FTGLPolygonFont Smooth Rendering Problem

[Jorufo]

I'm simply trying to get an FTGLPolygonFont to render smoothly. When glEnable(GL_POLYGON_SMOOTH), the triangle tessellation lines appear gray. Why is it doing this. This is a 2D application. What do I do???

[-NiCo-]

You have to be careful when using polygon smoothing. It's only well defined for a subset of all possible polygons.

Multisample antialiasing is most valuable for rendering polygons, because it requires no sorting for hidden surface elimination, and it correctly handles adjacent polygons, object silhouettes, and even intersecting polygons. If only points or
lines are being rendered, the “smooth” antialiasing mechanism provided by the base GL may result in a higher quality image. This mechanism is designed to allow multisample and smooth antialiasing techniques to be alternated during the
rendering of a single scene.

So unless you're anti-aliasing lines or points it's best to use multisampling rather than polygon smoothing.

[Jorufo]

I just modified FTGL to make it do what I want:

I rewrote the following function

FTPolyGlyph::FTPolyGlyph( FT_GlyphSlot glyph, bool useDisplayList)
: FTGlyph( glyph),
glList(0)
{
if( ft_glyph_format_outline != glyph->format)
{
err = 0x14; // Invalid_Outline
return;
}

FTVectoriser vectoriser( glyph);

if(( vectoriser.ContourCount() < 1) || ( vectoriser.PointCount() < 3))
{
return;
}

unsigned int horizontalTextureScale = glyph->face->size->metrics.x_ppem * 64;
unsigned int verticalTextureScale = glyph->face->size->metrics.y_ppem * 64;

vectoriser.MakeMesh( 1.0);

if( useDisplayList)
{
glList = glGenLists( 1);
glNewList( glList, GL_COMPILE);
}

const FTMesh* mesh = vectoriser.GetMesh();
for( unsigned int index = 0; index < mesh->TesselationCount(); ++index)
{
const FTTesselation* subMesh = mesh->Tesselation( index);
unsigned int polygonType = subMesh->PolygonType();

glBegin( polygonType);
for( unsigned int pointIndex = 0; pointIndex < subMesh->PointCount(); ++pointIndex)
{
FTPoint point = subMesh->Point(pointIndex);

glTexCoord2f( point.X() / horizontalTextureScale,
point.Y() / verticalTextureScale);

glVertex3f( point.X() / 64.0f,
point.Y() / 64.0f,
0.0f);
}
glEnd();
}



glEnable(GL_LINE_SMOOTH);
glBegin( GL_LINE_LOOP);

size_t numContours = vectoriser.ContourCount();
for( unsigned int c = 0; c < numContours; ++c)
{
const FTContour* contour = vectoriser.Contour(c);

glBegin( GL_LINE_LOOP);
for( unsigned int pointIndex = 0; pointIndex < contour->PointCount(); ++pointIndex)
{
FTPoint point = contour->Point(pointIndex);
glVertex2f( point.X() / 64.0f, point.Y() / 64.0f);
}
glEnd();
}

glDisable(GL_LINE_SMOOTH);

if(useDisplayList)
{
glEndList();
}
}

[Jorufo]

By the way,

glEnable(GL_LINE_SMOOTH);
glBegin( GL_LINE_LOOP);

size_t numContours = vectoriser.ContourCount();
for( unsigned int c = 0; c < numContours; ++c)
{
const FTContour* contour = vectoriser.Contour(c);

glBegin( GL_LINE_LOOP);
for( unsigned int pointIndex = 0; pointIndex < contour->PointCount(); ++pointIndex)
{
FTPoint point = contour->Point(pointIndex);
glVertex2f( point.X() / 64.0f, point.Y() / 64.0f);
}
glEnd();
}

glDisable(GL_LINE_SMOOTH);

is my addition