How to make objects initially invisible and visible when they're detected

Game Engine Game Engine Support and Discussion
1

Hi. I’am trying to make submarine game, working in UPBGE 0.3. I want to create some kind of echolocation system to detect enemies. Enemies should be first invisible to player. I can’t understand how to make them invisible and make appear when they detected. Can someone help and give any advice how to do this?

2

Like this?

Video Demonstration

Code Snippet

import bpy

LAST_DETECTED = []

def enemy_detected(self):
    
    # Detected enemy
    if self.sensors["Collision"].hitObjectList != "":
        for o in self.sensors["Collision"].hitObjectList:
            o.visible = True
            LAST_DETECTED.append(o)
    # Reset when enemy no longer detected
    if self.sensors["Collision"].status == 3:
        for o in LAST_DETECTED:
            o.visible = False
        LAST_DETECTED.clear()

Blend

UPBGE_03_Echolocation.blend (138.6 KB)

2 Likes
3

Well, that’s not the thing I want.
I’ll try to explain. I want it to be 3d and work same as real hydrolocation. Player activate radar - some kind of “ray” or “cone” goes to chosen direction (in 3d) from submarine/character that doesn’t move. When “ray/cone” meets invisible object it becomes visible to player.

4

So you want the character to be still an create an object that expands at some speed like radar? You can create an object and put it in a different layer and then create a keyboard sensor and an edit object actuator to add that object, a sphere or cone or whatever, when you press a key. The object will have an always sensor and a python controller. And then in python you can set the rate at which the object will scale. Not sure what the script is for scaling an object but i know it can be done. If you need one I can look through my files for one.
Then you just need a collision sensor on the objects you are toggling the visibility of to interact with a property value of the radar object and a visibility actuator.

5

Why doesn’t this one work for static objects?

6

Static objects are not influenced by collision. If you want them to be detectable, I suggest setting your objects as Dynamic and disabling movement for them.

1 Like
7

Thanks for your code, and your feedback!
Your advice helped me
However, I noticed some shortcomings.
For example, I have 2 objects that should disappear.
But if both objects (X/Y) hit the radar radius, and then the X object is outside the radar and the Y object is still in the radar, then both objects will be visible.
2023-01-26 23-30-14.mkv (4.1 MB)

The same goes for your file.

Can you help me to solve this issue?