/// <summary>
/// </summary>
/// <param name="fontBytes"></param>
/// <param name="fontSize"></param>
/// <param name="glyphCount"></param>
/// <param name="charSize">
/// Whether to create the characters in char size, on by default. If off the font size passed will
/// be the pixel size instead.
/// </param>
public FreeTypeAtlas(byte[] fontBytes, uint fontSize, int glyphCount = 128, bool charSize = true)
{
Glyphs = new Glyph[glyphCount];
Library library = new Library();
Face face = new Face(library, fontBytes, 0);
if (charSize)
{
face.SetCharSize(0, (int)fontSize, 96, 96);
}
else
{
face.SetPixelSizes(0, fontSize);
}
// Get line spacing.
LineSpacing = (float)face.Size.Metrics.Height;
Ascent = (float)face.Size.Metrics.Ascender.ToDouble();
// Get max size of the atlas texture.
int maxDimension = (int)((1 + face.Size.Metrics.Height) * Math.Ceiling(Math.Sqrt(glyphCount)));
int texWidth = 1;
while (texWidth < maxDimension)
{
texWidth <<= 1;
}
byte[] pixels = new byte[texWidth * texWidth];
int penX = 0;
int penY = 0;
// Cache all glyphs.
for (int i = 0; i < glyphCount; i++)
{
face.LoadChar((uint)i, LoadFlags.Render | LoadFlags.ForceAutohint, LoadTarget.Light);
FTBitmap bitmap = face.Glyph.Bitmap;
if (penX + bitmap.Width >= texWidth)
{
penX = 0;
penY += (int)(face.Size.Metrics.Height + 1);
}
// Copy pixels.
for (int row = 0; row < bitmap.Rows; row++)
{
for (int col = 0; col < bitmap.Width; col++)
{
int x = penX + col;
int y = penY + row;
pixels[y * texWidth + x] = bitmap.BufferData[row * bitmap.Pitch + col];
}
}
// Create glyph data.
Glyphs[i] = new Glyph
{
X = penX,
Y = penY,
Width = bitmap.Width,
Height = bitmap.Rows,
XOffset = face.Glyph.BitmapLeft,
YOffset = face.Glyph.BitmapTop,
MinX = (float)face.Glyph.Metrics.HorizontalBearingX.ToDouble(),
Advance = (float)face.Glyph.Metrics.HorizontalAdvance.ToDouble(),
YBearing = (float)(face.Size.Metrics.Ascender.ToDouble() - face.Glyph.Metrics.HorizontalBearingY.ToDouble()),
MaxX = (float)(face.Glyph.Metrics.HorizontalBearingX.ToDouble() + face.Glyph.Metrics.Width.ToDouble()),
MinY = (float)(face.Glyph.Metrics.HorizontalBearingY.ToDouble() - Math.Ceiling(face.Glyph.Metrics.Height.ToDouble())),
MaxY = (float)face.Glyph.Metrics.HorizontalBearingY.ToDouble()
};
// Increment pen. Leave one pixel space.
penX += bitmap.Width + 1;
bitmap.Dispose();
}
// Assign the face.
Face = face;
// Create texture.
GLThread.ExecuteGLThread(() =>
{
uint texturePointer = Engine.GraphicsManager.CreateTexture();
Engine.GraphicsManager.BindTexture(texturePointer);
// Set the red channel to the alpha channel and set all others to 1.
Engine.GraphicsManager.SetTextureMask(0xffffffff, 0xffffffff, 0xffffffff, 0xff000000);
Engine.GraphicsManager.UploadToTexture(pixels, new Vector2(texWidth, texWidth), TextureInternalFormat.R8, TexturePixelFormat.Red);
Texture = new GLTexture(texturePointer, new Vector2(texWidth, texWidth), Matrix4x4.CreateScale(1, -1, 1), $"{face.FamilyName} {fontSize}");
});
}
