Drawn Squares Constantly Flicker Between Assigned Colors

Question

I am very new to GameMaker 1.4, but I have some experience with Python and C++. I have created a matrix of random ints between 1 and 5 inclusive to represent the number of stories each building on a map has. I want to use this to draw a 10x10 set of squares with lighter grey squares representing taller buildings. Unfortunately, I can't get the squares to stay the same color. They constantly flicker between colors.

How can I get them to stop flickering and represent their relevant values appropriately?

Here is my script:

// Random 2D Map Height Generator

/*
Generates a matrix which is used for determining 
 the amount of stories per building in the game.

 Then draws squares of different colors to represent
 the number of stories of each building.
*/

ct = irandom(1);
// create array
for (i = 0; i <= global.height; i += 1) {
   for (j = 0; j <= global.width; j += 1) {
      mapArray[i, j] = irandom_range(1, 5);
      if (ct % 2 != 0 && mapArray[i, j] < 5) {
      mapArray[i, j] += 1;
   }
   ct += 1;
   }
}

// make colors
one = make_color_rgb(0, 0, 0);
two = make_color_rgb(51, 51, 51);
three = make_color_rgb(102, 102, 102);
four = make_color_rgb(153, 153, 153);
five = make_color_rgb(204, 204, 204);

// initialize coordinates
ex = 300;
wy = 100;

// count columns

// draw map
for (i = 0; i <= global.height; i += 1) {
   for (j = 0; j <= global.width; j += 1) {
      ex2 = ex + 30;
      wy2 = wy + 30;
      switch (mapArray[i, j])
      {
         case 1:
            draw_set_color(one);
            break;
         case 2:
            draw_set_color(two);
            break;
         case 3:
            draw_set_color(three);
            break;
         case 4:
            draw_set_color(four);
            break;
         case 5:
            draw_set_color(five);
            break;
         default:
            draw_text(200, 200, 
            "ERROR: scr_mapGeneration, case not met");
            break;
      }
      draw_rectangle(ex, wy, ex2, wy2, false);
      ex += 33;
      if (j == global.width) {
         wy += 33;
         ex = 300;
      }
   }
}

I call it in an object with the draw event and execute this code with it:

script_execute(scr_mapGeneration);

I call randomize(); in my initial room's creation code. The problem occurs in another room.

Here is a picture of what is produced, obviously this picture doesn't have flickering squares.

Please let me know if you need any more information.

Answer 1

The colors are constantly new assigned with new random values, since the draw funtion is called every frame.

randomize() does have nothing to do with your problem, random always creates a new random, it just changes the random seed. ;)

You should call the script in the create event once, and instead of drawing the rectangles you store them in e.g. a ds_grid (more info here) In the draw funtion you just draw the saved values from the grid.