# Sneaking Demo
**URL:** https://forum.makecode.com/t/sneaking-demo/4961
**Category:** Arcade
**Tags:** game
**Created:** [December 12, 2020, 12:52am UTC](https://forum.makecode.com/t/sneaking-demo/4961 "2020-12-12T00:52:51Z")
**Posts on this page:** 16
**Page:** 1
### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [December 12, 2020, 12:52am UTC](https://forum.makecode.com/t/sneaking-demo/4961/1 "2020-12-12T00:52:51Z")
It’s like a proof of concept and some exts. Not fully in blocks (yet).
> **[sneaking.demo](https://arcade.makecode.com/97022-62922-00013-89813)**
>
> 用❤️创造，Microsoft MakeCode Arcade出品。
1. FoV (distance and walls)
> **[felixtsu/pxt-sight](https://github.com/felixtsu/pxt-sight)**
>
> MakeCode 项目. Contribute to felixtsu/pxt-sight development by creating an account on GitHub.
1. Patrolling enemies
> **[felixtsu/pxt-waypoint-ext](https://github.com/felixtsu/pxt-waypoint-ext)**
>
> A MakeCode project. Contribute to felixtsu/pxt-waypoint-ext development by creating an account on GitHub.
More details later.
Cheers
---
### Author:  [@jwunderl](https://forum.makecode.com/u/jwunderl)
#### Post date: [December 12, 2020, 1:28am UTC](https://forum.makecode.com/t/sneaking-demo/4961/2 "2020-12-12T01:28:20Z")
The second example with the moving enemy where it even takes into account walls blocking the view is incredible! Great job!
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [December 12, 2020, 2:48am UTC](https://forum.makecode.com/t/sneaking-demo/4961/3 "2020-12-12T02:48:06Z")
For anyone interested, a simply illustration of the basic idea behind sensing with wall is here:
Sprite A can see sprite B if:
a) distance between A and B is less than or equal to range of sensing;
AND
b) there’s no wall between
For a), distance can be calculated by square root of (deltaX^2 + deltaY^2)
For b), consider the following,
in which,
1. finding the critical points requires some geometric calculation (similar triangles, tan/arctan)
2. tilemap ext is useful for checking if a certain tile is wall
An interactive demo is here, the line between the sprites is drawn and critical lat/long tiles are colored (lats are purple, longs are red).
> **[demo.sight](https://arcade.makecode.com/03708-34411-82502-44363)**
>
> 用❤️创造，Microsoft MakeCode Arcade出品。
Try moving sprites and changing range parameter (set to 128, full screen)
After that, on the shoulder of @richard, [the shader ext](https://forum.makecode.com/t/shader-extension/4860) is useful for showing enemy alert range for player.
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### Author:  [@Agent\_14](https://forum.makecode.com/u/Agent_14)
#### Post date: [December 19, 2020, 4:41am UTC](https://forum.makecode.com/t/sneaking-demo/4961/4 "2020-12-19T04:41:47Z")
I did something else. I had done this by finding the absolute value of the differences in x, to see if it was withing a difference range.
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### Author:  [@Agent\_14](https://forum.makecode.com/u/Agent_14)
#### Post date: [December 19, 2020, 5:19pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/5 "2020-12-19T17:19:51Z")
This gives me an error message.
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [December 20, 2020, 12:19am UTC](https://forum.makecode.com/t/sneaking-demo/4961/6 "2020-12-20T00:19:01Z")
oops, can you post the error here?
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### Author:  [@Agent\_14](https://forum.makecode.com/u/Agent_14)
#### Post date: [December 20, 2020, 3:13am UTC](https://forum.makecode.com/t/sneaking-demo/4961/7 "2020-12-20T03:13:34Z")
Does not want to show anything, so I don’t know. It just won’t run
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### Author:  [@MasterOfTheYeets](https://forum.makecode.com/u/MasterOfTheYeets)
#### Post date: [February 3, 2021, 4:24pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/8 "2021-02-03T16:24:30Z")
demo.sight doesn’t work. error:
Line 39: Property ‘toggleTestingTiles’ does not exist on type ‘typeof sight’.
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [February 4, 2021, 1:07am UTC](https://forum.makecode.com/t/sneaking-demo/4961/9 "2021-02-04T01:07:19Z")
> [@MasterOfTheYeets](#):
>
> toggleTestingTiles
😂 toogleTestingTiles() was a debugging function and was not exported in the current version. Exported and tagged a version v0.0.2
> **[demo.sight](https://arcade.makecode.com/05238-50967-53731-56569)**
>
> Made with ❤️ in Microsoft MakeCode Arcade.
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### Author:  [@brandodon](https://forum.makecode.com/u/brandodon)
#### Post date: [March 24, 2021, 1:49am UTC](https://forum.makecode.com/t/sneaking-demo/4961/10 "2021-03-24T01:49:12Z")
for some reason this is super confusing
can you explain how I can use this?
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [March 26, 2021, 3:33pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/11 "2021-03-26T15:33:52Z")
To use the detecting instruction
an extension is needed.
Try to import the extension by clicking ‘Extensions’
then, paste the extension url “[https://github.com/felixtsu/pxt-sight](https://github.com/felixtsu/pxt-sight)” then hit Enter,
after clicking the extension, the instruction can be dragged from ‘Sprite Sight’ group
sprite , otherSprite are the sprites under detection, following a number indicating the range of sight.
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### Author:  [@Agent\_14](https://forum.makecode.com/u/Agent_14)
#### Post date: [March 26, 2021, 4:20pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/12 "2021-03-26T16:20:12Z")
Can I ask what the boolean does?
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### Author:  [@brandodon](https://forum.makecode.com/u/brandodon)
#### Post date: [March 26, 2021, 7:04pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/13 "2021-03-26T19:04:43Z")
I’m in javascript, and I know what everything is but I just don’t know how to use them in the correct order.
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [March 27, 2021, 2:23am UTC](https://forum.makecode.com/t/sneaking-demo/4961/14 "2021-03-27T02:23:20Z")
The conditional returns true when distance between sprite and othersprite in less than `range` and there’s no wall between, otherwise false.
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### Author:  [@felixtsu](https://forum.makecode.com/u/felixtsu)
#### Post date: [March 27, 2021, 2:23am UTC](https://forum.makecode.com/t/sneaking-demo/4961/15 "2021-03-27T02:23:27Z")
> [@brandodon](#):
>
> the
Like this?
---
### Author:  [@Stickman4269](https://forum.makecode.com/u/Stickman4269)
#### Post date: [January 5, 2025, 8:16pm UTC](https://forum.makecode.com/t/sneaking-demo/4961/16 "2025-01-05T20:16:47Z")
I’m trying to use the directional version but in a demo I made it only works under specific circumstances like whether or not I’m moving clockwise, but then it swaps directions sometimes.
> **[Sight Test](https://arcade.makecode.com/S19608-68174-27810-91665)**
>
> Made with ❤️ in Microsoft MakeCode Arcade.