IOS OpenGLES, video is cut when landscape mode - ios

Question

my app(ios8.0) is render streaming video in GLKViewController with Opengl-es
i have a problem that video is cut when landscape mode
problem capture: http://i.stack.imgur.com/3SrpF.png
maybe.. i need scaling texture, use vertex shader.
typedef struct {
float Position[3];
float Color[4];
float TexCoordp[2];
} Vertex;
const Vertex Vertices[] = {
{{1, -1, 0}, {1, 1, 1, 1}, {1, 1}},
{{1, 1, 0}, {1, 1, 1, 1}, {1, 0}},
{{-1, 1, 0}, {1, 1, 1, 1}, {0, 0}},
{{-1, -1, 0}, {1, 1, 1, 1}, {0, 1}}
};
const GLubyte Indices[] = {
0, 1, 2,
2, 3, 0
};
#pragma mark - shaders
#define STRINGIZE(x) #x
#define STRINGIZE2(x) STRINGIZE(x)
#define SHADER_STRING(text) # STRINGIZE2(text)
NSString *const vertexShaderString = SHADER_STRING
(
attribute vec4 Position; // 1
attribute vec4 SourceColor; // 2
varying vec4 DestinationColor; // 3
attribute vec2 TexCoordIn;
varying vec2 TexCoordOut;
void main(void) { // 4
DestinationColor = SourceColor; // 5
gl_Position = Position; // 6
TexCoordOut = TexCoordIn; // New
}
);
setup GL Code
- (void)setupGL
{
[EAGLContext setCurrentContext:self.context];
glGenBuffers(1, &_vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);
glGenBuffers(1, &_indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);
// init the update render semaphore
_textureUpdateRenderSemaphore = dispatch_semaphore_create((long)1);
}
maybe i need change "Vertices", but i can't get any clue.
thank you so much for your help