//传入结构体

typedef struct {

    float Position[];

    float TexCoord[];

} Vertex;

//顶点数据

const Vertex Vertices[] = {

    {{, -, }, {, }},

    {{, , },{, }},

    {{-, , }, {, }},

    {{-, -, },{, }},

};

//顶点索引

const GLubyte Indices[] = {

    , , ,

    , ,

};

+ (GLuint)setupTexture:(UIImage *)pImage {

    CGImageRef spriteImage = pImage.CGImage;

    if (!spriteImage) {

        NSLog(@"Failed to load image ");

        exit();

    }

    size_t width = CGImageGetWidth(spriteImage);

    size_t height = CGImageGetHeight(spriteImage); 

    GLubyte * spriteData = (GLubyte *) calloc(width*height*, sizeof(GLubyte));

    CGContextRef spriteContext = CGBitmapContextCreate(spriteData, width, height, , width*,

                                                       CGImageGetColorSpace(spriteImage), kCGImageAlphaPremultipliedLast);

    CGContextDrawImage(spriteContext, CGRectMake(, , width, height), spriteImage);

    CGContextRelease(spriteContext);

    GLuint texName;

    //生成纹理数

    glGenTextures(, &texName);

    glBindTexture(GL_TEXTURE_2D, texName);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    //生成图片纹理

    glTexImage2D(GL_TEXTURE_2D, , GL_RGBA, width, height, , GL_RGBA, GL_UNSIGNED_BYTE, spriteData);

    free(spriteData);

    return texName;

}

 //获得图片纹理索引

 _imageTexture = [OpenGLHelper setupTexture:pImage];

//获得在GLSL中纹理的索引

   _texCoordSlot = glGetAttribLocation(_programHandle, "TexCoordIn");

    glEnableVertexAttribArray(_texCoordSlot);

    _textureUniform = glGetUniformLocation(_programHandle, "Texture");

//获得GLSL中顶点的索引

   _positionSlot = glGetAttribLocation(_programHandle, "vPosition");

     //传入顶点着色器的数据

    glVertexAttribPointer(_positionSlot, , GL_FLOAT, GL_FALSE,

                          sizeof(Vertex), );

    glVertexAttribPointer(_texCoordSlot, , GL_FLOAT, GL_FALSE,

                          sizeof(Vertex), (GLvoid*) (sizeof(float) *

                                                     ));

    glActiveTexture(GL_TEXTURE0);

    glBindTexture(GL_TEXTURE_2D, _imageTexture);

    glUniform1i(_textureUniform, );

    // 设置边缘截取模式  防止图片读取有问题

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[]),

                   GL_UNSIGNED_BYTE, );