[Note] Unity Profiler enhancement

split binary profiler data (in order to view more frames in profiler):
http://www.itdadao.com/articles/c19a766424p0.html

calculate FPS:
https://github.com/MattRix/UnityDecompiled/blob/master/UnityEditor/UnityEditor/GameViewGUI.cs
http://www.jianshu.com/p/1c22321d88af
https://gamedev.stackexchange.com/questions/118934/unity-stats-framerate-vs-time-deltatime
note about FPS calculation:
1. UnityStats.frameTime, UnityStats.renderTime seem can only be read in OnGUI()
2. the FPS in Profiler(and Unity stats window) seems to match the value (1.0f / (UnityStats.frameTime + UnityStats.renderTime)), not sure but currently my experimental results match the calculation

package download link:
https://drive.google.com/file/d/1weD2QOAh7wyUWINor8Na0Ix-d__15vlv/view?usp=sharing

[Note] convert transform matrix from right-handed coordinate system to left-handed coordinate system

Rotation:
angle: rotate negated angle
axis: negate z component

https://butterflyofdream.wordpress.com/2016/07/05/converting-rotation-matrices-of-left-handed-coordinate-system/
https://www.evl.uic.edu/ralph/508S98/coordinates.html

Translation:
negate z component

Then you have things like SteamVR pose to Unity pose conversion in SteamVR_Utils in Unity's SteamVR plugin:

                 public RigidTransform(HmdMatrix34_t pose)
{
var m = Matrix4x4.identity;

m[0, 0] =  pose.m0;
m[0, 1] =  pose.m1;
m[0, 2] = -pose.m2;
m[0, 3] =  pose.m3;

m[1, 0] =  pose.m4;
m[1, 1] =  pose.m5;
m[1, 2] = -pose.m6;
m[1, 3] =  pose.m7;

m[2, 0] = -pose.m8;
m[2, 1] = -pose.m9;
m[2, 2] =  pose.m10;
m[2, 3] = -pose.m11;

this.pos = m.GetPosition();
this.rot = m.GetRotation();
}

[Note] 3D triagnle mesh volume calculation

stackoverflow link

using sum of signed volume of tetrahedrons, very cool!

Unity UGUI text underline

reference

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
public class TextUnderline : MonoBehaviour {
 //Text that draws underline
 public Text underline;

 /*
  refText: Text that its text content will be underlined
  clear: clear underline
  underlineVerticalOffsetScale: control distance between refText and underline
 
  sample hierarchy structure:

  refText(components: Text)
   underline(components: Text, TextUnderline)   
 */
 public void setup(Text refText, bool clear = false, float underlineVerticalOffsetScale = 1.0f)
 {
  if(clear)
  {
   underline.text = "";
   return;
  }
  RectTransform rt = underline.GetComponent();
  RectTransform refRT = refText.GetComponent();

  underline.font = refText.font;
  underline.fontSize = refText.fontSize;
  //underline.fontStyle = refText.fontStyle;
  underline.color = refText.color;
  underline.text = "_";

  rt.localScale = refRT.localScale;
  float refHeight = refText.preferredHeight;

  float perlineWidth = underline.preferredWidth * rt.localScale.x;
  Debug.Log(perlineWidth);

  float refWidth = refText.preferredWidth;
  int lineCount = (int)Mathf.Round(refWidth / perlineWidth);
  Debug.Log(lineCount);
  for (int i = 1; i < lineCount; i++)
  {
   underline.text += "_";
  }

  float selfHeight = underline.preferredHeight;
  rt.anchoredPosition = new Vector2(0.0f, -(refHeight + selfHeight) * underlineVerticalOffsetScale);
 }
}

Unity load external script at runtime(using Visual Studio)

reference link

To load external script into Unity at runtime, the external script needs to be compiled as assembly(.dll), here are steps to do so.

1. Create a new C# project with Visual Studio, choose the project type as "Class Library"
2. Add UnityEngine.dll as project reference, the UnityEngine.dll is located at "<Unity_Install_Path>\Editor\Data\Managed". Add the dll to project reference by the following steps: 
right click project name in Solution Explorer -> Properties -> Reference Paths -> Folder -> browse to find the folder that contains .dll -> Add Folder


right click "References" in Solution Explorer -> Add References -> Assembly -> search the dll you added

3. in the created Class Library project, create a class that extends MonoBehaviour like what we usually do in Unity, you can implement its Start(), Update()...

4. Release build this library project and remember the path to the .dll created by this library project

5. use the WWWAssemblyLoader in the reference link above or my modified assembly loader below:

using UnityEngine;
using System.Collections;
using System;
using System.Reflection;

public class MyWWWAssemblyLoader
{

 public IEnumerator loadAssembly(string url, Action finishCallback)
 {
  if(url == null || finishCallback == null)
  {
   yield break;
  }
  WWW m_WWW = new WWW(url);
  while(!m_WWW.isDone)
  {
   yield return null;
  }

  Assembly assembly = LoadAssembly(m_WWW);
  if (assembly != null)
  {
   Debug.Log("load assembly: " + url + " Done");
   finishCallback(true, url, assembly);
  }
  else
  {
   Debug.Log("load assembly: " + url + " Failed");
   finishCallback(false, url, assembly);
  }

 }

 private Assembly LoadAssembly(WWW m_WWW)
 {
  try
  {
   return Assembly.Load(m_WWW.bytes);
  }
  catch (System.Exception e)
  {
   Debug.LogError(e.ToString());
   return null;
  }
 }
}

6. load the dll and use reflection to control it as following:

 IEnumerator Start()
 {
  //load script
  yield return StartCoroutine(loadAssemblyScriptAsync("file:///YourAssembly.dll", onAssemblyScriptLoaded));
 }

 private IEnumerator loadAssemblyScriptAsync(string url, Action callback)
 {
  MyWWWAssemblyLoader myLoader = new MyWWWAssemblyLoader();
  yield return StartCoroutine(myLoader.loadAssembly(url, callback));

 }

 private void onAssemblyScriptLoaded(bool success, string url, Assembly assembly)
 {
  if (!success)
  {
   Debug.LogError("onAssemblyScriptLoaded failed");
   return;
  }
  Debug.Log("Assembly url: " + url);

  System.Type type = assembly.GetType("YourClassNameSpace.YourClassName");
  if (type == null)
  {
   Debug.LogError("type is null");
   return;
  }
  FieldInfo field = type.GetField("YourFloatField");

  GameObject go = GameObject.Find("YourEmptyGameObject");
  //add loaded script to go
  Component comp = go.AddComponent(type);

  FieldInfo myFieldInfo = type.GetField("YourFloatField");

  Debug.Log("The field value of YourFloatField is " + myFieldInfo.GetValue(comp));

  myFieldInfo.SetValue(comp, 30.0f);

  Debug.Log("The new field value of YourFloatField is " + myFieldInfo.GetValue(comp));
 }

7. the external script for above code can be:

using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;
namespace YourClassNameSpace
{
    public class YourClassName : MonoBehaviour
 {
  public float YourFloatField = 1.0f;
  // Use this for initialization
  void Start()
  {

  }

  // Update is called once per frame
  void Update()
  {
   transform.Rotate(Vector3.up, YourFloatField * Time.deltaTime);
  }
 }
}

Unity depth mask using additional camera

reference
sample unity package
Note: this trick doesn't work with Unity SteamVR plugin's CameraRig
Note: this is a different implementation from the depth mask from unity wiki

The basic idea of depth mask is just like normal z-test. You use transparent objects (say mask objects) that are closer to the camera so other objects behind the mask objects will not pass the z-test and not be rendered.

However the problem is that under the same camera rendering, transparent objects can't be considered as passed z-test when opaque objects are behind them.

So the trick is just like the reference link above, use another camera (say camera2) that draws masked object after previous camera(say camera1) rendered the transparent masks.

In this case, camera1 draws first and makes transparent objects write to the z-buffer, then when camera2 is drawing, since the z-buffer is occupied by the transparent objects, the object behind the mask will fail the z-test.

Apparently, the camera1 and camera2 need some settings to achieve the mask effect. Just like the reference link, camera1 needs to render before camera2, so the "depth" property in Unity camera needs to be setup. Just set camera2's depth be larger than camera1's depth to achieve the rendering order.

Then since camera2 draws on top of camera1, camera2's "clear flags" needs to be set as "Don't clear".

Make sure that camera2 has exactly the same camera properties and 3D objects settings as camera1(transforms, fov...), otherwise the rendered scenes will not match.

Add transparent objects into the scene as mask. The transparent objects need to write into the z-buffer, you can use the shader code below to achieve this.

Finally, add a User Layer in Unity (say MaskedObject as the layer name), set masked object to be in the MaskedObject layer, set camera2's culling mask to MaskedObject, then try to move the masked object behind the transparent masks.

here is the result

the moving cube is masked at certain positions, those positions actually are occupied by transparent cubes and the transparent cubes occlude the masked cube.

the shader code for transparent mask object

Shader "SimpleTransparentZWrite"
{
 SubShader
 {
  Tags{ "Queue" = "Transparent" }
  Pass{
   Blend SrcAlpha OneMinusSrcAlpha
   ZTest LEqual
   Cull Back

   ZWrite On
   CGPROGRAM
   #pragma vertex vert
   #pragma fragment frag
   #include "UnityCG.cginc"
   struct appdata {
    float4 vertex : POSITION;
   };
   struct v2f {
    float4 pos : SV_POSITION;
   };
   v2f vert(appdata v) {
    v2f o;
    o.pos = UnityObjectToClipPos(v.vertex);
    return o;
   }
   half4 frag(v2f i) : SV_Target{
    return half4(0,0,0,0.0);
   }
   ENDCG
  }
 }
}

Windows Node JS app deployed on heroku(using GitHub)

03/14/2017 update: add new heroku deploy notes about modifying the app entry point. if the entry point is not modified, the heroku server always runs the heroku NodeJS sample

1. Download NodeJS here: https://nodejs.org/en/download/ , install NodeJS

2.  Go to GitHub and create a repository: https://github.com/

my repository name is TestNodeJS


3. Go to heroku and create an app: https://dashboard.heroku.com/apps

my heroku app name is myynodejstest

4. Setup heroku's NodeJS sample (follow the steps in the link): https://devcenter.heroku.com/articles/getting-started-with-nodejs#introduction

clone heroku NodeJS sample:
https://devcenter.heroku.com/articles/getting-started-with-nodejs#prepare-the-app

5. git push the heroku NodeJS sample to the GitHub repository created in step 2

6. link GitHub repository to heroku app and deploy to heroku

go to your heroku app dashboard: https://dashboard.heroku.com/apps/your_app_name
press the Deploy button


connect to the GitHub repository of your NodeJS project


deploy the GitHub repository branch


7. check your app by the link: https://your_heroku_app_name.herokuapp.com/

8. Windows NodeJS dev environment setup:
to make npm module globally accessible, you need to add npm module path to user's environment variable:
variable name: NODE_PATH
variable value: %USERPROFILE%\AppData\Roaming\npm\node_modules
for more info, please check here: http://stackoverflow.com/questions/9587665/nodejs-cannot-find-installed-module-on-windows

9. modify app entry point(03/14/2017 added)
not so sure but I changed the following fields
 -"app.json" - repository
 -"package.json" - main, scripts.start
 -"Procfile" - web: node {your_entry_point_file}(your server.js)

10 other things need to be noticed
 - npm package dependencies: need to modify "package.json" - dependencies
 - server's port: please use "port = process.env.PORT || 5000", if heroku can't bind the port

Notes about depth texture(using Unity shader code)

Depth texture used for effects like fog normally uses camera's depth texture, the shader code is as the following:

float depth01 = Linear01Depth(UNITY_SAMPLE_DEPTH(tex2D(_CameraDepthTexture, i.depthUV)));

Then you get the float in the range (0,1) for the depth value.

But the problem is that the depth texture of camera doesn't contains information about transparent objects, so we need to use fragment's depth in clip space, the shader code is as the following:

    struct appdata 
   {
          float4 vertex : POSITION;
  half2 texcoord : TEXCOORD0;
    };

    struct v2f 
    {
   float4 pos : SV_POSITION;
   float2 uv: TEXCOORD0;
        float2 depthUV : TEXCOORD1;
        float3 cameraToFarPlane : TEXCOORD2;
    float4 screenPos : TEXCOORD3;
    };
    
   v2f vert(appdata v) 
  {
    v2f o;
    o.pos = UnityObjectToClipPos(v.vertex);
o.screenPos = ComputeScreenPos(o.pos);
       ...
  }

  fixed4 frag (v2f i) : SV_Target 
 {
float depth01 = i.screenPos.w / (_ProjectionParams.z - _ProjectionParams.y);//normalize to the range(0,1)
  //i.screenPos.w: depth(z) in camera space, range(n, f), i think(could be wrong). Please check http://blog.csdn.net/zhao_92221/article/details/46844267 and http://www.songho.ca/opengl/gl_projectionmatrix.html for details. I guess unity uses projection matrix to map (n,f) to (0,1), could be wrong
  //_ProjectionParams.z - _ProjectionParams.y: camera far - near
  }

One use case of these two different values is that you can use it to measure the thickness of the transparent objects(e.g. the depth of water object). Simply use the depth for fragment in clip space to subtract the depth in camera's depth texture.

fixed Unity standard asset water reflection in VR environmemt(SteamVR only)

[DOWNLOAD the unity package] (note: need to import Unity SteamVR plugin first, tested with SteamVR plugin 1.1.1 and SteamVR plugin 1.2. Unity may show compilation error if the SteamVR plugin is not compatible with the script for the water, you can fix the script by following the instructions at the line where compilation error occurs)
The water module  from Unity standard asset has problem with reflection under VR environment.
This link has the solution to reflection under VR environment in Unity.
https://forum.unity3d.com/threads/5-4-beta15-reflection-rendering-wrong-in-openvr-htc-vive.398756/

Simply apply this solution to the water module's source code then the problem is solved.

02/10/2017 update(package is also updated for the download link):
Fixed the missing prefab problem from previous unity package. Added instructions to fix SteamVR plugin incompatible problem.

02/03/2017 update(package is also updated for the download link):
some modifications for single pass stereo rendering, removed the discontinuous texture sampling artifacts when single pass stereo rendering turned on.

Some notes:
The reflection use a camera for reflection. The reflection camera is at the reflection pose of the main camera by the reflection surface.

The reflection camera makes a render texture for the reflection surface plane.

The reflection camera modified it's projection matrix so that its clip plane will be the reflection plane(so that object between reflection camera and the reflection surface will not be rendered). It transforms it's view frustum to be oblique view frustum.
Oblique view frustum derivation
view frustum culling(the relationship between view frustum plane and projection matrix)
reflection matrix
oblique view frustum transform implemented by C#

The reflection camera has different pose for left eye and right eye in VR enivronment:
Vector3 eyePos = cam.transform.TransformPoint(SteamVR.instance.eyes[0].pos);
Quaternion eyeRot = cam.transform.rotation * SteamVR.instance.eyes[0].rot;
Matrix4x4 projectionMatrix = GetSteamVRProjectionMatrix(cam, Valve.VR.EVREye.Eye_Left);

 Vector3 eyePos = cam.transform.TransformPoint(SteamVR.instance.eyes[1].pos);
 Quaternion eyeRot = cam.transform.rotation * SteamVR.instance.eyes[1].rot;
 Matrix4x4 projectionMatrix = GetSteamVRProjectionMatrix(cam, Valve.VR.EVREye.Eye_Right);

The reflection camera has different render textures for left and right eye:
render the render texture for left and right eye on the same texture by specifying the range where the texture of each eye should be drawn:
    private static readonly Rect LeftEyeRect = new Rect(0.0f, 0.0f, 0.5f, 1.0f);
    private static readonly Rect RightEyeRect = new Rect(0.5f, 0.0f, 0.5f, 1.0f);
    ...
    m_ReflectionCamera.rect = camViewport;//camViewport is LeftEyeRect or RightEyeRect
So the reflection render texture's left half part is for left eye, right half part is for right eye.
And when sampling the reflection render texture, the uv coordinates need to be modified according to which eye is being used:
vert shader
o.screenPos = ComputeScreenPos(o.pos);
frag shader
half4 screenWithOffset = i.screenPos;
#ifndef UNITY_SINGLE_PASS_STEREO
if (unity_CameraProjection[0][2] < 0)
{
screenWithOffset.x = (screenWithOffset.x * 0.5f);//make x as 0 ~ 0.5
}
else if (unity_CameraProjection[0][2] > 0)
{
screenWithOffset.x = (screenWithOffset.x * 0.5f) + (screenWithOffset.w * 0.5f);//0.5~1
}
#endif

for Single Pass Stereo Rendering case, the "screenWithOffset" will be handled automatically since single pass stereo rendering treats the texture as a combined texture for left and right eye. It will use left half texture for left eye, right half texture for right eye, we don't need to modify the screenWithOffset.x as the case of non single pass stereo rendering