Function call from within another function

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george++

AGK Tool Maker

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Joined: 13th May 2007

Location: Thessaloniki, Hellas

Posted: 6th Dec 2012 22:27 Edited at: 6th Dec 2012 22:29

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Hi,
Please run the following code:

+ Code Snippet

type Vector2
	x as float
	y as float
endtype

myvector as Vector2
myvector.x = 10
myvector.y = 20

SetDisplayAspect( 0.66 )
do
	PrintC("x=")
	Print(myvector.x)
	PrintC("y=")
	Print(myvector.y)
	If getpointerpressed() then myvector = Vector2_Normalize(myvector)
	print(Vector2_Length(myvector))
	Sync()
loop

function Vector2_Length(v as Vector2)
	l as float
	l=sqrt(v.x*v.x+v.y*v.y)
endfunction l

function Vector2_Normalize(v as Vector2)
	l as float
	vn as Vector2
	l = Vector2_Length(v)
	vn.x = v.x/l
	vn.y = v.y/l
endfunction vn

The output is not correct. After the click the length of the vector length is calculated to 10.0. But it should be calculated to 1.0
If I change the function 'Normalize' as below then everything runs OK

+ Code Snippet

function Vector2_Normalize(v as Vector2)
	l as float
	vn as Vector2
	l = sqrt(v.x*v.x+v.y*v.y)
	vn.x = v.x/l
	vn.y = v.y/l
endfunction vn

but this is not good practice

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Ancient Lady

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Joined: 17th Mar 2004

Location: Anchorage, Alaska, USA

Posted: 6th Dec 2012 23:30

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Calling functions from within functions works fine.

It is actually something screwy happening in the Vector2_Length function.

I tweaked your code to show different steps:

type Vector2
	x as float
	y as float
endtype

global testvec as Vector2
global funclen as float
myvector as Vector2
holdvec as Vector2
mylenorg as float
mylen as float

// set up the values
myvector.x = 10
myvector.y = 20
holdvec = myvector
testvec = myvector
mylenorg = Vector2_Length(holdvec)
mylen = 0
SetDisplayAspect( 0.66 )
do
	If getpointerpressed()
		myvector = Vector2_Normalize(holdvec)
		mylen = Vector2_Length(myvector)
	endif
	Print("Click to demo error")
	Print("")
	Print("orig vec l="+str(mylenorg,2)+" x="+str(holdvec.x,2)+" y="+str(holdvec.y,2))
	Print("norm vec l="+str(mylen,2)+" x="+str(myvector.x,2)+" y="+str(myvector.y,2))
	Print("")
	Print("After click the y")
	Print("below becomes zero")
	Print("and messes up the calculation")
	Print("vec in func x="+str(testvec.x,2)+" y="+str(testvec.y,2))
	Print("len in func = "+str(funclen,2))
	Sync()
loop

function Vector2_Length(v as Vector2)
	l as float
	l=sqrt(v.x*v.x+v.y*v.y)
	if l > 1.0
		funclen = l
		testvec = v
	endif
endfunction l

function Vector2_Normalize(v as Vector2)
	l as float
	t as float
	vn as Vector2
	t=Vector2_Length(v)
	l=sqrt(v.x*v.x+v.y*v.y)
	vn.x = v.x/l
	vn.y = v.y/l
endfunction vn

+ Code Snippet

type Vector2
	x as float
	y as float
endtype

global testvec as Vector2
global funclen as float
myvector as Vector2
holdvec as Vector2
mylenorg as float
mylen as float

// set up the values
myvector.x = 10
myvector.y = 20
holdvec = myvector
testvec = myvector
mylenorg = Vector2_Length(holdvec)
mylen = 0
SetDisplayAspect( 0.66 )
do
	If getpointerpressed()
		myvector = Vector2_Normalize(holdvec)
		mylen = Vector2_Length(myvector)
	endif
	Print("Click to demo error")
	Print("")
	Print("orig vec l="+str(mylenorg,2)+" x="+str(holdvec.x,2)+" y="+str(holdvec.y,2))
	Print("norm vec l="+str(mylen,2)+" x="+str(myvector.x,2)+" y="+str(myvector.y,2))
	Print("")
	Print("After click the y")
	Print("below becomes zero")
	Print("and messes up the calculation")
	Print("vec in func x="+str(testvec.x,2)+" y="+str(testvec.y,2))
	Print("len in func = "+str(funclen,2))
	Sync()
loop

function Vector2_Length(v as Vector2)
	l as float
	l=sqrt(v.x*v.x+v.y*v.y)
	if l > 1.0
		funclen = l
		testvec = v
	endif
endfunction l

function Vector2_Normalize(v as Vector2)
	l as float
	t as float
	vn as Vector2
	t=Vector2_Length(v)
	l=sqrt(v.x*v.x+v.y*v.y)
	vn.x = v.x/l
	vn.y = v.y/l
endfunction vn

When you click the pointer, the testvec vector is set and it shows that the v.y value is changing to zero.

This is an issue related to passing a UDT variable twice. We've seen this intermittently and this bit of code shows the problem very nicely.

Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master

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AgentSam

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Years of Service

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Joined: 14th Mar 2012

Location: Virtual Space

Posted: 7th Dec 2012 01:39 Edited at: 7th Dec 2012 02:28

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I have to draw the same conclusion as Ancient lady.

My test code was a bit more extensive, but the findings are the same; in the nested call to "Vector2_Length", the Vector2.y value get's zapped for some reason -- a problem related to the UDT implementation in AGK.

Here's my test code (which I tested in AppGameKit 1076):

//  ------------------------------------------------------------
//  Keyboard input support
//  ------------------------------------------------------------
    // Declare constants
    #constant KEY_0 0x30
    #constant KEY_1 0x31
    #constant KEY_2 0x32
    #constant KEY_3 0x33
    #constant KEY_4 0x34
    #constant KEY_5 0x35
    #constant KEY_6 0x36
    #constant KEY_7 0x37
    #constant KEY_8 0x38
    #constant KEY_9 0x39

MyKeypress as integer

//  ------------------------------------------------------------
//  Buffered print output support
//  ------------------------------------------------------------

// Declare data type
    type TDebugOutput
        CntLines              as integer
        NumLines              as integer
        MaxLines              as integer
    endtype

// Create a global variable using custom data type
    global DebugOutput as TDebugOutput

// Set defaults
    DebugOutput.CntLines = 0
    DebugOutput.NumLines = 0
    DebugOutput.MaxLines = 50 // Change this to fit your needs

// Create the buffer array to hold "MaxLines" entries
    global dim DebugOutputArray[DebugOutput.MaxLines] as string

//  ------------------------------------------------------------
//  DATA TO DEMONSTRATE UDT PARAMETER BUG
//  ------------------------------------------------------------

// Declare data type
    type Vector2
      x as float
      y as float
    endtype

// Declare and initialize variables (outer scope locals)
    myvector as Vector2
    myvector.x = 10
    myvector.y = 20

//  ------------------------------------------------------------
//  TEST CODE
//  ------------------------------------------------------------

// Setup display (percentage based landscape orientation)
SetDisplayAspect(1.33)
SetPrintSize(2.0)

// Output some help info...
ShowHelp()
DebugOutputAdd("Initial vector data:")
DebugOutputAdd("  myvector.x = " + str(myvector.x))
DebugOutputAdd("  myvector.y = " + str(myvector.y))
DebugOutputAdd("")

do
    // Show output
    DebugOutputShow()

// Update display (and update device input flags)
    Sync()

// Did user press a key?
    MyKeypress = GetAnyKey()
    select MyKeypress
        case KEY_1: myvector = Vector2_Reset(myvector) : endcase
        case KEY_2: myvector = Vector2_Normalize_Works(myvector) : endcase
        case KEY_3: myvector = Vector2_Normalize_Fails(myvector) : endcase
        case KEY_4: DebugOutputClear() : ShowHelp() : endcase
        case KEY_0: exit : endcase
    endselect
loop

function Vector2_Reset(v as Vector2)
    // Reset values and return
    v.x = 10
    v.y = 20

DebugOutputAdd("FUNCTION - Vector2_Reset")
    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

function Vector2_Normalize_Fails(v as Vector2)
    l as float

DebugOutputAdd("FUNCTION - Vector2_Normalize_Fails")
    DebugOutputAdd("  Input:")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))

// Compute length (via function call)
    l = Vector2_Length(v) // <-- this call messes up the result

// Normalize
    v.x = v.x/l
    v.y = v.y/l

DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

function Vector2_Length(v as Vector2)
    l as float

// Get distance from 0,0 to x,y
    l = sqrt(v.x*v.x+v.y*v.y)

DebugOutputAdd("FUNCTION - Vector2_Length")
    DebugOutputAdd("  Input:")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    l   = " + str(l))
    DebugOutputAdd("")
endfunction l

// Works as expected...
function Vector2_Normalize_Works(v as Vector2)
    l as float

DebugOutputAdd("FUNCTION - Vector2_Normalize_Works")
    DebugOutputAdd("  Input: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))

// Compute length (inline)
    l = sqrt(v.x*v.x+v.y*v.y)

DebugOutputAdd("  Length (inline calculation): ")
    DebugOutputAdd("    l = " + str(l))

// Normalize
    v.x = v.x/l
    v.y = v.y/l

DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

//  ------------------------------------------------------------
//  SUPPORT ROUTINES ONLY
//  ------------------------------------------------------------

function ShowHelp()
    DebugOutputAdd("Keyboard help:")
    DebugOutputAdd("  1 = Initialize UDT data (reset)")
    DebugOutputAdd("  2 = Normalize vector (this works)")
    DebugOutputAdd("  3 = Normalize vector (this fails)")
    DebugOutputAdd("  4 = Clear Screen + Show help")
    DebugOutputAdd("  0 = Quit!")
    DebugOutputAdd("")
endfunction

function GetAnyKey()
    v_Scancode as integer
    v_Result   as integer
    v_Result   = 0
    v_Scancode = GetRawLastKey()
    if (GetRawKeyReleased(v_Scancode)) then v_Result = v_Scancode
endfunction v_Result

function DebugOutputAdd(a_strText as string)
    INC DebugOutput.NumLines
    if (DebugOutput.NumLines > DebugOutput.MaxLines)
        DebugOutput.NumLines = DebugOutput.MaxLines
        DebugOutputScroll() // This makes room for one more line
    endif
    inc DebugOutput.CntLines
    DebugOutputArray[DebugOutput.NumLines] = DebugOutputPadLineNum(str(DebugOutput.CntLines), " ", 4) + ": " + a_strText
endfunction

function DebugOutputShow()
    if (DebugOutput.NumLines > 0)
        for i = 1 to DebugOutput.NumLines
            print (DebugOutputArray[i])
        next
    endif
endfunction

function DebugOutputScroll()
    v_iIndex as integer
    if (DebugOutput.MaxLines > 1)
        for v_iIndex=1 to DebugOutput.MaxLines-1
            DebugOutputArray[v_iIndex] = DebugOutputArray[v_iIndex + 1]
        next
    endif
endfunction

function DebugOutputPadLineNum(a_StringToPad as string, a_strPadChar as string, a_iPadLen as integer)
    while ( Len(a_StringToPad) < a_iPadLen)
        a_StringToPad = a_StringToPad + a_strPadChar
    endwhile
endfunction a_StringToPad

function DebugOutputClear()
    // Reset line counter
    DebugOutput.NumLines = 0
endfunction

+ Code Snippet

//  ------------------------------------------------------------
//  Keyboard input support
//  ------------------------------------------------------------
    // Declare constants
    #constant KEY_0 0x30
    #constant KEY_1 0x31
    #constant KEY_2 0x32
    #constant KEY_3 0x33
    #constant KEY_4 0x34
    #constant KEY_5 0x35
    #constant KEY_6 0x36
    #constant KEY_7 0x37
    #constant KEY_8 0x38
    #constant KEY_9 0x39

    MyKeypress as integer

//  ------------------------------------------------------------
//  Buffered print output support
//  ------------------------------------------------------------

    // Declare data type
    type TDebugOutput
        CntLines              as integer
        NumLines              as integer
        MaxLines              as integer
    endtype

    // Create a global variable using custom data type
    global DebugOutput as TDebugOutput

    // Set defaults
    DebugOutput.CntLines = 0
    DebugOutput.NumLines = 0
    DebugOutput.MaxLines = 50 // Change this to fit your needs

    // Create the buffer array to hold "MaxLines" entries
    global dim DebugOutputArray[DebugOutput.MaxLines] as string

//  ------------------------------------------------------------
//  DATA TO DEMONSTRATE UDT PARAMETER BUG
//  ------------------------------------------------------------

    // Declare data type
    type Vector2
      x as float
      y as float
    endtype

    // Declare and initialize variables (outer scope locals)
    myvector as Vector2
    myvector.x = 10
    myvector.y = 20

//  ------------------------------------------------------------
//  TEST CODE
//  ------------------------------------------------------------

// Setup display (percentage based landscape orientation)
SetDisplayAspect(1.33)
SetPrintSize(2.0)

// Output some help info...
ShowHelp()
DebugOutputAdd("Initial vector data:")
DebugOutputAdd("  myvector.x = " + str(myvector.x))
DebugOutputAdd("  myvector.y = " + str(myvector.y))
DebugOutputAdd("")

do
    // Show output
    DebugOutputShow()

    // Update display (and update device input flags)
    Sync()

    // Did user press a key?
    MyKeypress = GetAnyKey()
    select MyKeypress
        case KEY_1: myvector = Vector2_Reset(myvector) : endcase
        case KEY_2: myvector = Vector2_Normalize_Works(myvector) : endcase
        case KEY_3: myvector = Vector2_Normalize_Fails(myvector) : endcase
        case KEY_4: DebugOutputClear() : ShowHelp() : endcase
        case KEY_0: exit : endcase
    endselect
loop

function Vector2_Reset(v as Vector2)
    // Reset values and return
    v.x = 10
    v.y = 20 

    DebugOutputAdd("FUNCTION - Vector2_Reset")
    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

function Vector2_Normalize_Fails(v as Vector2)
    l as float

    DebugOutputAdd("FUNCTION - Vector2_Normalize_Fails")
    DebugOutputAdd("  Input:")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))

    // Compute length (via function call)
    l = Vector2_Length(v) // <-- this call messes up the result

    // Normalize
    v.x = v.x/l
    v.y = v.y/l

    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

function Vector2_Length(v as Vector2)
    l as float

    // Get distance from 0,0 to x,y
    l = sqrt(v.x*v.x+v.y*v.y)

    DebugOutputAdd("FUNCTION - Vector2_Length")
    DebugOutputAdd("  Input:")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    l   = " + str(l))
    DebugOutputAdd("")
endfunction l

// Works as expected...
function Vector2_Normalize_Works(v as Vector2)
    l as float

    DebugOutputAdd("FUNCTION - Vector2_Normalize_Works")
    DebugOutputAdd("  Input: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))

    // Compute length (inline)
    l = sqrt(v.x*v.x+v.y*v.y)

    DebugOutputAdd("  Length (inline calculation): ")
    DebugOutputAdd("    l = " + str(l))

    // Normalize
    v.x = v.x/l
    v.y = v.y/l

    DebugOutputAdd("  Output: ")
    DebugOutputAdd("    v.x = " + str(v.x))
    DebugOutputAdd("    v.y = " + str(v.y))
    DebugOutputAdd("")
endfunction v

//  ------------------------------------------------------------
//  SUPPORT ROUTINES ONLY
//  ------------------------------------------------------------

function ShowHelp()
    DebugOutputAdd("Keyboard help:")
    DebugOutputAdd("  1 = Initialize UDT data (reset)")
    DebugOutputAdd("  2 = Normalize vector (this works)")
    DebugOutputAdd("  3 = Normalize vector (this fails)")
    DebugOutputAdd("  4 = Clear Screen + Show help")
    DebugOutputAdd("  0 = Quit!")
    DebugOutputAdd("")
endfunction

function GetAnyKey()
    v_Scancode as integer
    v_Result   as integer
    v_Result   = 0
    v_Scancode = GetRawLastKey()
    if (GetRawKeyReleased(v_Scancode)) then v_Result = v_Scancode
endfunction v_Result

function DebugOutputAdd(a_strText as string)
    INC DebugOutput.NumLines
    if (DebugOutput.NumLines > DebugOutput.MaxLines)
        DebugOutput.NumLines = DebugOutput.MaxLines
        DebugOutputScroll() // This makes room for one more line
    endif
    inc DebugOutput.CntLines
    DebugOutputArray[DebugOutput.NumLines] = DebugOutputPadLineNum(str(DebugOutput.CntLines), " ", 4) + ": " + a_strText
endfunction

function DebugOutputShow()
    if (DebugOutput.NumLines > 0)
        for i = 1 to DebugOutput.NumLines
            print (DebugOutputArray[i])
        next
    endif
endfunction

function DebugOutputScroll()
    v_iIndex as integer
    if (DebugOutput.MaxLines > 1)
        for v_iIndex=1 to DebugOutput.MaxLines-1
            DebugOutputArray[v_iIndex] = DebugOutputArray[v_iIndex + 1]
        next
    endif
endfunction

function DebugOutputPadLineNum(a_StringToPad as string, a_strPadChar as string, a_iPadLen as integer)
    while ( Len(a_StringToPad) < a_iPadLen)
        a_StringToPad = a_StringToPad + a_strPadChar
    endwhile
endfunction a_StringToPad

function DebugOutputClear()
    // Reset line counter
    DebugOutput.NumLines = 0
endfunction

Here's a screenshot of the result:

This is another case demonstrating how flaky the UDT implementation in AppGameKit TIER1 Basic is.

I'd love to see this UDT issue fixed ASAP. I've encountered the same problem myself many times, which has caused me to avoid passing and returning UDT's to/from functions completely.

Another finding I happened to make, is that UDT's, like arrays, are given global scope, even when declared without the "global" keyword.

Here are some related reports from the AppGameKit issues list,
with my comments below:

http://code.google.com/p/agk/issues/detail?id=146
* Although stated as fixed in 107 series, definately NOT fixed in 1076.

http://code.google.com/p/agk/issues/detail?id=270
* Stated as fixed, yet appears NOT to be fixed.
* Perhaps someone should check these in the 108 beta series, and see if they ARE actually fixed or not. (I myself am still holding back on upgrading until a stable 108 release.)

Cheers,
AgentSam - the grumpy old software engineer who's very disappointed in AGK

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Ancient Lady

Valued Member

20

Years of Service

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Joined: 17th Mar 2004

Location: Anchorage, Alaska, USA

Posted: 7th Dec 2012 16:23

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AgentSam, can you please post this as a bug in the google board with your code to demonstrate it?

Once you do, I'll get it onto the AppGameKit CT site and flag it as confirmed.

Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master

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AgentSam

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Joined: 14th Mar 2012

Location: Virtual Space

Posted: 7th Dec 2012 20:49

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Ancient Lady, I just got back to checking this, and was about to post the issue, but I notice you already posted it. (Honestly, I was just going to do it, although I hate writing those reports.)

Thanks AL!

For completeness sake, here's a linkback to the issue entry:
Passing UDTs from one function to another STILL NOT WORKING

Sincerely,
AgentSam

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Ancient Lady

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Joined: 17th Mar 2004

Location: Anchorage, Alaska, USA

Posted: 7th Dec 2012 20:50

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No sweat. I just wanted to try my new bits on the AppGameKit CT site (better handling of code notations).

Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master

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george++

AGK Tool Maker

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Joined: 13th May 2007

Location: Thessaloniki, Hellas

Posted: 4th Jan 2013 20:10

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The issue still remains in the v1086

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AppGameKit Classic Chat / Function call from within another function

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