/// <summary>
/// Calculates the optimal size for the font texture and TexturePacker, and creates both.
/// </summary>
private void PrepareTexturePacker()
{
// Calculate the size of the texture packer. We want a power-of-two size
// that is less than 1024 (supported in Geforce256-era cards), but large
// enough to hold at least 256 (16*16) font glyphs.
// TODO: Find the actual card limits, maybe?
int size = (int)(font.Size * 16);
size = (int)System.Math.Pow(2.0, System.Math.Ceiling(System.Math.Log((double)size, 2.0)));
if (size > 1024)
{
size = 1024;
}
texture_width = size;
texture_height = size;
pack = new TexturePacker <Glyph>(texture_width, texture_height);
GL.GenTextures(1, out texture);
GL.BindTexture(TextureTarget.Texture2D, texture);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)All.Linear);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)All.Linear);
if (GL.SupportsExtension("Version12"))
{
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)All.ClampToEdge);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)All.ClampToEdge);
}
else
{
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)All.Clamp);
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)All.Clamp);
}
GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Alpha, texture_width, texture_height, 0,
OpenTK.Graphics.PixelFormat.Rgba, PixelType.UnsignedByte, IntPtr.Zero);
}