OpenGLES Video Texture渲染出错

Question

第一次用OpenGLES，在iOS端开发一个应用，须要实时渲染摄像头数据，写出来以后发现图像宽度不对，旁边出了四个灰度的原图。

代码大致如下：

shader：

const char* box_video_vert="uniform mat4 trans;\n"
"uniform mat4 proj;\n"
"attribute vec4 coord;\n"
"attribute vec2 texcoord;\n"
"varying vec2 vtexcoord;\n"
"\n"
"void main(void)\n"
"{\n"
"    vtexcoord = texcoord;\n"
"    gl_Position = proj*trans*coord;\n"
"}\n"
"\n"
;

const char* box_video_frag="#ifdef GL_ES\n"
"precision highp float;\n"
"#endif\n"
"varying vec2 vtexcoord;\n"
"uniform sampler2D texture;\n"
"\n"
"void main(void)\n"
"{\n"
"    vec4 color = texture2D(texture, vtexcoord);\n"
"    gl_FragColor = vec4(color[2],color[1],color[0],color[3]);\n"
"}\n"
"\n"
;

setup opengl 环境

    _eaglLayer = (CAEAGLLayer*) self.layer;
    _eaglLayer.opaque = YES;

    EAGLRenderingAPI api = kEAGLRenderingAPIOpenGLES2;
    _context = [[EAGLContext alloc] initWithAPI:api];
    if (!_context)
        NSLog(@"Failed to initialize OpenGLES 2.0 context");
    if (![EAGLContext setCurrentContext:_context])
        NSLog(@"Failed to set current OpenGL context");

    GLuint frameBuffer;
    glGenFramebuffers(1, &frameBuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);

    glGenRenderbuffers(1, &_colorRenderBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, _colorRenderBuffer);
    [_context renderbufferStorage:GL_RENDERBUFFER fromDrawable:_eaglLayer];
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _colorRenderBuffer);

    int width, height;
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &width);
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &height);

    GLuint depthRenderBuffer;
    glGenRenderbuffers(1, &depthRenderBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, depthRenderBuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, width, height);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderBuffer);
    
    program_box = glCreateProgram();
    GLuint vertShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertShader, 1, &box_video_vert, 0);
    glCompileShader(vertShader);
    GLuint fragShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragShader, 1, &box_video_frag, 0);
    glCompileShader(fragShader);
    glAttachShader(program_box, vertShader);
    glAttachShader(program_box, fragShader);
    
    glLinkProgram(program_box);
    glUseProgram(program_box);
    pos_coord_box = glGetAttribLocation(program_box, "coord");
    pos_tex_box = glGetAttribLocation(program_box, "texcoord");
    pos_trans_box = glGetUniformLocation(program_box, "trans");
    pos_proj_box = glGetUniformLocation(program_box, "proj");
    TextureID = glGetUniformLocation(program_box, "texture");
    
    glGenBuffers(1, &vbo_coord_box);
    glBindBuffer(GL_ARRAY_BUFFER, vbo_coord_box);
    const GLfloat cube_vertices[4][3] = {{1.0f, 1.0f, 0.f},{1.0f, -1.0f, 0.f},{-1.0f, -1.0f, 0.f}, {-1.0f, 1.0f, 0.f}};
    glBufferData(GL_ARRAY_BUFFER, sizeof(cube_vertices), cube_vertices, GL_DYNAMIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    
    glGenBuffers(1, &vbo_tex_box);
    glBindBuffer(GL_ARRAY_BUFFER, vbo_tex_box);
    const GLubyte cube_vertex_texs[4][2] = {{0, 0},{1, 0},{1, 1},{0, 1}};
    glBufferData(GL_ARRAY_BUFFER, sizeof(cube_vertex_texs), cube_vertex_texs, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    
    glGenBuffers(1, &vbo_faces_box);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbo_faces_box);
    const GLushort cube_faces[] = {3, 0, 1, 2};
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(cube_faces), cube_faces, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    
    glUniform1i(TextureID, 0);
    glGenTextures(1, &texture_id);
    glBindTexture(GL_TEXTURE_2D, texture_id);
    
    glHint(GL_GENERATE_MIPMAP_HINT, GL_NICEST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

渲染逻辑：

    if (!((AppDelegate*)[[UIApplication sharedApplication]delegate]).active)
            return;
    
    videoDimensions = videoTexture.videoDimensions;
    memcpy(bwImage,videoTexture->bwImage,640*480*4);
 
    int width = self.frame.size.width;
    int height = self.frame.size.height;
    
    glClearColor(0.f, 0.f, 0.f, 1.f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glViewport(0, 0, width, height);
    glBindTexture(GL_TEXTURE_2D, texture_id);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, videoDimensions.width, videoDimensions.height,0, GL_RGBA, GL_UNSIGNED_BYTE, bwImage);
    glBindTexture(GL_TEXTURE_2D, 0);

    glm::mat4 cameraview, projectionMatrix;
    
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_DEPTH_TEST);
    glEnableVertexAttribArray(pos_coord_box);
    glEnableVertexAttribArray(pos_tex_box);
    glUseProgram(program_box);

    glBindBuffer(GL_ARRAY_BUFFER, vbo_coord_box);
    glVertexAttribPointer(pos_coord_box, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    
    glBindBuffer(GL_ARRAY_BUFFER, vbo_tex_box);
    glVertexAttribPointer(pos_tex_box, 2, GL_UNSIGNED_BYTE, GL_FALSE, 0, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    
    glUniformMatrix4fv(pos_trans_box, 1, 0, glm::value_ptr(cameraview));
    glUniformMatrix4fv(pos_proj_box, 1, 0, glm::value_ptr(projectionMatrix));
    
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbo_faces_box);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture_id);
    glUniform1i(TextureID, 0);
    
    glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, 0);
    glBindTexture(GL_TEXTURE_2D, 0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    glDisableVertexAttribArray(pos_coord_box);
    glDisableVertexAttribArray(pos_tex_box);
    
    (void)displayLink;
    glBindRenderbuffer(GL_RENDERBUFFER, _colorRenderBuffer);
    [_context presentRenderbuffer:GL_RENDERBUFFER];

自己检查了好多遍，感觉没问题，glview也没错6s下375*667，摄像头数据也拿到了，结果就是不对。我哪里细节出错了吗，只在这些地方用到OpenGLES的东西。身边没有这方面的人询问，跪求渲染大神抢救。