couple of questions- nurbs, transparency, etc

[popapez]

I am very new to opengl and I am trying to draw a peacock. I have an raw image of a feather that has white as the background and am trying to convert the white pixels to transparent pixels but am not sure how.

struct RGBA 
{						// The data on one RGB pixel
    unsigned char red;
    unsigned char green;
    unsigned char blue;
	unsigned char alpha;
};
 
RGBA image1[texHeight][texWidth];				// The image
 
 
 
 
 
if ( in ) 
	{
 
        for ( int r = texHeight-1; r >= 0; r-- ) 
		{
            for ( int c = 0; c < texWidth; c++ ) 
			{
				if ( 
					in.read( reinterpret_cast<char*>(&amp;image[r][c]), sizeof(RGB)) );
            }

how would you assign this image an alpha value while reading it in?





also, I have drawn a nurbs surface and was wondering how to texture map it?

[popapez]

please?

[dletozeun]

Set alpha to zero when you are on the background. Note that a white background is not judicious since the white color is very common is nature. You should set something less natural as background like pink: 0xff00ff or (1.0, 0.0, 1.0).

Then when you have created your texture with opengl you can use alpha testing or blending to remove the background when rendering.