Drawing to a Window or View

MyOpenGLView.h

#import <Cocoa/Cocoa.h>

@interface MyOpenGLView : NSOpenGLView
{
}
- (void) drawRect: (NSRect) bounds;
@end

MyOpenGLView.m

#import "MyOpenGLView.h"
#include <OpenGL/gl.h>

@implementation MyOpenGLView{

}

static void drawAnObject ()
{
    glColor3f(1.0f, 0.85f, 0.35f);
    glBegin(GL_TRIANGLES);
    {
        glVertex3f(  0.0,  0.6, 0.0);
        glVertex3f( -0.2, -0.3, 0.0);
        glVertex3f(  0.2, -0.3 ,0.0);
    }
    glEnd();
}

-(void) drawRect: (NSRect) bounds{
    glClearColor(0, 0, 0, 0);
    glClear(GL_COLOR_BUFFER_BIT);
    drawAnObject();
    glFlush();
}

@end