Spherical panorama view, iOS
Switch branches/tags
Nothing to show
Clone or download
Latest commit 3caaedc Dec 30, 2017

readme.md

360° spherical panorama view

Features

  • OpenGL powered
  • orientation sensors to look around
  • touch interactive
    • pan to look around
    • pinch to zoom
  • a split screen mode for VR headsets
  • helper functions to orient direction of camera and touches

example

Equirectangular projections

OpenGL has strict texture size requirements

acceptable image sizes:

  • 4096 × 2048
  • 2048 × 1024
  • 1024 × 512
  • 512 × 256
  • 256 × 128
  • ... (any smaller power of 2)

4096 supported on iPhone 4s / iPad2 and newer

Methods

image

-(void) setImage:(UIImage*)image
-(void) setImageWithName:(NSString*)fileName  // path or bundle. will check at both

orientation

 // auto-update (usually only one of these at a time is recommended)
-(void) setOrientToDevice:(BOOL)   // activate motion sensors
-(void) setTouchToPan:(BOOL)       // activate UIPanGesture

 // aligns z-axis (into screen)
-(void) orientToVector:(GLKVector3)
-(void) orientToAzimuth:(float) Altitude:(float)

// rotate cardinal north around the image horizon. in degrees
-(void) setCardinalOffset:(float)

field of view

-(void) setFieldOfView:(float)     // in degrees
-(void) setPinchToZoom:(BOOL)      // activate UIPinchGesture

touches

-(void) setShowTouches:(BOOL)      // overlay latitude longitude intersects
-(BOOL) touchInRect:(CGRect)       // hotspot detection in world coordinates

2D - 3D conversion

-(CGPoint) screenLocationFromVector:(GLKVector3) // 2D screen point from a 3D point
-(GLKVector3) vectorFromScreenLocation:(CGPoint) // 3D point from 2D screen point
-(CGPoint) imagePixelAtScreenLocation:(CGPoint)  // 3D point from 2D screen point
  // except this 3D point is expressed as 2D pixel unit in the panorama image

VR Split screen

-(void) setVRMode:(BOOL)

This activates a split screen that works inside of VR headsets like Google Cardboard. TBD if more VR best practices are needed, such as a barrel shader.

  • Illusion of varying depth is not available. The two screens are rendered using the same image with no difference between camera IPD.

Installation

copy PanoramaView.h/.m into your project or use CocoaPods

  1. use a GLKViewController instead of UIViewController
  2. initialize your panoramaView and set it as self.view
  3. implement glkView:drawInRect:
@interface ViewController (){
	PanoramaView *panoramaView;
}
@end

@implementation ViewController
- (void)viewDidLoad{
	[super viewDidLoad];
	panoramaView = [[PanoramaView alloc] init];
	[panoramaView setImageWithName:@"image.jpg"];
	[self setView:panoramaView];
}
-(void) glkView:(GLKView *)view drawInRect:(CGRect)rect{
	[panoramaView draw];
}
@end

Swift

  • installation is easiest with CocoaPods. add use_frameworks! to your podfile
  • or, create a bridging header, copy in PanoramaView.h/.m
import PanoramaView

class ViewController: GLKViewController {

	let panoramaView:PanoramaView

	required init?(coder aDecoder: NSCoder) {
		panoramaView = PanoramaView()
		super.init(coder: aDecoder)
	}
	override func viewDidLoad() {
		super.viewDidLoad()
		panoramaView.setImageWithName("image.jpg")
		self.view = panoramaView
	}
	override func glkView(_ view: GLKView, drawIn rect: CGRect) {
		panoramaView.draw()
	}
}

make sure

  • no device landscape/portrait auto-rotation

device

  • any of the 4 device orientations works, use only 1.

Orientation

  • azimuth and altitude
  • look direction, the Z vector pointing through the center of the screen

coordinates

The program begins by facing the center column of the image, or azimuth 0°

wikipedia

About equirectangular

sample

equirectangular images mapped to the inside of a celestial sphere come out looking like the original scene, and the math is relatively simple http://en.wikipedia.org/wiki/Equirectangular_projection

License

MIT