Image IO - iOS Core Animation - page 314

//check success
if ( glCheckFramebufferStatus ( GL_FRAMEBUFFER ) != GL_FRAMEBUFFER_COMPLETE )
{
NSLog ( @"Failed to make complete framebuffer object: %i" ,
glCheckFramebufferStatus ( GL_FRAMEBUFFER ));
}
}
- ( void )tearDownBuffers
{
if ( _framebuffer )
{
//delete framebuffer
glDeleteFramebuffers ( 1 , & _framebuffer );
_framebuffer = 0 ;
}
if ( _colorRenderbuffer )
{
//delete color render buffer
glDeleteRenderbuffers ( 1 , & _colorRenderbuffer );
_colorRenderbuffer = 0 ;
}
}
- ( void )drawFrame
{
//bind framebuffer & set viewport
glBindFramebuffer ( GL_FRAMEBUFFER , _framebuffer );
glViewport ( 0 , 0 , _framebufferWidth , _framebufferHeight );
//bind shader program
[ self . effect prepareToDraw ];
//clear the screen
glClear ( GL_COLOR_BUFFER_BIT );
glClearColor ( 0.0 , 0.0 , 0.0 , 0.0 );
//set up vertices
GLfloat vertices[] =
{
- 1.0f , - 1.0f ,
- 1.0f , 1.0f ,
1.0f , 1.0f ,
1.0f , - 1.0f
};