }

    public int getVertexSize() {
        return vertexSize;
    }

    public void setVertexSize(int vertexSize) {
        this.vertexSize = vertexSize;
    }

    public int getCoordinateSize() {
        return coordinateSize;
    }

    public void setCoordinateSize(int coordinateSize) {
        this.coordinateSize = coordinateSize;
    }

    public int getVertexStride() {
        return vertexStride;
    }

    public void setVertexStride(int vertexStride) {
        this.vertexStride = vertexStride;
    }

    public int getCoordinateStride() {
        return coordinateStride;
    }

    public void setCoordinateStride(int coordinateStride) {
        this.coordinateStride = coordinateStride;
    }

    public int getVertexCount() {
        return vertexCount;
    }

    public void setVertexCount(int vertexCount) {
        this.vertexCount = vertexCount;
    }

    public int getCoordinateCount() {
        return coordinateCount;
    }

    public void setCoordinateCount(int coordinateCount) {
        this.coordinateCount = coordinateCount;
    }

    public int getProgram() {
        return program;
    }

    public void setProgram(int program) {
        this.program = program;
    }

    public int getFboTextureId() {
        return fboTextureId;
    }

    public void setFboTextureId(int fboTextureId) {
        this.fboTextureId = fboTextureId;
    }

    public int getFboId() {
        return fboId;
    }

    public void setFboId(int fboId) {
        this.fboId = fboId;
    }

    public int getVboId() {
        return vboId;
    }

    public void setVboId(int vboId) {
        this.vboId = vboId;
    }

    public String getVertexFilename() {
        return vertexFilename;
    }

    public void setVertexFilename(String vertexFilename) {
        this.vertexFilename = vertexFilename;
    }

    public String getFragFilename() {
        return fragFilename;
    }

    public void setFragFilename(String fragFilename) {
        this.fragFilename = fragFilename;
    }

    public int getWidth() {
        return width;
    }

    public void setWidth(int width) {
        this.width = width;
    }

    public int getHeight() {
        return height;
    }

    public void setHeight(int height) {
        this.height = height;
    }

    public boolean isBindFbo() {
        return isBindFbo;
    }

    public void setBindFbo(boolean bindFbo) {
        isBindFbo = bindFbo;
    }

    public int getPosLocation() {
        return aPosLocation;
    }

    public void setPosLocation(int aPosLocation) {
        this.aPosLocation = aPosLocation;
    }

    public int getCoordinateLocation() {
        return aCoordinateLocation;
    }

    public void setCoordinateLocation(int aCoordinateLocation) {
        this.aCoordinateLocation = aCoordinateLocation;
    }

    public int getSamplerLocation() {
        return uSamplerLocation;
    }

    public void setSamplerLocation(int uSamplerLocation) {
        this.uSamplerLocation = uSamplerLocation;
    }

    public boolean isCreate() {
        return isCreate;
    }

    public void setCreate(boolean create) {
        isCreate = create;
    }

    public boolean isChange() {
        return isChange;
    }

    public void setChange(boolean change) {
        isChange = change;
    }

    public BaseRenderBean getRenderBean() {
        return renderBean;
    }

    public void setRenderBean(BaseRenderBean renderBean) {
        this.renderBean = renderBean;
    }

    public void updateRenderBean(BaseRenderBean renderBean) {
        setRenderBean(renderBean);
    }
}
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代码有点长，但是里面尽可能地考虑到了渲染和扩展的需求

顶点着色器 vertex.frag

attribute vec4 aPos;
attribute vec2 aCoordinate;
varying vec2 vCoordinate;
void main(){
    vCoordinate = aCoordinate;
    gl_Position = aPos;
}
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片元着色器 frag.frag

precision mediump float;
uniform sampler2D uSampler;
varying vec2 vCoordinate;
void main(){
    gl_FragColor = texture2D(uSampler, vCoordinate);
}
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注意到，里面有用到一个工具类OpenGLESUtils和实体类BaseRenderBean具体就不贴出来了，可以到Github上查看

四、BaseOesRender

注意到，BaseRender里面绑定的纹理是2D纹理，而如果想实现相机预览，则需要使用Oes纹理，所以需要创建一个BaseOesRender为相机做渲染

package com.yk.media.opengles.render.base;

import android.content.Context;
import android.graphics.SurfaceTexture;
import android.opengl.GLES11Ext;
import android.opengl.GLES20;

import com.yk.media.utils.OpenGLESUtils;

public class BaseOesRender extends BaseRender {
    /**
     * oes纹理id
     */
    private int oesTextureId;

    /**
     * 顶点变换矩阵位置
     */
    private int uMatrixLocation;

    /**
     * 纹理变换矩阵位置
     */
    private int uOesMatrixLocation;

    /**
     * oes尺寸
     */
    private int oesW = -1;
    private int oesH = -1;

    /**
     * 顶点变换矩阵
     */
    private float[] mMVPMatrix = new float[16];

    /**
     * 纹理变换矩阵
     */
    private float[] mOesMatrix = {
            1, 0, 0, 0,
            0, 1, 0, 0,
            0, 0, 1, 0,
            0, 0, 0, 1
    };

    /**
     * 是否准备好绘制
     */
    private boolean isReadyToDraw = false;

    /**
     * SurfaceTexture
     */
    private SurfaceTexture surfaceTexture;

    /**
     * SurfaceTexture回调
     */
    private OnSurfaceTextureListener onSurfaceTextureListener;

    public BaseOesRender(Context context) {
        super(context, "render/base/oes/vertex.frag", "render/base/oes/frag.frag");
        setBindFbo(true);
        oesTextureId = OpenGLESUtils.getOesTexture();
    }

    @Override
    public void onInitCoordinateBuffer() {
        setCoordinateBuffer(OpenGLESUtils.getSquareCoordinateBuffer());
    }

    @Override
    public boolean onReadyToDraw() {
        if (!isReadyToDraw) {
            if (onSurfaceTextureListener != null) {
                if (surfaceTexture != null) {
                    surfaceTexture.release();
                    surfaceTexture = null;
                }
                surfaceTexture = new SurfaceTexture(oesTextureId);
                onSurfaceTextureListener.onSurfaceTexture(surfaceTexture);
                isReadyToDraw = true;
            } else if (surfaceTexture != null) {
                surfaceTexture.attachToGLContext(oesTextureId);
                isReadyToDraw = true;
            } else {
                return false;
            }
        }
        return oesW != -1 && oesH != -1;
    }

    @Override
    public void onDrawPre() {
        super.onDrawPre();
        mMVPMatrix = OpenGLESUtils.getMatrix(getWidth(), getHeight(), oesW, oesH);

        surfaceTexture.updateTexImage();

        float[] oesMatrix = new float[16];
        surfaceTexture.getTransformMatrix(oesMatrix);
        if (!OpenGLESUtils.isIdentityM(oesMatrix)) {
            mOesMatrix = oesMatrix;
        }
    }

    @Override
    public void onInitLocation() {
        super.onInitLocation();
        uMatrixLocation = GLES20.glGetUniformLocation(getProgram(), "uMatrix");
        uOesMatrixLocation = GLES20.glGetUniformLocation(getProgram(), "uOesMatrix");
    }

    @Override
    public void onActiveTexture(int textureId) {
        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureId);
        GLES20.glUniform1i(getSamplerLocation(), 0);
    }

    @Override
    public void onSetOtherData() {
        super.onSetOtherData();
        GLES20.glUniformMatrix4fv(uMatrixLocation, 1, false, mMVPMatrix, 0);
        GLES20.glUniformMatrix4fv(uOesMatrixLocation, 1, false, mOesMatrix, 0);
    }

    @Override
    public void onRelease() {
        super.onRelease();
        onDeleteTexture(oesTextureId);
    }

    /**
     * 绘制
     */
    public void onDrawSelf() {
        super.onDraw(oesTextureId);
    }

    /**
     * 设置oes尺寸
     */
    public void setOesSize(int width, int height) {
        oesW = width;
        oesH = height;
    }

    /**
     * 设置SurfaceTexture
     */
    public void setSurfaceTexture(SurfaceTexture surfaceTexture) {
        this.surfaceTexture = surfaceTexture;
        isReadyToDraw = false;
    }

    /**
     * 设置SurfaceTexture回调
     */
    public void setOnSurfaceTextureListener(OnSurfaceTextureListener onSurfaceTextureListener) {
        this.onSurfaceTextureListener = onSurfaceTextureListener;
        isReadyToDraw = false;
    }
}
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顶点着色器 vertex.frag

attribute vec4 aPos;
attribute vec4 aCoordinate;
uniform mat4 uMatrix;
uniform mat4 uOesMatrix;
varying vec2 vCoordinate;
void main(){
    vCoordinate = (uOesMatrix * aCoordinate).xy;
    gl_Position = uMatrix * aPos;
}
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片元着色器 frag.frag

#extension GL_OES_EGL_image_external:require
precision mediump float;
uniform samplerExternalOES uSampler;
varying vec2 vCoordinate;
void main(){
    gl_FragColor = texture2D(uSampler, vCoordinate);
}
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BaseOesRender是继承BaseRender的

加入了一些变量

• oesW和oesH

  用于计算矩阵

• mMVPMatrix

  通过width、height、oesW、oesH计算的矩阵

• mOesMatrix

  通过SurfaceTexture获取的矩阵

• isReadyToDraw

  是否准备好渲染

重写了一些方法

• onInitCoordinateBuffer

  BaseOesRender需要绑定FBO，所有纹理坐标需要设置好，不然会出现倒立

• onReadyToDraw

  此处做一些SurfaceTexture绑定纹理和回调

• onDrawPre

  此处做矩阵相关的计算

• onInitLocation

  获取矩阵的Location

• onActiveTexture

  前面有说到，预览相机使用的是SurfaceTexture，所有需要修改绑定为Oes纹理

• onSetOtherData

  此处传入矩阵的数据

• onRelease

  此处做一些释放资源的工作

OnSurfaceTextureListener

public interface OnSurfaceTextureListener {
    /**
     * SurfaceTexture回调
     */
    void onSurfaceTexture(SurfaceTexture surfaceTexture);
}
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onDrawSelf

public void onDrawSelf() {
    super.onDraw(oesTextureId);
}
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因为oesTextureId是内部创建的，故渲染的话，直接调用super.onDraw(oesTextureId)，方便外部调用

五、OesRender

前面有说过，EGLTextureView的setRenderer只能调用一次，故才会创建BaseRender，现在来创建Renderer调度者

public class OesRender implements Renderer {
    private Context context;

    /**
     * 输入（FBO保存数据）
     */
    private BaseOesRender inputRender;

    /**
     * 输出（屏幕显示）
     */
    private BaseRender outputRender;

    private int width;
    private int height;

    public OesRender(Context context) {
        this.context = context;
        inputRender = new BaseOesRender(context);
        outputRender = new BaseRender(context);
    }

    @Override
    public void onCreate() {
        inputRender.onCreate();
        outputRender.onCreate();
    }

    @Override
    public void onChange(int width, int height) {
        this.width = width;
        this.height = height;
        inputRender.onChange(width, height);
        outputRender.onChange(width, height);
    }

    @Override
    public void onDraw() {
        inputRender.onDrawSelf();
        outputRender.onDraw(inputRender.getFboTextureId());
    }

    public void setOesSize(int width, int height) {
        inputRender.setOesSize(width, height);
    }

    public void setOnSurfaceTextureListener(OnSurfaceTextureListener onSurfaceTextureListener) {
        inputRender.setOnSurfaceTextureListener(onSurfaceTextureListener);
    }

    public void setSurfaceTexture(SurfaceTexture surfaceTexture) {
        inputRender.setSurfaceTexture(surfaceTexture);
    }

    public int getFboTextureId() {
        return inputRender.getFboTextureId();
    }
}
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注意到，OesRender里面，有两个Render

• BaseOesRender

  渲染Oes纹理，并绑定了Fbo

• BaseRender

  做为输出显示

六、CameraView

完成了上面的工作，接下来就可以进入正题，如何在Android中，使用OpenGLES + Camera1实现相机预览？

既然我们已经完成了“容器”和Renderer的创建，那么下面的工作就比较轻松

还记得上一章的Android Camera1相机预览，不记得的同学可以点击链接进入查看，因为接下来需要用到上一章介绍的CameraManager

public class CameraView extends EGLTextureView implements OnCameraListener {
    private final CameraManager cameraManager = new CameraManager();

    private Activity activity;

    public OesRender render;

    public CameraView(Context context) {
        this(context, null);
    }

    public CameraView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }

    private void init(Context context) {
        setEGLContextClientVersion(2);
        render = new OesRender(context);
        setRenderer(render);
        setRenderMode(EGLTextureView.RENDERMODE_WHEN_DIRTY);

        activity = (Activity) context;
        cameraManager.addOnCameraListener(this);
    }

    public void openCamera() {
        render.setOnSurfaceTextureListener(new OnSurfaceTextureListener() {
            @Override
            public void onSurfaceTexture(SurfaceTexture surfaceTexture) {
                surfaceTexture.setOnFrameAvailableListener(new SurfaceTexture.OnFrameAvailableListener() {
                    @Override
                    public void onFrameAvailable(SurfaceTexture surfaceTexture) {
                        requestRender();
                    }
                });
                cameraManager.openCamera(activity, surfaceTexture);
            }
        });
        requestRender();
    }

    public void closeCamera() {
        cameraManager.closeCamera();
    }

    public void switchCamera() {
        cameraManager.switchCamera();
        openCamera();
    }

    public void switchCamera(int facing) {
        cameraManager.switchCamera(facing);
        openCamera();
    }

    public void addOnCameraListener(OnCameraListener onCameraListener) {
        cameraManager.addOnCameraListener(onCameraListener);
    }

    @Override
    public void onCameraOpened(Size cameraSize, int facing) {
        render.setOesSize(cameraSize.getHeight(), cameraSize.getWidth());
        requestRender();
    }

    @Override
    public void onCameraClosed() {

    }

    @Override
    public void onCameraError(Exception e) {

    }

    public CameraManager getCameraManager() {
        return cameraManager;
    }

    public int getFboTextureId() {
        return render.getFboTextureId();
    }
}
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新建CameraView，继承EGLTextureView

初始化

private void init(Context context) {
    setEGLContextClientVersion(2);
    render = new OesRender(context,process);
    setRenderer(render);
    setRenderMode(EGLTextureView.RENDERMODE_WHEN_DIRTY);
    activity = (Activity) context;
    cameraManager.addOnCameraListener(this);
}
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此处做了一些初始化工作

• setEGLContextClientVersion

  此处传入的是2，表示使用的是OpenGLES 2.0

• setRenderer

  此处将上面创建的OesRender传入

• setRenderMode

  此处传入EGLTextureView.RENDERMODE_WHEN_DIRTY，表示只有在调用requestRender()方法时才会渲染

  对应的，还有一个是EGLTextureView.RENDERMODE_CONTINUOUSLY，表示会不停的渲染

• addOnCameraListener

  设置相机的回调

打开相机

public void openCamera() {
    render.setOnSurfaceTextureListener(new OnSurfaceTextureListener() {
        @Override
        public void onSurfaceTexture(SurfaceTexture surfaceTexture) {
            surfaceTexture.setOnFrameAvailableListener(new SurfaceTexture.OnFrameAvailableListener() {
                @Override
                public void onFrameAvailable(SurfaceTexture surfaceTexture) {
                    requestRender();
                }
            });
            cameraManager.openCamera(activity, surfaceTexture);
        }
    });
    requestRender();
}
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首先，设置SurfaceTexture的回调监听，并调用requestRender()方法进行渲染请求

在拿到SurfaceTexture后，需要对SurfaceTexture进行设置setOnFrameAvailableListener监听，表示当SurfaceTexture每帧数据到来的时候，都会调用requestRender()请求渲染

接下来，就是使用CameraManager的openCamera方法，传入activity和surfaceTexture进行打开摄像头的操作

关闭相机

public void closeCamera() {
    cameraManager.closeCamera();
}
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关闭相机比较简单，直接调用CameraManager的closeCamera()方法即可

切换相机

public void switchCamera() {
    cameraManager.switchCamera();
    openCamera();
}
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切换相机和上一章，先调用cameraManager的switchCamera()方法切换facing，再调用openCamera()即可

Github

以上相关代码都可以在下面找到

Camera相关实现代码

OpenGLES

TakePhotoActivity