psets4 sepia not working correctly

Question

my code works but the sky looks shiny blue, its like its working in all others pixels but not on the sky, i do not get what i am doing wrong.

void sepia(int height, int width, RGBTRIPLE image[height][width])
{

    BYTE red, auxred;
    BYTE blue, auxblue;
    BYTE green, auxgreen;
    for(int i = 0; i < height; i++)
    {
        for(int j = 0; j < width; j++)
        {
            red = image[i][j].rgbtRed;
            blue = image[i][j].rgbtBlue;
            green = image[i][j].rgbtGreen;

            auxred = round((float).393 * red + (float).769 * green + (float).189 * blue);
            if(auxred > 0xff)
            {
                image[i][j].rgbtRed = 0xff;
            }else
            {
                image[i][j].rgbtRed = auxred;
            }
            auxblue = round((float).272 * red + (float).534 * green + (float).131 * blue);
            if(auxblue > 0xff)
            {
                image[i][j].rgbtBlue = 0xff;
            }else
            {
                image[i][j].rgbtBlue = auxblue;
            }
            auxgreen = round((float).349 * red + (float).686 * green + (float).168 * blue);
            if(auxgreen > 0xff)
            {
                image[i][j].rgbtGreen = 0xff;
            }else
            {
                image[i][j].rgbtGreen = auxgreen;
            }
        }
    }

    return;
}

Answer 1

On a quick glance, one thing jumped out at me.

The calculations are putting the results into auxred, auxgreen and auxblue. The calculations can generate results over 255, but these are all of type BYTE (range 0 to 255), which will result in an overflow condition that won't trigger an error. It will just overflow the contents of these vars and lead to unpredictable results.

Try declaring these (and any other potential overflowing vars) as int and not BYTE.

This may not be the full solution but it certainly jumped off the screen at me. ;-)

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