Beware the widget



The Jabberwock, as illustrated by John Tenniel

 

"Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
The frumious Bandersnatch!"

 

So, I wanted a simple drop down list so a tester/player could pick a scene and then go there.  I didn't find what I wanted, but there was this nice feature of the Corona Widget object library called the newTableView:

 

Looks good, maybe more complicated than what I need but the code looks straight forward (okay, not as easy and straight forward as old school classic VB 6 - but not as weird and hard as Visual C++ MFC of the same era - and once again I'm dating myself...)

 

The demo's I found here and here provided the basics - but!  I need to incorporate this inside the Corona Storyboard construct.  And that is where the fun and games began...

 

Now a mea maxima culpa is in order - what follows is probably due to my being overzealous in getting rid of memory issues.

 

I created two arrays - one is a straight forward array with the names of the scenes in order that I want to provide.

 

The second is an array of arrays used by the tableView object.  One of the weaknesses in using Corona is the documentation is sparse and terse - just enough to get you into trouble - but the stuff you really need to know is found in the forums. From what I've figured out is the row construct in the list allows you to have a picture object, a title and then descriptive text. There may be more, but this is far more at this point than what I really need.  Hence an array of arrays - or to use the Lua way of thinking - a table with individual rows that could contain a number of fields (columns) greater than one.  Let's move on.

 

He took his vorpal sword in hand:
Long time the manxome foe he sought—
So rested he by the Tumtum tree,
And stood awhile in thought. 

 

Got my lists, got my tableView, and wow - it actually displays what I want!

 

 

It's just that the damn thing crashes when I do a selection.  This one got me. 

 

And as in uffish thought he stood,

The Jabberwock, with eyes of flame,
Came whiffling through the tulgey wood,
And burbled as it came!


 

So I unsheathed my vorpal sword - er, I started to really use the Lua Glider debugger.  Need to go back a bit here.  In my desire not to create any more memory leaks I had made sure in the storyboard function scene:exitScene I set any variable I declared to nil.  And that was the source of my errors. 

 

One, two! One, two! and through and through
The vorpal blade went snicker-snack!
He left it dead, and with its head
He went galumphing back.

 

The errors were just - weird.  Didn't make sense.  And here is where using Lua Glider saved the day (used as my vorpal blade).  I set a break point for the listener function in my code - the code that gets fired when a user clicks on a selection in the list.

 

And as I expected the code worked perfectly - selecting the correct item in the selection array based off the event index.  But then we went down the rabbit hole...

 

It turns out after all of that the storyboard code kicked in.  The exitScene code got called - setting all of my variable to nil.  Oh - and then the listener function got called again - and since everything had just been set to nil it set off errors - oh my...

 

Okay, I'm sure my code isn't the most efficient at this point.  Why the listener function is getting called twice I can't answer.  However I did learn a valuable lesson here.

 

"And hast thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!"
He chortled in his joy.

'Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.

 

Clearly, at this point in my Lua/Corona development the ONLY stuff I should be setting to nil (null) in the storyboard scene:exitScene function are those objects that get inserted into the display view/self view group.  Anything else - well as the maps used to say here be dragons...

 

Cross posted at my other blog Greffin's Feather





Bugs and Options

This week has been a combination of extending the UI and continuing the debugging.

As a team we started using Lua Glider as our main development platform for working on our game.  I had installed a demo version of Corona Project Manager – which is now known as Outlaw – and worked with it for a short while.  I just liked Lua Glider better.

Lua Glider has a lot of hooks into our project tools:

·         Works with Corona SDK

·         Provides debug capability with the ability to set breakpoints with Corona SDK

·         Works with both Subversion and Git

·         Works with Bugzilla and JIRA (no plug in that I can find for Mantis BT)

So it’s been a week of tracking down and taking care of bugs using Glider.

The more interesting part of the week has been adding an options menu to the game.

If you tap twice on the of part of Flights of Fancy (note the elipse around the word) – and then click the Play button:

You get this menu screen.

Set Auto Fire – this button either turns it on or off.  It does a read/write to a save state JSON file.  Code has been added to the scenes to utilize this - and I've found a couple of 'features'...

First one - I've not commented out the tap listeners in the scenes.  So you can double the fire rate by allowing the autofire to go, and them supliment the rate of fire by tapping like mad.

Second 'feature' - in scene 3 where there are multiple enemy planes - the shots coming from the player can show two bullets side by side.  Nice!  Just need to be able to replicate it as a feature later on!

Change Side – this button changes the side that you picked – so if you started working for the  Allies you now work with the Axis powers and shoot down your former buddies.  Again, does a read/write to the same JSON file.

After selecting either of these buttons you go back to the main menu screen.

Do Intro – this button allows you to redo the intro/training missions.  Once pressed you go immediately to the first scene of the intro.

Scene List – this one took a bit of time to get in.  Clicking this button displays another screen:

 

This screen uses a Corona Widget table view object.  It’s a bit cranky, but when it works it opens up the scene that gets picked from the displayed list. 

I'm going to write another post on an issue I ran into using this object.

Moving On

New Stuff

Spread Shot

Added a new ‘spread shot’ feature to the game.  First I tried to do it programmatically, which didn’t work as I thought it would.  Simply put – I was trying to use the same graphic image twice –both images had the same vertical axis but the horizontal axis would be slightly different for the individual shot.  Just couldn’t get it to work.

So, I created a new graphic which has three shots in it.  Looks nice, and is easier to control.  Here is a screen shot: 

New Enemy Plane

Added a new enemy plane which for now debuts in level 3:

This isn’t working as well as I wanted, and I’m going to have to put some more effort into it.  What I wanted to see was first the default red enemy planes, then my new planes, then the boss.  For right now that isn’t happening, the new planes don’t display – so for demonstration purposes I changed the ‘default’ enemy plane to the new one for this level.

Intro Level

I made some refactoring changes here as well.  First of all, I pulled in Jim’s code that provides more player ship movement - it now moves up and down on the screen as well as rotates in the direction of travel.  Looks a lot better this way. 

Travis had originally gotten rid of the health bar and the multiple lives for the intro; unfortunately they both got reintroduced due to the additional code.  Changes were made to again not display the health bar and the additional player lives.

Lua IDE’s

Downloaded and installed then started working with two Lua/Corona SDK IDE’s:

·         Corona Project Manager – now known as Outlaw

·         Cider – now known as Lua Glider

I’m more impressed with Glider but I’ll be playing with both off and on.  My original editor was TextPad which I still like – but it clearly does NOT have all the features a full blown IDE has.

One thing I liked about Lua Glider, and should see if Outlaw also has – Glider ‘understands’ Subversion.  I was able to look at the back history of modules (as long as comments were posted to the SVN commit).  Very nice feature.