Composite Objects with Movies

C4WorkSpace.m

//
//  C4WorkSpace.m
//  Composite Objects Tutorial
//
//  Created by Travis Kirton.
//

#import "C4WorkSpace.h"

@implementation C4WorkSpace

-(void)setup {
    //create 2 movies
    C4Movie *mainMovie = [C4Movie movieNamed:@"inception.mov"];
    C4Movie *maskedMovie = [mainMovie copy];
    
    //create a mask shape object
    C4Shape *maskShape = [C4Shape ellipse:CGRectMake(0, 0, mainMovie.height * 1.5f, mainMovie.height * 1.5f)];

    //create a shape that will become the hole
    CGMutablePathRef hole = CGPathCreateMutableCopy([C4Shape ellipse:CGRectMake(0, 0, mainMovie.height, mainMovie.height)].path);
    
    //copy our maskShape's path, add the hole to make a donut
    CGMutablePathRef donut = CGPathCreateMutableCopy(maskShape.path);
    CGFloat diff = (maskShape.height-mainMovie.height)/2.0f;
    const CGAffineTransform displacement = CGAffineTransformMakeTranslation(diff,diff);
    CGPathAddPath(donut, &displacement, hole);

    //reset the mask shape's path to the donut
    maskShape.path = donut;

    //switch to the even-odd fill rule so the hole is transparent
    maskShape.fillRule = FILLEVENODD;
    
    //set the maskShape as the mask for the masked movie
    maskedMovie.mask = maskShape;
    
    //move the mask shape to the center of the masked movie
    maskShape.center = CGPointMake(mainMovie.width/2,mainMovie.height/2);

    //create a copy of the maskedShape's path
    C4Shape *whiteShape = [maskShape copy];

    //make it white
    whiteShape.fillColor = [UIColor whiteColor];
    whiteShape.lineWidth = 0.0f;

    //center it on the center of the movie
    whiteShape.center = maskShape.center;

    //add it to the movie (this makes it look like this part of the movie is cut out)
    [mainMovie addShape:whiteShape];

    //center the main movie to the canvas
    mainMovie.center = self.canvas.center;
    [mainMovie addMovie:maskedMovie];
    
    [self.canvas addMovie:mainMovie];
    
    //animate the main movie to rotate every 5 seconds (the masked movie will also rotate in with the main movie)
    mainMovie.animationOptions = REPEAT;
    mainMovie.animationDuration = 5.0f;
    mainMovie.rotation = TWO_PI;

    //rotate the masked movie (inside the main movie) in the opposite direction
    maskedMovie.animationOptions = REPEAT | LINEAR;
    maskedMovie.animationDuration = 10.0f;
    maskedMovie.rotation = -TWO_PI;

    //play and loop both movies
    mainMovie.shouldAutoplay = YES;
    mainMovie.loops = YES;
    maskedMovie.shouldAutoplay = YES;
    maskedMovie.volume = 0.0f;
    maskedMovie.loops = YES;
}
@end