Re: [osg-users] How to disable Antialiasing of an osg::Text

[Robert Osfield]

Hi Lv,

It looks like you are position the text in a 3D scene and leaving it
to scale in object coordinates, which is fine, but it does mean that
the scale will and orientation will vary, this is very different
challenge for rendering clear text than rendering a fixed font to a
fixed 2D projection like you have with a typical Qt application.  You
simple can't compare fonts working in 3D and 2D domains.

That aside to get the best quality of text in a 3d scene you'll
typically want to aim for a font resolution around the on screen
resolution that the text will typically be rendered at, in full 3D
scene this scaling obviously varies so there won't be one ideal
resolution, you'll just have to pick the best one for your the size of
your text and the distances you view them at.

Disabling of placing text into the transparent bin could cause real
problems as the blending of the text could be broken.  Text is put in
the transparent bin to make sure it's rendered after the rest of the
3D scene to make sure that the transparent parts of the text are
correctly blending and the quads text doesn't interfere with with the
zbuffer.  I don't know whether this is affecting quality for you as
you don't say anything about what you by "decluttering".

Robert.

On 14 March 2017 at 17:07, Lv Qing  wrote:
> Hi,
>
> Thx Robert!
>
>I use one of osgEarth fuction to rendering my text.
>
>
>
> Code:
>
>
> osg::ref_ptr PowerPlaceNode::createPlaceNodeTextDrawable(const 
> std::string& text,
> const TextSymbol* symbol, const osg::Vec3& positionOffset)
> {
> osg::ref_ptr < osgText::Text > t = new osgText::Text();
> osgText::String::Encoding text_encoding = 
> osgText::String::ENCODING_UNDEFINED;
> if (symbol && symbol->encoding().isSet())
> {
> switch (symbol->encoding().value())
> {
> case TextSymbol::ENCODING_ASCII:
> text_encoding = osgText::String::ENCODING_ASCII;
> break;
> case TextSymbol::ENCODING_UTF8:
> text_encoding = osgText::String::ENCODING_UTF8;
> break;
> case TextSymbol::ENCODING_UTF16:
> text_encoding = osgText::String::ENCODING_UTF16;
> break;
> case TextSymbol::ENCODING_UTF32:
> text_encoding = osgText::String::ENCODING_UTF32;
> break;
> default:
> text_encoding = osgText::String::ENCODING_UTF8;
> break;   //editby lvqing 20140509
> }
> }
>
> t->setText(text, osgText::String::ENCODING_UTF8);
>
>
> if (symbol && symbol->pixelOffset().isSet())
> {
> t->setPosition(
> osg::Vec3(positionOffset.x() + 
> symbol->pixelOffset()->x(),
> positionOffset.y() + 
> symbol->pixelOffset()->y(), positionOffset.z()));
> }
> else
> {
> t->setPosition(positionOffset);
> }
>
> osgText::Font* font = 0L;
> if (symbol && symbol->font().isSet())
> {
> font = osgText::readFontFile(*symbol->font()); // read font*/
> }
>
> t->setFontResolution(256,256);
>
> t->setAutoRotateToScreen(false);
> t->setCharacterSizeMode(osgText::Text::OBJECT_COORDS);
>
> if (symbol != NULL)
> {
> if (symbol->size() != NULL)
> {
> t->setCharacterSize( symbol && symbol->size().isSet() 
> ? *symbol->size() : 20.0f );
> }
> else
> {
> t->setCharacterSize( 20.0f );
> }
> }
>
> if (!font)
> font = Registry::instance()->getDefaultFont();
> if (font)
> {
> t->setFont(font);
> }
>
> t->setColor(symbol && symbol->fill().isSet() ? 
> symbol->fill()->color() : Color::White);
>
> if (symbol)
> {
> // they're the same enum.
> osgText::Text::AlignmentType at = 
> (osgText::Text::AlignmentType) symbol->alignment().value();
> t->setAlignment(at);
> }
>
> if (symbol && symbol->halo().isSet())
> {
> t->setBackdropColor(symbol->halo()->color());
> t->setBackdropType(osgText::Text::OUTLINE);
>
> if (symbol->haloOffset() != NULL)
> {
> if (symbol->haloOffset().isSet())
> {
> t->setBackdropOffset(*symbol->haloOffset(), 
> *symbol->haloOffset());
> }
> }
> }
> else if (!symbol)
> {
>

Re: [osg-users] How to disable Antialiasing of an osg::Text

[Robert Osfield]

Hi Lv,

>  You mention A 1:1 ratio will likely minimize these effects.Which 
> function excatly I should call?

There isn't a single function that you can use to do, as well, it's
impossible to implement in a general purpose 3d text implementation.
Only if you have screen aligned text can you start to think about
setting the font resolution (Text::setFontResolution(..) to match the
on screen resolution,

You haven't said anything about you are rendering your text really
can't provide any specific recommendations.

Robert.
___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

Re: [osg-users] How to disable Antialiasing of an osg::Text

[Lv Qing]

robertosfield wrote:
> HI Lv,
> 
> osgText::Text renders into a 3D scene using OpenGL, which is quite
> different than Qt rendering to a 2D window where font resolutions can
> exactly matched to the pixels on screen, so you can't really compare
> the two.
> 
> osgText::Text itself doesn't implement anti-aliasing, anti-aliasing is
> a property of the GraphicsWindow that you've created.  For the
> blurriness you reporting it's unlikely to be an high level
> anti-aliasing issue.
> 
> My guess is that it's more likely an issue of undersampling of the
> glyph texture (magnification) if the size of glyph on screen is lower
> than the font resolution, or possible magnification if the glyph on
> screen is smaller than the font resolution.  A 1:1 ratio will likely
> minimize these effects.
> 
> You don't provide any guidance on how you are rendering so I can't
> provide any more details than this.
> 
> Robert.
> 
> On 2 March 2017 at 17:41, Lv Qing <> wrote:
> 
> > Hi,
> > 
> > In linux we are using  osg::Text to display some chinese characters.Then
> > we find the  osg::Text looks a little blur when the size of characters is 
> > small.Or,the Black characters  seems a little gray when the character size 
> > is small.I have setFontSolution(128,128),it not help.
> > 
> > Then I fond our old app which using QT to draw text,and with the same 
> > font,QT text looks better than  osg::Text.
> > 
> > I fond QT use QPaint to loading font and drawing text ,and It can enable or 
> > disable Antialiasing of text  like below.
> > 
> > 
> > 
> > Code:
> > class Q_GUI_EXPORT QPainter
> > {
> > Q_DECLARE_PRIVATE(QPainter)
> > Q_GADGET
> > Q_FLAGS(RenderHint RenderHints)
> > 
> > public:
> > enum RenderHint {
> > Antialiasing = 0x01,
> > TextAntialiasing = 0x02,
> > SmoothPixmapTransform = 0x04,
> > HighQualityAntialiasing = 0x08,
> > NonCosmeticDefaultPen = 0x10
> > };
> > 
> > 
> > 
> > 
> > So my question is ,does osg can  enable or disable Antialiasing to an 
> > osg::Text?
> > 
> > 
> > 
> > 
> > ...
> > 
> > Thank you!
> > 
> > Cheers,
> > Lv
> > Code:
> > 
> > 
> > 
> > 
> > --
> > Read this topic online here:
> > http://forum.openscenegraph.org/viewtopic.php?p=70395#70395
> > 
> > 
> > 
> > 
> > 
> > ___
> > osg-users mailing list
> > 
> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> > 
> ___
> osg-users mailing list
> 
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> 
>  --
> Post generated by Mail2Forum




Thx! robert!

 You mention A 1:1 ratio will likely minimize these effects.Which function 
excatly I should call?
 
   ThX 
again!

--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=70406#70406





___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

Re: [osg-users] How to disable Antialiasing of an osg::Text

[Robert Osfield]

HI Lv,

osgText::Text renders into a 3D scene using OpenGL, which is quite
different than Qt rendering to a 2D window where font resolutions can
exactly matched to the pixels on screen, so you can't really compare
the two.

osgText::Text itself doesn't implement anti-aliasing, anti-aliasing is
a property of the GraphicsWindow that you've created.  For the
blurriness you reporting it's unlikely to be an high level
anti-aliasing issue.

My guess is that it's more likely an issue of undersampling of the
glyph texture (magnification) if the size of glyph on screen is lower
than the font resolution, or possible magnification if the glyph on
screen is smaller than the font resolution.  A 1:1 ratio will likely
minimize these effects.

You don't provide any guidance on how you are rendering so I can't
provide any more details than this.

Robert.

On 2 March 2017 at 17:41, Lv Qing  wrote:
> Hi,
>
> In linux we are using  osg::Text to display some chinese characters.Then
>  we find the  osg::Text looks a little blur when the size of characters is 
> small.Or,the Black characters  seems a little gray when the character size is 
> small.I have setFontSolution(128,128),it not help.
>
>Then I fond our old app which using QT to draw text,and with the same 
> font,QT text looks better than  osg::Text.
>
>I fond QT use QPaint to loading font and drawing text ,and It can enable 
> or disable Antialiasing of text  like below.
>
>
>
> Code:
> class Q_GUI_EXPORT QPainter
> {
> Q_DECLARE_PRIVATE(QPainter)
> Q_GADGET
> Q_FLAGS(RenderHint RenderHints)
>
> public:
> enum RenderHint {
> Antialiasing = 0x01,
> TextAntialiasing = 0x02,
> SmoothPixmapTransform = 0x04,
> HighQualityAntialiasing = 0x08,
> NonCosmeticDefaultPen = 0x10
> };
>
>
>
>
>  So my question is ,does osg can  enable or disable Antialiasing to an 
> osg::Text?
>
>
>
>
> ...
>
> Thank you!
>
> Cheers,
> Lv
> Code:
>
>
>
>
> --
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=70395#70395
>
>
>
>
>
> ___
> osg-users mailing list
> osg-users@lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

[osg-users] How to disable Antialiasing of an osg::Text

[Lv Qing]

Hi,

In linux we are using  osg::Text to display some chinese characters.Then
 we find the  osg::Text looks a little blur when the size of characters is 
small.Or,the Black characters  seems a little gray when the character size is 
small.I have setFontSolution(128,128),it not help.

   Then I fond our old app which using QT to draw text,and with the same 
font,QT text looks better than  osg::Text.

   I fond QT use QPaint to loading font and drawing text ,and It can enable or 
disable Antialiasing of text  like below.



Code:
class Q_GUI_EXPORT QPainter
{
Q_DECLARE_PRIVATE(QPainter)
Q_GADGET
Q_FLAGS(RenderHint RenderHints)

public:
enum RenderHint {
Antialiasing = 0x01,
TextAntialiasing = 0x02,
SmoothPixmapTransform = 0x04,
HighQualityAntialiasing = 0x08,
NonCosmeticDefaultPen = 0x10
};




 So my question is ,does osg can  enable or disable Antialiasing to an 
osg::Text?




... 

Thank you!

Cheers,
Lv
Code:




--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=70395#70395





___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org