public static unsafe DrawableFontAtlas RenderFontStbPacked(byte[] ttf, float fontSize, Vector2 atlasSize, int numChars, Font f, out StbTrueType.stbtt_fontinfo fontInfo)
{
var atlasObj = new DrawableFontAtlas(f, fontSize);
fontSize = atlasObj.FontSize;
fontInfo = new StbTrueType.stbtt_fontinfo();
fixed(byte *ttPtr = &ttf[0])
{
StbTrueType.stbtt_InitFont(fontInfo, ttPtr, 0);
float scaleFactor = StbTrueType.stbtt_ScaleForMappingEmToPixels(fontInfo, fontSize);
int ascent, descent, lineGap;
StbTrueType.stbtt_GetFontVMetrics(fontInfo, &ascent, &descent, &lineGap);
atlasSize *= 3; // Needs to be big as the packing sucks, and glyphs getting cut out messes with the tests.
var pixels = new byte[(int)atlasSize.X * (int)atlasSize.Y];
var pc = new StbTrueType.stbtt_pack_context();
fixed(byte *pixelsPtr = pixels)
{
StbTrueType.stbtt_PackBegin(pc, pixelsPtr, (int)atlasSize.X, (int)atlasSize.Y, (int)atlasSize.X, 1, null);
}
var cd = new StbTrueType.stbtt_packedchar[numChars];
fixed(StbTrueType.stbtt_packedchar *charPtr = cd)
{
StbTrueType.stbtt_PackFontRange(pc, ttPtr, 0, -fontSize, 0, numChars, charPtr);
}
StbTrueType.stbtt_PackEnd(pc);
for (var i = 0; i < cd.Length; ++i)
{
var atlasGlyph = DrawableGlyph.CreateForTest(cd[i].xadvance, cd[i].xoff, cd[i].x1 - cd[i].x0, cd[i].y1 - cd[i].y0);
atlasGlyph.GlyphUV = new Rectangle(cd[i].x0, cd[i].y0, atlasGlyph.Width, atlasGlyph.Height);
atlasObj.Glyphs[(char)i] = atlasGlyph;
}
}
return(atlasObj);
}
