OpenGl ES iPhone, strange line

I have a strange problem. Sometimes it happens, sometimes it doesn't.

I have an array of GLfloat with 8 items. When EAGLView draw it, it shows the two lines of the array, but also an additional line.

EAGLView.m

+ (Class)layerClass {
    return [CAEAGLLayer class];
}

- (id)initWithCoder:(NSCoder*)coder {


    if ((self = [super initWithCoder:coder])) {
        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;

        eaglLayer.opaque = NO;
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:NO], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLD开发者_C百科rawablePropertyColorFormat, nil];

        context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

        if (!context || ![EAGLContext setCurrentContext:context]) {
            [self release];
            return nil;
        }


    }
    return self;
}


- (void)drawView {

    int numero=malloc_size(puntosPintar)/sizeof(GLfloat);

    [EAGLContext setCurrentContext:context];

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glViewport(0, 0, backingWidth, backingHeight);    

    glClear(GL_COLOR_BUFFER_BIT);

    glVertexPointer(2, GL_FLOAT, 0, puntosPintar);

    glEnableClientState(GL_VERTEX_ARRAY);

    glColor4f(1,1,1,1);

    glDrawArrays(GL_LINES, 0, numero);

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];

    free(puntosPintar);
}


- (void)layoutSubviews {
    [EAGLContext setCurrentContext:context];

    [self destroyFramebuffer];
    [self createFramebuffer];
    [self drawView];
}


- (BOOL)createFramebuffer {

    glGenFramebuffersOES(1, &viewFramebuffer);
    glGenRenderbuffersOES(1, &viewRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)self.layer];
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);

    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
    if (USE_DEPTH_BUFFER) {
        glGenRenderbuffersOES(1, &depthRenderbuffer);
        glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
        glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
        glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);
    }



    if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {
        NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
        return NO;
    }


    return YES;
}


- (void)destroyFramebuffer {

    glDeleteFramebuffersOES(1, &viewFramebuffer);
    viewFramebuffer = 0;
    glDeleteRenderbuffersOES(1, &viewRenderbuffer);
    viewRenderbuffer = 0;

    if(depthRenderbuffer) {
        glDeleteRenderbuffersOES(1, &depthRenderbuffer);
        depthRenderbuffer = 0;
    }
}



- (void)dealloc {


    if ([EAGLContext currentContext] == context) {
        [EAGLContext setCurrentContext:nil];
    }

    [context release];  
    [super dealloc];
}

@end

puntosPintar

puntosPintar=(GLfloat*)malloc(sizeof(GLfloat)*8);
    puntosPintar[0] = -0.25f;
    puntosPintar[1] = -1.49f;
    puntosPintar[2] = -0.1f;
    puntosPintar[3] = 0.0f;
    puntosPintar[4] = 0.25f;
    puntosPintar[5] = -1.49f;
    puntosPintar[6] = 0.1f;
    puntosPintar[7] = 0.0f;

You should be passing '4' into the count argument of glDrawArrays, not 8 (this is the count of vertexes, not the count of floats).