VideoMixView.m

/*
 
File: VideoMixView.m
 
Abstract:   The VideoMixView is a subclass of NSOpenGLView.
        Here you find the code for the view interaction as
        well as the setup of the OpenGL context with the
        setting up of the OpenGL state.
 
Version: 1.0
 
© Copyright 2005 Apple Computer, Inc. All rights reserved.
 
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*/ 
 
#import "VideoMixView.h"
#import <OpenGL/gl.h>
#import <OpenGL/glext.h>
#import "LiveVideoMixerController.h"
 
@implementation VideoMixView
 
 
//--------------------------------------------------------------------------------------------------
 
- (void)awakeFromNib
{
    pthread_mutexattr_t attr;
    
    pthread_mutexattr_init(&attr);
    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);  // the recursive thread allows us to aquire the same lock again from the same thread
                                // but still lock against another thread
 
    pthread_mutex_init(&drawingLock, &attr);
        
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)setupSharedContext
{
    sharedContext = [[NSOpenGLContext alloc] initWithFormat:[NSOpenGLView defaultPixelFormat] shareContext:nil];
    
    [self setOpenGLContext:[[[NSOpenGLContext alloc] initWithFormat:[NSOpenGLView defaultPixelFormat] shareContext:sharedContext] autorelease]];
    [[self openGLContext] setView:self];
}
 
//--------------------------------------------------------------------------------------------------
- (NSOpenGLContext*)sharedContext
{
    return sharedContext;
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)dealloc
{
    pthread_mutex_destroy(&drawingLock);
    [super dealloc];
}
 
//--------------------------------------------------------------------------------------------------
//--------------------------------------------------------------------------------------------------
 
- (BOOL)isFlipped
{
    return YES;
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)lock
{
    pthread_mutex_lock(&drawingLock);
    if(contextIsInitialized)
        [[self openGLContext] makeCurrentContext];
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)unlock
{
    pthread_mutex_unlock(&drawingLock);
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)update
{
    // The NSOpenGLView issues OpenGL calls in its update method. Therefore it is important to lock
    // around this call as it would otherwise run in conflict with our rendering thread
    [self lock];
    [super update];
    [self unlock];
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)reshape     // scrolled, moved or resized
{
    needsReshape = YES; // reset the viewport etc. on the next draw
    
    // if we are not playing, force an immediate draw otherwise it will update with the next frame 
    // coming through. This makes the resize performance better as it reduces the number of redraws
    // espcially on the main thread
    if(![controller isPlaying]) 
    {
    [self setDirty:YES];
    [self flushOutput];
    }
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)clear
{
    [self lock];
    // clear content
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);
    [self unlock];
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)flushOutput
{
    [self lock];
    if(needsReshape)
    {
    NSRect      frame = [self frame];
    NSRect      bounds = [self bounds];
    GLfloat     minX, minY, maxX, maxY;
 
    minX = NSMinX(bounds);
    minY = NSMinY(bounds);
    maxX = NSMaxX(bounds);
    maxY = NSMaxY(bounds);
 
    [[self openGLContext] makeCurrentContext];
    [self update]; 
 
    // the first time we need to setup the OpenGL environment in this view
    if(!contextIsInitialized)
    {
        const GLint swapInterval = 1;
        
        [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLCPSwapInterval]; // synchronize the glFlush with the VBL
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glEnable( GL_BLEND );                   // enable blending
        glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );    // blend func for non premultiplied images
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
        glHint(GL_CLIP_VOLUME_CLIPPING_HINT_EXT, GL_FASTEST);
        contextIsInitialized = YES;
    }
 
    if(NSIsEmptyRect([self visibleRect])) 
    {
        glViewport(0, 0, 1, 1);
    } else {
        glViewport(0, 0,  frame.size.width ,frame.size.height);
    }
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(minX, maxX, maxY, minY, -1.0, 1.0);
 
    glClearColor(0.0, 0.0, 0.0, 0.0);
 
    glClear(GL_COLOR_BUFFER_BIT);
    needsReshape = NO;
    }
    if([self dirty])
    [controller drawContent];   // invoke the controller to draw all the video channels
    [self setDirty:NO];
    [self unlock];
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)setDirty:(BOOL)inDirty
{
    dirty = inDirty;
}
 
//--------------------------------------------------------------------------------------------------
 
- (BOOL)dirty
{
    return dirty;
}
 
//--------------------------------------------------------------------------------------------------
 
- (void)mouseDown:(NSEvent *)theEvent
{
    // mouse handling is done in the controller as it handles the video channels 
    [controller mouseDown:(NSEvent *)theEvent]; 
}
 
 
@end