FGFS-4.1/OpenSceneGraph
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Improvements to SDF and outline generation

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This commit is contained in:
Robert Osfield
2017-09-26 10:42:47 +01:00
parent 708ae1c076
commit 6d4128324b
2 changed files with 28 additions and 22 deletions
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39
src/osgText/Glyph.cpp
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@@ -164,7 +164,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
int upper = glyph->t()+search_distance;
float multiplier = 1.0/255.0f;
float max_distance = sqrtf(float(search_distance*search_distance)*2.0f);
float max_distance = glyph->getFontResolution().first/4;
int num_channels = TEXTURE_IMAGE_NUM_CHANNELS;
@@ -177,8 +178,12 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
bool use_SDF_for_Outline = true;
float outer_outline_distance = float(search_distance);
float inner_outline_distance = float(outer_outline_distance)/2.0f;
float outer_outline_distance = float(glyph->getFontResolution().first)*0.14f;
float inner_outline_distance = outer_outline_distance*0.5f;
unsigned char full_on = 255;
unsigned char mid_point = full_on/2;
float mid_point_f = float(mid_point)*multiplier;
for(int dr=lower; dr<=upper; ++dr)
{
@@ -195,19 +200,19 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float center_value_f = center_value*multiplier;
float min_distance = FLT_MAX;
if (center_value>0 && center_value<255)
if (center_value>0 && center_value<full_on)
{
inner_max_value = 255;
outer_max_value = 255;
if (center_value_f>=0.5f)
if (center_value_f>=mid_point_f)
{
min_distance = center_value_f-0.5f;
min_distance = center_value_f-mid_point_f;
value = 128+(min_distance/max_distance)*127;
}
else
{
min_distance = 0.5f-center_value_f;
min_distance = mid_point_f-center_value_f;
value = 127-(min_distance/max_distance)*127;
}
}
@@ -235,8 +240,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_multiplier = (abs(dx)>abs(dy)) ? D/float(abs(dx)) : D/float(abs(dy));
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 (center_value==0) local_distance += (mid_point_f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - mid_point_f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
@@ -263,8 +268,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_multiplier = (abs(dx)>abs(dy)) ? D/float(abs(dx)) : D/float(abs(dy));
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 (center_value==0) local_distance += (mid_point_f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - mid_point_f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
@@ -292,8 +297,8 @@ 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 (center_value==0) local_distance += (mid_point_f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - mid_point_f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
@@ -320,8 +325,8 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
float local_multiplier = (abs(dx)>abs(dy)) ? D/float(abs(dx)) : D/float(abs(dy));
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 (center_value==0) local_distance += (mid_point_f-local_value_f)*local_multiplier;
else local_distance += (local_value_f - mid_point_f)*local_multiplier;
if (local_distance<min_distance) min_distance = local_distance;
@@ -349,7 +354,7 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
// signed distance field value
*(dest_ptr++) = value;
float outline_distance = max_distance/3.0f;
float outline_distance = inner_outline_distance;
// compute the alpha value of outline, one texel thick
unsigned char outline = 0;
@@ -376,7 +381,7 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
*(dest_ptr++) = outline;
outline_distance *= 2.0f;
outline_distance = outer_outline_distance;
// compute the alpha value of outline, one texel thick
outline = 0;