LineXY

Saki · **Posted:** Sun Sep 13, 2020 5:03 pm

Thanks Wilbert,
i don't use it, because i primarily didn't see any advantage over point and plot.
With assembler this is something different again !

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

@mk-soft For now, you are way over my head, but maybe when I know PB better.

I did a test routine I'm for a start are satisfied with:

Code:

lenght.w = 1600                                           ; window size
height.w = 800
scale.w = 200
xpos.w = 500                                              ; center for unit circle
ypos.w = 500
x.f = 0                                                   ; periferi coordinates for unit circle
y.f = 0
t.f = 0                                                   ; start circle 3 o clock

If OpenWindow(0, 0, 0, lenght, height, "2D-test", #PB_Window_SystemMenu | #PB_Window_Normal)
    If CreateImage(0, lenght, height) And StartDrawing(ImageOutput(0))
      Box(0, 0, lenght, height, RGB(255, 255, 255))
                     
      Repeat
        
        x = Cos(t) * scale        
        y = Sin(t) * scale
        
        y *-1                                             ; move normal anti clockwise for unit circle 
        
        x + xpos
        y + ypos
        
        LineXY(500, 500, x, y, $FF0000)
        ;Plot(x, y, RGB (0, 0, 255))
        
        t + 0.0314                                        ; jump 1/100 PI RADIAN
        
        ;Debug Str(Int(xpos+x)) + "," + Str(Int(ypos+y))
        
      Until t >= #PI                                      ; half unit circle = 1 PI RADIAN

      StopDrawing() 
      ImageGadget(0, 0, 0, 200, 200, ImageID(0))
    EndIf
    
    Repeat
      Event = WaitWindowEvent()
    Until Event = #PB_Event_CloseWindow
  EndIf

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

The line:

LineXY(500, 500, x, y, $FF0000)

should of course have been:

LineXY(xpos, ypos, x, y, $FF0000)

kernadec · **Joined:** Tue Jan 05, 2010 10:35 am **Posts:** 109

hello
Little description

Code:

x.l = 100
y.l = 100
x1.l = 400
y1.l = 400
If OpenWindow(0, 0, 0, 600, 600, "Description Function Drawing line", #PB_Window_SystemMenu | #PB_Window_ScreenCentered)
  CanvasGadget(0, 0, 0,600, 600)
  
  StartDrawing(CanvasOutput(0))
  
  DrawingMode(#PB_2DDrawing_Outlined)
  
  Box(x, y, x1, y1,#Black)
  
  Line(x, y, x1, y1,#Red) 
  
  ;  Analysis Function Drawing Line in PureBasic
  ;  angle projection line = atn( x1 / y1 ) = 45 deg
  ;  long  projection line = square( x1 ^ 2 + y1 ^ 2 ) = 565.685425 
  ;  example diameter hypothenus square to 45 degree
  
  Circle(x1 - 100, y1 - 100, 565 / 2, #Blue)
  
  StopDrawing()
  
  Repeat : Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf

best regard

mk-soft · **Posted:** Mon Sep 14, 2020 11:10 am

Example with Macros ...
At time need alway color parameter.

Code:

;-TOP

DeclareModule Flip2d
  Global _OffsetY_.i
  
  Macro _PB_(_Function_)
    _Function_
  EndMacro
  
  Macro SetOffset(_Value_)
    _OffsetY_ = _Value_
  EndMacro
  
  Macro Line(x, y, Width, Height, Color)
    _PB_(Line)(x, _OffsetY_ - (y), Width, (Height) * -1, Color)
  EndMacro
  
  Macro Box(x, y, Width, Height, Color)
    _PB_(Box)(x, _OffsetY_ - (y), Width, (Height) * -1, Color)
  EndMacro
  
  Macro Circle(x, y, Radius, Color)
    _PB_(Cirle)(x, _OffsetY_ - (y), Radius, Color)
  EndMacro
  
EndDeclareModule

Module Flip2d
  
EndModule


If OpenWindow(0, 0, 0, 200, 200, "2DDrawing Example", #PB_Window_SystemMenu | #PB_Window_ScreenCentered)
  If CreateImage(0, 200, 200) And StartDrawing(ImageOutput(0))
    
    Box(0, 0, 200, 200, RGB(255, 255, 255))
    Box(160, 20, 20, 20, RGB(255, 0, 0))
    
    UseModule Flip2d
    SetOffset(200)
    
    Box(160, 20, 20, 20, RGB(0, 255, 0))
    
    For Width = 1 To 180 Step 5
      Line(10, 10, Width, 180, RGB(Random(255), Random(255), Random(255)))
    Next Width
    StopDrawing() 
    ImageGadget(0, 0, 0, 200, 200, ImageID(0))
  EndIf
  
  Repeat
    Event = WaitWindowEvent()
  Until Event = #PB_Event_CloseWindow
EndIf

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

I'm currently writing a program that needs a lot of collision detection and scrolling.

I converted some of my code from BBC BASIC to Pure Basic with ease, but the upside-down for y-values adds another layer of difficulties that makes it extra hard and is a hurdle for me.

I really, really like PB but for now I have to be productive again because of a deadline.

Cheers.

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

Little John wrote:

Ivan wrote:

@Little John

"(this is the classic behaviour of the BASIC programming language)." - not the BBC Basic I was used to in the eighties.

OK. But it works that way in many classic BASIC flavours, IIRC e.g. in GW-BASIC, QBASIC, QuickBASIC, Turbo BASIC, PowerBASIC, ...

Ivan wrote:

That very little I know about a coordinate system and math: Incrementing y-values goes up - not down.

This is true for the "normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various other coordinate systems, and everyone is free to define her/his own coordinate system. The creators of many classic BASIC flavours took the freedom to define it the way that incrementing y-values go down from the top.

("normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various...)

With my little knowledge in matematics and geometry I assumed that most programmers are not matemathecians allthough we use matematics to some extend and could use the knowledge we already have.

Little John · **Posted:** Wed Sep 16, 2020 9:59 am

Ivan wrote:

Little John wrote:

Ivan wrote:

@Little John

"(this is the classic behaviour of the BASIC programming language)." - not the BBC Basic I was used to in the eighties.

OK. But it works that way in many classic BASIC flavours, IIRC e.g. in GW-BASIC, QBASIC, QuickBASIC, Turbo BASIC, PowerBASIC, ...

Ivan wrote:

That very little I know about a coordinate system and math: Incrementing y-values goes up - not down.

This is true for the "normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various other coordinate systems, and everyone is free to define her/his own coordinate system. The creators of many classic BASIC flavours took the freedom to define it the way that incrementing y-values go down from the top.

("normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various...)

With my little knowledge in matematics and geometry I assumed that most programmers are not matemathecians allthough we use matematics to some extend and could use the knowledge we already have.

You don't have to be a mathematician in order to be able to use PureBasic's LineXY() command properly (and I didn't write that).
When you start using a new programming language, you better should be prepared for learning new stuff.
Usage of PureBasic's LineXY() command is documented properly, and you've got a lot of additional information in this thread.

So what is the problem now :?:

Saki · **Posted:** Wed Sep 16, 2020 10:09 am

Little John is right !

It is a strange large thread.
Making simple things mostly complicated. :wink:

You have to do it like it says in the manual :!:

oreopa · **Posted:** Wed Sep 16, 2020 10:15 am

Does BBC BASIC invert the Y coords? Didn't know that... interesting...

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

Little John wrote:

Ivan wrote:

Little John wrote:

Ivan wrote:

@Little John

"(this is the classic behaviour of the BASIC programming language)." - not the BBC Basic I was used to in the eighties.

OK. But it works that way in many classic BASIC flavours, IIRC e.g. in GW-BASIC, QBASIC, QuickBASIC, Turbo BASIC, PowerBASIC, ...

Ivan wrote:

That very little I know about a coordinate system and math: Incrementing y-values goes up - not down.

This is true for the "normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various other coordinate systems, and everyone is free to define her/his own coordinate system. The creators of many classic BASIC flavours took the freedom to define it the way that incrementing y-values go down from the top.

("normal" Cartesian coordinate system that most people learn at school. Hoewever, mathematicians also work with various...)

With my little knowledge in matematics and geometry I assumed that most programmers are not matemathecians allthough we use matematics to some extend and could use the knowledge we already have.

You don't have to be a mathematician in order to be able to use PureBasic's LineXY() command properly (and I didn't write that).
When you start using a new programming language, you better should be prepared for learning new stuff.
Usage of PureBasic's LineXY() command is documented properly, and you've got a lot of additional information in this thread.

So what is the problem now :?:

Of course you have to learn new stuff, if you try another languages - what else.

I was apparently not succesfull in explaining that in a x,y coordinat system I know of will y increment, when you go up - that it.

No problem, if you ask me.

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

oreopa wrote:

Does BBC BASIC invert the Y coords? Didn't know that... interesting...

BBC BASIC does what I have learned about coordinate systems.

For me it's logically when y = 0 then you are on the floor and increasing y-values goes upwards.

And that view goes fine with the origin at 0,0 and move in a quadrant or in an octant 0,0,0

Ivan · **Joined:** Fri Sep 11, 2020 1:53 pm **Posts:** 25

Saki wrote:

Little John is right !

It is a strange large thread.
Making simple things mostly complicated. :wink:

You have to do it like it says in the manual :!:

Agreed.

If I won't follow the manual I'll have to invert y myself.

I thought I had explained that.

Little John · **Posted:** Wed Sep 16, 2020 1:08 pm

Ivan wrote:

Of course you have to learn new stuff, if you try another languages - what else.

Well, you previously wrote

Quote:

I assumed that [.. we ..] could use the knowledge we already have.

Hence my respective reply.

Ivan wrote:

No problem, if you ask me.

I still do not understand why in this message you quoted text from me, and what the purpose of that message was ...
However, when there are no problems, that's fine. :-)

oreopa · **Posted:** Thu Sep 17, 2020 2:51 am

Ivan wrote:

oreopa wrote:

Does BBC BASIC invert the Y coords? Didn't know that... interesting...

BBC BASIC does what I have learned about coordinate systems.

For me it's logically when y = 0 then you are on the floor and increasing y-values goes upwards.

And that view goes fine with the origin at 0,0 and move in a quadrant or in an octant 0,0,0

It's not an issue for me for you to have your own preference

I have no comment on that at all...

I should have been clearer. I was simply interested in the way the BBC is handling this internally... it means that bitmap memory is stored left-right/bottom-up? Or that it's just simply a translation in basic interpreter that y=0 is the bottom? Curious... I will look into it...

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