SoundEffect 为画笔添加系统提示声音

1.初始化系统声音方法
    +(id)soundEffectWithContentsOfFile:(NSString *)aPath
    -(id)initWithContentsOfFile:(NSString *)path

2.播放系统声音方法
    -(void)play

3.释放声音资源
    -(void)dealloc

DrawingBoardVC 实现UI，并切换画笔颜色、清空屏幕事件

1.实现UI、添加事件按钮
    - (void)setUpUI
3.清理屏幕 
    - (IBAction)earse:(id)sender 
  播放系统声音并抹去视图
    - (void)eraseView
  调用PaintView中的erase⽅方法

2.修改画笔颜色，选择控制器事件响应 
    -(void)changBrushColor:(id)sender
   调用PaintView 中的- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue

PaintView 实现绘制、修改画笔颜色、 清空屏幕等事件

1.初始化PaintView
    initWithCoder:(NSCoder *)aDecoder

2.-(void)layoutSubviews
    没有初始化initialized 绘制”加 油!”
        -(BOOL)initGL 
        手写着⾊器程序
            pointv.vsh
            pointf.fsh
        加载纹理 - (textureInfo_t)textureFromName:(NSString *)name
        加载Shader - (void)setupShaders
        绘制已经存储顶点的”加油” -(void)paint
        在2点之间绘制线条 -(void)renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end
    已经初始化
        - (BOOL)resizeFromLayer:(CAEAGLLayer *)layer
   
3.修改画笔颜⾊
    - (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue

 4.清理屏幕
    -(void)erase

5.开始绘制(任意图形、线条)
    -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
    -(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event 
        将2点绘制成线条 
            -(void)renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end
    -(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event 
        将2点绘制成线条
            -(void)renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end
    -(void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event

Demo: 05-OpenGLES画板