GML Efficient 'mouse in sprite' script

[MeBoingus]

Howdy all,

Often times I'll draw a sprite to the screen, and need to detect whether or not the mouse is 'inside' of it.
I normally use 'point_in_rectangle' for this, but the obviously this won't work for sprites with a precise collision mask.

Take this sprite, for example:




My goal is to run some code if the mouse is inside of the sprite, using a precise mask.
The only script/method I can think of that achieves this is:

///mouse_in_sprite(sprite, x, y);

var tempO = instance_create(argument1, argument2, obj_mousein);
tempO.sprite_index = argument0;


if (position_meeting(mouse_x, mouse_y, tempO))
{
    with (tempO) { instance_destroy(); }
    return true;
}

with (tempO) { instance_destroy(); }
return false;

However, (obviously) creating and destroying an instance constantly (this code runs in the draw event, as we are drawing the sprite to the screen) is HORRIBLY inefficient.


Does anyone know of a better way to handle this?
Warm regards .

 

[TheouAegis]

Will these always be built-in/included sprites? If so, write up a quick little program to store the alphas of each pixel to a buffer and then save that buffer to a file. Include the file with your project.

When you draw a sprite and need it traced, take the mouse coordinates relative to the sprite's top-left corner and condense the two values down to a single value. Then load the file for that sprite and check if the alpha at the value for the mouse position is not 0.

 

[YellowAfterlife]

You can reuse a single instance of that special invisible object (creating it if there isn't one yet) - no need to create-destroy it.

 

[TheouAegis]

I still like my idea better. Someone should speed-test them. lol Granted, mine uses more RAM, though.