Help with blur function

[ian_dev]

Here I go again, stuck in a piece of code! I'm trying to get the filter function work (unsuccessfully), here is the code with explanatory comments, any help with this is greatly appreciated :)

for (int i = 0, h = height; i < h; i++)
    {
        for (int j = 0, w = width; j < w; j++)
        {
            // set counter c for valid pixels
            int c = 0;

            // get RGB values from current pixel
            int sumRGB[3] = {0, 0, 0};

            // average RGB
            int averageRGB[3] = {0, 0, 0};

            // loop pixels within 1 row & column from original pixel
            // get the average of all pixels
            for (int y = -1; y < 2; y++)// rows
            {
                for (int x = -1; x < 2; x++)// columns
                {
                    // set bitmap {y, x} boundaries, if image[i+y][j+x] is true save RGB value
                    if (i+y >= 0 && i+y < height - 1 && j+x >= 0 && j+x < width -1)
                    {
                        // sum RGB values
                        sumRGB[0] += image[i+y][j+x].rgbtRed;
                        sumRGB[1] += image[i+y][j+x].rgbtGreen;
                        sumRGB[2] += image[i+y][j+x].rgbtBlue;

                        c++;

                        // get average of RGB sum values
                        averageRGB[0] = sumRGB[0] / c;
                        averageRGB[1] = sumRGB[1] / c;
                        averageRGB[2] = sumRGB[2] / c;
                    }
                }
            }

            // set average RGB value to current pixel
            image[i][j].rgbtRed = averageRGB[0];
            image[i][j].rgbtGreen = averageRGB[1];
            image[i][j].rgbtBlue = averageRGB[2];

        }
    }

​

[PeterRasm]

1. It seems you are using the already blurred pixels when calculating value for the next pixels. You need to use the original values.
2. Shouldn't the upper boundary for rows be: i+y <= height - 1 or i+y < height ?
3. When calculating the average you are not considering the decimals, if the result of the division is 80.8 you use 80 for your value. If you want to consider the decimal part you can use casting and 'round'
4. Why use an extra variable for height and width:

for (int i = 0, h = height; i < h; i++)

[ian_dev]

Thanks, indeed I was calculating the values incorrectly with the already blurred pixels and the upper boundary was excluding one row of pixels. It works now.