// Create a display list coresponding to the give character.
// return character width
private int make_dlist(Face face, uint ch, uint list_base, uint[] tex_base)
{
int charWidth = 0;
//The first thing we do is get FreeType to render our character
//into a bitmap. This actually requires a couple of FreeType commands:
//Load the Glyph for our character.
face.LoadGlyph(face.GetCharIndex(ch), LoadFlags.Default, LoadTarget.Normal);
//Move the face's glyph into a Glyph object.
Glyph glyph = face.Glyph.GetGlyph();
//Convert the glyph to a bitmap.
glyph.ToBitmap(RenderMode.Normal, new FTVector26Dot6(0, 0), true);
BitmapGlyph bitmap_glyph = glyph.ToBitmapGlyph();
//This reference will make accessing the bitmap easier
FTBitmap bitmap = bitmap_glyph.Bitmap;
//Use our helper function to get the widths of
//the bitmap data that we will need in order to create
//our texture.
int width = next_p2(bitmap.Width);
int height = next_p2(bitmap.Rows);
//Allocate memory for the texture data.
byte[] expanded_data = new byte[2 * width * height];
//Here we fill in the data for the expanded bitmap.
//Notice that we are using two channel bitmap (one for
//luminocity and one for alpha), but we assign
//both luminocity and alpha to the value that we
//find in the FreeType bitmap.
//We use the ?: operator so that value which we use
//will be 0 if we are in the padding zone, and whatever
//is the the Freetype bitmap otherwise.
for (int j = 0; j < height; j++)
{
for (int i = 0; i < width; i++)
{
expanded_data[2 * (i + j * width)] = 255;
if (i >= bitmap.Width || j >= bitmap.Rows)
{
expanded_data[2 * (i + j * width) + 1] = 0;
}
else
{
expanded_data[2 * (i + j * width) + 1] = bitmap.BufferData[i + bitmap.Width * j];
}
}
}
//Now we just setup some texture paramaters.
glView.glBindTexture2D(tex_base[ch]);
glView.glTex2DParameterMinFilterLinear();
glView.glTex2DParameterMagFilterLinear();
//Here we actually create the texture itself, notice
//that we are using GL_LUMINANCE_ALPHA to indicate that
//we are using 2 channel data.
glView.glTexImage2D_IntFormatRGBA_formatLumAlpha_bytes(width, height, expanded_data);
//So now we can create the display list
glView.glNewListCompile(list_base + ch);
glView.glBindTexture2D(tex_base[ch]);
glView.glPushMatrix(); // better results with popping the matrix here..
//first we need to move over a little so that
//the character has the right amount of space
//between it and the one before it.
glView.glTranslate((float)bitmap_glyph.Left, 0f, 0f);
//Now we move down a little in the case that the
//bitmap extends past the bottom of the line
//(this is only true for characters like 'g' or 'y'.
//GL.PushMatrix(); // better results without popping the matrix before top translation
int topOffset = bitmap_glyph.Top - bitmap.Rows;
glView.glTranslate(0f, (float)topOffset, 0f);
//glTranslatef(0, (GLfloat)bitmap_glyph->top-bitmap.rows, 0);
//Now we need to account for the fact that many of
//our textures are filled with empty padding space.
//We figure what portion of the texture is used by
//the actual character and store that information in
//the x and y variables, then when we draw the
//quad, we will only reference the parts of the texture
//that we contain the character itself.
float x = (float)bitmap.Width / (float)width,
y = (float)bitmap.Rows / (float)height;
//Here we draw the texturemaped quads.
//The bitmap that we got from FreeType was not
//oriented quite like we would like it to be,
//so we need to link the texture to the quad
//so that the result will be properly aligned.
glView.glBeginQuads();
glView.glTexCoord2(0, 0); glView.glVertex2(0f, (float)bitmap.Rows);
glView.glTexCoord2(0, y); glView.glVertex2(0f, 0f);
glView.glTexCoord2(x, y); glView.glVertex2((float)bitmap.Width, 0);
glView.glTexCoord2(x, 0); glView.glVertex2((float)bitmap.Width, (float)bitmap.Rows);
glView.glEnd();
glView.glPopMatrix();
glView.glTranslate((float)(face.Glyph.Advance.X), 0f, 0f);
// set the char width
charWidth = (int)face.Glyph.Advance.X;
//Finish the display list
glView.glEndList();
// free the glyph memory (bugfix)
bitmap.Dispose();
bitmap_glyph.Dispose();
glyph.Dispose();
// return the character width
return(charWidth);
}
