PureBasic Forums - English

Posted: **Sat Sep 16, 2006 3:31 am**

Here's an example to show what I mean (the 64x64 PNG I used can be downloaded here)

UsePNGImageDecoder()

Structure vertex
    sx.f
    sy.f
    sz.f
    rhw.f
    color.l
    specular.l
    tu.f
    tv.f
EndStructure 

  Structure PB_Sprite3D
     Texture.l              ; DirectX7 surface
     Vertice.vertex[4] ; The 4 vertices for the rectangle sprite
     Width.w
     Height.w
  EndStructure 

InitSprite()
InitSprite3D()

OpenScreen(640,480,32,"example")

CatchSprite(0,?bitmap,#PB_Sprite_Texture | #PB_Sprite_AlphaBlending)
CreateSprite3D(0,0)
ZoomSprite3D(0,64,64)
CreateSprite3D(1,0)
ZoomSprite3D(1,64,64)

*sprite.PB_Sprite3D=IsSprite3D(1)

Sprite3DQuality(1)

x.f=0

Repeat
  
  x=x+0.05
  If x>576
    x=0
  EndIf
  
  f.f=x-Round(x,0)
  
  *sprite\Vertice[0]\sx=f
  *sprite\Vertice[1]\sx=64+f
  *sprite\Vertice[2]\sx=f
  *sprite\Vertice[3]\sx=64+f
    
  ClearScreen(RGB(0,0,64))
  Start3D()
    DisplaySprite3D(0,x,0,255)      
    DisplaySprite3D(1,Round(x,0),64,255)
  Stop3D()

  FlipBuffers()

Until GetAsyncKeyState_($1B)

CloseScreen()

End

DataSection

bitmap:
IncludeBinary("test.png")

EndDataSection

The top sprite jumps a whole pixel every 20 frames - the x position is rounded to the nearest pixel. The bottom sprite show how it would look with my proposed feature request - the sprite moves smoothly.

Posted: **Sat Sep 16, 2006 6:16 pm**

I've never noticed that before.

Posted: **Sat Sep 23, 2006 11:05 pm**

Floats and doubles are ignored for positioning? I'm about to convert some code into a PureBASIC engine I'm developing, and if this is as bad as it seems I might need to re-think my use of PureBASIC.

This has serious implications for smooth movement in games - a major priority Fred.

Posted: **Fri Oct 06, 2006 4:57 pm**

Steve Elliott wrote:This has serious implications for smooth movement in games - a major priority Fred.

Only when movements are slower than (DisplayedFramesPerSecond)*pixel/second.
Usually, when movements are slower than 30 pixel/second.

But i second this request, of course!

Posted: **Fri Oct 06, 2006 5:52 pm**

third, i wondered why my scrolling maps seemed to move kind of jerky...

Posted: **Thu Nov 09, 2006 11:00 am**

Any news on this issue Fred?

Posted: **Mon Jan 15, 2007 2:15 pm**

chris_b wrote:Presumably with both DirectX and OpenGL the various parameters for positioning, rotating and transforming Sprite3Ds will be converted to floating point values anyway - so there's no reason for Sprite3D functions not to accept floats for these parameters.

i second the request, but what about 2d sprites?? are they meant to accept floats for positioning aswell?? would be cool.

c ya,
nco2k

Posted: **Mon Jan 15, 2007 2:36 pm**

2D sprites only consist of complete pixel.
there is no smoothing between the pixels.
according to this, 2D sprites only can positioned on full pixels,
so there is no use for float-parameters.

concerning float parameters for Sprite3D-commands:

would not only be a good idea, but its essetially.
maybe it was easier that way before PB supported Doubles,
but not it does, so the Sprite3D-Lib should be changed soon.

I think the 3D-features on Linux and on Mac support floats, too, don't they?

Posted: **Mon Nov 18, 2013 8:10 am**

Very sorry to resurrect such an old thread (I couldn't find a newer one addressing this), but has this been added / changed as of PB 5.2x? It doesn't appear to be possible in the 5.20 demo. It's something that is somewhat important to me, to be able to draw sprites at non-whole number positions for smooth slow speed movement. Is there a good workaround if not? (Something mutiplatform...)

Thanks!

Posted: **Mon Nov 18, 2013 10:18 am**

You can't draw sprite at a non-whole number position as in PB the base unit is the pixel and you can't have an half pixel. Just you float if you need slow motion and it will display it slower, on pixel basis.

Posted: **Mon Nov 18, 2013 12:01 pm**

Fred wrote:You can't draw sprite at a non-whole number position as in PB the base unit is the pixel and you can't have an half pixel. Just you float if you need slow motion and it will display it slower, on pixel basis.

You can.
TransformSprite() accept floats, so you can make move on sub pixel base, like in this example.
On top the normal DisplaySprite, on bottom the sub pixel move with TransformSprite().

Code: Select all

InitSprite()

UsePNGImageDecoder()

Enumeration
	#Window
	#Sprite
EndEnumeration

OpenWindow(#Window, 0, 0, 300, 300, "Sprite", #PB_Window_SystemMenu|#PB_Window_ScreenCentered)
OpenWindowedScreen(WindowID(#Window), 0, 0, WindowWidth(#Window), WindowHeight(#Window), 0, 0, 0)
SpriteQuality(#PB_Sprite_BilinearFiltering)

CreateSprite(#Sprite, 32, 32)
StartDrawing(SpriteOutput(#Sprite))
	Box(10, 1, 2, 30, $FF8080)
	Box(16, 1, 2, 30, $80FF80)
	Box(22, 1, 2, 30, $8080FF)
	Line(1, 16, 30, 1, $FFFFFF)
StopDrawing()

Define Start = ElapsedMilliseconds()
Define X.f

Repeat
	
	Repeat
		
		Select WindowEvent()
			Case #PB_Event_CloseWindow
				End
			Case #Null
				Break
		EndSelect
		
	ForEver
	
	ClearScreen(0)
	
	X = 50+(ElapsedMilliseconds()-Start)/1000
	
	ZoomSprite(#Sprite, 32, 32)
	DisplaySprite(#Sprite, X, X)
	
	TransformSprite(#Sprite, X, X+50, X+SpriteWidth(#Sprite), X+50, X+SpriteWidth(#Sprite), X+50+SpriteHeight(#Sprite), X, X+50+SpriteHeight(#Sprite))
	DisplaySprite(#Sprite, 0, 0)
	
	FlipBuffers()
	
ForEver

Posted: **Mon Nov 18, 2013 12:34 pm**

Now that's interesting, always something new to learn

.

ps: on my screen it looks a bit wierd, like a bit of intensity change when being between pixels (I guess it's GFX card interpolations to emulate this)

Posted: **Mon Nov 18, 2013 2:51 pm**

Fred wrote:ps: on my screen it looks a bit wierd, like a bit of intensity change when being between pixels (I guess it's GFX card interpolations to emulate this)

This is the SpriteQuality(#PB_Sprite_BilinearFiltering), so there is a linear fitting between two texture pixels.
Bilinear means, a white sub-pixel and a black sub-pixel gets a gray full pixel (intensity change)
If you change it to #PB_Sprite_NoFiltering, you can't see this fitting.

Posted: **Mon Nov 18, 2013 3:00 pm**

Fred wrote: ps: on my screen it looks a bit wierd, like a bit of intensity change when being between pixels (I guess it's GFX card interpolations to emulate this)

It's due to the bilinear filtering. Just change SpriteQuality to #PB_Sprite_NoFiltering and this does not work anymore.
In fact it's not the same image drawn when using subpixel movement, or it would not be possible to move something composed by pixels by less than a pixel when the physical screen resolution is a pixel. The filtering change the pixels colors and give a simil-antialiased illusion of smaller movements and cause the weird effect you are seeing.

Also, if you change the sprite to this one:

Code: Select all

StartDrawing(SpriteOutput(#Sprite))
   Box(0, 0, 32, 32, $FF0000) 
StopDrawing()

does not work even with the filtering active.

EDIT: Well, too late

Posted: **Mon Nov 18, 2013 3:39 pm**

@STARGÅTE, yep, exactly what I'm asking about. I thought that enabling bilinear filtering would do it for DisplaySprite(), but thanks for the TransformSprite() tip.

Too bad using RotateSprite() or ZoomSprite(), etc. resets the previous matrix transformations..

@Fred, yeah, I know you can send a float and it will round to the nearest pixel, but IMO this looks worse for certain sprites (not all), than interpolating. The GFX card is basically changing the alpha of image pixels depending on "how much" they are in a physical pixel, so it actually looks good with sprites that already have an antialiased edge to them. (The GFX card is already essentially doing this when transforming image pixels to other resolutions than native.)

EDIT:
It also helps movement appear smoother at fast speeds:

With this image:

Code: Select all

InitSprite()

UsePNGImageDecoder()

Enumeration
   #Window
   #Sprite
EndEnumeration

OpenWindow(#Window, 0, 0, 300, 300, "Sprite", #PB_Window_SystemMenu|#PB_Window_ScreenCentered)
OpenWindowedScreen(WindowID(#Window), 0, 0, WindowWidth(#Window), WindowHeight(#Window), 0, 0, 0)
SpriteQuality(#PB_Sprite_BilinearFiltering)

;CreateSprite(#Sprite, 32, 32)
; StartDrawing(SpriteOutput(#Sprite))
;    Box(10, 1, 2, 30, $FF8080)
;    Box(16, 1, 2, 30, $80FF80)
;    Box(22, 1, 2, 30, $8080FF)
;    Line(1, 16, 30, 1, $FFFFFF)
;    StopDrawing()
   
   LoadSprite(#Sprite, "circle.png", #PB_Sprite_AlphaBlending)

Define Start = ElapsedMilliseconds()
Define X.f
Define delta.f

Repeat
   
   Repeat
      
      Select WindowEvent()
         Case #PB_Event_CloseWindow
            End
         Case #Null
            Break
      EndSelect
      
    ForEver
    
    delta = (ElapsedMilliseconds() - Start)/1000
    Start = ElapsedMilliseconds()
   
   ClearScreen($FFFFFF)
   
   X = X+9*delta
   
   ZoomSprite(#Sprite, 32, 32)
   DisplayTransparentSprite(#Sprite, X, X)
   
   TransformSprite(#Sprite, X, X+50, X+SpriteWidth(#Sprite), X+50, X+SpriteWidth(#Sprite), X+50+SpriteHeight(#Sprite), X, X+50+SpriteHeight(#Sprite))
   DisplayTransparentSprite(#Sprite, 0, 0)
   
   FlipBuffers()
   
 ForEver

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Sprite3D functions to accept floats

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