Create a light effect in GameMaker

Tutorial 14: Creating a Light Effect in Game Maker

You could demonstrate this effect in a separate room instead of your main playing room. If so, create a button to it on the start screen.

1. Create a new object called objLight
2. Add a Create event to this object with the following code:

   /// @description Create a surface the size of the current room
   
   surf = surface_create(room_width, room_height);
   surface_set_target(surf);
   draw_clear_alpha(c_black, 0);
   surface_reset_target();

3. Add a Step Step event to this light object and paste this code.
   Look out for where the player object and player lazer is referenced in the code below.

   if (surface_exists(surf)) {
   surface_set_target(surf);
   // The following three lines set the 'dark' overlay
   
   draw_set_color(c_black);
   draw_set_alpha(0.8);
   draw_rectangle(0, 0, room_width, room_height, 0);
   gpu_set_blendmode(bm_subtract);
   draw_set_color(c_white);
   
   // Draw circles in the overlay with your different light sources
   // Note that I add randomization to the position and radius to mimic a flicker effect
   //each with statement needs to know what object you are creating the light effect around
   
   with (objPlayer) //light on the player
   draw_circle(x + random_range(-1, 1), y + random_range(-1, 1), 50 + random_range(-1, 1), false);
   
   with (objEnemy1)//light on the enemy
   draw_circle(x + random_range(-1, 1), y + random_range(-1, 1), 50 + random_range(-1, 1), false);
   
   with (objPlayerLazer) //if your player lazer has a different name change this
   //you will need to play with the values inside of here to show your lazer
   draw_rectangle(x-20,y-40,x+20,y+40,false);
   // Reset all of your draw stuff
   gpu_set_blendmode(bm_normal);
   draw_set_alpha(1);
   surface_reset_target();
   
   } else {
   
   surf = surface_create(room_width, room_height);
   surface_set_target(surf);
   draw_clear_alpha(c_black, 0);
   surface_reset_target();
   }

4. Create a Draw End event on the light object, and copy and paste this code into it.

   if (!surface_exists(surf)) {
   surf = surface_create(room_width, room_height);
   
   } else {
   
   if (view_current == 0) {
   draw_surface(surf, 0, 0);
   
   }
   }

5. In a Room End event, paste this code:

   // Clean up the surface memory manually
   
   if (surface_exists(surf))
   
   surface_free(surf);

6. Drag the light object into a room to test it.
7. If you do not want it to be part of your main game room, create a new room for it, and link to it as a bonus room for the start screen

Challenge:

Add With() conditions to the Step Step event if you want to see your enemy lazers