/*

     File: MyOpenGLView.m

 Abstract:  An NSView subclass that delegates to separate "scene" 

 and "controller" objects for OpenGL rendering and input event handling.

  Version: 1.1

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*/

#import "MyOpenGLView.h"

#import "MainController.h"

#import "Scene.h"

@implementation MyOpenGLView

- (NSOpenGLContext*) openGLContext

{

    return openGLContext;

}

- (NSOpenGLPixelFormat*) pixelFormat

{

    return pixelFormat;

}

- (void) setMainController:(MainController*)theController;

{

    controller = theController;

}

- (CVReturn) getFrameForTime:(const CVTimeStamp*)outputTime

{

    // There is no autorelease pool when this method is called because it will be called from a background thread

    // It's important to create one or you will leak objects

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    // Update the animation

    CFAbsoluteTime currentTime = CFAbsoluteTimeGetCurrent();

    [[controller scene] advanceTimeBy:(currentTime - [controller renderTime])];

    [controller setRenderTime:currentTime];

    [self drawView];

    [pool release];

    return kCVReturnSuccess;

}

// This is the renderer output callback function

static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp* now, const CVTimeStamp* outputTime, CVOptionFlags flagsIn, CVOptionFlags* flagsOut, void* displayLinkContext)

{

    CVReturn result = [(MyOpenGLView*)displayLinkContext getFrameForTime:outputTime];

    return result;

}

- (void) setupDisplayLink

{

    // Create a display link capable of being used with all active displays

    CVDisplayLinkCreateWithActiveCGDisplays(&displayLink);

    // Set the renderer output callback function

    CVDisplayLinkSetOutputCallback(displayLink, &MyDisplayLinkCallback, self);

    // Set the display link for the current renderer

    CGLContextObj cglContext = [[self openGLContext] CGLContextObj];

    CGLPixelFormatObj cglPixelFormat = [[self pixelFormat] CGLPixelFormatObj];

    CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(displayLink, cglContext, cglPixelFormat);

}

- (id) initWithFrame:(NSRect)frameRect shareContext:(NSOpenGLContext*)context

{

    NSOpenGLPixelFormatAttribute attribs[] =

    {

        kCGLPFAAccelerated,

        kCGLPFANoRecovery,

        kCGLPFADoubleBuffer,

        kCGLPFAColorSize, 24,

        kCGLPFADepthSize, 16,

        0

    };

    pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attribs];

    if (!pixelFormat)

        NSLog(@"No OpenGL pixel format");

    // NSOpenGLView does not handle context sharing, so we draw to a custom NSView instead

    openGLContext = [[NSOpenGLContext alloc] initWithFormat:pixelFormat shareContext:context];

    if (self = [super initWithFrame:frameRect]) {

        [[self openGLContext] makeCurrentContext];

        // Synchronize buffer swaps with vertical refresh rate

        GLint swapInt = 1;

        [[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval]; 

        [self setupDisplayLink];

        // Look for changes in view size

        // Note, -reshape will not be called automatically on size changes because NSView does not export it to override 

        [[NSNotificationCenter defaultCenter] addObserver:self 

                                                 selector:@selector(reshape) 

                                                     name:NSViewGlobalFrameDidChangeNotification

                                                   object:self];

    }

    return self;

}

- (id) initWithFrame:(NSRect)frameRect

{

    self = [self initWithFrame:frameRect shareContext:nil];

    return self;

}

- (void) lockFocus

{

    [super lockFocus];

    if ([[self openGLContext] view] != self)

        [[self openGLContext] setView:self];

}

- (void) reshape

{

    // This method will be called on the main thread when resizing, but we may be drawing on a secondary thread through the display link

    // Add a mutex around to avoid the threads accessing the context simultaneously

    CGLLockContext([[self openGLContext] CGLContextObj]);

    // Delegate to the scene object to update for a change in the view size

    [[controller scene] setViewportRect:[self bounds]];

    [[self openGLContext] update];

    CGLUnlockContext([[self openGLContext] CGLContextObj]);

}

- (void) drawRect:(NSRect)dirtyRect

{

    // Ignore if the display link is still running

    if (!CVDisplayLinkIsRunning(displayLink))

        [self drawView];

}

- (void) drawView

{

    // This method will be called on both the main thread (through -drawRect:) and a secondary thread (through the display link rendering loop)

    // Also, when resizing the view, -reshape is called on the main thread, but we may be drawing on a secondary thread

    // Add a mutex around to avoid the threads accessing the context simultaneously

    CGLLockContext([[self openGLContext] CGLContextObj]);

    // Make sure we draw to the right context

    [[self openGLContext] makeCurrentContext];

    // Delegate to the scene object for rendering

    [[controller scene] render];

    [[self openGLContext] flushBuffer];

    CGLUnlockContext([[self openGLContext] CGLContextObj]);

}

- (BOOL) acceptsFirstResponder

{

    // We want this view to be able to receive key events

    return YES;

}

- (void) keyDown:(NSEvent *)theEvent

{

    // Delegate to the controller object for handling key events

    [controller keyDown:theEvent];

}

- (void)mouseDown:(NSEvent *)theEvent

{

    // Delegate to the controller object for handling mouse events

    [controller mouseDown:theEvent];

}

- (void) startAnimation

{

    if (displayLink && !CVDisplayLinkIsRunning(displayLink))

        CVDisplayLinkStart(displayLink);

}

- (void) stopAnimation

{

    if (displayLink && CVDisplayLinkIsRunning(displayLink))

        CVDisplayLinkStop(displayLink);

}

- (void) dealloc

{

    // Stop and release the display link

    CVDisplayLinkStop(displayLink);

    CVDisplayLinkRelease(displayLink);

    // Destroy the context

    [openGLContext release];

    [pixelFormat release];

    [[NSNotificationCenter defaultCenter] removeObserver:self 

                                                    name:NSViewGlobalFrameDidChangeNotification

                                                  object:self];

    [super dealloc];

}   

@end