GLuint vertexBufferID;

 glGenBuffers(,  &vertexBufferID);

   glBindBuffer(GL_ARRAY_BUFFER, vertexBufferID);

   glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices,  GL_STATIC_DRAW); 

glEnableVertexAttribArray(GLKVertexAttribPosition);

   glVertexAttribPointer(

      GLKVertexAttribPosition,

      ,

      GL_FLOAT,

      GL_FALSE,

      sizeof(SceneVertex),

      NULL);    

   glDrawArrays(GL_TRIANGLES, ,); 

@interface OpenGLESViewController : GLKViewController

{

   GLuint vertexBufferID;

}

@property (strong, nonatomic) GLKBaseEffect *baseEffect;

@end

#import "OpenGLESViewController.h"

@implementation OpenGLESViewController

@synthesize baseEffect;

/////////////////////////////////////////////////////////////////

// This data type is used to store information for each vertex

typedef struct {

   GLKVector3  positionCoords;

}

SceneVertex;

// Define vertex data for a triangle to use in example

static const SceneVertex vertices[] =

{

   {{-0.5f, -0.5f, 0.0}}, // lower left corner

   {{ 0.5f, -0.5f, 0.0}}, // lower right corner

   {{-0.5f,  0.5f, 0.0}}  // upper left corner

};

/////////////////////////////////////////////////////////////////

// Called when the view controller's view is loaded

// Perform initialization before the view is asked to draw

- (void)viewDidLoad

{

   [super viewDidLoad];

   // Verify the type of view created automatically by the

   // Interface Builder storyboard

   GLKView *view = (GLKView *)self.view;

   NSAssert([view isKindOfClass:[GLKView class]],

      @"View controller's view is not a GLKView");

   // Create an OpenGL ES 2.0 context and provide it to the

   // view

   view.context = [[EAGLContext alloc]

      initWithAPI:kEAGLRenderingAPIOpenGLES2];

   // Make the new context current

   [EAGLContext setCurrentContext:view.context];

   // Create a base effect that provides standard OpenGL ES 2.0

   // Shading Language programs and set constants to be used for

   // all subsequent rendering

   self.baseEffect = [[GLKBaseEffect alloc] init];

   self.baseEffect.useConstantColor = GL_TRUE;

   self.baseEffect.constantColor = GLKVector4Make(

      1.0f, // Red

      1.0f, // Green

      1.0f, // Blue

      1.0f);// Alpha

   // Set the background color stored in the current context

   glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // background color

   // Generate, bind, and initialize contents of a buffer to be

   // stored in GPU memory

   glGenBuffers(,                // STEP 1

      &vertexBufferID);

   glBindBuffer(GL_ARRAY_BUFFER,  // STEP 2

      vertexBufferID);

   glBufferData(                  // STEP 3

      GL_ARRAY_BUFFER,  // Initialize buffer contents

      sizeof(vertices), // Number of bytes to copy

      vertices,         // Address of bytes to copy

      GL_STATIC_DRAW);  // Hint: cache in GPU memory

}

/////////////////////////////////////////////////////////////////

// GLKView delegate method: Called by the view controller's view

// whenever Cocoa Touch asks the view controller's view to

// draw itself. (In this case, render into a frame buffer that

// shares memory with a Core Animation Layer)

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect

{

   [self.baseEffect prepareToDraw];

   // Clear Frame Buffer (erase previous drawing)

   glClear(GL_COLOR_BUFFER_BIT);

   // Enable use of positions from bound vertex buffer

   glEnableVertexAttribArray(      // STEP 4

      GLKVertexAttribPosition);

   glVertexAttribPointer(          // STEP 5

      GLKVertexAttribPosition,

      ,                   // three components per vertex

      GL_FLOAT,            // data is floating point

      GL_FALSE,            // no fixed point scaling

      sizeof(SceneVertex), // no gaps in data

      NULL);               // NULL tells GPU to start at

                           // beginning of bound buffer

   // Draw triangles using the first three vertices in the

   // currently bound vertex buffer

   glDrawArrays(GL_TRIANGLES,      // STEP 6

      ,  // Start with first vertex in currently bound buffer

      ); // Use three vertices from currently bound buffer

}

/////////////////////////////////////////////////////////////////

// Called when the view controller's view has been unloaded

// Perform clean-up that is possible when you know the view

// controller's view won't be asked to draw again soon.

- (void)viewDidUnload

{

   [super viewDidUnload];

   // Make the view's context current

   GLKView *view = (GLKView *)self.view;

   [EAGLContext setCurrentContext:view.context];

   // Delete buffers that aren't needed when view is unloaded

   if ( != vertexBufferID)

   {

      glDeleteBuffers (,          // STEP 7

                       &vertexBufferID);

      vertexBufferID = ;

   }

   // Stop using the context created in -viewDidLoad

   ((GLKView *)self.view).context = nil;

   [EAGLContext setCurrentContext:nil];

}

@end