transparency

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_ALPHA_TEST);
glAlphaFunc(GL_GREATER, 0);

this will(should) make your bitmaps black parts transparent.

are you using tga or bmp file? i am using bmp and works ok. if you use tga maybe the image alpha channel disabled? and try to use: glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); i dont know if it effects...

>>this will(should) make your bitmaps black parts transparent.<<

no it wont, u also need a bit more,
what u need to do is during the image loading phase check each pixel to see if its black if it is set that pixels alpha to 0.0 else set it to 1.0. and then u can do

glEnable(GL_ALPHA_TEST);
glAlphaFunc(GL_GREATER,0.0f);

oh i see, i thought he made this part.
ok so you should use someting like this to load bitmap dara:

unsigned char *LoadBitmapFileWithAlpha(char *filename, BITMAPINFOHEADER *bitmapInfoHeader)
{
unsigned char *bitmapImage = LoadBitmapFile(filename, bitmapInfoHeader); //load a bitmap file normally
unsigned char *bitmapWithAlpha = (unsigned char *)malloc(bitmapInfoHeader->biSizeImage * 4 / 3);

if (bitmapImage == NULL || bitmapWithAlpha == NULL)
return NULL;

// loop bitmap data
for (unsigned int src = 0, dst = 0; src < bitmapInfoHeader->biSizeImage; src +=3, dst +=4)
{
// if the pixel is black, set the alpha to 0. Otherwise, set it to 255.
if (bitmapImage[src] == 0 && bitmapImage[src+1] == 0 && bitmapImage[src+2] == 0)
bitmapWithAlpha[dst+3] = 0;
else
bitmapWithAlpha[dst+3] = 0xFF;

// copy pixel data over
bitmapWithAlpha[dst] = bitmapImage[src];
bitmapWithAlpha[dst+1] = bitmapImage[src+1];
bitmapWithAlpha[dst+2] = bitmapImage[src+2];
}

free(bitmapImage);

return bitmapWithAlpha;
} // end LoadBitmapFileWithAlpha()

i hope it helps...