unsafe public OpenGLFont(Font font)
{
IntPtr hdc = myTempGraphics.GetHdc();
IntPtr hfont = font.ToHfont();
SelectObject(hdc, hfont);
if (!GetCharWidth32(hdc, 0, 255, CharacterWidths))
{
throw new SystemException("Unable to measure character widths.");
}
tagTEXTMETRIC metrics = new tagTEXTMETRIC();
GetTextMetrics(hdc, ref metrics);
myLeadingSpace = metrics.tmInternalLeading;
myTrailingSpace = metrics.tmExternalLeading;
myTempGraphics.ReleaseHdc(hdc);
int width = 0;
for (int i = myFirstCharacterOfInterest; i <= myLastCharacterOfInterest; i++)
{
CharacterWidths[i] += myLeadingSpace + myTrailingSpace;
width += CharacterWidths[i];
}
myHeight = (int)Math.Round(myTempGraphics.MeasureString(myCharactersOfInterest, font).Height);
mySquareDim = (int)Math.Ceiling(Math.Sqrt(width * myHeight));
mySquareDim = Texture.GetValidTextureDimensionFromSize(mySquareDim);
float fSquareDim = mySquareDim;
Bitmap bitmap = new Bitmap(mySquareDim, mySquareDim, PixelFormat.Format16bppRgb565);
using (Graphics g = Graphics.FromImage(bitmap))
{
int x = 0;
int y = 0;
for (char i = myFirstCharacterOfInterest; i <= myLastCharacterOfInterest; i++)
{
if (x + CharacterWidths[i] >= mySquareDim)
{
y += myHeight;
x = 0;
}
CharacterLocations[i] = new Point(x, y);
float uStart = x / fSquareDim;
float uEnd = (x + CharacterWidths[i]) / fSquareDim;
float vStart = y / fSquareDim;
float vEnd = (y + myHeight) / fSquareDim;
TextureCoordinates[i] = new GlyphTexCoords(uStart, vStart, uEnd, vEnd);
g.DrawString(i.ToString(), font, myWhiteBrush, x, y);
x += CharacterWidths[i];
}
}
byte[] alphaBytes = new byte[bitmap.Width * bitmap.Height];
BitmapData data = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, PixelFormat.Format16bppRgb565);
int pixCount = 0;
for (int y = 0; y < bitmap.Height; y++)
{
short *yp = (short *)((int)data.Scan0 + data.Stride * y);
for (int x = 0; x < bitmap.Width; x++, pixCount++)
{
short *p = (short *)(yp + x);
short pixel = *p;
byte b = (byte)((pixel & 0x1F) << 3);
byte g = (byte)(((pixel >> 5) & 0x3F) << 2);
byte r = (byte)(((pixel >> 11) & 0x1F) << 3);
byte totalAlpha = (byte)((r + g + b) / 3);
alphaBytes[pixCount] = totalAlpha;
}
}
bitmap.UnlockBits(data);
uint tex = 0;
gl.GenTextures(1, &tex);
myName = tex;
gl.BindTexture(gl.GL_TEXTURE_2D, myName);
fixed(byte *alphaBytesPointer = alphaBytes)
{
gl.TexImage2D(gl.GL_TEXTURE_2D, 0, gl.GL_ALPHA, mySquareDim, mySquareDim, 0, gl.GL_ALPHA, gl.GL_UNSIGNED_BYTE, (IntPtr)alphaBytesPointer);
}
gl.TexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MIN_FILTER, gl.GL_LINEAR);
gl.TexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MAG_FILTER, gl.GL_LINEAR);
gl.TexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_WRAP_S, gl.GL_CLAMP_TO_EDGE);
gl.TexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_WRAP_T, gl.GL_CLAMP_TO_EDGE);
// below is debug code I used to see the results of my texture generation
//try
//{
// Directory.CreateDirectory("\\Temp");
//}
//catch (Exception)
//{
//}
//bitmap.Save("\\temp\\temp.png", ImageFormat.Png);
//for (int i = myFirstCharacterOfInterest; i <= myLastCharacterOfInterest; i++)
//{
// using (Bitmap ch = new Bitmap(bfont.CharacterWidths[i], height, PixelFormat.Format16bppRgb565))
// {
// using (Graphics tg = Graphics.FromImage(ch))
// {
// tg.DrawImage(bitmap, 0, 0, new Rectangle(bfont.CharacterLocations[i].X, bfont.CharacterLocations[i].Y, ch.Width, ch.Height), GraphicsUnit.Pixel);
// }
// ch.Save(string.Format("\\temp\\{0}.png", i), ImageFormat.Png);
// }
//}
bitmap.Dispose();
}
extern static bool GetTextMetrics(IntPtr hdc, ref tagTEXTMETRIC lptm);