Feb
15
2012

Demos // Unity3d

Raycast Visibility 2.2

An article by mgear

64 Comments

This is just a updated version of the: fake realtime raycast shadows (its not really shadows though..)

Features in v2.0

Mesh is pre-build
In update loop we just modify the existing vertices (no need to triangulate, create uv’s, etc in every frame)
50000 raycasts starts to get slow, but 10k is still 60fps in editor.
Would be interesting to add this also: Precalculated sin cos arrays
Some overlapping lines seem to appear (see those white lines..) not sure why, but atleast its fast : )

Ideas to try:

– Use low quality mesh in LateUpdate(?)

Bug fixes for script: “ShadowRayScan2.js”

Find line:

vertices[i] = Vector3(tmp.x,0.5,tmp.z);

Replace with:

vertices[i] = Vector3(tmp.x,0,tmp.z);  // now the mesh wont go upwards

Find line:

vertices[i] = Vector3(tmp2.x,0.5,tmp2.z);

Replace with:

vertices[i] = Vector3(tmp2.x,0,tmp2.z);

*Fix for “upside down” mesh:

Find:

triangles[n] = newvertices.Length-1;

Replace with:

triangles[n+2] = newvertices.Length-1;

Find:

triangles[n+2] = i;

Replace with:

triangles[n] = i;

Find:

    triangles[triangles.length-3] = newvertices.Length-1;
triangles[triangles.length-2] = 0;
triangles[triangles.length-1] = i-1;

Replace with:

    triangles[triangles.length-1] = newvertices.Length-1;
triangles[triangles.length-2] = 0;
triangles[triangles.length-3] = i-1;

*Fix for disappearing mesh (if go further away from 0,0,0)

Find:

var tmp2 = lightmeshholder.transform.InverseTransformPoint(lightmeshholder.transform.position+dir);

Replace with:

var tmp2 = lightmeshholder.transform.InverseTransformPoint(lightmeshholder.transform.position+dir*distance);

Find (inside update loop):

mesh.vertices = vertices;

Insert line after it:

mesh.RecalculateBounds();

*More info here: http://forum.unity3d.com/threads/35897-Object-disappear-when-zooming-in-lt-URGENT!?p=628496&viewfull=1#post628496

—

Webplayer:
http://unitycoder.com/upload/demos/mShadowRayScan2/

Source:
mRaycastVisibility2.unityPackage

—

Image#2

Profiler image for ShadowRayScan4.js (512 rays)
– using SinCos lookup tables didnt make any difference
– it seems the actual raycast takes only half of the total scanning loop..?)

—

Image #3 : Fading light with blending shader: “Blend One OneMinusDstColor”

Shader for the fade light:


Shader "UnityCoder/LightMeshShaderGradient1"
{
SubShader
{
Tags { "RenderType"="Opaque" }
Blend One OneMinusDstColor
Lighting Off
Cull Front
CGPROGRAM
#pragma surface surf Lambert
#include "UnityCG.cginc"

struct Input
{
float2 uv_MainTex;
float4 screenPos;
};

void surf (Input IN, inout SurfaceOutput o)
{
float2 screenUV = IN.screenPos.xy / IN.screenPos.w;
float xx = 0.5-screenUV.x;
float yy = 0.5-screenUV.y;
float d = 2-(xx*xx+yy*yy)*9; // 2 & 9 are from just testing what values work on this distance..
half3 c = half3(d,d,d);
o.Albedo = c;
o.Alpha = 1; //c.r;
}
ENDCG
}
}

—

Image #4 : 10000 times multiplied Albedo with “Blend DstColor SrcColor” (couldnt get it any brighter..?)

Image #5: if you clone the lightmeshHolder, you get brighter light..

—
Image#6: Quick test using DX11 features.. so far its only 1ms faster with 20000 rays..

Tags: cone, fake, range, raycast, shadow, visibility

About the Author:

.fi

64 Comments + Add Comment

mgear 15/02/2012 at 11:18

Should do a small change to it,
instead of moving the (last) middle vertex to the player position,
move the visibility-gameobject(where the created mesh is) to the player position.

Reply
- mgear 18/02/2012 at 13:14
  
  This didnt work so well, the mesh is “stuttering”.. better just set the last vertex to player position, instead of moving the object..
  
  Reply
Marrt 17/02/2012 at 03:54

Awsome, tested it in my game, you can download the webplayer, take a look and tell me what you think about it:
http://forum.unity3d.com/threads/123143-Cone-of-Sight-Visualization?p=827826#post827826

Reply
Marrt 17/02/2012 at 23:59

I want to apply a depthMask shader for the created mesh.
so i can use this mesh as a cutout of a viewport… but if i add the shader only the white error lines do the masking…
why is the rest of the mesh not masking? maybe you immediately know…

anyway THANKS so far, i helped me a lot

Reply
mgear 18/02/2012 at 00:07

Not sure about that shader, but it looks like the created mesh is upside down.. have to try fix that.

Reply
- Marrt 18/02/2012 at 00:21
  
  lol, genius! that must be it!
  
  Reply
mgear 18/02/2012 at 02:04

Added couple other bug fixes on the post.
*Adding the reversed normal fix now also, it was just a small thing.

Reply
Marrt 18/02/2012 at 03:28

added the bugfixes, 2 more questions:
-i checked: if i watch the mesh from underneath it does the masking thing… can you show how to draw it NOT upside down? i cant simply rotate it, can i?

not important:
-when i the camera(specificaly the viewport reticle) moves a certain distance away from the mesh it stops rendering it (the camera can move away from the player, so moving the mesh with the player doesnt help in this case). can i set something like always render?

Thanks for your support on this,

Reply
Marrt 18/02/2012 at 03:29

OHH, your faster than me, forget the above post, i will insert the upside down thing

😀 many thanks

Reply
Marrt 18/02/2012 at 20:06

I made it to use the created Mesh as my cutout mask, looks awsome, now i can hide parts of the enemy, a few tweaks in my camera scripts and i can upload the next version.

i managed the disappearance of the mesh by enabling Spherical Culling + extending cullingDistance for the MeshLayer, now i can move as far away with the splitcamera, the mesh is still drawn

Thanks, when i finish a few tweaks i let you know what YOU made me achieve 😀

Reply
- mgear 19/02/2012 at 01:20
  
  sounds interesting, I tried the demo earlier and it looks good 🙂
  
  Reply
  - Marrt 19/02/2012 at 04:15
    
    Ah, i was wrong, i thought ive seen it working but its not, the spherical culling + layer distance didn’t fix the not-rendering of the mesh, anyway
    Iam interested in your thoughts on THAT:
    http://forum.unity3d.com/threads/124019-SpaceNox-Working-Title?p=834143#post834143
    
    Reply
    - mgear 19/02/2012 at 15:52
      
      added 2 fixes, one problem was, if the ray doesnt hit anything, the vertex wasnt drown in right position (the end of the ray), and then it seems to help, if you make the lightmeshholder to follow player position. (not yet sure why..)
      
      Reply
      - Marrt 19/02/2012 at 19:08
        
        Yes, it worked, but only for the ship camera, the reticule camera in game can move far away from the meshholding ship and the same problem reappears for the other side of the splitscreen
        also, as i attach the mesh to the player, the mesh gets very jumpy and shakes a bit as the ship rotates.
        
        -when the ray doesnt hit anything, the triangles are missing (shadow), thats why i setted the distance high and created a collision bound on the edge of the map
        
        there must be a “always render” flag or smth, but i didnt found it yet…
        
        if you are interested in messing around with it, i can send you the project, but i warn you, when you see my scripts you may facepalm so hard that the inertia of your eyeballs pulls them both out – right before your neck snaps – thrusting your head on the floor behind your seat creating an impact of one kiloton of TNT.
      - mgear 19/02/2012 at 19:49
        
        yes, I could try the files, so I can see whats happening.
        my email is here, http://unitycoder.com/blog/requests/
        
        also have a look at this, could be more elegant solution (although I had problems making it scan 360..but maybe 360 view is not needed)
        http://www.unity3d-france.com/unity/phpBB3/viewtopic.php?p=18274&sid=63231ea639a16863123a5a58efc08e44#p18274
mgear 19/02/2012 at 21:14

Added 1 fix..(uh..the blog post is starting to explode, should make a new fixed package later..)

See the link for disappearing mesh, adding “RecalculateBounds” fixes it.
Or by making the lighmeshHolder to follow player position, inside FixedUpdate(), not inside Update() (then it doesnt shake)

Reply
- Marrt 20/02/2012 at 01:56
  
  Awsome, i thought i already tried that by uncommenting this line in your initial script
  // mesh.RecalculateBounds();
  but i didnt see that this line wasnt in the update routine :D, stupid me.
  
  Reply
mgear 20/02/2012 at 11:27

just putting a note to myself to test these later:
– would soft shadows be possible with this kind of mesh plane system(?)
– special shader (borders get transparency?)
– vertex transparency?
– dark “glow”?
– duplicate plane? (scale just a bit smaller, then original plane is 50% transparent?)
– lengthen ray, add extra vertices to the end, with vertex transparency?

Reply
Marrt 09/04/2012 at 09:22

took me some time, but i finally managed to modify your code. didnt understand anything at the time i took the first look at it.
i tried to get better performance and now i have my solution:
since the rays are limited, i had a jumpy visibility polygon when looking at distant edges while moving.
But now i rotate the rays (not the mesh) with my ship AND increase the density of the rays in the forward direction, because that is the only direction in which distant looks(jumpy edges) happen anyway.
i took a cos to increase the density in forward direction while decreasing the backward density so i get the feel of +4000 rays while using only 1024 now.

//generate improved angles
impAngles = new float[RaysToShoot];
for (int i=0;i<RaysToShoot;i++){
impAngles[i] = Mathf.PI*2 * (-Mathf.Cos( Mathf.PI*((float)i/(float)RaysToShoot) )*0.5F + 0.5F );
}

so thanks again for your help, now im very happy with this implementation

Reply
- mgear 10/04/2012 at 21:00
  
  sounds interesting!
  btw. if you need to run the game on deep profiler (to see whats using the most cpu), we have pro version at the office.
  
  Reply
  - Marrt 12/08/2012 at 15:56
    
    Hey, i’ve just seen your offer to test my game in deep profiler, i will come back to that in september when i have finished my master thesis and finished the 0.9 version of my game 😀
    
    Reply
    - mgear 13/08/2012 at 00:43
      
      Ok, msg/email me then!
      
      I hope 4.0 is here by then..
      Also 3.5.x has some mesh improvements, havent checked them yet, if could make it faster..
      
      (and there is one more “fake shadow shader” also, not published in blog yet, might be faster..?)
      
      Reply
      - Marrt 13/08/2012 at 01:27
        
        the shader stuff looks interesting but as far as i have seen all shader solutions have a limited resolution on very distant objects, and your raycast + my CosDensityDistribution works best so far….
        
        ivkonis method needs a draw call for each shadow thats on draw call for every object in my scene (or at least on for the visible ones, but to determine which are visible raycast are needed again):
        http://www.zmeiko.com/samples/shadows.html
        
        thats the very first thing i stumbled upon as i began my search in February before i ever programmed anything:
        http://www.catalinzima.com/2010/07/my-technique-for-the-shader-based-dynamic-2d-shadows/
Akira Kido 18/07/2012 at 06:01

Hello mgear !

I developing a AI enemies library. I have a some problems about FOV of enemies. I have a idea is create FOV using Raycast Visibility. I only want my enemies FOV is 60 (degree) so i were change source like this :

In Update() (snip code)

var angle:float = -Mathf.PI/3;
for (var i:int=0;i<RaysToShoot;i++)
{
var x = Mathf.Sin(angle);
var y = Mathf.Cos(angle);
angle += 2*Mathf.PI/(3*RaysToShoot);
………
………

But i have a some problem. Could you help me solve this problem ! ( That problem in red cycle of image ) Thanks so much ( sorry my bad english )
This is image :
http://imageshack.us/photo/my-images/84/problem1j.png/

Reply
- mgear 23/07/2012 at 01:01
  Looks like some face is upside down..(?)
  
  Try if you remove/comment all these lines out (they are in function BuildMesh())
```
// central point
newvertices[newvertices.Length-1] = new Vector3(0,0,0);
triangles[triangles.length-1] = newvertices.Length-1;
triangles[triangles.length-2] = 0;
triangles[triangles.length-3] = i-1;
```
  test this one also,
  http://www.unity3d-france.com/unity/phpBB3/viewtopic.php?p=18274&sid=63231ea639a16863123a5a58efc08e44#p18274
  Reply
mgear 14/08/2012 at 02:31
Some speed increase if you remove/comment the line “vertices = ..”
its not needed inside the Update() loop (and using now LateUpdate() in v5.0)
```
function LateUpdate () 
{
//	vertices = mesh.vertices; // saves 3ms on my pc, when casting 20000 rays
```
Reply
serumas 17/10/2012 at 11:00

its very posible to get visibility polygon without ray casting, 1000-10000 rays? its very slow method if it tooks 1mls than its possible to take just 0,01 mls and if there are lots of objects that needs this effect. I have code for that working fine.Demo is at my website serumas.gamedev.lt. I could share the code…

Reply
- mgear 17/10/2012 at 11:51
  
  Looks amazing, I’ll try it soon!
  
  This one seems like good solution also,
  http://forum.unity3d.com/threads/142532-2D-Mesh-Based-Volumetric-Lights
  
  Reply
  - serumas 17/10/2012 at 16:41
    
    as i saw , its based on raycast too and very very slow 20 lights and lag just with 4 walls…
    better results using computational geometry… :).
    My algorithm not perfect yet, but it tooks ~0,02-0,04 mls with 10 walls so it could be 100s of lights, it depends on wall count. And algorithm can be optimized and speeded ~2x, not finished fully yet.
    
    Reply
    - mgear 18/10/2012 at 19:54
      
      Your demo was very smooth, does it work with moving objects also?
      
      Reply
serumas 18/10/2012 at 21:20

My algo has no history :), works with momential plygon positions. there is effect in action with moveing objects and explosions lights.

Reply
mgear 04/11/2012 at 17:15

Got something similar working, no raycasts used,
http://unitycoder.com/blog/2012/10/29/2d-raycasting-visibility-voxel-travelsal/

But will be bit difficult to handle moving objects..

Reply
serumas 04/11/2012 at 22:24

But its still rays. You wrote that its 512 rays in your demo. 🙂 Whats the problem with moveing objects? Chopy movement of visibility polygon?

Reply
serumas 20/11/2012 at 14:52

That is my newiest game prototype, that uses visibility effect on each explosion dynamicaly
http://serumas.gamedev.lt/index.php?id=combat1&sid=

Reply
- mgear 26/11/2012 at 22:31
  
  That game look good too!
  
  This one sounds interesting to try, maybe its similar to your solution?
  http://www.redblobgames.com/articles/visibility/
  
  Reply
Luis Fonseca 07/12/2012 at 15:52

Would this be suitable to create a field of vision for a NPC?

Reply
- mgear 07/12/2012 at 19:34
  
  I guess it should, but raycasts are bit heavy, so have to try it if it gets too slow (with many enemies)..
  
  Reply
  - Luis Fonseca 07/12/2012 at 19:40
    
    Thanks! Do you recommend anything else then?
    
    Reply
    - mgear 09/12/2012 at 13:45
      
      No experience on those.. but I was thinking something like this instead: http://unitycoder.com/blog/2012/12/09/enemy-visibility-cone/
      
      Reply
strobes 13/12/2012 at 12:48

Hi mgear, I was wondering how do you achieve the effect of fading lights as shown? I am by no means a shader programmer, could you explain a little about what shader did you use?

Reply
- mgear 13/12/2012 at 19:53
  
  Added the shader ^ (since our player is always in middle of the screen, we just fade the color based on distance from middle..)
  
  Other ways could be, set vertex colors or alpha for the edge vertices.
  
  Reply
  - strobes 14/12/2012 at 09:26
    
    Thanks for the quick response! Also, another question, is there any ways to limit the raycast distance? Currently, if even one of the raycasts doesn’t hit something, the entire mesh would just show up in weird positions.
    
    Reply
    - strobes 14/12/2012 at 09:38
      
      Ah, I seem to have found the solution by changing :
      
      var tmp2 = lightmeshholder.transform.InverseTransformPoint(lightmeshholder.transform.position+dir);
      
      to :
      
      var tmp2 = transform.position+dir*distance;
      
      Reply
Joakim 06/02/2013 at 19:30

Hi, great site you got and a lot of nice stuff you done!

Question, is it possible or easy to use this script, and make it “open-up” the world when you navigate through it. As it is now, it is a more shadow behavior and LOS function. I need a script that the user needs to explore a dark world, but once a area is discovered, I want it to be visible.

Joakim

Reply
- Joakim 06/02/2013 at 19:31
  
  Forgotten to subcribe 😉
  
  Reply
- mgear 06/02/2013 at 22:11
  
  Something like this?
  Fog of War: http://forum.unity3d.com/threads/39837-Fog-of-war-Mesh
  (theres some free download too, didnt try it yet..)
  
  Reply
mgear 08/02/2013 at 10:25

Should check this also,
http://forum.unity3d.com/threads/169476-Field-Of-View-2D-Based-On-Ray-Tracing-Free-Package

Reply
- Joakim 08/02/2013 at 12:39
  
  Thanks, exactly what i was searching for.
  
  Keep it up!
  
  Joakim
  
  Reply
mgear 07/04/2013 at 01:19

Looks interesting also,
Visual concealment for games using Javascript
http://www.codeproject.com/Articles/545808/Visual-concealment-for-games-using-Javascript

Reply
Mars 20/04/2013 at 00:02

Awesome!
Wish I could download, but it still doesn’t recognise my toolbar. I even tried stopping the page and copying the URL. Didn’t work :[
Awesome stuff though :]

Reply
- mgear 20/04/2013 at 16:51
  
  ^ how about now?
  
  Reply
castor 18/07/2013 at 06:23

I would like to use this to “mask” the scene representing what the actor sees independently from any lights in the scene. How could I go about doing it? Is it possible to generate the inverse of the current mesh and just have a black material on it?
(sorry for all the questions, very new to Unity and been trying to do something like this for ages!)

Reply
mgear 01/08/2013 at 05:34

2D Dynamic shadows (with source)
http://forum.unity3d.com/threads/165283-2D-Dynamic-Shadows/page2?p=1316115#post1316115

Reply
mgear 09/02/2014 at 21:54

Line Of Sight / Field of View (webplayer demo)
http://forum.unity3d.com/threads/227342-Line-Of-Sight-Field-of-View

Reply
- mgear 08/05/2014 at 12:25
  
  explained:
  http://forum.unity3d.com/threads/227342-Line-Of-Sight-Field-of-View?p=1525883&viewfull=1#post1525883
  
  Reply
mgear 27/05/2014 at 17:01

Some info about raycasting performance, see “Figure 8 : Primitive vs Mesh colliders physics profiler data”
http://unity3d.com/learn/tutorials/modules/intermediate/physics/physics-best-practices

Reply
mgear 14/01/2015 at 13:53

this could help alot: go vote for “Enable PhysX raycast batching”
http://feedback.unity3d.com/suggestions/enable-physx-raycast-batching

Reply
mgear 07/09/2015 at 09:26

at 9:59, using local cubemap to generate “visibility” map where light can reach:
Enhancing your Unity Mobile Games – Unite Europe 2015
https://youtu.be/Z5y-PQIpSbw?t=9m59s

Reply
mgear 16/01/2018 at 15:35

fov raycast from camera
https://forum.unity.com/threads/using-a-camera-to-do-a-fan-of-raycasts.512817/

using unity 2D threaded job system,
https://twitter.com/LotteMakesStuff/status/952273492015243264

Reply
serumas 16/01/2018 at 21:32

Hi there again, so how good your algorithm? Still ray cast? 🙂 jokin

Reply
- mgear 18/01/2018 at 17:53
  
  raycast-all-the-things is future:
  https://twitter.com/LotteMakesStuff/status/953734045883621377
  
  Reply
Gerry 26/07/2018 at 22:23

Hi there, it seems I can’t extract the zip file. It said that the zip can’t be open by 7zip.

Reply
- mgear 27/07/2018 at 00:14
  
  thanks for reporting! should be fixed now
  
  Reply
  - Gerry 28/07/2018 at 23:04
    
    I just successfully imported it to my project, thank you!
    
    Reply