MiniLibX

Basic introduction, tutorials, tips & tricks.

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How to draw a pixel on the window with MLX?

Continuing from the previous tutorial, drawing a single pixel is very straight-forward.

#include "mlx.h"

int main()
{
    void *mlx = mlx_init();
    void *win = mlx_new_window(mlx, 640, 360, "Tutorial Window - Draw Pixel");

    mlx_pixel_put(mlx, win, 640/2, 360/2, 0xFFFFFF);

    mlx_loop(mlx);
}

If you look closely, this will draw a white pixel at the very center of the window.

MLX tutorial pixel

The main takeaway from this is how the color is determined by MLX. The mlx_pixel_put manual explains that it takes 3 bytes to define a color with 16’777’216 shades.

0x  FF FF FF
Hex RR GG BB

To make any sense of colors in this format, you’ll need to wrap your head around hexadecimal (base 16) numbers. Here’s a very good resource to get yourself started. This will also help you!

I would also strongly recommend creating yourself a function such as rgb_to_int so that you can easily create the colors you need.

int rgb_to_int(double r, double g, double b)
{
    int color = 0;
    color |= (int)(b * 255);
    color |= (int)(g * 255) << 8;
    color |= (int)(r * 255) << 16;
    return (color);
}

42 Students: Remember that you must be able to explain your code during a defense. Write your own function, or find out exactly how/why the above function works. And if you’re reading this, make sure to question the people you are evaluating!