FGFS-4.1/OpenSceneGraph
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Impprovide the computation of the Signed Distance Field

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This commit is contained in:
Robert Osfield 2017-09-14 15:58:38 +01:00
parent 70b3a3a442
commit a12a43d352
2 changed files with 41 additions and 3 deletions
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42
src/osgText/Glyph.cpp
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@ -226,6 +226,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_distance = sqrtf(float(radius*radius)+float(span*span));
if (center_value==0) local_distance += (0.5f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - 0.5f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
}
}
@ -249,6 +251,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_distance = sqrtf(float(radius*radius)+float(span*span));
if (center_value==0) local_distance += (0.5f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - 0.5f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
}
}
@ -272,6 +276,7 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_distance = sqrtf(float(radius*radius)+float(span*span));
if (center_value==0) local_distance += (0.5f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - 0.5f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
}
}
@ -296,6 +301,7 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_distance = sqrtf(float(radius*radius)+float(span*span));
if (center_value==0) local_distance += (0.5f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - 0.5f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
}
}
@ -319,8 +325,9 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
// signed distance field value
*(dest_ptr++) = value;
float outline_distance = max_distance/4.0f;
float outline_distance = max_distance/3.0f;
#if 0
// compute the alpha value of outline, one texel thick
unsigned char outline = center_value;
if (center_value<255)
@ -329,11 +336,27 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
else if (min_distance<outline_distance) outline = 255*(outline_distance-min_distance);
else outline = 0;
}
#else
// compute the alpha value of outline, one texel thick
unsigned char outline = 0;
if (center_value<255)
{
float inner_outline = outline_distance-1.0f;
if (min_distance<inner_outline) outline = 255;
else if (min_distance<=outline_distance) outline = (unsigned char)(255.0*(outline_distance-min_distance)/(outline_distance-inner_outline));
else outline = 0;
}
if (outline>center_value)
{
outline -= center_value;
}
#endif
*(dest_ptr++) = outline;
outline_distance *= 2.0f;
#if 0
// compute the alpha vlaue of outline two texel thick
outline = center_value;
if (center_value<255)
@ -342,6 +365,21 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
else if (min_distance<outline_distance) outline = 255*(outline_distance-min_distance);
else outline = 0;
}
#else
// compute the alpha value of outline, one texel thick
outline = 0;
if (center_value<255)
{
float inner_outline = outline_distance-1.0f;
if (min_distance<inner_outline) outline = 255;
else if (min_distance<=outline_distance) outline = (unsigned char)(255.0*(outline_distance-min_distance)/(outline_distance-inner_outline));
else outline = 0;
}
if (outline>center_value)
{
outline -= center_value;
}
#endif
*(dest_ptr++) = outline;
// original alpha value from glyph image

2
src/osgText/Text.cpp
View File

@ -684,7 +684,7 @@ void Text::computeGlyphRepresentation()
osg::Vec2 maxtc = glyph->getMaxTexCoord();
osg::Vec2 vDiff = maxtc - mintc;
float texelMargin = 4.0f;
float texelMargin = 5.0f;
float fHorizTCMargin = texelMargin / glyph->getTexture()->getTextureWidth();
float fVertTCMargin = texelMargin / glyph->getTexture()->getTextureHeight();