PureBasic Forums - English

Posted: **Sat Dec 16, 2023 9:10 am**

Hi there, I started using PureBasic yesterday for the first time.

I like it so far, but I have to get used to the syntax.

But I have a weird problem here, but perhaps I am overlookign something.

I created a function to define RenderObjects by passing position to draw a sprite. )With Z I want to sort the drawing order later):

Code: Select all

Procedure DefineRenderObjectAsImage(*rdrObject.RenderObject, ident$, x.i, y.i, sizeX.i, sizeY.i, z.i)
  Static objId.i
  *rdrObject\Id = objId.i
  *rdrObject\ValId = GetImage(ident$)
  *rdrObject\X = x
  *rdrObject\Y = y
  *rdrObject\Width = sizeX
  *rdrObject\Height = sizeY
  *rdrObject\Z = z
  *rdrObject\Type = #Sprite
  objId.i = objId.i + 1
  EndProcedure

Here are three objects I use:

Code: Select all

DefineRenderObjectAsImage(rdrObj1, "bia", 5, 5, 300, 300, 1)
DefineRenderObjectAsImage(rdrObj2, "bia", 155, 5, 600, 200, 25)
DefineRenderObjectAsImage(rdrObj3, "bia", 175, 85, 600, 200, 20)

But when I execute the drawing like that:

Code: Select all

Procedure RenderAll()
  SortStructuredList(RENDERCONT\RenderObjs(), #PB_Sort_Ascending, OffsetOf(RenderObject\Z), TypeOf(RenderObject\Z))
  Protected c.i = 0
  ForEach RENDERCONT\RenderObjs()
    Debug Str(c) + " . " + Str(RENDERCONT\RenderObjs()\Z) + " . " + Str(RENDERCONT\RenderObjs()\Id)
    Select RENDERCONT\RenderObjs()\Type
      Case #Sprite
        DrawSprite(RENDERCONT\RenderObjs())
    EndSelect
    c = c + 1
    ; FreeMemory(RENDERCONT\RenderObjs())
  Next
  ClearList(RENDERCONT\RenderObjs())
EndProcedure

Thing is, the drawing order becomes something like that, here see the debug:

0 . 20 . 2
1 . 25 . 1
2 . 1 . 0

So apparently in second place is z=25, so depending on ascending or descending it should either be first or last, but ends up in the middle. Am I missing something?

Posted: **Sat Dec 16, 2023 10:22 am**

I hate to create my own code to reproduce the behavior.
And I'm not sure if my version is like yours:

Code: Select all

EnableExplicit

#Sprite = 1

Structure RenderObject
  Id.i
  ValId.i
  X.i
  Y.i
  Width.i
  Height.i
  Z.i
  Type.i
  objId.i
EndStructure


Structure Test_Structure
  List RenderObjs.RenderObject()
EndStructure



Global RENDERCONT.Test_Structure

Procedure DefineRenderObjectAsImage(*rdrObject.RenderObject, ident$, x.i, y.i, sizeX.i, sizeY.i, z.i)
  Static objId.i
  *rdrObject\Id = objId.i
  *rdrObject\ValId = 1
  *rdrObject\X = x
  *rdrObject\Y = y
  *rdrObject\Width = sizeX
  *rdrObject\Height = sizeY
  *rdrObject\Z = z
  *rdrObject\Type = #Sprite
  objId.i = objId.i + 1
EndProcedure


Procedure RenderAll()
  SortStructuredList(RENDERCONT\RenderObjs(), #PB_Sort_Ascending, OffsetOf(RenderObject\Z), TypeOf(RenderObject\Z))
  Protected c.i = 0
  ForEach RENDERCONT\RenderObjs()
    Debug Str(c) + " . " + Str(RENDERCONT\RenderObjs()\Z) + " . " + Str(RENDERCONT\RenderObjs()\Id)
    Select RENDERCONT\RenderObjs()\Type
      Case #Sprite
        ;DrawSprite(RENDERCONT\RenderObjs())
    EndSelect
    c = c + 1
    ; FreeMemory(RENDERCONT\RenderObjs())
  Next
  ClearList(RENDERCONT\RenderObjs())
EndProcedure


Define.i rdrObj1, rdrObj2, rdrObj3

rdrObj1 = AddElement(RENDERCONT\RenderObjs())
rdrObj2 = AddElement(RENDERCONT\RenderObjs())
rdrObj3 = AddElement(RENDERCONT\RenderObjs())

DefineRenderObjectAsImage(rdrObj1, "bia", 5, 5, 300, 300, 1)
DefineRenderObjectAsImage(rdrObj2, "bia", 155, 5, 600, 200, 25)
DefineRenderObjectAsImage(rdrObj3, "bia", 175, 85, 600, 200, 20)

RenderAll()

This results in;

0 . 1 . 0
1 . 20 . 2
2 . 25 . 1

So ... no problem here,

Posted: **Sat Dec 16, 2023 12:25 pm**

Thanks

, worked for me to this way.

I think I found the problem.

I was doing it like that, passing the structure objects to a procedure:

Code: Select all

Structure RenderContainer
  List *RenderObjs.RenderObject()
EndStructure

Global RENDERCONT.RenderContainer

Procedure AddRenderObject(*rdrObj.RenderObject)
  AddElement(RENDERCONT\RenderObjs())
  RENDERCONT\RenderObjs() = *rdrObj
EndProcedure

as you see, i am using a pointer to add. apparently sorting this does not work correctly.

On the other hand, is there 1) a way and how do i pass a structure to a procedure where it is processed and then added to some list as a value type?

Posted: **Sat Dec 16, 2023 12:28 pm**

In this case you need CopyStructure() because else you copy only the address to an object which maybe freed later.
With CopyStructure() you copy the content.

Code: Select all

Procedure AddRenderObject(*rdrObj.RenderObject)
  AddElement(RENDERCONT\RenderObjs())
  CopyStructure(*rdrObj, RENDERCONT\RenderObjs(), RenderObject)
EndProcedure

Posted: **Sat Dec 16, 2023 12:45 pm**

Btw. your structure should look like this:

Code: Select all

Structure RenderContainer
  List RenderObjs.RenderObject()
EndStructure

not List *RenderObjs.RenderObject()

Posted: **Sat Dec 16, 2023 2:26 pm**

Makes sense. Thx.

Posted: **Sat Dec 16, 2023 2:44 pm**

another question!

I defined a prototype with

Code: Select all

Prototype.i PRenderFunc(*rdrObj.RenderObject)

Now I tried to assign it:

Code: Select all

        test.PRenderFunc = @DrawSprite
        test(RENDERCONT\RenderObjs())

What is the correct syntax to create this function pointer? Can function pointers also be used in lists or maps?

Posted: **Sat Dec 16, 2023 3:25 pm**

FranzWesten wrote: Sat Dec 16, 2023 2:44 pm What is the correct syntax to create this function pointer?

@DrawSprite()

FranzWesten wrote: Sat Dec 16, 2023 2:44 pm Can function pointers also be used in lists or maps?

Yes

PureBasic Forums - English

Sorting list of structure

Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure

Re: Sorting list of structure