Shader For VR / Different color on each eye

How can I write a simple shader to have different colour on each eye? I can use single or multiple pass. I will add a cube to the scene. I will add a material with my custom shader. I will add 2 color properties to this shader. i.e. Left eye will see this cube as red, right eye will see this cube as green.

 

ive seen this mentioned "‘unity_StereoEyeIndex"
https://docs.unity3d.com/Manual/SinglePassStereoRendering.html

 

For single pass, use unity_StereoEyeIndex as suggested by @mgear. For multi pass you have to setup two cameras, one for each eye, and use layer masks. Annoyingly they don't set unity_StereoEyeIndex for multi pass VR, but I suspect they consider that mode deprecated internally as once single pass was added they haven't really touched it.

Note that in a vertex fragment shader to access that variable you need to use a couple of macros to initialize that value in the fragment shader. See this page:
https://docs.unity3d.com/Manual/SinglePassInstancing.html

The last example on that page is in fact exactly what you're looking to do.

 

Hi there,
I am doing a different application. I have used https://docs.unity3d.com/Manual/SinglePassInstancing.html to show different colors on each eye.

How can I make these object transparent ? I don't know shader scripting very well.


Shader "XR/StereoEyeIndexColor"
{
Properties
{
_LeftEyeColor("Left Eye Color", COLOR) = (0,1,0,0.5)
_RightEyeColor("Right Eye Color", COLOR) = (1,0,0,0.5)
}

SubShader
{
Tags { "RenderType" = "Opaque" }

Pass
{
CGPROGRAM

#pragma vertex vert
#pragma fragment frag

float4 _LeftEyeColor;
float4 _RightEyeColor;

#include "UnityCG.cginc"

struct appdata
{
float4 vertex : POSITION;

UNITY_VERTEX_INPUT_INSTANCE_ID
};

struct v2f
{
float4 vertex : SV_POSITION;

UNITY_VERTEX_INPUT_INSTANCE_ID
UNITY_VERTEX_OUTPUT_STEREO
};

v2f vert (appdata v)
{
v2f o;

UNITY_SETUP_INSTANCE_ID(v);
UNITY_INITIALIZE_OUTPUT(v2f, o);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);

o.vertex = UnityObjectToClipPos(v.vertex);

return o;
}

fixed4 frag (v2f i) : SV_Target
{
UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);

return lerp(_LeftEyeColor, _RightEyeColor, unity_StereoEyeIndex);
}
ENDCG
}
}
}