OpenGL ES_手把手教你打造VR全景播放器

OpenGL ES _ 入门_01
OpenGL ES _ 入门_02
OpenGL ES _ 入门_03
OpenGL ES _ 入门_04
OpenGL ES _ 入门_05
OpenGL ES _ 入门练习_01
OpenGL ES _ 入门练习_02
OpenGL ES _ 入门练习_03
OpenGL ES _ 入门练习_04
OpenGL ES _ 入门练习_05
OpenGL ES _ 入门练习_06
OpenGL ES _ 着色器 _ 介绍
OpenGL ES _ 着色器 _ 程序
OpenGL ES _ 着色器 _ 语法
OpenGL ES_着色器_纹理图像
OpenGL ES_着色器_预处理
OpenGL ES_着色器_顶点着色器详解
OpenGL ES_着色器_片断着色器详解
OpenGL ES_着色器_实战01
OpenGL ES_着色器_实战02
OpenGL ES_着色器_实战03

让学习成为一种习惯
实战2中，详细介绍了多屏显示的原理和实现过程,今天我们继续我们的OpenGL 旅程！技术再牛逼也要学习! 学习是一件开心的额事情

学习目标

打造全景视频，以及VR 眼镜专用的双屏显示框架!

你应该知道的

网络截图

• 全景显示的原理
  通俗的将，好比红色区域就是你的手机屏幕，当你旋转手机的时候，我们球体向相反的方向旋转，这样，你就可以看到球体上的画面了.

准备工作

找一个全景视频，添加到项目中去。

• 实现步骤
  1.创建一个球体模型
  2.获取视频数据的每一帧数据 转换成RGB 格式，渲染到球体上
  3.通过手势的变换，改变球体模型视图矩阵值
  4.如果是VR模式,则通过角度传感器获取用户的行为，调整视图矩阵。

实现了那些功能

• 支持普通视频播放
• 支持全景视频播放
• 支持VR 双屏显示模式
• 支持快进，快退
• 支持播放，暂停
• 支持暂停广告功能

核心代码讲解

如果你想要和我一样,能够从零开始把代码敲出来，请确保自己有OpenGL ES 2.0 的基础知识 和 GLSL 的简单基本知识，如果你不具备这方面的知识，没关系，我已经写好了OpenGL学习教程和GLSL教程,请移步开始学习。下面开始我们的内容讲解.

• 视频采集

<p>工程中的两个文件 XJVRPlayerViewController.h和XJVRPlayerController.m主要负责视频数据采集,界面布局在XJVRPlayerViewController中可以更改,主要使用AVFoundation框架这部分内容今天咱不讲解,后面我会写关于视频采集的教程</p>

• 模型创建
  a.全景播放器生成球体的顶点坐标和纹理坐标
  b.普通播放器生成长方形的顶点坐标和纹理坐标
  两个生成函数在OSShere.h中

• 将数据加载到GPU中去

  // 加载顶点索引数据
   glGenBuffers(1, &_indexBuffer);
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
   glBufferData(GL_ELEMENT_ARRAY_BUFFER, _numIndices*sizeof(GLushort), _indices, GL_STATIC_DRAW);
  
  // 加载顶点坐标
  glGenBuffers(1, &_vertexBuffer);
  glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
  glBufferData(GL_ARRAY_BUFFER,   numVertices*strideNum*sizeof(GLfloat), _vertices, GL_STATIC_DRAW);
  glEnableVertexAttribArray(GLKVertexAttribPosition);
  glVertexAttribPointer(GLKVertexAttribPosition, strideNum, GL_FLOAT, GL_FALSE, strideNum*sizeof(GLfloat), NULL);
  
  //加载纹理坐标
  glGenBuffers(1, &_textureCoordBuffer);
  glBindBuffer(GL_ARRAY_BUFFER, _textureCoordBuffer);
  glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat)*2*numVertices, _texCoords, GL_DYNAMIC_DRAW);
  glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
  glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, 2*sizeof(GLfloat), NULL);
  

以上函数的具体用法，在之前的教程中都讲过,这里就不赘述了。

• 着色器程序
  我把着色器分为两种类型，一种是渲染全景视频的，一种是渲染普通视频的，两个没有多大区别，只是在全景着色器中添加了一个视图转换矩阵 (全景着色器:ShadePanorama,普通着色器:ShaderNormal)
  下面给出的是全景的着色器的代码:
  a.顶点着色器

  attribute vec4 position; // 顶点坐标属性
  attribute vec2 texCoord0;// 纹理坐标
  varying  vec2 texCoordVarying;// 片段着色器输入变量,负责获取纹理坐标的值
  uniform mat4 modelViewProjectionMatrix;//视图变换矩阵
  void main (){
  texCoordVarying = texCoord0;
  gl_Position = modelViewProjectionMatrix*position;
  }
  

b.片段着色器

  precision mediump float;//设置float精度
  varying  vec2 texCoordVarying;
  uniform sampler2D sam2DY;  // 纹理采样器Y
  uniform sampler2D sam2DUV;// 纹理采样器UV
  void main(){
  mediump vec3 yuv;
  lowp vec3 rob;
  // YUV  转RGB 的转换矩阵 
  mediump mat3 convert = mat3(1.164,  1.164, 1.164,
                            0.0, -0.213, 2.112,
                            1.793, -0.533,   0.0);
  yuv.x = texture2D(sam2DY,texCoordVarying).r - (16.0/255.0);
  yuv.yz = texture2D(sam2DUV,texCoordVarying).rg - vec2(0.5, 0.5);
  rgb = convert*yuv;
  gl_FragColor = vec4(rgb,1);
  }

如果想要了解更多关于着色器语言的知识，请猛戳我

• 创建着色器程序
  创建着色器程序的目的是编译刚才我们编写好的着色器源代码，以及将着色器的变量和我们的应用程序代码相关联

  /**
   *  创建编译shader程序
   *
   *  @param vshName 顶点着色器文件名称
   *  @param fshName 片段着色器文件名称
   */
   -(void)createShaderProgramVertexShaderName:  (NSString*)vshName FragmentShaderName:  (NSString*)fshName{
    self.shaderManager = [[OSShaderManager alloc]init];
    // 编译连个shader 文件
    GLuint vertexShader,fragmentShader;
    NSURL *vertexShaderPath = [[NSBundle mainBundle]URLForResource:vshName withExtension:@"vsh"];
    NSURL *fragmentShaderPath = [[NSBundle mainBundle]URLForResource:fshName withExtension:@"fsh"];
    if (![self.shaderManager compileShader:&vertexShader type:GL_VERTEX_SHADER URL:vertexShaderPath]||!  [self.shaderManager compileShader:&fragmentShader type:GL_FRAGMENT_SHADER URL:fragmentShaderPath]){
      return ;
    }
  
    // 注意获取绑定属性要在连接程序之前 location 随便你写,如果你随便写请记住他，后面要用到
    [self.shaderManager   bindAttribLocation:GLKVertexAttribPosition   andAttribName:"position"];
    [self.shaderManager bindAttribLocation:GLKVertexAttribTexCoord0 andAttribName:"texCoord0"];
  
    // 将编译好的两个对象和着色器程序进行连接
    if(![self.shaderManager linkProgram]){
      [self.shaderManager deleteShader:&vertexShader];
      [self.shaderManager deleteShader:&fragmentShader];
    }
    _textureBufferY = [self.shaderManager   getUniformLocation:"sam2DY"];
    _textureBufferUV = [self.shaderManager getUniformLocation:"sam2DUV"];
    _modelViewProjectionMatrixIndex = [self.shaderManager getUniformLocation:"modelViewProjectionMatrix"];
  
    [self.shaderManager detachAndDeleteShader:&vertexShader];
    [self.shaderManager detachAndDeleteShader:&fragmentShader];
    // 启用着色器
    [self.shaderManager useProgram];
    }
  

// 上面的OSShaderManager 这个类，我把着色器程序编译链接的一些方法简单的封装了一下,具体的方向看下面

    /**
     *  编译shader程序
     *  @param shader shader名称
     *  @param type   shader 类型
     *  @param URL    shader 本地路径
     *  @return 是否编译成功
   */
    - (BOOL)compileShader:(GLuint *)shader type:(GLenum)type URL:(NSURL *)URL;
   /**
   *  连接程序
   *  @return 连接程序是否成功
   */
  - (BOOL)linkProgram;
  /**
   *  验证程序是否成功
   *  @param prog 程序标示
   *  @return 返回是否成功标志
   */
  - (BOOL)validateProgram;
  /**
   *  绑定着色器的属性
   *  @param index 属性在shader 程序的索引位置
   *  @param name  属性名称
   */
  - (void)bindAttribLocation:(GLuint)index andAttribName:  (GLchar*)name;
  /**
   *  删除shader
   */
  - (void)deleteShader:(GLuint*)shader;
  /**
   *  获取属性值索引位置
   *  @param name 属性名称
   *  @return 返回索引位置
   */
  - (GLint)getUniformLocation:(const GLchar*) name;
  /**
   * 释放, 删除shader
   *  @param shader 着色器名称
   */
  -(void)detachAndDeleteShader:(GLuint*)shader;
  /**
   *  使用程序
   */
  -(void)useProgram;

方法的具体实现请阅读工程文件

• 纹理采样器指向

  glUniform1i(_textureBufferY, 0); // 0 代表GL_TEXTURE0
  glUniform1i(_textureBufferUV, 1); // 1 代表GL_TEXTURE1
  

在这里我有必要提醒你，这两个方法，一定要放在着色器程序链接成功之后，不然你调用这个两个方法，没有效果。

• 如何将YUV 数据分离，并且加载到两个着色器中去, 这里我们又要用到之前我们使用过的框架了CoreVideo. 干涉么的呢，专门处理我们的像素数据的。我们从视频采集到的视频是CVPixelBufferRef 类型的
  下面我们先看一下我们像素数据的格式

    <CVPixelBuffer 0x7fa27962c9c0 width=2048     height=1024 pixelFormat=420v iosurface=0x0 planes=2>
    <Plane 0 width=2048 height=1024 bytesPerRow=2048>
    <Plane 1 width=1024 height=512 bytesPerRow=2048>
    <attributes=<CFBasicHash 0x7fa279623910 [0x10296ba40]>{type = immutable dict, count = 4,
    entries =>
  1 : <CFString 0x102d183b8 [0x10296ba40]>{contents = "PixelFormatType"} = <CFArray 0x7fa27c414bc0   [0x10296ba40]>{type = mutable-small, count = 1, values = (
  0 : <CFNumber 0xb000000343230763 [0x10296ba40]>{value = +875704438, type = kCFNumberSInt64Type}
  )}
  2 : <CFString 0x102d17e78 [0x10296ba40]>{contents = "Height"} = <CFNumber 0xb000000000004002 [0x10296ba40]>{value = +1024, type = kCFNumberSInt32Type}
  5 : <CFString 0x102d17d38 [0x10296ba40]>{contents = "PropagatedAttachments"} = <CFBasicHash 0x7fa27c51c590 [0x10296ba40]>{type = mutable dict, count = 4,
    entries =>
  0 : <CFString 0x102d18058 [0x10296ba40]>{contents = "CVImageBufferYCbCrMatrix"} = <CFString 0x102d18098 [0x10296ba40]>{contents = "ITU_R_601_4"}
  1 : <CFString 0x102d181b8 [0x10296ba40]>{contents = "CVImageBufferTransferFunction"} = <CFString 0x102d18078 [0x10296ba40]>{contents = "ITU_R_709_2"}
  2 : <CFString 0x106eadc88 [0x10296ba40]>{contents = "ColorInfoGuessedBy"} = <CFString 0x106eadca8 [0x10296ba40]>{contents = "VideoToolbox"}
  5 : <CFString 0x102d18138 [0x10296ba40]>{contents = "CVImageBufferColorPrimaries"} = <CFString 0x102d18178 [0x10296ba40]>{contents = "SMPTE_C"}
      }
  6 : <CFString 0x102d17e58 [0x10296ba40]>{contents = "Width"} = <CFNumber 0xb000000000008002 [0x10296ba40]>{value = +2048, type = kCFNumberSInt32Type}
      }
       propagatedAttachments=<CFBasicHash 0x7fa27962caa0 [0x10296ba40]>{type = mutable dict, count = 10,
      entries =>
  0 : <CFString 0x106eadc88 [0x10296ba40]>{contents = "ColorInfoGuessedBy"} = <CFString 0x106eadca8 [0x10296ba40]>{contents = "VideoToolbox"}
  1 : <CFString 0x102d18058 [0x10296ba40]>{contents = "CVImageBufferYCbCrMatrix"} = <CFString 0x102d18098 [0x10296ba40]>{contents = "ITU_R_601_4"}
  2 : <CFString 0x102d17ed8 [0x10296ba40]>{contents = "CVFieldCount"} = <CFNumber 0xb000000000000012 [0x10296ba40]>{value = +1, type = kCFNumberSInt32Type}
  3 : <CFString 0x102d17f98 [0x10296ba40]>{contents = "CVPixelAspectRatio"} = <CFBasicHash 0x7fa279728c10 [0x10296ba40]>{type = immutable dict, count = 2,
      entries =>
  1 : <CFString 0x102d17fb8 [0x10296ba40]>{contents = "HorizontalSpacing"} = <CFNumber 0xb000000000000012 [0x10296ba40]>{value = +1, type = kCFNumberSInt32Type}
  2 : <CFString 0x102d17fd8 [0x10296ba40]>{contents = "VerticalSpacing"} = <CFNumber 0xb000000000000012 [0x10296ba40]>{value = +1, type = kCFNumberSInt32Type}
      }
  4 : <CFString 0x102d17d78 [0x10296ba40]>{contents = "QTMovieTime"} = <CFBasicHash 0x7fa27c51db40 [0x10296ba40]>{type = immutable dict, count = 2,
      entries =>
  0 : <CFString 0x102d17d98 [0x10296ba40]>{contents = "TimeValue"} = <CFNumber 0xb000000000000003 [0x10296ba40]>{value = +0, type = kCFNumberSInt64Type}
  1 : <CFString 0x102d17db8 [0x10296ba40]>{contents = "TimeScale"} = <CFNumber 0xb000000000075302 [0x10296ba40]>{value = +30000, type = kCFNumberSInt32Type}
        }
  5 : <CFString 0x102d18138 [0x10296ba40]>{contents = "CVImageBufferColorPrimaries"} = <CFString 0x102d18178 [0x10296ba40]>{contents = "SMPTE_C"}
  8 : <CFString 0x102d181b8 [0x10296ba40]>{contents = "CVImageBufferTransferFunction"} = <CFString 0x102d18078 [0x10296ba40]>{contents = "ITU_R_709_2"}
  9 : <CFString 0x102d18318 [0x10296ba40]>{contents = "CVImageBufferChromaSubsampling"} = <CFString 0x102d18278 [0x10296ba40]>{contents = "TopLeft"}
  10 : <CFString 0x102d18218 [0x10296ba40]>{contents = "CVImageBufferChromaLocationBottomField"} = <CFString 0x102d18338 [0x10296ba40]>{contents = "4:2:0"}
  12 : <CFString 0x102d181f8 [0x10296ba40]>{contents = "CVImageBufferChromaLocationTopField"} = <CFString 0x102d18338 [0x10296ba40]>{contents = "4:2:0"}
      }
     nonPropagatedAttachments=<CFBasicHash 0x7fa27962ca60 [0x10296ba40]>{type = mutable dict, count = 0,
    entries =>
  }
  >
  

我们从上面的日志输出找到了下面的东西

    <CVPixelBuffer 0x7fa27962c9c0 width=2048     height=1024 pixelFormat=420v iosurface=0x0 planes=2>
    <Plane 0 width=2048 height=1024 bytesPerRow=2048>
    <Plane 1 width=1024 height=512 bytesPerRow=2048>

我们能得到的信息是:
像素格式: 420v
数据通道: 2 个
通道1: width=2048 height=1024
通道2: width=1024 height=512

从上面信息可以得出我们数据的排列方式为YY....YY....UV.....UV,
2048\1024 个Y 数据，1024\512 从 bytesPerRow 可以看出每个Y、U、V 各占一个字节.
接下来就是如何将数据加载到我们的纹理缓冲区去了

CVReturn CVOpenGLESTextureCacheCreateTextureFromImage(
CFAllocatorRef CV_NULLABLE allocator,
CVOpenGLESTextureCacheRef CV_NONNULL textureCache,
CVImageBufferRef CV_NONNULL sourceImage,
CFDictionaryRef CV_NULLABLE textureAttributes,
GLenum target,
GLint internalFormat,
GLsizei width,
GLsizei height,
GLenum format,
GLenum type,
size_t planeIndex,
CV_RETURNS_RETAINED_PARAMETER CVOpenGLESTextureRef CV_NULLABLE * CV_NONNULL textureOut ) 

这个函数作用是: 通过CVImageBufferRef 创建一个纹理对象
allocator : 写默认值就可以了 kCFAllocatorDefault
textureCache：我们需要手动创建一个纹理缓冲对象,
sourceImage：传我们的CVImageBufferRef 数据
textureAttributes：纹理属性，可以为NULL
target:纹理的类型(GL_TEXTURE_2D 和GL_RENDERBUFFER)
internalFormat:数据格式,就是这个数据步伐的意思
width：纹理的高度
height : 纹理的长度
format: 像素数据的格式
type: 数据类型
planeIndex: 通道索引

接下来看我们的代码:

 // 启用纹理缓冲区0
glActiveTexture(GL_TEXTURE0);
err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                                   _videoTextureCache,
                                                   pixelBuffer,
                                                   NULL,
                                                   GL_TEXTURE_2D,
                                                   GL_RED_EXT,
                                                   width,
                                                   height,
                                                   GL_RED_EXT,
                                                   GL_UNSIGNED_BYTE,
                                                   0,
                                                   &_lumaTexture);
if (err) {
    NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
    
}

glBindTexture(CVOpenGLESTextureGetTarget(_lumaTexture), CVOpenGLESTextureGetName(_lumaTexture));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

// UV-plane.
// 启用纹理缓冲区1
glActiveTexture(GL_TEXTURE1);
err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                                   _videoTextureCache,
                                                   pixelBuffer,
                                                   NULL,
                                                   GL_TEXTURE_2D,
                                                   GL_RG_EXT,
                                                   width /2,
                                                   height /2,
                                                   GL_RG_EXT,
                                                   GL_UNSIGNED_BYTE,
                                                   1,
                                                   &_chromaTexture);
if (err) {
    NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
}


glBindTexture(CVOpenGLESTextureGetTarget(_chromaTexture), CVOpenGLESTextureGetName(_chromaTexture));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

GL_RED_EXT 代表 1位数据 GL_RG_EXT 代表2位数据 。UV 就是两位数据 所以我们选择GL_RG_EXT。

刚才说了，参数中需要一个纹理缓冲TextureCacha,接下来我们就自己创建一个.

  CVReturn err = CVOpenGLESTextureCacheCreate(kCFAllocatorDefault, NULL, self.eagContext, NULL, &_videoTextureCache);

以上基本的工作都做完了，接下来，我们就只剩下显示了

• 渲染绘制

    // 清除颜色缓冲区
    glClearColor(0, 0, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);
    if (_isVR){
    // 渲染双屏
    glViewport(0, 0, self.view.bounds.size.width, self.view.bounds.size.height*2);
    glDrawElements(GL_TRIANGLES, _numIndices, GL_UNSIGNED_SHORT, 0);
    glViewport(self.view.bounds.size.width, 0, self.view.bounds.size.width, self.view.bounds.size.height*2);
    glDrawElements(GL_TRIANGLES, _numIndices, GL_UNSIGNED_SHORT, 0);
    }else{
    // 渲染单屏
    glViewport(0, 0, self.view.bounds.size.width*2, self.view.bounds.size.height*2);
    glDrawElements(GL_TRIANGLES, _numIndices, GL_UNSIGNED_SHORT, 0);
    }
  

到这里,视频已经可以显示了。

• 视图矩阵初始化

  -(void)initModelViewProjectMatrix{
  // 创建投影矩阵
  float aspect = fabs(self.view.bounds.size.width / self.view.bounds.size.height);
  _projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(OSVIEW_CORNER), aspect, 0.1f, 400.0f);
  _projectionMatrix = GLKMatrix4Rotate(_projectionMatrix, ES_PI, 1.0f, 0.0f, 0.0f);
  
  // 创建模型矩阵
  _modelViewMatrix = GLKMatrix4Identity;
  float scale = OSSphereScale;
  _modelViewMatrix = GLKMatrix4Scale(_modelViewMatrix, scale, scale, scale);
  
  // 最终传入到GLSL中去的矩阵
  _modelViewProjectionMatrix = GLKMatrix4Multiply(_projectionMatrix, _modelViewMatrix);
  glUniformMatrix4fv(_modelViewProjectionMatrixIndex, 1, GL_FALSE, _modelViewProjectionMatrix.m);
  }
  

• 全景单屏模式
  手势操纵矩阵

  - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  if(self.isVR || self.vedioType == OSNormal ) return;
  UITouch *touch = [touches anyObject];
  float distX = [touch locationInView:touch.view].x - [touch previousLocationInView:touch.view].x;
  float distY = [touch locationInView:touch.view].y - [touch previousLocationInView:touch.view].y;
  distX *= -0.005;
  distY *= -0.005;
  self.fingerRotationX += distY *  OSVIEW_CORNER / 100;
  self.fingerRotationY -= distX *  OSVIEW_CORNER / 100;
  _modelViewMatrix = GLKMatrix4Identity;
  float scale = OSSphereScale;
  _modelViewMatrix = GLKMatrix4Scale(_modelViewMatrix, scale, scale, scale);
  _modelViewMatrix = GLKMatrix4RotateX(_modelViewMatrix, self.fingerRotationX);
  _modelViewMatrix = GLKMatrix4RotateY(_modelViewMatrix, self.fingerRotationY);
  _modelViewProjectionMatrix = GLKMatrix4Multiply(_projectionMatrix, _modelViewMatrix);
  glUniformMatrix4fv(_modelViewProjectionMatrixIndex, 1, GL_FALSE, _modelViewProjectionMatrix.m);
  }
  
  - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent   *)event {
    if (self.isVR || self.vedioType == OSNormal) return;
    for (UITouch *touch in touches) {
    [self.currentTouches removeObject:touch];
    }
  }
  - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
  for (UITouch *touch in touches) {
    [self.currentTouches removeObject:touch];
  }
  }
  

• 全景 VR模式
  使用角度传感器

  -(void)startMotionManager{
  self.motionManager = [[CMMotionManager alloc]init];
  self.motionManager.deviceMotionUpdateInterval = 1.0 / 60.0;
  self.motionManager.gyroUpdateInterval = 1.0f / 60;
  self.motionManager.showsDeviceMovementDisplay = YES;
  [self.motionManager startDeviceMotionUpdatesUsingReferenceFrame:CMAttitudeReferenceFrameXArbitraryCorrectedZVertical];
  self.referenceAttitude = nil;
  [self.motionManager startGyroUpdatesToQueue: [[NSOperationQueue alloc]init] withHandler:^(CMGyroData * _Nullable gyroData, NSError * _Nullable error) {
   if(self.isVR) {
    
      [self calculateModelViewProjectMatrixWithDeviceMotion:self.motionManager.deviceMotion];
    }
    
  }];
  self.referenceAttitude = self.motionManager.deviceMotion.attitude;
  }
  -(void)calculateModelViewProjectMatrixWithDeviceMotion:(CMDeviceMotion*)deviceMotion{
  
  _modelViewMatrix = GLKMatrix4Identity;
  float scale = OSSphereScale;
  _modelViewMatrix = GLKMatrix4Scale(_modelViewMatrix, scale, scale, scale);
    if (deviceMotion != nil) {
        CMAttitude *attitude = deviceMotion.attitude;
        
        if (self.referenceAttitude != nil) {
            [attitude multiplyByInverseOfAttitude:self.referenceAttitude];
            
        } else {
            self.referenceAttitude = deviceMotion.attitude;
        }
        
        float cRoll = attitude.roll;
        float cPitch = attitude.pitch;
        
        _modelViewMatrix = GLKMatrix4RotateX(_modelViewMatrix, -cRoll);
        _modelViewMatrix = GLKMatrix4RotateY(_modelViewMatrix, -cPitch*3);
  
        _modelViewProjectionMatrix = GLKMatrix4Multiply(_projectionMatrix, _modelViewMatrix);
        // 下边这个方法必须在主线程中完成.
        dispatch_async(dispatch_get_main_queue(), ^{
             glUniformMatrix4fv(_modelViewProjectionMatrixIndex, 1, GL_FALSE, _modelViewProjectionMatrix.m);
        });
    }}
  

操作矩阵这里，暂时不想讲,后面我会专门来讲矩阵变换和角度传感器的使用,因为这两个东西在游戏和VR,还是AR的世界,都太重要了。今天先说的这里，给几张展示图欣赏一下。

全景模式下
普通视频 普通视频双屏展示 全景视频VR模式 全景.gif

需要代码在这里和这里

全景播放器-实现方案2

使用SceneKit 也可以实现全景播放器,需要了解的朋友请查看这里

加群了