BCMeshTransform left curtain

gistfile1.m

/*
BCMutableMeshTransform+DemoTransforms.m
*/

+ (instancetype)curtainMeshTransformAtPoint:(CGPoint)point boundsSize:(CGSize)boundsSize
{
    const float Frills = 3;
    
    point.x = MIN(point.x, boundsSize.width);
    
    BCMutableMeshTransform *transform = [BCMutableMeshTransform identityMeshTransformWithNumberOfRows:20 numberOfColumns:50];
    
    CGPoint np = CGPointMake(1.0 - point.x/boundsSize.width, point.y/boundsSize.height);
    
    [transform mapVerticesUsingBlock:^BCMeshVertex(BCMeshVertex vertex, NSUInteger vertexIndex) {
        float dy = vertex.to.y - np.y;
        float bend = 0.25f * (1.0f - expf(-dy * dy * 10.0f));
        
        float x = 1.0 - vertex.to.x;
        
        vertex.to.z = 0.1 + 0.1f * sin(-1.4f * cos(x * x * Frills * 2.0 * M_PI)) * (1.0 - np.x);
        vertex.to.x = 1.0 - (x * np.x + x * bend * (1.0 - np.x));
        
        return vertex;
    }];
    
    return transform;
}


/*
  BCCurtainDemoViewController.m
*/

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    CGPoint point = [gestureRecognizer locationInView:self.transformView];
    
    return point.x < 30.0;
}

- (void)pan:(UIPanGestureRecognizer *)sender
{
    CGPoint point = [sender locationInView:self.transformView];
    
    
    switch (sender.state) {
        case UIGestureRecognizerStateBegan:
            self.surplus = point.x;
            
            // FALL THROUGH
        case UIGestureRecognizerStateChanged:
            self.transformView.meshTransform = [BCMutableMeshTransform curtainMeshTransformAtPoint:CGPointMake(point.x - self.surplus, point.y)
                                                                                        boundsSize:self.transformView.bounds.size];
            break;
        case UIGestureRecognizerStateEnded:
        case UIGestureRecognizerStateCancelled:
        {
            CGFloat percent = 1.0 - point.x/self.transformView.bounds.size.width;
            
            NSTimeInterval duration = 0.1 + 0.5 * percent;
            [UIView animateWithDuration:duration animations:^{
                [self setIdleTransform];
            }];
            break;
        }
            
        default:
            break;
    }
}

- (void)setIdleTransform
{
    self.transformView.meshTransform = [BCMutableMeshTransform curtainMeshTransformAtPoint:CGPointMake(0, self.view.bounds.size.height/2.0)
                                             boundsSize:self.transformView.bounds.size];
}