explaining comment

main.c

@@ -339,6 +339,8 @@ draw_horizontal_line(
     if (dx < 1) return;
 
     for (int32_t x = x0; x <= x1; x++) {
+        /* doing bresenham in the z-axis to find the points where we
+         * should/shouldn't draw */
         eps += dz;
         while (eps > 0) {
             eps -= dx;