/*

File: Camera.mm

Abstract: Implemtation of the Camera Class wrapping OpenGL camera positions

Version: 1.0

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    <1> 08/08/2005  initial release

*/

#import "Camera.h"

@implementation Camera

// class method to create a Camera object

+(Camera*)camera

{

    return [[[self alloc] init] autorelease];

}

// initialize the Camara with the default coordinates

-(id)init

{

    [super init];   

    _start.z = _end.z = -kCameraDefaultDistance;

    return self;

}

// NSCoder protocal method called when camera data is being loaded back from disk

-(id)initWithCoder:(NSCoder*)coder

{

    [super init];

    _start.x = [coder decodeDoubleForKey:@"X"];

    _start.y = [coder decodeDoubleForKey:@"Y"];

    _start.z = [coder decodeDoubleForKey:@"Z"];

    _start.longitude = [coder decodeDoubleForKey:@"Longitude"];

    _start.latitude = [coder decodeDoubleForKey:@"Latitude"];

    _end = _start;

    return self;

}

// returns orientation values for the camera 

-(Orientation)orientationForTime:(const CVTimeStamp*)timeStamp

{

    double t = [self isAnimatedForTime:timeStamp]

               ? double(timeStamp->hostTime - _startTime) / (_endTime - _startTime)

               : timeStamp->hostTime < _startTime ? 0 : 1;

    Orientation orientation =

    {

        _start.x + (_end.x - _start.x) * t,

        _start.y + (_end.y - _start.y) * t,

        _start.z + (_end.z - _start.z) * t,

        _start.longitude + (_end.longitude - _start.longitude) * t,

        _start.latitude  + (_end.latitude - _start.latitude) * t,

    };

    return orientation;

}

// creates a new translated orientation

-(void)lookForTime:(const CVTimeStamp*)timeStamp

{

    Orientation orientation = [self orientationForTime:timeStamp];

    glTranslated(orientation.x, orientation.y, orientation.z);

    glRotated(orientation.longitude, 0, 1, 0);

    glRotated(orientation.latitude,  1, 0, 0);

}

// handles panning

-(void)panX:(double)x Y:(double)y Z:(double)z forTime:(const CVTimeStamp*)timeStamp

{

    _end = [self orientationForTime:timeStamp];

    _end.x += x;

    _end.y += y;

    _end.z = MIN(-1.5, _end.z + z);

    _endTime = timeStamp->hostTime;

}

// handles rotation

-(void)rotateX:(double)x Y:(double)y forTime:(const CVTimeStamp*)timeStamp

{

    _end = [self orientationForTime:timeStamp];

    _end.longitude += x;

    _end.latitude  += y;

    _endTime = timeStamp->hostTime;

}

// sets up camera orientations from a start time with a duration

-(void)animateTo:(Camera*)camera over:(double)duration

{

    CVTimeStamp now;

    now.hostTime = UInt64(AudioGetCurrentHostTime());   

    _start = [self orientationForTime:&now];

    _end = [camera orientationForTime:&now];

    _startTime = now.hostTime;

    _endTime = now.hostTime + UInt64(AudioGetHostClockFrequency() * duration);

}

// NSCoder protocal method for saving camera data to disk

-(void)encodeWithCoder:(NSCoder*)coder

{

    CVTimeStamp now;

    now.hostTime = UInt64(AudioGetCurrentHostTime());

    Orientation orientation = [self orientationForTime:&now];

    [coder encodeDouble:orientation.x forKey:@"X"]; 

    [coder encodeDouble:orientation.y forKey:@"Y"]; 

    [coder encodeDouble:orientation.z forKey:@"Z"]; 

    [coder encodeDouble:orientation.longitude forKey:@"Longitude"]; 

    [coder encodeDouble:orientation.latitude  forKey:@"Latitude"]; 

}

// returns true if we're animating

-(BOOL)isAnimatedForTime:(const CVTimeStamp*)timeStamp

{

    return timeStamp->hostTime >= _startTime && timeStamp->hostTime < _endTime;

}

@end