Tag Archives: Xcode

The Beginning of the Cocoa Kinect Example

Edit: I now have a new slightly polished cocoa-freenect wrapper for use in your Kinect-Cocoa projects! Check out the post here.

Today I pushed the final application of my libfreenect on the mac beginners guide to GitHub for everyone to see and download. Hopefully this will help a lot of Kinect beginners get started with their projects and produce some cool things πŸ™‚

I did forget to mention in the Readme but you will need to be running Mac OS X 7 (Lion) to build this program. Im not sure if the included app will work on older versions but you can give it a go πŸ™‚ If however you would like to run it on an older version you will need to change some of the code in the “Kinect Processing.m” file. The code causing problems is the “@autoreleasepool {}” function which is not present in earlier versions of the SDK, so you will have to change this to its older version. It’s not too hard though and I won’t be making the change myself I’m afraid because the code looks nicer this way :).

Also, for all of you out their without a Kinect I have included a sample point cloud file which you can import into the app (in all the usual mac ways. i.e. dragging the file onto the app icon, double clicking the file, using the File->Open… menu and of course by using the “Import” button in the app.

I hope you enjoy πŸ™‚ and here is the Readme that is on the GitHub page:

OpenKinect Cocoa Example

This uses the libfreenect library produced by the good people of the OpenKinect community. This code gives an example on how to use the libfreenect library with your Cocoa applications in Mac OS X.

It took me ages to learn how to begin programming with the Kinect on my Mac and there wasnt a great deal of help on the internet that I could find 😦 so I spent a long time figuring it all out (especially with OpenGL, that thing is a bastard) and then I finally created this app which will form the final application to a guide I will make in the summer.

The guide will take a semi-begginner programmer (someone who is already experienced with Objective-C, im not going to go and teach that but I will give a link to a guy on youtube who taught me), show them how to install all the libraries they need and then take them though all the steps necessary to produce this code.
To be honest I wish I found this on the internet myself ha ha, oh well πŸ™‚ I like working things out.

To use this code you will first need to install libfreenect:
– Theres the OpenKinect website which will be more up to date – http://openkinect.org/wiki/Getting_Started
– Or there is my website where I have outlined a method – https://jamesreuss.wordpress.com/2012/01/28/installing-openkinect-and-opencv-the-easy-way-on-a-mac/

And then you will need to download the code from this GitHub page, your best bet is probably using the download as .zip button or by going into your Terminal app and pasting in:
git clone git://github.com/jimjibone/OpenKinect-Cocoa-Example.git

You can then open up the “OpenKinect Cocoa Example.xcodeproj” file and build & run it and have a play. Make sure you have a Kinect though πŸ˜‰

A feature you might like though is where you can export and import point cloud files (.pcf), I’ll include one in there for you to play with if you dont have a Kinect yet.

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How can I do some processing of Kinect data?

The next task in my project, find out the location and size of all the objects in the scene! Sounds a bit tricky…

After a quick bit of looking around I found PCL (the Point Cloud Library) which contains a lot of functions all to do with manipulating and calculating features and other things to do with point clouds, the stuff the KInect gives us πŸ™‚ good stuff.

Lets give it an install and have a play with the tutorials (they look wicked, definitely the best tutorials for a library I’ve seen so far πŸ™‚ ).

So. After trying many attempts of an install over a week! I finally got it to install properly. That was soooo hard! I documented down the easy way of doing it in the end so I can share it if this next bit works out… After it was all installed properly everything seemed awesome until I tried to compile a sample C++ code in Xcode. This did not work out so nicely 😦

I think the problem is that Xcode does not see the correct header files or it is looking in the wrong place for them. When trying to #include the PCL libraries it makes you put the folder “plc-1.4/pcl/…” at the front which messes up with all the other #include statements within the header files as they are only looking for “pcl/…”.

So after lots of hunting on the internet for any way I can fix this I tried compiling the sample code with CMake using the defined method and it worked fine! This led me to believe that the libraries were all working fine and that it was just something to do with how Xcode works.

So, I did lots more searching around and found a post (look near the bottom) which talks pretty much about the problem I’m having I think. So what I need to do at some point now is uninstall homebrew and the libraries it installed and install macports and install it that way. Which will involve A LOT more painful installing and compiling (because macports takes loads longer for some reason) and I find its harder to use (I love how simple the commands for homebrew are πŸ™‚ )

So, when I eventually get round to installing this, which may be sometime soon, I’ll be able to come back and tell everyone how it went and how to fix/avoid all the problems that I came in to.

Please, please, please let PCL work. It would make things sooooo much easier!!

bla

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Installing OpenKinect and OpenCV the easy way on a Mac

Edit: I now have a new slightly polished cocoa-freenect wrapper for use in your Kinect-Cocoa projects! Check out the postΒ here. On the repo there also new and improved installation instructions!

For ages I tried to find an easy way to install both libfreenect (OpenKinect) and OpenCV on my mac without having to follow loads of lines of instructions and getting lots of errors in the process.

So, after quite a while of searching around for an easy install, which didn’t involve me installing loads of different package managers, I came across these methods which work really nicely πŸ™‚

First, Install Homebrew, if you don’t have it already:

  • It’s super easy… just follow the instruction… GO!
  • That was crazy fast, now do one of these, or both, or none…

OpenKinect:

  • If you still have your terminal open type in (or copy and paste) these commands one at a time and press enter.
cd /usr/local/Library/Formula

 

curl --insecure -O "https://raw.github.com/OpenKinect/libfreenect/master/platform/osx/homebrew/libfreenect.rb"
curl --insecure -O "https://raw.github.com/OpenKinect/libfreenect/master/platform/osx/homebrew/libusb-freenect.rb"
brew install libfreenect
  • Then, once all thats finished you’re done for OpenKinect πŸ™‚ you can give it a test by typing this into the terminal (as long as your still in the install directory..)
glview

OpenCV (2.3.1a):

  • Now, OpenCV is even easier again! Just type in (or copy and paste again) this command:
brew install opencv
  • This one takes a bit longer than OpenKinect…
  • And then, You’re all done!
  • You can close terminal now πŸ™‚

Now the last task. If you want to use these libraries in Xcode just follow these steps:

  • These instructions are for Xcode 4 by the way. Sorry Xcode 3 people, I started using Xcode from version 4.. But don’t worry Xcode 3 people, if you know what you’re doing then this is pretty much the same process as using the built in Mac libraries.
  • If your creating a Cocoa application it’s a little simpler:
    • Open your YourApp.xcodeproj file
    • Select the target you want to add it to, there will usually only be one
    • Then click “Summary”
    • And under “Linked Frameworks and Libraries” press the plus button
    • In the search field that shows up type in “libfreenect”
    • You will see all the libraries that begin with libfreenect. So now you can choose one πŸ™‚ I usually use libfreenect_sync because it is easier to use this in objective-c programs, from what I have seen so far. So select the latest version of it that shows up.
    • That’s it for that. Now to include it in your application code just type this #import <libfreenect/libfreenect_sync.h>
  • Now, if it isn’t a Cocoa application but a Console application do these things:
    • Open your YourApp.xcodeproj file
    • Select the target you want to add it to
    • Click on the “Build Phases” tab
    • Then under “Link Binary With Libraries” press the plus button
    • In the search field that shows up type in “libfreenect”
    • Now you can select which library you would like to use as I discussed in the second to last point of the Cocoa app method.
    • All done!

So now you should be all sorted with OpenKinect and OpenCV (the libraries when searching are called libopencv… there are quite a few tho, don’t really wanna go into what does what and what you need and all that… I don’t really know that myself just yet..)

Anyways, bye bye everyone

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Working out how to use libfreenect in Objective-C

I’ve finally got round to starting it… working out how to use this libfreenect thing in my project. So, I’ve downloaded the libfreenect files and I’ve started looking at the .c example. It creates a window using OpenGL and displays basic Kinect data in it (RGB view and IR view).

My task now is to work out how to use it in my project. Firstly, work out how to use it in C and then see if I can also use it in Objective-C.

… lots of reverse engineering of code…

… a while later…

DONE! -ish. I have managed to reverse engineer the example program to a point where I can get my own program to find the number of Kinect devices connected, connect to the device, change the tilt and LED colour of the device and then disconnect from the device.

I have managed to recreate it in C and then I realised that it would be even easier to make it work in Objective-C! Well kinda easier for me because I’ve been using Objective-C so much recently..

So, here is my C version of the program (the main.c file) which carries out basic movement every time it connects successfully.

#include "libfreenect.h"
#include <stdio.h>

freenect_context *freenectContext;
freenect_device *freenectDevice;
int noDevicesConnected;
int error;

int main(int argc, char **argv) {
    // freenect_init initialises a freenect context. The second parameter can be NULL if not using mutliple contexts.
    // freenect_set_log_level sets the log level for the specified freenect context.
    // freenect_select_subdevices selects which subdevices to open when connecting to a new kinect device.
    freenect_init(&freenectContext, NULL);
    freenect_set_log_level(freenectContext, FREENECT_LOG_DEBUG);
    freenect_select_subdevices(freenectContext, (freenect_device_flags)(FREENECT_DEVICE_MOTOR | FREENECT_DEVICE_CAMERA));

    noDevicesConnected = freenect_num_devices(freenectContext);
    printf("Number of devices connected: %d\n", noDevicesConnected);
    // Exit the app if there are no devices connected.
    if (noDevicesConnected < 1) return 1;

    // freenect_open_device opens a Kinect device.
    error = freenect_open_device(freenectContext, &freenectDevice, 0);
    if (error < 0) {
        // Then exit the app if there was an error while connecting.
        printf("Could not open the Kinect device.");
        return 1;
    }

    freenect_set_tilt_degs(freenectDevice, 30);
    freenect_set_led(freenectDevice, LED_BLINK_RED_YELLOW);
    printf("Done Functions\n");

    freenect_close_device(freenectDevice);
    freenect_shutdown(freenectContext);
    printf("Done!\n");

    return 0;
}

And now theres my Objective-C program which gives you a GUI and allows you to manually control the tilt of the Kinect using a slider control. Here is the interface file:

#import <Foundation/Foundation.h>
#import "libfreenect.h"

@interface KinectMotorController : NSObject {
    freenect_context *kinectContext;
    freenect_device *kinectDevice;

    NSNumber *noDevicesConnected;
    NSInteger error;
}
@property (assign) IBOutlet NSTextField *numberOfDevices;
@property (assign) IBOutlet NSTextField *connectedBool;
@property (assign) IBOutlet NSSlider *tiltControl;

- (IBAction)findDevices:(id)sender;
- (IBAction)connectDevices:(id)sender;
- (IBAction)changeTilt:(id)sender;
- (IBAction)disconnectDevices:(id)sender;

@end

And now the implementation file:

#import "KinectMotorController.h"

@implementation KinectMotorController
@synthesize numberOfDevices;
@synthesize connectedBool;
@synthesize tiltControl;

- (IBAction)findDevices:(id)sender {
	// Initialise the freenect library.
	freenect_init(&kinectContext, NULL);
	freenect_set_log_level(kinectContext, FREENECT_LOG_DEBUG);
	freenect_select_subdevices(kinectContext, (freenect_device_flags)(FREENECT_DEVICE_MOTOR | FREENECT_DEVICE_CAMERA));

	// Find the devices collected and show the user the number.
	noDevicesConnected = [NSNumber numberWithInt:freenect_num_devices(kinectContext)];
	[numberOfDevices setStringValue:[noDevicesConnected stringValue]];
}

- (IBAction)connectDevices:(id)sender {
	error = freenect_open_device(kinectContext, &kinectDevice, 0);
	if (error < 0) {
		[connectedBool setStringValue:@"Failed to connect!"];
	} else {
		freenect_set_led(kinectDevice, LED_GREEN);
		[connectedBool setStringValue:@"Connected!"];
	}
}

- (IBAction)changeTilt:(id)sender {
	freenect_set_tilt_degs(kinectDevice, [tiltControl intValue]);
}

- (IBAction)disconnectDevices:(id)sender {
	freenect_set_led(kinectDevice, LED_RED);
	freenect_close_device(kinectDevice);
	freenect_shutdown(kinectContext);
	[connectedBool setStringValue:@"Disconnected."];
}
@end

So there we are πŸ™‚ That really wasn’t as bad as I thought it would be. When I first saw the libfreenect code it looked like a bit of nightmare but at the moment its fine. We will see what happens when I try to start getting the camera data though… It might turn out to be a bit mental.

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