[Csgl-users] textures news...

[Lloyd D. <ll...@ga...>]

i am currently in the process of finishing a new OpenGL font class.
there is actually 3 examples font class.

and i discover a bug in the bitmap/texture loading process.

Bitmap img = new Bitmap("image file");
// ...
BitmapData tex = img.LockBits(/*some param*/);
tex.Scan0 seems to begin in the upper left corner and not in the lower 
left corner, as needed by glTexImage2D....

for this you should call
img.RotateFlip(RotateFlipType.RotateNoneFlipY);
before locking data.

i will try to provide an OpenGLTexture utility object, as exemple, 
though i lack idea (and practice) here, as you could have multiple 
texture for multiple scale and different filtering for each texture.

so i copy/paste here my current (and basic) OpenGLTexture object and 
wait for your critics.....

------------ OpenGLTexture ---------------
using System;
using System.Drawing;
using System.Drawing.Imaging;

namespace CsGL.OpenGL
{
	/// <summary>
	/// load a texture from an image, though a simple topic
	/// there is problem of reverse order and such things which are handled
	/// byt this class.
	/// </summary>
	public abstract class OpenGLTexture : GL, IDisposable
	{
		uint[] texture = new uint[1];
		
		public OpenGLTexture(Bitmap img)
		{
			img = (Bitmap) img.Clone();
			img.RotateFlip(RotateFlipType.RotateNoneFlipY);

			BitmapData tex;
			Rectangle rect;
			rect = new Rectangle(0, 0, img.Width, img.Height);
			tex = img.LockBits(rect, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);

			glGenTextures(texture.Length, texture);
			
			glBindTexture(GL_TEXTURE_2D, texture[0]);
			glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
			glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
			glTexImage2D(GL_TEXTURE_2D, 0, (int)GL_RGB8,
		                img.Width, img.Height,
		                0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, tex.Scan0);
			
			img.UnlockBits(tex);
			img.Dispose();
		}
		
		public uint this[int texID]
		{
			get { return texture[texID]; }
		}
		
		public int Length { get { return texture.Length; } }
		
		public void Dispose()
		{
			glDeleteTextures(texture.Length, texture);
		}
	}
}