Logic trouble (help asked)

[DirectuX]

Hi ,

I've got trouble understanding these two lines of code:

line 33 & line 34

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1 2	'TBGL_RenderMatrix2D(0,1,800,601) 'this works better but is not logic for me TBGL_RenderMatrix2D(1,1,800,600) 'this don't work properly

in this little piece of code

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'---Script created on 12-19-2018 17:30:47 by   uses "TBGL" uses "console"   dim htbgl as DWord 'handler for draw window   const max_x Value = 800 'window size const max_y value = 600   Function tbmain()     call window_init   call draw_loop     TBGL_DestroyWindow   end function   function draw_box()     TBGL_Line (1,1,1,max_y)   TBGL_Line (1,max_y,max_x,max_y)   TBGL_Line (max_x,max_y,max_x,1)   TBGL_Line (max_x,1,1,1)   end Function   function window_init()     htbgl = TBGL_CreateWindowEx ("800x600 - ESC to quit", 800,600,16,%TBGL_WS_WINDOWED + %TBGL_WS_DONTSIZE)   tbgl_ShowWindow   'TBGL_RenderMatrix2D(0,1,800,601) 'this works better but is not logic for me   TBGL_RenderMatrix2D(1,1,800,600) 'this don't work properly   TBGL_Color (255,255,255)   end Function   Function draw_loop()   ' -- Main loop   While tbgl_IsWindow(htbgl)     If tbgl_GetWindowKeyState(htbgl, %VK_ESCAPE) Then Exit While     tbgl_ClearFrame       call draw_box       tbgl_DrawFrame     tbgl_ResetKeyState()     Wend   end Function

[ReneMiner]

Hmm its obvious, think "openGL" - not Windows...
The order of width and height must be in another order. I think it was just clockwise but am not sure.
I did a lot using 2d-matrix, if you don't find it for example in thinICE-project you will find for sure here in this game:
https://www.thinbasic.com/community/...end-(game-RPG)

If you experience problems of the sound in the game then it's related to GetTickCount-Function, I replaced it using thinbasic Hires-timer but I don't remember if I uploaded it. Anyway its not about the game but the order of left - down - right - top or something

[DirectuX]

Hmm its obvious, think "openGL" - not Windows...
The order of width and height must be in another order. I think it was just clockwise but am not sure.

Hi Rene,

this is not about that, but about the difference between the working line 33 and the not working line 34.

Look, help for TBGL_RenderMatrix2D states that

TBGL_RenderMatrix2D[( leftX, bottomY, rightX, topY )]
leftX Specifies X coordinate for left side of current viewport
bottomY Specifies Y coordinate for bottom side of current viewport
rightX Specifies X coordinate for right side of current viewport
topY Specifies Y coordinate for top side of current viewport

so,

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const max_x Value = 800 'window size const max_y value = 600 htbgl = TBGL_CreateWindowEx ("800x600 - ESC to quit",max_x,max_y,16,%TBGL_WS_WINDOWED + %TBGL_WS_DONTSIZE) TBGL_RenderMatrix2D(1,1,max_x,max_y) 'this don't work properly TBGL_Line (1,1,1,max_y) 'drawing a box TBGL_Line (1,max_y,max_x,max_y) TBGL_Line (max_x,max_y,max_x,1) TBGL_Line (max_x,1,1,1)   ... rest of the code ...

logically, for this code, one has to see a box at the utter limit of the drawing area. This isn't the case, there is a one pixel shift and in addition not for every parameter. To work around this issue, one has to cheat with TBGL_RenderMatrix2D(0,1,max_x,max_y+1). I found it weird and illogic.

[Petr Schreiber]

Hi,

thanks a lot for this discussion, you really discovered something worth closer look.

The way raw OpenGL rasterizes some primitives is a bit unintuitive, so I tried to address it with a bit of help.

Please find here attached new version of TBGL, which should draw points and lines correctly from "expectation" point of view

You can test with the following variation of posted code below.

Before launching the code, please download and unzip the updated DLL to ThinBasic/Lib directory:
https://we.tl/t-IGCQmO63x9

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uses "TBGL"    begin const   %max_x = 800   %max_y = 600 end const    function tbMain()      window_init()   draw_loop()      tbgl_destroyWindow    end function    function draw_box()     tbgl_line (1, 1, 1, %max_y)   tbgl_line (1, %max_y, %max_x, %max_y)   tbgl_line (%max_x, %max_y, %max_x, 1)   tbgl_line (%max_x, 1, 1, 1)   end function    function window_init()      global g_win as dword = tbgl_CreateWindowEx ("Pixel perfect 2D rendering - ESC to quit", 800, 600, 32, %TBGL_WS_WINDOWED or %TBGL_WS_DONTSIZE)   tbgl_showWindow   tbgl_renderMatrix2D (1, 1, 800, 600, %TBGL_PIXEL_PERFECT_2D) ' -- New, optional switch, for pixel perfect graphics   tbgl_color 255 , 0, 255    end function    function draw_loop()      ' -- Main loop   tbgl_resetKeyState()       while tbgl_isWindow(g_win)     if tbgl_getWindowKeyState(g_win, %VK_ESCAPE) then exit while       tbgl_clearFrame          draw_box()        tbgl_drawFrame     wend    end function

Let me know how does it work for you.


Petr

[Petr Schreiber]

I performed further testing, and here is more robust version of the fix, please download here:
https://we.tl/t-3SEOPzgXCD

It will work with my example above.

Let me know whether it works for you.


Petr

[DirectuX]

I performed further testing, and here is more robust version of the fix, please download here:
https://we.tl/t-3SEOPzgXCD

It will work with my example above.

Let me know whether it works for you.


Petr

Hi Petr,

I read your answer but can't download the file : it expired meanwhile I was disconnected for Christmas break. Could you please share it anew?

[Petr Schreiber]

Sure thing,

please find it attached to this post


Petr

[DirectuX]

Thanks Petr,
I just tried it, the new parameter works ok.

By the way what do you think about the suggestion in the support thread ? https://www.thinbasic.com/community/...hp?issueid=555

[Petr Schreiber]

Very nice idea, Directux!

As TBGL development continues on gitHub, I created an issue for it:
https://github.com/ThinBASIC/thinBasic_TBGL/issues/3

Regarding pixel perfect mode, I will try to ensure it gets to the next release of thinBasic, so you can count on it.


Petr

[DirectuX]

Thanks Petr,
I just tried it, the new parameter works ok.

Hi Petr,

• too quick. There are glitches.
  Here is a sample: perfecttest.zip (use T to toggle views)
  
• In the same sample you can also notice that there is something odd with TBGL_MouseGetPos... : is there a hidden limit to returned values ? , because mouse get unexpectedly off the window at right or bottom, this doesn't occur on a smaller window.
  
• I've read github version of the issue, "...does not allow to draw visible lines using the following code" is not what I meant: lines are visible but off-setted.
  While running the illustration code you provided on github, i got this bmp which curiously is ok for me: oddity.zip
  Meanwhile, I'll try to understand the commit.

Edit: in src/tbgl_Frame.inc , line 153
why when mode2d ≠ %TBGL_PIXEL_PERFECT_2D don't you reset pixelOffset to zero ? As it is now, when switching pixel perfect mode on then off again, you don't get back the starting state (0) but (-0.5).