[Solved] Reading pixel color issue

[thatoneguy]

I'm using SFML 2.0 and the getPixel() fuction of the Image class. The function returns 2,0,1 for what I drew to be 0, 0, 0 in Photoshop. http://stackoverflow.com/questions/16601839/reading-wrong-pixel-color.

[Laurent]

Please show your code and upload the image.

[thatoneguy]

    sf::Image map;
    ImageHandler::SetImage(map, "/Data/Maps/001.png");
    for (uchar x = 0; x < map_width; ++x) {
        for (uchar y = 0; y < map_height; ++y) {
            tiles[x][y].index = ColorToIndex(map.getPixel(x, y));
            SetTile(x, y, tiles[x][y].index);
        }
    }

[Laurent]

Your image link is broken. And how are we supposed to know what your functions do? Please write a complete and minimal example that reproduces the problem.

[thatoneguy]

Fixed now. I went through debugging and the value of the pixel at 0, 0 returns 2, 0, 1 for getPixel(). Code below was used to test it while debugging.

uchar TileGrid::ColorToIndex(sf::Color &color) {
    return 1;
    if (color == sf::Color(2, 0, 1)) {
        return 2;
    } else if (color == sf::Color(0, 255, 0)) {
        return 1;
    } else {
        Root::SetStatus(EXIT_FAILURE);
        return 255;
    }
}

[Laurent]

Can you please show a minimal example? We don't care about what's around it, about your whole project. Just write a main() which loads an image and calls getPixel on it. That will be enough (and needed!) to solve your problem

[thatoneguy]

Sorry I didn't know what you meant by a minimal example 
I still don't understand what's going on.

#include <SFML/Graphics.hpp>
#include <iostream>

int main(int argc, char **argv) {
    sf::Image img;
    img.loadFromFile("D:/Maps/001.png");
    sf::Color tmp(img.getPixel(0, 0));
    if (tmp == sf::Color (0, 0, 0)) {
        std::cout << "Black";
    } else {
        std::cout << "Other";
    }
}

[Nexus]

What is the actual pixel value in the image, and what do you get from SFML? Don't just compare with black, output the RGBA components.

Also, verify that loading suceeds.

[thatoneguy]

The image loads fine.
Through debugging SFML gives me the value 2, 0, 1 while in Photoshop it gives me 0, 0, 0
I tried printing it out, and I'm not getting the same results. I'll look more into it.

[Nexus]

If your debugger is not buggy itself, the results must be the same when you use std::cout. Just keep in mind you have to cast the sf::Color members to int, because they are interpreted as characters by the C++ streams.

std::cout << static_cast<int>(color.r) << ", " << ... << "\n";

[thatoneguy]

I re-saved the image again and it seems to be working fine. Was not an issue with SFML I guess it had to do with the way I saved it.