public TextGenerator(string path, string fontName, uint fontSize = 12)
{
if (_textPs == null)
{
LoadProgramShader();
}
FontName = fontName;
FontSize = fontSize;
SharpFont.Library fontLib = new SharpFont.Library();
SharpFont.Face fontFace = new SharpFont.Face(fontLib, path);
fontFace.SetPixelSizes(0, FontSize);
GL.PixelStore(PixelStoreParameter.UnpackAlignment, 1);
for (char c = (char)0x20; c <= (char)0x7E; c++)
{
fontFace.LoadChar(c, LoadFlags.Render, LoadTarget.Normal);
Texture texture = Texture.CreateTexture(
fontFace.Glyph.Bitmap.Width,
fontFace.Glyph.Bitmap.Rows,
PixelInternalFormat.R8,
PixelFormat.Red,
fontFace.Glyph.Bitmap.Buffer);
Character character = new Character(
texture.ID,
new Vector2(fontFace.Glyph.Bitmap.Width, fontFace.Glyph.Bitmap.Rows),
new Vector2(fontFace.Glyph.BitmapLeft, fontFace.Glyph.BitmapTop),
(int)fontFace.Glyph.Advance.X);
_characters.Add(c, character);
}
fontFace.Dispose();
fontLib.Dispose();
vao = VAO.Create();
vao.LinkPS(_textPs);
vbo = VBO.Create <float>(vertices.Length, 4, "vertex");
indices = new IndicesCollection();
indices.Add(4, vertices.Length);
vao.AddVBuff(vbo);
vao.AddIndicesCollection(indices);
}
private Glyph LoadGlyph(int codePoint, int characterSize, bool bold, float outlineThickness)
{
Glyph glyph = new Glyph();
if (_face == null)
{
return(null);
}
// Set the character size
if (!SetCurrentSize(characterSize))
{
return(glyph);
}
// Load the glyph corresponding to the code point
var flags = LoadFlags.ForceAutohint;
if (outlineThickness != 0)
{
flags |= LoadFlags.NoBitmap;
}
_face.LoadChar((uint)codePoint, flags, SharpFont.LoadTarget.Normal);
// Retrieve the glyph
SharpFont.Glyph glyphDesc = _face.Glyph.GetGlyph();
// Apply bold if necessary -- first technique using outline (highest quality)
SharpFont.Fixed26Dot6 weight = new SharpFont.Fixed26Dot6(1);
bool outline = glyphDesc.Format == SharpFont.GlyphFormat.Outline;
if (outline)
{
if (bold)
{
SharpFont.OutlineGlyph outlineGlyph = glyphDesc.ToOutlineGlyph();
outlineGlyph.Outline.Embolden(weight);
}
if (outlineThickness != 0)
{
_stroker.Set((int)(outlineThickness * Fixed26Dot6.FromInt32(1).Value),
StrokerLineCap.Round, StrokerLineJoin.Round, Fixed16Dot16.FromSingle(0));
// This function returning a new instance of Glyph
// Because the pointer may changed upon applying stroke to the glyph
glyphDesc = glyphDesc.Stroke(_stroker, false);
}
}
// Convert the glyph to a bitmap (i.e. rasterize it)
glyphDesc.ToBitmap(SharpFont.RenderMode.Normal, new FTVector26Dot6(0, 0), true);
SharpFont.FTBitmap bitmap = glyphDesc.ToBitmapGlyph().Bitmap;
// Apply bold if necessary -- fallback technique using bitmap (lower quality)
if (!outline)
{
if (bold)
{
bitmap.Embolden(_library, weight, weight);
}
if (outlineThickness != 0)
{
Logger.Warning("Failed to outline glyph (no fallback available)");
}
}
// Compute the glyph's advance offset
glyph.Advance = _face.Glyph.Metrics.HorizontalAdvance.ToSingle();
if (bold)
{
glyph.Advance += weight.ToSingle();
}
int width = bitmap.Width;
int height = bitmap.Rows;
if ((width > 0) && (height > 0))
{
// Leave a small padding around characters, so that filtering doesn't
// pollute them with pixels from neighbors
int padding = 1;
// Get the glyphs page corresponding to the character size
Page page = _pages[characterSize];
// Find a good position for the new glyph into the texture
glyph.TexCoords = FindGlyphRectangle(page, width + 2 * padding, height + 2 * padding);
var texRect = glyph.TexCoords;
// Make sure the texture data is positioned in the center
// of the allocated texture rectangle
glyph.TexCoords = new Rectangle(texRect.X + padding, texRect.Y + padding,
texRect.Width - 2 * padding, texRect.Height - 2 * padding);
// Compute the glyph's bounding box
float boundsX = (float)(_face.Glyph.Metrics.HorizontalBearingX);
float boundsY = -(float)(_face.Glyph.Metrics.HorizontalBearingY);
float boundsWidth = (float)(_face.Glyph.Metrics.Width) + outlineThickness * 2;
float boundsHeight = (float)(_face.Glyph.Metrics.Height) + outlineThickness * 2;
glyph.Bounds = new RectangleF(boundsX, boundsY, boundsWidth, boundsHeight);
// Extract the glyph's pixels from the bitmap
byte[] pixelBuffer = new byte[width * height * 4];
for (int i = 0; i < pixelBuffer.Length; i++)
{
pixelBuffer[i] = 255;
}
unsafe
{
byte *pixels = (byte *)bitmap.Buffer.ToPointer();
if (bitmap.PixelMode == SharpFont.PixelMode.Mono)
{
// Pixels are 1 bit monochrome values
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
// The color channels remain white, just fill the alpha channel
int index = (x + y * width) * 4 + 3;
pixelBuffer[index] = (byte)((((pixels[x / 8]) & (1 << (7 - (x % 8)))) > 0) ? 255 : 0);
}
pixels += bitmap.Pitch;
}
}
else
{
// Pixels are 8 bits gray levels
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
// The color channels remain white, just fill the alpha channel
int index = (x + y * width) * 4 + 3;
pixelBuffer[index] = pixels[x];
}
pixels += bitmap.Pitch;
}
}
}
// Write the pixels to the texture
int tx = glyph.TexCoords.Left;
int ty = glyph.TexCoords.Top;
int tw = glyph.TexCoords.Width;
int th = glyph.TexCoords.Height;
page.texture.Update(pixelBuffer, tx, ty, tw, th);
}
// Delete the FT glyph
glyphDesc.Dispose();
return(glyph);
}