Hello!
This is an example I've made for tweaking the light in the screen!
I'm not good at explaing how the code works, but theres some values to change and it has been documented.
Tweaks in-game:Left key = reduce light intensity on screen
Right key = add light intensity on screen
Up key = add darkness to dark areas on screen
Down key = reduce darkness to dark areas on screen
A key = reduce light spread(bloom)
S key = add light spread(bloom)
Space key = Toggle effect
I used a screenshot from the awesome looking OoT2D remake someone is doing, hope you don't mind!
Check in the step event for more things to tweak!
Every time you use screen_redraw(), GM calls the draw event on all the objects. So that means that if you redraw the image in the step event, the drawing will "duplicated". That's why I added a global named redraw so that you can seperate in the draw event what's redraw or not, so the current image is not blended to the next buffer etc etc.
Also, I think you need to be registred!
Try it out and I hope you can use it for something!
Credit wouldn't hurt