第八章 OpenGL层

-(BOOL)canDrawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
forLayerTime:(CFTimeInterval)timeIntervaldisplayTime:(const CVTimeStamp *)timestamp;

-(void)drawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
forLayerTime:(CFTimeInterval)intervaldisplayTime:(const CVTimeStamp *)timestamp;

CVReturnMyDisplayLinkCallback ( CVDisplayLinkRef displayLink,
const CVTimeStamp *inNow,
const CVTimeStamp*inOutputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut,
void *displayLinkContext);

-(BOOL)canDrawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
forLayerTime:(CFTimeInterval)timeIntervaldisplayTime:(const CVTimeStamp *)timeStamp
{
  if( !qtVisualContext ) {
     // If the visual context forthe QTMovie has not been set up
     // we initialize it now
     [selfsetupVisualContext:glContext withPixelFormat:pixelFormat];
  }
  // Check to see if a newframe (image) is ready to be drawn at // the current time by passing NULL asthe second param if(QTVisualContextIsNewImageAvailable(qtVisualContext,NULL))
  {
    // Release the previous frame
    CVOpenGLTextureRelease(currentFrame);
    // Copy the current frameinto the image buffer
    QTVisualContextCopyImageForTime(qtVisualContext,NULL,NULL, ¤tFrame);
    // Returns the texturecoordinates for the
    // part of the image thatshould be displayed CVOpenGLTextureGetCleanTexCoords(currentFrame,lowerLeft, lowerRight,upperRight, upperLeft);
    return YES; 
  }
  return NO;
 }

-(void)setupVisualContext:(CGLContextObj)glContextwithPixelFormat:(CGLPixelFormatObj)pixelFormat;
{
                OSStatus error;
                NSDictionary *attributes =nil;
                attributes = [NSDictionarydictionaryWithObjectsAndKeys:
                [NSDictionarydictionaryWithObjectsAndKeys:
                [NSNumbernumberWithFloat:[self frame].size.width],kQTVisualContextTargetDimensions_WidthKey,
                [NSNumbernumberWithFloat:[self frame].size.height],kQTVisualContextTargetDimensions_HeightKey, nil],
                kQTVisualContextTargetDimensionsKey,[NSDictionary dictionaryWithObjectsAndKeys:
                [NSNumber numberWithFloat:[selfframe].size.width], kCVPixelBufferWidthKey,
                [NSNumbernumberWithFloat:[self frame].size.height], kCVPixelBufferHeightKey, nil],
                kQTVisualContextPixelBufferAttributesKey,nil];
                // Create the QuickTimevisual context
                error = QTOpenGLTextureContextCreate(NULL,glContext,
                pixelFormat,(CFDictionaryRef)attributes, &qtVisualContext);
                // Associate it with themovie
                SetMovieVisualContext([moviequickTimeMovie],qtVisualContext); 
        }

        -(void)drawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
        forLayerTime:(CFTimeInterval)intervaldisplayTime:(const CVTimeStamp *)timeStamp
        {
        NSRect bounds =NSRectFromCGRect([self bounds]);
        GLfloat minX, minY, maxX,maxY;
        minX = NSMinX(bounds); minY =NSMinY(bounds); maxX = NSMaxX(bounds); maxY = NSMaxY(bounds);
        glMatrixMode(GL_MODELVIEW);glLoadIdentity(); glMatrixMode(GL_PROJECTION); glLoadIdentity();
        glOrtho( minX, maxX, minY,maxY, -1.0, 1.0); glClearColor(0.0, 0.0, 0.0, 0.0);
        glClear(GL_COLOR_BUFFER_BIT);
        CGRect imageRect = [selfframe];
        // Enable target for thecurrent frame glEnable(CVOpenGLTextureGetTarget(currentFrame));
        // Bind to the current frame
        // This tells OpenGL whichtexture we want
        // to draw so when we makethe glTexCord and
        // glVertex calls, thecurrent frame gets drawn
        // to the contextglBindTexture(CVOpenGLTextureGetTarget(currentFrame),
        CVOpenGLTextureGetName(currentFrame));glMatrixMode(GL_TEXTURE);
        glLoadIdentity();glColor4f(1.0, 1.0, 1.0, 1.0); glBegin(GL_QUADS);
        // Draw the quads
        glTexCoord2f(upperLeft[0],upperLeft[1]); glVertex2f (imageRect.origin.x,
        imageRect.origin.y +imageRect.size.height); glTexCoord2f(upperRight[0], upperRight[1]);
        glVertex2f(imageRect.origin.x + imageRect.size.width, imageRect.origin.y +imageRect.size.height);
        glTexCoord2f(lowerRight[0],lowerRight[1]);
        glVertex2f(imageRect.origin.x + imageRect.size.width,
        imageRect.origin.y);glTexCoord2f(lowerLeft[0], lowerLeft[1]);
        glVertex2f(imageRect.origin.x, imageRect.origin.y);
        glEnd();
        // This CAOpenGLLayer isresponsible to flush // the OpenGL context so we call super
        [superdrawInCGLContext:glContext
        pixelFormat:pixelFormatforLayerTime:interval
        displayTime:timeStamp]; //Task the context
        QTVisualContextTask(qtVisualContext);
}

glEnable(CVOpenGLTextureGetTarget(currentFrame));glBindTexture(CVOpenGLTextureGetTarget(currentFrame),

CVOpenGLTextureGetName(currentFrame));

- (void)initVideoChannels; {
int i = 0;
if( videoChannels != nil )
[videoChannels release],videoChannels = nil; 
videoChannels = [[NSMutableArray alloc] init];
// Create a grid kColCountacross
float vidWidth = [selfframe].size.width / kColCount; vidWidth = vidWidth - kMargin;
float vidHeight = [selfframe].size.height; if( [videoPaths count] > kColCount )
vidHeight = [selfframe].size.height / (((float)[videoPaths count])/kColCount);
vidHeight = vidHeight -kMargin; int row = 0;
int col = 0;
for (i = 0; i <[videoPaths count]; ++i) {
  NSString *path = [videoPaths objectAtIndex:i]; 
  QTMovie *m = [QTMovie movieWithFile:path error:nil];

  // Mute each video
  [m setMuted:YES];

  // Force the movie to loop
  [m setAttribute:[NSNumber numberWithBool:YES] forKey:QTMovieLoopsAttribute];
  float x = col*vidWidth; 
  floaty = row*vidHeight;
  if( i!= 0 && (i+1) %(int)kColCount == 0 ) {
    row++; 
  }
  CGRect currentRect =CGRectMake(x+kMargin, y+kMargin,
  vidWidth-kMargin,vidHeight-kMargin);

  // Instantiate a videochannel for each QTMovie // object we’ve created
  VideoChannel *channel =
  [[[VideoChannel alloc]initWithMovie:m usingDisplayRect:currentRect] autorelease];
  [videoChannels addObject:channel];
  col++;
  if( col > kColCount-1 ) col = 0;
}
if( videoController != nil ){
  [videoController release]; 
}
videoController =[[VideoChannelController alloc] init];
[videoController setVideoChannels:videoChannels]; 
}

-(void)awakeFromNib; {
NSString *path1 =@”/System/Library/Compositions/Eiffel Tower.mov”;
NSString *path2 =@”/System/Library/Compositions/Fish.mov”;
NSString *path3 = [[NSBundlemainBundle] pathForResource:@”stirfry”
ofType:@”mp4”]; NSString*path4 = @”/System/Library/Compositions/Rollercoaster.mov”;
NSString *path5 =@”/System/Library/Compositions/Sunset.mov”;
NSString *path6 =@”/System/Library/Compositions/Yosemite.mov”;
NSArray *paths = [NSArrayarrayWithObjects:path1, path2,
path3, path4, path5, path6,nil];
gridLayer =[[OpenGLVidGridLayer alloc] initWithVideoPaths:paths
usingContentFrame:
NSRectToCGRect([[windowcontentView] bounds])];
[[window contentView]setWantsLayer:YES];
[[[window contentView] layer]addSublayer:gridLayer]; [gridLayer playMovies];
}

-(BOOL)canDrawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
forLayerTime:(CFTimeInterval)timeIntervaldisplayTime:(const CVTimeStamp *)timeStamp
{
if( ![videoControllerisPlaying] )
return NO;
[videoControllersetVisualContext:glContext
withPixelFormat:pixelFormat];
BOOL ready = [videoControllerchannelsReadyToDraw:(CVTimeStamp*)timeStamp];
return ready; 
}

-(void)drawInCGLContext:(CGLContextObj)glContextpixelFormat:(CGLPixelFormatObj)pixelFormat
forLayerTime:(CFTimeInterval)intervaldisplayTime:(const CVTimeStamp *)timeStamp
{
NSRect bounds =NSRectFromCGRect([self bounds]); 
[videoController drawAllInRect:bounds];
// This forces OpenGL toflush the context
[superdrawInCGLContext:glContext pixelFormat:pixelFormat
forLayerTime:intervaldisplayTime:timeStamp];
[videoController taskAll]; 
}

-(BOOL)channelsReadyToDraw:(CVTimeStamp*)timeStamp; {
BOOL stillOk = NO;
int i = 0;
for (i=0; i<[videoChannelscount]; ++i) {
VideoChannel *currentChannel=
[videoChannelsobjectAtIndex:i];
if( [currentChannel readyToDrawNextFrame:timeStamp]) {
stillOk = YES; }
if( !stillOk ) return NO;
}
return stillOk; 
}

-(BOOL)readyToDrawNextFrame:(CVTimeStamp*)timeStamp {
if(QTVisualContextIsNewImageAvailable(qtVisualContext,NULL)) {
CVOpenGLTextureRelease(currentFrameImageBuffer);
QTVisualContextCopyImageForTime(qtVisualContext,
NULL,
NULL,¤tFrameImageBuffer);
CVOpenGLTextureGetCleanTexCoords(currentFrameImageBuffer,
lowerLeft, lowerRight,upperRight, upperLeft);
return YES; 
}
return NO; 
}

-(void)drawAllInRect:(NSRect)rect; {
GLfloat minX, minY, maxX,maxY;
minX = NSMinX(rect); minY =NSMinY(rect); maxX = NSMaxX(rect); maxY = NSMaxY(rect);
glMatrixMode(GL_MODELVIEW);glLoadIdentity(); glMatrixMode(GL_PROJECTION); glLoadIdentity();
glOrtho(minX, maxX, minY,maxY, -1.0, 1.0);
glClearColor(0.0, 0.0, 0.0,0.0); glClear(GL_COLOR_BUFFER_BIT);
int i = 0;
for (i=0; i<[videoChannelscount]; ++i) {
VideoChannel *currentChannel= [videoChannels objectAtIndex:i];
[currentChannel drawChannel];
}
}

- (void)drawChannel; {
[self drawImage]; }
- (void)drawImage; {
[selfdrawImage:mainDisplayRect
withOpacity:opacity];
withOpacity:(GLfloat)op;
}
-(void)drawImage:(CGRect)imageRect {
glEnable(CVOpenGLTextureGetTarget(
currentFrameImageBuffer));
glBindTexture(CVOpenGLTextureGetTarget(
currentFrameImageBuffer),CVOpenGLTextureGetName(
currentFrameImageBuffer));
glMatrixMode(GL_TEXTURE);glLoadIdentity(); glColor4f(1.0, 1.0, 1.0, op); glBegin(GL_QUADS);
glTexCoord2f(upperLeft[0],upperLeft[1]); glVertex2f (imageRect.origin.x,
imageRect.origin.y +imageRect.size.height);
glTexCoord2f(upperRight[0],upperRight[1]);
glVertex2f(imageRect.origin.x + imageRect.size.width,
imageRect.origin.y +imageRect.size.height);
glTexCoord2f(lowerRight[0], lowerRight[1]);
glVertex2f(imageRect.origin.x + imageRect.size.width,
imageRect.origin.y);glTexCoord2f(lowerLeft[0], lowerLeft[1]);
glVertex2f(imageRect.origin.x, imageRect.origin.y);
glEnd(); 
}