Author Archives: Tom

What should be paid-for, and what should be free?

Posted on May 7, 2010 by Tom

Here are two reviews of an iPhone app on the Apple App Store, copied mostly word-for-word

Fantastic game 🙂 ***** (5/5 stars rated)
Awesome music soundtrack, great gameplay, just pure love.  I agree that the update should be free, but I still bought the map pack because at least my money goes to the developer who really deserves it.

Pay for new content  *  (1/5 stars rated)
Game is good but having to pay for new maps is ridiculous.  Also saying 5 star rating will keep updates coming.  If I have to pay for updates, what’s the point.

Here I have discovered two immediately accessible cases of opposing attitudes of rating, but similar attitudes about product expectation. Myself, I found the game as a free promotional offer.  I assume it is normally a paid-for app.

I’ll say person A is the 5 star rating, and person B is the 1 star rating.

Person A has a good attitude.  There are a lot of apps out there that are good for fun or for usefulness and should be paid for, or tolerate any advertising that is present in the app to cover some costs of development or maintenance.

Person B expects too much.  What is the point of getting a game if expansions must be paid for?  Sounds like someone who might pay 200 dollars for the Nintendo Wii, or 300-400 for the Sony PS3 but expect 10 games to come with the console, or a full party-pack of controllers instead of the single ones that come packaged.

Maybe lots of people have expectations.  But when they’re very harsh opinions that get tossed into the public domain where anyone can be influenced, the problem that I recognize isn’t the unreasonable harshness or the 1/5 rating despite the first few words being “Game is good”… The real problem is the cultural expectation of what should be free and what should be paid-for.

This is something I’ve been thinking about recently, relating to my own project.

Personally, I think the paid-for content should be anything that is above and beyond the original scope of the project, unless it is an enhancement to the product that actually fits within the original scope.

Now I have been thinking of a number of specific examples of this idea.

When I submit the first release of this product to Apple for approval to the App Store, I am going to make it either free or paid.  My general desire is paid.  This way, NO one tries the app unless it is paid for, and my personal expectation is that only people who really like the app will pay for it because I’m going to have appropriate (but very limited) marketing- good example screen shots of gameplay, not just menus.  Also I plan on marketing a few videos on Youtube.  So it can be known what the game is like and people who want it will buy it, and those who wouldn’t like to pay will just go get something else, for free.  This is my reasoning.  More info follows.

Any app that has better performance developed, say bringing a game from 20 frames-per-second to 30 or 40 fps, is a great development upgrade, and that should be included for free.  It is something that is contained within the original scope because it has no extension to the project.  It is an enhancement of the product but not a true extension/expansion.

Any new artwork that replaces original artwork is also enhancement, but not expansions/extensions.

But any new levels that are adding to gameplay that are not included in the original app are extensions.  It is a good thing for the developer/publisher to have a price set, or make it free if they want.

Another expansion/extension is multiplayer.  This is one of the most significant aspects of a game.  But when is it appropriate to charge for multiplayer?  Seems like it’s always free!

Well, I would say if an app is released as single-player on the app sore, and is FREE, then the multiplayer should be a paid-for extension because the original app is already free for everyone to enjoy.  Adding multiplayer support within a game can be very complicated, and take many hours/days/weeks to setup and polish.  It is in so many games already for free, but most of these games are paid-for and so the consumer may expect multiplayer feature to be free.  I know I would.

So now for any free app, any extension is reasonable to be a paid extension, and even upgrades may be chargable.

The point of a free game is to have a free game.   Can it be any more obvious?  There should be no high expectations.

A paid-for game should have far more content than a free game.  extensions may be free, and some may be paid.  Deciding to make extensions free will be a very welcome thing to anyone who has paid for your app.  Making extensions paid must mean the extensions should be very, very good, sort of like the quality of a whole new app.  Something that adds new vibrancy to the game.

In my case, I am thinking of making large environments in the future, and will try selling them with a custom pricing model (say 1 sub environment for $1, 5 sub environments for $2, 10 sub environments for $5, and so on.

There are many different influencing factors, but one of the biggest influences is whether the app is free on the app store, or paid.

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iPhone app orientation (portrait vs landscape)

Posted on April 20, 2010 by Tom

Introduction

The UIInterfaceOrientation property that can be put in an iPhone app’s Info.plist file, has lead me into a confusing environment of iPhone app orientation design.
At the top level, there are two ways the orientation can be considered: 1- the physical orientation of the device; 2- the orientation of the on-screen user interface.
And when developing an app, these two things can be inconsistent, and confusing.
The iPhone has 7 different physical DEVICE orientations, 3 of which I am not covering (face-up, face-down, unknown).  The 4 device orientations that are considered in this writing are: landscape-left (homebutton is on right), landscape-right (home button is on left), portrait (home button is down), portrait-upside-down (home button is up).
The iPhone has 4 different interface orientations. Two are portrait and portrait-upside-down that equal the physical device portrait orientations.  The other two are the landscape-right and landscape-left, but these are the opposite: interface-landscape-right = device-landscape-left,  and the other is flipped too.  If the device is rotated one way, the interface rotates the other way, to maintain a consistent “up” direction.

Setup

The specifics of my app:
I have a subclassed UIViewController, and its main view property is assigned a subclassed UIView object.
The main view is added to the UIApplication’s window.
Standard setup so far.
The UIView subclass has an overrided – (void) layoutSubviews method.
The UIViewController subclass has a method registered by the app delegate to receive notifications on orientation change, through the default notification centre.

Testing

There is something inconsistent between the notification centre for orientation change, and the value of [UIApplication sharedApplication].statusBarOrientation value.
Now to test:
For a start, the Info.plist file has the UIInterfaceOrientation key set to UIInterfaceOrientationLandscapeRight.
layoutSubviews will always fire first, and a check during the method for [UIApplication sharedApplication].statusBarOrientation shows landscape-right, as defined in the plist.
Then, sometimes-or-not, the orientation-change notification is sent to the registered object.
Starting the app while the device is physically in portrait, NO orientation change notification gets sent.
However, starting while the device is in any other physical orientation, then an orientation change notification is sent.
So it seems there is an expected default physical Portrait orientation, which cannot be manually defined, yet the default interface orientation can be pre-defined using [UIApplication sharedApplication].statusBarOrientation.
There are more haywire behaviours beyond this, if the device is then physically re-oriented after the app starts, more confusing behaviours.

Conclusions

Today was spent working on front-end app menu screens. My project originally started with the style and layout of screens drawn on paper in landscape orientation.  But, before today, I did not know it’s possible to use landscape-orientation images in Interface Builder nib files.  Now I know, and they can be displayed properly, if the right combination of settings are applied, such as the “Simulated User Interface Element-Orientation” setting in the inspector of IB, set to landscape, and interface orientation in the app.
Before today, I’ve done all my customized orientation positioning and rotation using the views’ center, frame, bounds and transform properties.
So, now, I can possibly adopt the built-in auto resize/rotation system.  Even if I don’t use that resize/rotation system, it could also make positioning easier.  It’s not difficult (now), to calculate the horizontal and vertical center of a shape, and position it within another shape whose width and height keeps changing.  Still, an easier way is always a good thing!
Working with all this is leading me to the following conclusions:
  • An app that has some parts that work only in landscape, and other parts that work only in portrait, should be upgraded so all parts work in all orientations.
  • An app that supports either (aka every) orientation, should not have the UIDeviceOrientation key set, because it leads to confusing situations (unless someone can suggest a good reason for it).
  • But, an app that supports any orientation … should, as a standard, start with the Default image designed to be portrait-oriented, not landscape, like so many iPhone games are that I’ve bought.
  • This final concluding point, personally speaking, is the the biggest problem to be solved: the conflicting desires or requirements: the desire to be universal and support either/every orientation (oh the bad memories of the browser wars come flying back), and the desire also prioritize one orientation with the other less-prioritized.

That’s all, folks!

Terrible conflict, but I am happy I could articulate this whole mess!
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Game Optimization Adventures, part 1

Posted on April 16, 2010 by Tom

Starting on Wednesday (today is Friday) I began the process of optimizing the iPhone game app.

Using Instruments, I could see a total Live Bytes value of around 40 MB for an average while the game was running.  Now, I’ve done a couple tasks and also introduced a PVR texture (not got it working yet).  Suddenly, the live bytes (after everything has loaded) has been reduced not to 20 or 30, but 4.  When the app is started, it loads up about 15-20 MB of memory, and then dumps it all except 4.  I’ll mention more about this later on.

Now, that’s a colossal drop in memory use.  From peaking at 40 to down to 15-20, and then now a mysterious (but very happy) drop after loading to around 4.

In the last 4 hours (and some hours yesterday) I’ve been making pages of notes on values and changes from different configurations of the app.  For the configurations, one thing I’ve done is I have built 4 separate Instruments save files using the Xcode Run>Run with Performance Tool>Object Allocations automated setup.  The four setups use these configurations: using JPG texture and stop recording when at peak live bytes, using JPG texture and stop recording after drop to 4 MB, using PVR texture and stop recording when at peak live bytes, using PVR and stop recording after drop to 4 MB.

These files have let me discover the strange, inexplicable fact of the moment (and which I have not built any conclusion about):  the memory being allocated internally by glTexImage2D for my JPG textures is being released.

One reason I dropped initially from 40 MB to a moderately lower amount is I removed an unused texture that was hogging 12 MB by itself, and wasn’t even being used.  My bad.  Actually it wasn’t my fault. haha- blame someone else.  It was from the 3rd texture channel in blender, and the game engine I use claims to only use two texture channels from Blender, because OpenGL ES only supports two texture channels.  Fine.  So that’s why the documentation for the game engine recommends using texture channels outside the first two.  That I did.  But apparently it exports the rest anyway despite them being beyond the first and second channels.  So I removed that texture (2048×2048 pixels x 3 bytes/pixel = 12 MB).  Also I have removed a handful of other textures that I used before and now I have reduced the peak load size from 40 to 15-20.  The 5 MB difference there is the size of the JPG vs the PVR.

So assuming I’m still using a JPG texture

The peak live bytes is 20.30 MB, and the drop-live bytes is 4.67 MB.  Watching the ObjectAlloc graph in the upper pane of Instruments, it will be at the peak for a second, and then it suddenly nose-dives to the low drop.

Now to examine the useJPG-peakLiveBytes instruments file: sort the Live Bytes column in Summary View from high-to-low, and a person can see what Malloc categories are taking up the most space.  And in my case, the biggest ones  are  Malloc 4.00 MB ( # Living = 2 ), Malloc 1.00 MB (# Living = 5 ).   Beyond that, there is Malloc 2.66 MB (this is not a texture, it is part of the Bullet physics engine so I ignore it), and Malloc 256.00 KB ( # living = 4 ) Add up only the 2×4 + 5×1 + 4×0.25 and there’s 14 MB out of 20 MB right there.  There are dozens or hundreds more memory allocations but they become very small and they are not the significance that these large image textures are.

Examining the useJPG-dropLiveBytes Instruments file in the same manner, the biggest live bytes categories are Malloc 2.66 MB (the previously-mentioned physics stuff) … and nothing of the Malloc 4.00 MB and Malloc 1.00 MB.  So I clicked the Category column header to sort by category, and scrolled down to Malloc 4.00 MB and see the # living = 0, and Malloc 1.00 MB # living = 0, and Malloc 256.00 KB # living = 0.

That was predictable.

But the chart still shows a peak and a nose-dive, and so I asked myself “why does this build up and then nose-dive, and when I started this on Wednesday, it was building up to 40 MB and just staying there?”

Now I know why the peak isn’t so high, but why does it fall?  Instruments to the rescue!

Using the dropLiveBytes file, still sorted by Category, I click the right-pointing arrow-in-circle beside Malloc 4.00 MB.  This shows two rows, and both the rows have a blank cell under the Live column.  If looking at this same Malloc 4.00 category selection in the peakLiveBytes file, the cells would have a little black dot.

Then I clicked on the Extended Detail View button and looked at each of the two rows… in each case the 4 MB were being realloc’ed within glTexImage2D.

Now this is where random clicking and exploring Instruments really helped me.  Clicking the right-pointing arrow-in-circle beside the Object Address values in a row will show the history for that Object Address.  The columns of interest in my case are Event Type, Timestamp, Size, Responsible Caller.  I sort the list of two rows by Timestamp, ascending.

The order of Event type, shows Malloc, and Free. Okay! So what else is in the second row along with Free?  well, obviously the same Address, that’s not important. the Size, shows – 4194304 (which is 4x1024x1024.. = 4.00 MB) and Responsible caller shows glDrawElements.

So I examined the other 4MB and the 1 MB alloc objects in the same manner as above, and discover that they were all being Free’ed in glDrawElements.

So a quick jump over to khronos.org’s glDrawElements page and search the page for “free” came up with no successful information.

And now I’m puzzled… why are these objects being realloc’ed in glTexImage2D, and then freed, but they weren’t being freed before?

I have no idea.  But I know I’ve got to get the PVR texture working, and it’s nice to know that the game should not get dumped by the iPhone OS anymore ( I hope ).

More adventures will follow.  Take care.

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Bezier timing

Posted on April 7, 2010 by Tom

I have just finished a bezier timing algorithm, and I’ll give a small description here.

I will be using the bezier values a linear stepping value in a loop… layman’s terms: a counter that counts up evenly, 0,1,2,3 or 0,2,4,6, etc.

There are methods to do this in the iPhone SDK but I already wrote half of the code, and it wasn’t much effort to complete.  Plus, I looked up the CAMediaTimingFunction class, and it seemed too complicated just for what I wanted (just an in-and-out structure).

So all I did is this: create a 100-element array.

.. and it gets a bit complicated, so here’s the code to build the array:

float t;
int i;
CGPoint bpoints[1000];
CGPoint bypoints[100];
for (i = 0; i < 1000; i++) {
 t = i / 1000.0f;
 bpoints[i].x = (1-t)*(1-t)*(1-t)* 0  + 3*(1-t)*(1-t)*t*0.5 + 3*(1-t)*t*t* 0.5 + t*t*t*1.0;
 bpoints[i].y = (1-t)*(1-t)*(1-t)* 0  + 3*(1-t)*(1-t)*t*0.05 + 3*(1-t)*t*t* 0.95 + t*t*t*1.0;
}
for ( transitionTimeStep =0; transitionTimeStep < 100; transitionTimeStep++) {
 float closest = 1.1;
 int closestI = -1;
 // Find the index in bpoints where .x is the closest to the transitionTimestep percent
 for (int x = 0; x < 1000; x++) {
  if ( fabs( bpoints[x].x - ( transitionTimeStep /100.0f)) < closest) {
   closest = fabs( bpoints[x].x - ( transitionTimeStep /100.0f));
   closestI = x;
  }
 }
 bypoints[transitionTimeStep] = bpoints[closestI].y;
}

The first loop creates a high-resolution set of points on a quadratic bezier curve (see Wikipedia’s page for Bezier curves) where the 4 points are between 0.0 and 1.0.  The points (0,1,2,3) have the following x,y coordinates:

  • 0,0
  • 0.5, 0.05
  • 0.5, 0.95
  • 1.0, 1.0

If a person even multiplied these values by 100 and then used a program like Adobe Illustrator, the curve would look something vaguely like a capitol letter S.  Rather, it’s actually more like a forward-slash /  and little curves at the top and bottom .

So I collect the high-resolution points of the line, and then loop through my time-step array.  For every element in the time-step array, I examine every x-coordinate value of the bpoints array.  If the value is closest to the current time-step index value, then I save the bpoints array y-coordinate value.

Yes, this seems very complicated now, but when I was doing it, it seemed very easy.  I guess sometimes I just get on a roll and create complicated stuff.

Also, I know there are better ways to do this, but I only want a look-up table and when I see it in live operation before typing this post, it works beautifully.

An important note!  The bpoint array is VERY important.  It is not good to simply create an exact-resolution array and fill it with values.  I did that at first, and found that there were too many indexes being dropped, that when the timing animation was run, there was a lot of choppy movement, like if the smooth slope of the curve was suddenly turned into a staircase of jagged edges.

So, creating the higher-resolution array first and then scanning it for the closest x value was the logical solution.  Perhaps I could have done it with a 200 element array, but I didn’t try it.

The process only takes a split-second, and it’s only done once at the beginning of the program.

That’s all, take care everyone.

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Late night quick post

Posted on March 25, 2010 by Tom

Tonight I have finished hooking up and testing another major component of my project: cannons and cannonballs.
And in-game menu screens.

But the most important thing to mention is the bugs that still appear in the game app. Some are partly deliberate, those that allow me to break up the system when I need to see things but also bugs from stupid mistakes like memory leaks and such.
These are all good to talk about if I am going to build a conclusion but tonight I think a quick mention is all that can be mustered.
Tomorrow I will try implementing a health system. Seems the obvious next step after cannonballs have been added.

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iPhone accelerometer orientation

Posted on March 18, 2010 by Tom

After searching for information about the iPhone accelerometer in search engines and the apple documentation, I did not find anything simple as what I am going to post here.

This is a bit of a tutorial, or just an explanation, how to determine the iPhone and iPod Touch (possibly the iPad) and its orientation relative to the flat ground at our feet.

The orientation uses 3-dimensional coordinate concepts, so a person has to be familiar with x, y, z and rotation concepts.  To get the information, you should be developing a native app (I don’t know if this works in Mobile Safari for web apps yet).  The UIAccelerometer class has a class method to provide you the shared accelerometer. The way to do this follows:

[[UIAccelerometer sharedAccelerometer] setDelegate: myObject ];

Additionally, setting the time interval (measured in seconds) to receive updates is a good task:

[[UIAccelerometer sharedAccelerometer] setUpdateInterval:( 1.0f / 30.0f )];

Now your class that myObject is instantiated from must implement the following method (the actual variable names can be customized to whatever you want):

– (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration

The UIAcceleration object called “acceleration” contains the important 3-dimensional values.

* * *

The iPhone cannot determine how far off the ground it is, but it can tell which side/edge/face of itself is closest to the ground.  That’s the point I am going to work with. Pretend the iphone is a 6-sided box, even though the 4 side edges are very slim, they are still sides of the box.

The device has 6 orientations, when one of the sides is directly facing the ground:

  1. Portrait
  2. Portrait upside-down
  3. Landscape left (rotate the device counter-clockwise 90 degrees from portrait)
  4. Landscape right (rotate the deviceclockwise 90 degrees from portrait)
  5. Face up
  6. Face down

Each time the accelerometer:didAccelerate method responds, you can get information about its orientation from the UIAcceleration object (using the above name) as follows:

float x = acceleration.x;
float y = acceleration.y;
float z = acceleration.z;

And now, comes the final bit of useful information, the pictures.

Basically, the pictures show the values of x, y, z,  for the 6 different orientations.

The way I personally interpret this is by way of the relative positions of one side to its opposite side.  The screen and the back are Z sides, the top with the lock button and bottom with the dock connection are the Y sides, and the two left-right edges are the X sides.

iPhone face-down

iPhone face-down, z approaches 1

iPhone face-up

iPhone face-up, z approaches -1

iPhone portrait

iPhone portrait, y approaches -1

iPhone portrait upside-down

iPhone portrait upside-down, y approaches 1

iPhone landscape right

iPhone landscape right, x approaches 1

iPhone landscape left

iPhone landscape left, x approaches -1

Until I wrote all this info down on paper, exactly as it’s described here, I couldn’t figure out how to interpret weird angles.

I had to do this research because the pre-packaged method for detecting orientation-changes was causing my app to jump back and forth.  Probably has to do with the update frequency too.  But this way now, I can build my own custom orientation code.

Take care everyone.

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The “freemium” business model.

Posted on March 11, 2010 by Tom

From Wikipedia’s Freemium page:

Freemium is a business model that works by offering basic Web services, or a basic downloadable digital product, for free, while charging a premium for advanced or special features. The word “freemium” is a portmanteau created by combining the two aspects of the business model: “free” and “premium”.

There are hundreds or thousands of games on the Apple AppStore.  The popularity of it is rising according to numerous reports, and probably it is a very profitable model.  I just heard of the term and so looked it up.  It seemed fairly obvious given the context: a review written for an iPhone game, talking about the free nature and how the extra features are paid (something this particular reviewer did not like).

So, now the question of the moment: should this app I am developing follow the freemium model?  I don’t think I can answer that during the time of this blog post writing, but I will give it some writable thought.

A freemium app gives the public something to try-before-you-buy, but the Apple acceptance for new apps to the AppStore requires all apps to provide a “complete” product, even if it is minimal.

Pros:

  • You can get more initial market penetration
  • Possibly take advantage of alternate marketing techniques.
  • “Free-buyers” may be able to customize their experience of the product in the extensions
  • Coming from the previous point, the buyers may find their experience enhanced by a product that can interpret specific combinations of extensions, for example: a car-building game, buying a “racing stripe” paint job and an “air foil” extensions separately may each add individual looks or enhancements to speed, but together they gain a bonus, a synergy from the two.

Cons:

  • The product’s “extras” that are premium may not be accepted as “worth the money”, and a greater majority of people may consume the product’s free version, and then carry on with the next shiny thing that catches their eye.
  • The “extras” require specific development that extend beyond the core “Free” product scope.  More levels, more characters, etc, cost more time and money to create.
  • A buyer may be surprised to find “extras” that he or she, individually, naturally expects as part of the “Free” product, and complain or spread bad reviews complaining about “premiums that ought to be free”
  • An update to the free product that requires the previous purchase of a (very) popular extension should only be publicly released after making the popular extension become part of the core free product.  The Apple AppStore’s in-app purchases feature does not permit game logic upgrades, but does permit static data files like artwork (decals) and 3D models (new cars or whatever) and sound.  No new multi-player features, however there are ways around that…  So, realistically, an update to the free product that requires the previous purchase of an extension should not be an update to the free product, rather it should be a paid extension, perhaps one that absorbs and eliminates the previous popular extension

After this analysis, it seems the benefits are all mostly in favour of the end-user, and to a lesser extent, benefiting the company/developer.  The Cons are all weighing more heavily on the company/developer.  There are no major cons to the end-user except for those people who have personal expectations of extra free things, and the free-release of previously paid for products.

I like the idea of the fremium model, and may chose it but for now, the core game must completed.

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Progress in movement algorithm design

Posted on February 19, 2010 by Tom

The album Bolero Gypsies: new flamenco is playing in my ears and the book iPhone cool projects from apress is spread open on my lap and I am typing a blog update on the iPod touch.

The chapter in the book I am reading is about the subject of networking. This may be getting ahead of myself, but it’s good to know for when the opportunity presents itself, and it will.

Yesterday, I created the movement of one of the principle game assets that will be moving constantly in the game. Let’s call this object a “bird” (it’s not in the game, neither is it in the air but it serves for this explanation).  The movement requires intelligence, not merely a simple movement like a rotation of some degrees on every game loop (eg. coins in Super Mario games or rings in Sonic the Hedgehog games). The game world may be large when the game is finished. The first draft for movement has become the following: a “home path” in the same style of the common footpath worn by animals in their native environments, when they travel the paths frequently. So it is with this movent. A path throughout any part of the game world.

This path is achieved by using a number of data variables.

The most important is the array of “checkpoints”. These are the same as checkpoints in a racetrack. In my first version of the movement system, the checkpoints are created as cubes in the world 3d model file, with special object names and serial number prefixes, such as “homepath001”. The name is searched and all the points are loaded into an array.

After the array, the most important variable is for storing the index serial number for the checkpoint the bird will be moving toward. Optionally, this destination may be interupted an replaced with any arbitrary location and the bird will move toward there instead.

Now, storing the index value of the next checkpoint allows us to determine the direction of movement whenever we want to. So now, this permits us to consider other random travel destinations.  If any arbitrary destination is chosen at anytime, another variable must store the yes/no status indicating if the object is moving toward the next checkpoint or not. So this possibility brings the necessity of another variable to store the actual destination location instead of only referencing the next checkpoint from the next-checkpoint-index. When the next checkpoint is reached, the index of the next checkpoint is updated, and the location for the new next-checkpoint is copied to this destination as the default destination.

This is just the tip of the iceberg.

Assuming movement toward some arbitrary location is part of the object’s life cycle, not only following a path forever, then it stands to reason to store not only the next destination separate to the next checkpoint as we’ve discussed, but also store the current home-path-location of the bird as soon as a new, arbitrary, destination is created. This will give the bird next-destination options to choose between, when it reaches the arbitrary location.  It may chose to return to it’s home path from where it left the path, somewhat tracing it’s path backward. Or, it may choose to continue to the next checkpoint directly.

In the case of the city pigeon bird, a home path might be the path around a large office building, and its checkpoints are lamp posts and parking lots (it may choose to walk in a parking lot).  When it is anywhere flying or walking, it may decide to go look at something away from its path, but it will try to keep its home building in sight, and if it decides to return, it can go onto wherever it wants, in the direction of its home!

Having more options is always a better thing than few options or only one.

Following this, I have implemented bezier curves for a smooth transition from approaching one checkpoint to the start of the next checkpoint’s path.  It doesn’t work well if a bird (or any other creature) is moving in a straight line and then instantly is moving in a separate direction..

Never before have I worked with bezier curve equations, so it’s brand new.  But I got the equation from Wikipedia’s page and plugged it in, and now it works.  This is a complicated issue, and not really part of algorithm design, but of implementation.

That will remain for some other day.

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Late night development progress

Posted on February 18, 2010 by Tom

Feb 17th, I have stayed awake almost all night. My iPhone app in development is coming along very well, in spite of the very painful lack of reference and learning materials for the main 3D engine.

There are many things to do yet, but today I have done more in a single day than I have any single day previously.

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