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

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One Comment

  1. For the step event, you can replace the “black” for white instead. Personally I find the colour white more suiting for my game due to my background colour being bright.

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