#include <windows.h>

GLuint BitmapToTexture(char* filename, COLORREF key/*= RGB(255, 0, 255)*/, unsigned char alpha/*=255*/, unsigned char key_alpha/*=0*/)
{
	GLuint texture = 0;							//the return value				
	BITMAP bmp;									//used only to get bmp dimensions
	HDC hDC = CreateCompatibleDC(NULL);			//choose DC like the desktop
	HBITMAP hBitmap = (HBITMAP)LoadImage(NULL,	//load the bitmap
										 filename,
										 IMAGE_BITMAP,
										 0, 0, 
										 LR_CREATEDIBSECTION|LR_DEFAULTSIZE|LR_LOADFROMFILE);

	if(hBitmap == NULL)							//bitmap failed to load
	{
		return 0;
	}
	//get bitmap dimensions
	GetObject(hBitmap, sizeof(BITMAP), &bmp);

	//allocate memory for the bitmap
	COLORREF *data = new COLORREF[bmp.bmWidth * bmp.bmHeight];

	//put it into our device context for GetPixel calls
	SelectObject(hDC, hBitmap);
	for(int y = 0; y < bmp.bmHeight; y++)
	{
		for(int x = 0; x < bmp.bmWidth; x++)
		{
			data[x + (y*bmp.bmHeight)] = GetPixel(hDC, x, y);
			if(key != data[x + (y*bmp.bmHeight)])
			{
				data[x + (y*bmp.bmHeight)] |= (alpha << 24);
			}
			else
			{
				data[x + (y*bmp.bmHeight)] |= (key_alpha << 24);
			}


		}
	}
	
	//get rid of some GDI stuff we used to convert to RGB buffer
	DeleteDC(hDC);
	DeleteObject(hBitmap);
		
	//finally generate a texture
	glGenTextures(1, &texture);
	glBindTexture(GL_TEXTURE_2D, texture);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA4, bmp.bmWidth, bmp.bmHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	delete data;
	return texture;
}