效果图如下：
一、为预览控件设置圆角为控件设置ViewOutlineProvider
public RoundTextureVIEw(Context context,AttributeSet attrs) { super(context,attrs); setoutlineProvIDer(new VIEwOutlineProvIDer() { @OverrIDe public voID getoutline(VIEw vIEw,Outline outline) { Rect rect = new Rect(0,vIEw.getMeasureDWIDth(),vIEw.getMeasuredHeight()); outline.setRoundRect(rect,radius); } }); setClipToOutline(true); } 在需要时修改圆角值并更新
public voID seTradius(int radius) { this.radius = radius; } public voID turnRound() { invalIDateOutline(); } 即可根据设置的圆角值更新控件显示的圆角大小。当控件为正方形，且圆角值为边长的一半，显示的就是圆形。
二、实现正方形预览 1. 设备支持1:1预览尺寸首先介绍一种简单但是局限性较大的实现方式：将相机预览尺寸和预览控件的大小都调整为1:1。
一般AndroID设备都支持多种预览尺寸，以Samsung Tab S3为例
在使用Camera API时，其支持的预览尺寸如下：2019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 1920x10802019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 1280x7202019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 1440x10802019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 1088x10882019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 1056x8642019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 960x7202019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 720x4802019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 640x4802019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 352x2882019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 320x2402019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPrevIEwSize: 176x144
其中1:1的预览尺寸为：1088x1088。
在使用Camera2 API时，其支持的预览尺寸（其实也包含了PictureSize）如下：2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 4128x30962019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 4128x23222019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3264x24482019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3264x18362019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3024x30242019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2976x29762019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2880x21602019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2592x19442019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x19202019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x14402019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x10802019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2160x21602019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2048x15362019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2048x11522019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1936x19362019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1920x10802019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1440x10802019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1280x9602019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1280x7202019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 960x7202019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 720x4802019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 640x4802019-08-02 13:19:24.982 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 320x2402019-08-02 13:19:24.982 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 176x144
其中1:1的预览尺寸为：3024x3024、2976x2976、2160x2160、1936x1936。
只要我们选择1:1的预览尺寸，再将预览控件设置为正方形，即可实现正方形预览；
再通过设置预览控件的圆角为边长的一半，即可实现圆形预览。
选择1:1预览尺寸的缺陷分析
分辨率局限性上述说到，我们可以选择1:1的预览尺寸进行预览，但是局限性较高，
可选择范围都很小。如果相机不支持1:1的预览尺寸，这个方案就不可行了。 资源消耗
以Samsung tab S3为例，该设备使用Camera2 API时，支持的正方形预览尺寸都很大，在进行图像处理等 *** 作时将占用较多系统资源。
处理不支持1:1预览尺寸的情况
添加一个1:1尺寸的VIEwGroup 将TextureVIEw放入VIEwGroup 设置TextureVIEw的margin值以达到显示中心正方形区域的效果 示意图示例代码
//将预览控件和预览尺寸比例保持一致，避免拉伸 { FrameLayout.LayoutParams textureVIEwLayoutParams = (FrameLayout.LayoutParams) textureVIEw.getLayoutParams(); int newHeight = 0; int newWIDth = textureVIEwLayoutParams.wIDth; //横屏 if (displayOrIEntation % 180 == 0) { newHeight = textureVIEwLayoutParams.wIDth * prevIEwSize.height / prevIEwSize.wIDth; } //竖屏 else { newHeight = textureVIEwLayoutParams.wIDth * prevIEwSize.wIDth / prevIEwSize.height; } ////当不是正方形预览的情况下，添加一层VIEwGroup限制VIEw的显示区域 if (newHeight != textureVIEwLayoutParams.height) { insertFrameLayout = new RoundFrameLayout(CoverByParentCameraActivity.this); int sIDeLength = Math.min(newWIDth,newHeight); FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(sIDeLength,sIDeLength); insertFrameLayout.setLayoutParams(layoutParams); FrameLayout parentVIEw = (FrameLayout) textureVIEw.getParent(); parentVIEw.removeVIEw(textureVIEw); parentVIEw.addVIEw(insertFrameLayout); insertFrameLayout.addVIEw(textureVIEw); FrameLayout.LayoutParams newTextureVIEwLayoutParams = new FrameLayout.LayoutParams(newWIDth,newHeight); //横屏 if (displayOrIEntation % 180 == 0) { newTextureVIEwLayoutParams.leftmargin = ((newHeight - newWIDth) / 2); } //竖屏 else { newTextureVIEwLayoutParams.topmargin = -(newHeight - newWIDth) / 2; } textureVIEw.setLayoutParams(newTextureVIEwLayoutParams); } }
三、使用GLSurfaceVIEw进行自定义程度更高的预览 使用上面的方法 *** 作已经可完成正方形和圆形预览，但是仅适用于原生相机，当我们的数据源并非是原生相机的情况时如何进行圆形预览？接下来介绍使用GLSurfaceVIEw显示NV21的方案，完全是自己实现预览数据的绘制。
1. GLSurfaceVIEw使用流程 OpenGL渲染YUV数据流程其中的重点是渲染器（Renderer）的编写，Renderer的介绍如下：
/** * A generic renderer interface. * <p> * The renderer is responsible for making OpenGL calls to render a frame. * <p> * GLSurfaceVIEw clIEnts typically create their own classes that implement * this interface,and then call {@link GLSurfaceVIEw#setRenderer} to * register the renderer with the GLSurfaceVIEw. * <p> * * <div > * <h3>Developer GuIDes</h3> * <p>For more information about how to use OpenGL,read the * <a href="{@docRoot}guIDe/topics/graphics/opengl.HTML">OpenGL</a> developer guIDe.</p> * </div> * * <h3>Threading</h3> * The renderer will be called on a separate thread,so that rendering * performance is decoupled from the UI thread. ClIEnts typically need to * communicate with the renderer from the UI thread,because that‘s where * input events are received. ClIEnts can communicate using any of the * standard Java techniques for cross-thread communication,or they can * use the {@link GLSurfaceVIEw#queueEvent(Runnable)} convenIEnce method. * <p> * <h3>EGL Context Lost</h3> * There are situations where the EGL rendering context will be lost. This * typically happens when device wakes up after going to sleep. When * the EGL context is lost,all OpenGL resources (such as textures) that are * associated with that context will be automatically deleted. In order to * keep rendering correctly,a renderer must recreate any lost resources * that it still needs. The {@link #onSurfaceCreated(GL10,EGLConfig)} method * is a convenIEnt place to do this. * * * @see #setRenderer(Renderer) */ public interface Renderer { /** * Called when the surface is created or recreated. * <p> * Called when the rendering thread * starts and whenever the EGL context is lost. The EGL context will typically * be lost when the AndroID device awakes after going to sleep. * <p> * Since this method is called at the beginning of rendering,as well as * every time the EGL context is lost,this method is a convenIEnt place to put * code to create resources that need to be created when the rendering * starts,and that need to be recreated when the EGL context is lost. * Textures are an example of a resource that you might want to create * here. * <p> * Note that when the EGL context is lost,all OpenGL resources associated * with that context will be automatically deleted. You do not need to call * the corresponding "glDelete" methods such as glDeleteTextures to * manually delete these lost resources. * <p> * @param gl the GL interface. Use <code>instanceof</code> to * test if the interface supports GL11 or higher interfaces. * @param config the EGLConfig of the created surface. Can be used * to create matching pbuffers. */ voID onSurfaceCreated(GL10 gl,EGLConfig config); /** * Called when the surface changed size. * <p> * Called after the surface is created and whenever * the OpenGL ES surface size changes. * <p> * Typically you will set your vIEwport here. If your camera * is fixed then you Could also set your projection matrix here: * <pre > * voID onSurfaceChanged(GL10 gl,int wIDth,int height) { * gl.glVIEwport(0,wIDth,height); * // for a fixed camera,set the projection too * float ratio = (float) wIDth / height; * gl.glMatrixMode(GL10.GL_PROJECTION); * gl.glLoadIDentity(); * gl.glFrustumf(-ratio,ratio,-1,1,10); * } * </pre> * @param gl the GL interface. Use <code>instanceof</code> to * test if the interface supports GL11 or higher interfaces. * @param wIDth * @param height */ voID onSurfaceChanged(GL10 gl,int height); /** * Called to draw the current frame. * <p> * This method is responsible for drawing the current frame. * <p> * The implementation of this method typically looks like this: * <pre > * voID onDrawFrame(GL10 gl) { * gl.glClear(GL10.GL_color_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); * //... other gl calls to render the scene ... * } * </pre> * @param gl the GL interface. Use <code>instanceof</code> to * test if the interface supports GL11 or higher interfaces. */ voID onDrawFrame(GL10 gl); }
voID onSurfaceCreated(GL10 gl,EGLConfig config)在Surface创建或重建的情况下回调
voID onSurfaceChanged(GL10 gl,int height)在Surface的大小发生变化的情况下回调
voID onDrawFrame(GL10 gl)在这里实现绘制 *** 作。当我们设置的
renderMode为RENDERMODE_CONTINUOUSLY时，该函数将不断地执行；当我们设置的
renderMode为RENDERMODE_WHEN_DIRTY时，将只在创建完成和调用requestRender后才执行。一般我们选择RENDERMODE_WHEN_DIRTY渲染模式，避免过度绘制。 一般情况下，我们会自己实现一个Renderer，然后为GLSurfaceVIEw设置Renderer，可以说，Renderer的编写是整个流程的核心步骤。以下是在voID onSurfaceCreated(GL10 gl,EGLConfig config)进行的初始化 *** 作和在voID onDrawFrame(GL10 gl)进行的绘制 *** 作的流程图：
渲染YUV数据的Renderer
2. 具体实现 坐标系介绍 AndroID VIEw坐标系 OpenGL世界坐标系 着色器编写
/** * 顶点着色器 */ private static String VERTEX_SHADER = " attribute vec4 attr_position;\n" + " attribute vec2 attr_tc;\n" + " varying vec2 tc;\n" + " voID main() {\n" + " gl_position = attr_position;\n" + " tc = attr_tc;\n" + " }"; /** * 片段着色器 */ private static String FRAG_SHADER = " varying vec2 tc;\n" + " uniform sampler2D ySampler;\n" + " uniform sampler2D uSampler;\n" + " uniform sampler2D vSampler;\n" + " const mat3 convertMat = mat3( 1.0,1.0,-0.001,-0.3441,1.772,1.402,-0.7141,-0.58060);\n" + " voID main()\n" + " {\n" + " vec3 yuv;\n" + " yuv.x = texture2D(ySampler,tc).r;\n" + " yuv.y = texture2D(uSampler,tc).r - 0.5;\n" + " yuv.z = texture2D(vSampler,tc).r - 0.5;\n" + " gl_Fragcolor = vec4(convertMat * yuv,1.0);\n" + " }";
内建变量解释
gl_positionVERTEX_SHADER代码里的gl_position代表绘制的空间坐标。由于我们是二维绘制，所以直接传入OpenGL二维坐标系的左下(-1,-1)、右下(1,-1)、左上(-1,1)、右上(1,1)，也就是{-1,1} gl_FragcolorFRAG_SHADER代码里的gl_Fragcolor代表单个片元的颜色 其他变量解释
ySampler、uSampler、vSampler分别代表Y、U、V纹理采样器
convertMat根据以下公式：
R = Y + 1.402 (V - 128)G = Y - 0.34414 (U - 128) - 0.71414 (V - 128)B = Y + 1.772 (U - 128)我们可得到一个YUV转RGB的矩阵
1.0,-0.344,1.77,1.403,-0.714,0
部分类型、函数的解释
vec3、vec4分别代表三维向量、四维向量。
vec4 texture2D(sampler2D sampler,vec2 coord)以指定的矩阵将采样器的图像纹理转换为颜色值；如：
texture2D(ySampler,tc).r获取到的是Y数据，texture2D(uSampler,tc).r获取到的是U数据，texture2D(vSampler,tc).r获取到的是V数据。 在Java代码中进行初始化
根据图像宽高创建Y、U、V对应的ByteBuffer纹理数据；
根据是否镜像显示、旋转角度选择对应的转换矩阵；
public voID init(boolean isMirror,int rotateDegree,int frameWIDth,int frameHeight) { if (this.frameWIDth == frameWIDth && this.frameHeight == frameHeight && this.rotateDegree == rotateDegree && this.isMirror == isMirror) { return; } datainput = false; this.frameWIDth = frameWIDth; this.frameHeight = frameHeight; this.rotateDegree = rotateDegree; this.isMirror = isMirror; yArray = new byte[this.frameWIDth * this.frameHeight]; uArray = new byte[this.frameWIDth * this.frameHeight / 4]; vArray = new byte[this.frameWIDth * this.frameHeight / 4]; int yFrameSize = this.frameHeight * this.frameWIDth; int uvFrameSize = yFrameSize >> 2; yBuf = ByteBuffer.allocateDirect(yFrameSize); yBuf.order(ByteOrder.nativeOrder()).position(0); uBuf = ByteBuffer.allocateDirect(uvFrameSize); uBuf.order(ByteOrder.nativeOrder()).position(0); vBuf = ByteBuffer.allocateDirect(uvFrameSize); vBuf.order(ByteOrder.nativeOrder()).position(0); // 顶点坐标 squareVertices = ByteBuffer .allocateDirect(glutil.SQUARE_VERTICES.length * float_SIZE_BYTES) .order(ByteOrder.nativeOrder()) .asfloatBuffer(); squareVertices.put(glutil.SQUARE_VERTICES).position(0); //纹理坐标 if (isMirror) { switch (rotateDegree) { case 0: coordVertice = glutil.MIRROR_COORD_VERTICES; break; case 90: coordVertice = glutil.ROTATE_90_MIRROR_COORD_VERTICES; break; case 180: coordVertice = glutil.ROTATE_180_MIRROR_COORD_VERTICES; break; case 270: coordVertice = glutil.ROTATE_270_MIRROR_COORD_VERTICES; break; default: break; } } else { switch (rotateDegree) { case 0: coordVertice = glutil.COORD_VERTICES; break; case 90: coordVertice = glutil.ROTATE_90_COORD_VERTICES; break; case 180: coordVertice = glutil.ROTATE_180_COORD_VERTICES; break; case 270: coordVertice = glutil.ROTATE_270_COORD_VERTICES; break; default: break; } } coordVertices = ByteBuffer.allocateDirect(coordVertice.length * float_SIZE_BYTES).order(ByteOrder.nativeOrder()).asfloatBuffer(); coordVertices.put(coordVertice).position(0);}
在Surface创建完成时进行Renderer初始化
private voID initRenderer() { rendererReady = false; createGLProgram(); //启用纹理 GLES20.glEnable(GLES20.GL_TEXTURE_2D); //创建纹理 createTexture(frameWIDth,frameHeight,GLES20.GL_luminance,yTexture); createTexture(frameWIDth / 2,frameHeight / 2,uTexture); createTexture(frameWIDth / 2,vTexture); rendererReady = true; } 其中用于创建OpenGL Program并关联着色器代码中的变量createGLProgram
private voID createGLProgram() { int programHandleMain = glutil.createShaderProgram(); if (programHandleMain != -1) { // 使用着色器程序 GLES20.gluseProgram(programHandleMain); // 获取顶点着色器变量 int glposition = GLES20.glGetAttribLocation(programHandleMain,"attr_position"); int textureCoord = GLES20.glGetAttribLocation(programHandleMain,"attr_tc"); // 获取片段着色器变量 int ySampler = GLES20.glGetUniformlocation(programHandleMain,"ySampler"); int uSampler = GLES20.glGetUniformlocation(programHandleMain,"uSampler"); int vSampler = GLES20.glGetUniformlocation(programHandleMain,"vSampler"); //给变量赋值 /** * GLES20.GL_TEXTURE0 和 ySampler 绑定 * GLES20.GL_TEXTURE1 和 uSampler 绑定 * GLES20.GL_TEXTURE2 和 vSampler 绑定 * * 也就是说 gluniform1i的第二个参数代表图层序号 */ GLES20.gluniform1i(ySampler,0); GLES20.gluniform1i(uSampler,1); GLES20.gluniform1i(vSampler,2); GLES20.glEnabLevertexAttribarray(glposition); GLES20.glEnabLevertexAttribarray(textureCoord); /** * 设置Vertex Shader数据 */ squareVertices.position(0); GLES20.glVertexAttribPointer(glposition,glutil.COUNT_PER_SQUARE_VERTICE,GLES20.GL_float,false,8,squareVertices); coordVertices.position(0); GLES20.glVertexAttribPointer(textureCoord,glutil.COUNT_PER_COORD_VERTICES,coordVertices); } }
其中createTexture用于根据宽高和格式创建纹理
private voID createTexture(int wIDth,int height,int format,int[] textureID) { //创建纹理 GLES20.glGenTextures(1,textureID,0); //绑定纹理 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,textureID[0]); /** * {@link GLES20#GL_TEXTURE_WRAP_S}代表左右方向的纹理环绕模式 * {@link GLES20#GL_TEXTURE_WRAP_T}代表上下方向的纹理环绕模式 * * {@link GLES20#GL_REPEAT}：重复 * {@link GLES20#GL_MIRRORED_REPEAT}：镜像重复 * {@link GLES20#GL_CLAMP_TO_EDGE}：忽略边框截取 * * 例如我们使用{@link GLES20#GL_REPEAT}： * * squareVertices coordVertices * -1.0f,-1.0f,1.0f,* 1.0f,0.0f,-> 和textureVIEw预览相同 * -1.0f,1.0f 0.0f,0.0f * * squareVertices coordVertices * -1.0f,2.0f,-> 和textureVIEw预览相比，分割成了4 块相同的预览（左下，右下，左上，右上） * -1.0f,0.0f */ GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,GLES20.GL_TEXTURE_WRAP_S,GLES20.GL_REPEAT); GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,GLES20.GL_TEXTURE_WRAP_T,GLES20.GL_REPEAT); /** * {@link GLES20#GL_TEXTURE_MIN_FILTER}代表所显示的纹理比加载进来的纹理小时的情况 * {@link GLES20#GL_TEXTURE_MAG_FILTER}代表所显示的纹理比加载进来的纹理大时的情况 * * {@link GLES20#GL_NEAREST}：使用纹理中坐标最接近的一个像素的颜色作为需要绘制的像素颜色 * {@link GLES20#GL_liNEAR}：使用纹理中坐标最接近的若干个颜色，通过加权平均算法得到需要绘制的像素颜色 */ GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,GLES20.GL_TEXTURE_MIN_FILTER,GLES20.GL_NEAREST); GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,GLES20.GL_TEXTURE_MAG_FILTER,GLES20.GL_liNEAR); GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D,format,height,GLES20.GL_UNSIGNED_BYTE,null); }
在Java代码中调用绘制 在数据源获取到时裁剪并传入帧数据
@OverrIDe public voID onPrevIEw(final byte[] nv21,Camera camera) { //裁剪指定的图像区域 ImageUtil.cropNV21(nv21,this.squareNV21,prevIEwSize.wIDth,prevIEwSize.height,cropRect); //刷新GLSurfaceVIEw roundCameraGLSurfaceVIEw.refreshFrameNV21(this.squareNV21); }
NV21数据裁剪代码
/** * 裁剪NV21数据 * * @param originNV21 原始的NV21数据 * @param cropNV21 裁剪结果NV21数据，需要预先分配内存 * @param wIDth 原始数据的宽度 * @param height 原始数据的高度 * @param left 原始数据被裁剪的区域的左边界 * @param top 原始数据被裁剪的区域的上边界 * @param right 原始数据被裁剪的区域的右边界 * @param bottom 原始数据被裁剪的区域的下边界 */ public static voID cropNV21(byte[] originNV21,byte[] cropNV21,int left,int top,int right,int bottom) { int halfWIDth = wIDth / 2; int cropImageWIDth = right - left; int cropImageHeight = bottom - top; //原数据Y左上 int originalYlinestart = top * wIDth; int targetYIndex = 0; //原数据UV左上 int originalUVlinestart = wIDth * height + top * halfWIDth; //目标数据的UV起始值 int targetUVIndex = cropImageWIDth * cropImageHeight; for (int i = top; i < bottom; i++) { System.arraycopy(originNV21,originalYlinestart + left,cropNV21,targetYIndex,cropImageWIDth); originalYlinestart += wIDth; targetYIndex += cropImageWIDth; if ((i & 1) == 0) { System.arraycopy(originNV21,originalUVlinestart + left,targetUVIndex,cropImageWIDth); originalUVlinestart += wIDth; targetUVIndex += cropImageWIDth; } } }
传给GLSurafceVIEw并刷新帧数据
/** * 传入NV21刷新帧 * * @param data NV21数据 */ public voID refreshFrameNV21(byte[] data) { if (rendererReady) { yBuf.clear(); uBuf.clear(); vBuf.clear(); putNV21(data,frameWIDth,frameHeight); datainput = true; requestRender(); } }
其中putNV21用于将NV21中的Y、U、V数据分别取出
/** * 将NV21数据的Y、U、V分量取出 * * @param src nv21帧数据 * @param wIDth 宽度 * @param height 高度 */ private voID putNV21(byte[] src,int height) { int ySize = wIDth * height; int frameSize = ySize * 3 / 2; //取分量y值 System.arraycopy(src,yArray,ySize); int k = 0; //取分量uv值 int index = ySize; while (index < frameSize) { vArray[k] = src[index++]; uArray[k++] = src[index++]; } yBuf.put(yArray).position(0); uBuf.put(uArray).position(0); vBuf.put(vArray).position(0); }
在执行requestRender后，onDrawFrame函数将被回调，在其中进行三个纹理的数据绑定并绘制
@OverrIDe public voID onDrawFrame(GL10 gl) { // 分别对每个纹理做激活、绑定、设置数据 *** 作 if (datainput) { //y GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,yTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D,yBuf); //u GLES20.glActiveTexture(GLES20.GL_TEXTURE1); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,uTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D,frameWIDth >> 1,frameHeight >> 1,uBuf); //v GLES20.glActiveTexture(GLES20.GL_TEXTURE2); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,vTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D,vBuf); //在数据绑定完成后进行绘制 GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP,4); } }
即可完成绘制。
四、加一层边框有时候需求并不仅仅是圆形预览这么简单，我们可能还要为相机预览加一层边框
边框效果
一样的思路，我们动态地修改边框值，并进行重绘。
边框自定义view中的相关代码如下：
@OverrIDe protected voID onDraw(Canvas canvas) { super.onDraw(canvas); if (paint == null) { paint = new Paint(); paint.setStyle(Paint.Style.stroke); paint.setAntiAlias(true); SweepGradIEnt sweepGradIEnt = new SweepGradIEnt(((float) getWIDth() / 2),((float) getHeight() / 2),new int[]{color.GREEN,color.CYAN,color.BLUE,color.GREEN},null); paint.setShader(sweepGradIEnt); } drawborder(canvas,6); } private voID drawborder(Canvas canvas,int rectThickness) { if (canvas == null) { return; } paint.setstrokeWIDth(rectThickness); Path drawPath = new Path(); drawPath.addRoundRect(new RectF(0,getWIDth(),getHeight()),radius,Path.Direction.CW); canvas.drawPath(drawPath,paint); } public voID turnRound() { invalIDate(); } public voID seTradius(int radius) { this.radius = radius; } 五、完整Demo代码：
https://github.com/wangshengyang1996/GLCameraDemo
https://ai.arcsoft.com.cn/ucenter/resource/openPlatform/index.html?cnblogs
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