Compile and crash

[wiebowParticipant]

Sorry Mark, I have another one. This code results in a compile error, but the application starts anyway, and I need to kill the process:

Monkey

Namespace test #Import "<std>" #Import "<mojo>" Using std.. Using mojo.. #Import "assets/sprites.png" #Import "assets/arcade.ttf" Class MyTest Extends Window Field canvas:Canvas Field i:Image Method New() ' this sets title. no other way to do this. Super.New("Test!!!") i = Image.Load("asset::sprites.png") i.Handle = New Vec2f(0.0, 0.5) canvas.Font = Font.Load( "asset::arcade.ttf", 10 ) End Method End Class Function Main:Void() New AppInstance New MyTest App.Run() End Function

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Namespace test   #Import "<std>" #Import "<mojo>"   Using std.. Using mojo..   #Import "assets/sprites.png" #Import "assets/arcade.ttf"   Class MyTest Extends Window   Field canvas:Canvas Field i:Image   Method New()   ' this sets title. no other way to do this. Super.New("Test!!!")   i = Image.Load("asset::sprites.png") i.Handle = New Vec2f(0.0, 0.5) canvas.Font = Font.Load( "asset::arcade.ttf", 10 ) End Method   End Class   Function Main:Void() New AppInstance New MyTest App.Run() End Function

This is the output from mx2cc:

Parsing…
Semanting…
Translating…
Compiling….
Linking /home/wiebo/Monkey2Stuff/boulderdash/bd.buildv009/desktop_debug_linux/bd
Running /home/wiebo/Monkey2Stuff/boulderdash/bd.buildv009/desktop_debug_linux/bd

Memory access violation
{{!DEBUG!}}
>Font:Void(font:mojo.graphics.Font);/home/wiebo/Monkey2/modules/mojo/graphics/canvas.monkey2;1110018;4431205
font:mojo.graphics.Font=@0x1848420
>new:Void();/home/wiebo/Monkey2Stuff/boulderdash/bd.monkey2;110594;3342060
>Main:Void();/home/wiebo/Monkey2Stuff/boulderdash/bd.monkey2;147457;89

When I remove the canvas:Canvas field from the Class, the program compiles, but ofcourse it does not work. I was trying this to see if I can get to the canvas in the window.  Still no luck

After killing the application I get the rest of the output:

***** Fatal mx2cc error *****

Build error.
:build_project_debug FAILED

BUILD FAILED

FAILURE: Build failed with an exception.

* Where:
Build file ‘/home/wiebo/Monkey2Stuff/boulderdash/build.gradle’ line: 16

* What went wrong:
Execution failed for task ‘:build_project_debug’.
> Build project failed with exit code: 255

* Try:
Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output.

Total time: 23.415 secs
[Finished in 23.8s with exit code 1]

[DaniloParticipant]

wiebow:
Your ‘Field canvas:Canvas’ is not initialized by using ‘New’
or a getter function/method. Means ‘canvas’ is Null, and you
write to canvas.Font

If ‘i = Image.Load()’ returns Null, accessing ‘i.Handle’ would
also crash (at least if they are Classes, not so with Structs).

[DaniloParticipant]

Try something like this…

Monkey

Namespace test #Import "<std>" #Import "<mojo>" Using std.. Using mojo.. #Import "assets/sprites.png" #Import "assets/arcade.ttf" Class MyTest Extends Window Field initialized:Bool Field i:Image Method New() ' this sets title. no other way to do this. 'Super.New("Test!!!") Title = "Test!!!" ' Title is a property in class Window i = Image.Load("asset::sprites.png") ' Check for Null If i <> Null i.Handle = New Vec2f(0.0, 0.5) Endif 'Later in MX2, the Null-Check would be as easy as that: ' i?.Handle = New Vec2f(0.0, 0.5) ClearColor=New Color( 1,1,0 ) End Method Method Init(canvas:Canvas) canvas.Font = Font.Load( "asset::arcade.ttf", 10 ) initialized = True End Method Method OnRender( canvas:Canvas ) Override If Not initialized Then Init(canvas) App.RequestRender() End Method End Class Function Main:Void() New AppInstance New MyTest App.Run() End Function

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Namespace test #Import "<std>" #Import "<mojo>" Using std.. Using mojo.. #Import "assets/sprites.png" #Import "assets/arcade.ttf"   Class MyTest Extends Window Field initialized:Bool Field i:Image Method New() ' this sets title. no other way to do this. 'Super.New("Test!!!")   Title = "Test!!!" ' Title is a property in class Window i = Image.Load("asset::sprites.png")           ' Check for Null If i <> Null             i.Handle = New Vec2f(0.0, 0.5)         Endif           'Later in MX2, the Null-Check would be as easy as that:         ' i?.Handle = New Vec2f(0.0, 0.5)   ClearColor=New Color( 1,1,0 )          End Method       Method Init(canvas:Canvas) canvas.Font = Font.Load( "asset::arcade.ttf", 10 ) initialized = True     End Method   Method OnRender( canvas:Canvas ) Override       If Not initialized Then Init(canvas)   App.RequestRender()       End Method End Class Function Main:Void() New AppInstance New MyTest App.Run() End Function

 

[Mark SiblyKeymaster]

Sorry Mark, I have another one.

No problem – I want to get the bugs out ASAP.

It is actually working as expected though. The program successfully compiles and runs but generates a ‘memory access violation’ due to the null pointer, so it’s not the compiler crashing at least. And on the 97% finished version of Ted2 I’ve got running here, the debugger pops up and you can actually see where the error is – what luxury!

When I remove the canvas:Canvas field from the Class, the program compiles

Doesn’t here – I get ‘identifier canvas not found’ (as I would have expected).

I was trying this to see if I can get to the canvas in the window.

You can’t. The render canvas is ‘special’, and I want to make sure it’s state is not changed behind my back, and that I can change it on the fly if necessary (ie: you may not always get the same canvas in ‘OnRender’) for future features.

You can always render to an ‘image canvas’ and just DrawImage that to the render canvas in OnRender. This allows you to ‘draw’ at any time, and to apply funky effects at OnRender time like fade out etc. I’ll probably end up adding a CanvasView that does just that eventually, but the whole view system needs cleaning up and doccing before that’s realistic, so that’s an after V1.0 thing.

 

 

 

 

 

[DaniloParticipant]

Mark Sibly wrote:

You can’t. The render canvas is ‘special’, and I want to make sure it’s state is not changed behind my back, and that I can change it on the fly if necessary (ie: you may not always get the same canvas in ‘OnRender’) for future features.

So, if the canvas doesn’t preserve all states, it would be:

Monkey

Namespace test #Import "<std>" #Import "<mojo>" Using std.. Using mojo.. #Import "assets/sprites.png" #Import "assets/arcade.ttf" Class MyTest Extends Window Field i:Image Field myFont:Font Method New() ' this sets title. no other way to do this. 'Super.New("Test!!!") Title = "Test!!!" ' Title is a property in class Window i = Image.Load("asset::sprites.png") ' Check for Null If i <> Null i.Handle = New Vec2f(0.0, 0.5) Endif 'Later in MX2, the Null-Check would be as easy as that: ' i?.Handle = New Vec2f(0.0, 0.5) ClearColor=New Color( 1,1,0 ) myFont = Font.Load( "asset::arcade.ttf", 10 ) End Method Method OnRender( canvas:Canvas ) Override canvas.Font = myFont App.RequestRender() End Method End Class Function Main:Void() New AppInstance New MyTest App.Run() End Function

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Namespace test #Import "<std>" #Import "<mojo>" Using std.. Using mojo..   #Import "assets/sprites.png" #Import "assets/arcade.ttf"   Class MyTest Extends Window       Field i:Image     Field myFont:Font       Method New()           ' this sets title. no other way to do this.         'Super.New("Test!!!")           Title = "Test!!!" ' Title is a property in class Window           i = Image.Load("asset::sprites.png")           ' Check for Null         If i <> Null             i.Handle = New Vec2f(0.0, 0.5)         Endif           'Later in MX2, the Null-Check would be as easy as that:         ' i?.Handle = New Vec2f(0.0, 0.5)           ClearColor=New Color( 1,1,0 )           myFont = Font.Load( "asset::arcade.ttf", 10 )       End Method       Method OnRender( canvas:Canvas ) Override           canvas.Font = myFont           App.RequestRender()       End Method End Class Function Main:Void()     New AppInstance     New MyTest     App.Run() End Function

[Mark SiblyKeymaster]

That’d work.

Also, not sure if it’s docced yet but each view also has a ‘Style’ object that has DefaultColor and DefaultFont properties. These are set just before OnRender is called, so you can provide a default font and color for OnRender, eg:

 

Monkey

Method New() 'Window ctor     Style.DefaultFont=...     Style.DefaultColor=... End

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Method New()  'Window ctor     Style.DefaultFont=...     Style.DefaultColor=... End

 

[wiebowParticipant]

This makes sense now. Thanks.   The inner workings of Monkey 2 and mojo are most interesting to explore

@Mark: Oh that default style looks interesting. I’ll go dive into the style code. Thanks.

@Danillo: Thanks for the tip about setting the font in the render method. It’s something I can live with!

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