I have two custom shaders, a skybox shader, and a billboard shader - eventually a corona for a star. Some parts of the Corona shader have to be transparent, however when outputting transparency from the fragment, it is only used when the color is against some other object, but not the skybox. If ZWrite is On, then fully opaque color is drawn, and if ZWrite is Off, nothing. Blending is Blend SrcAlpha OneMinusSrcAlpha. Below is the code for Star_Corona, and vr_skybox. Incidentally, the problem is solved when clearing the camera from a color instead of the skybox - then, the correct alpha is applied.
EDIT: I should add that the alpha is rendered correctly in the scene view, just not in the game view.
Scene View (Correct, though a different angle):
Game View (Incorrect, still incorrect if viewed from any angle):
Code:
Shader “Custom/Star_Corona”
{
Properties
{
}
SubShader
{
Tags
{
"Queue"="Transparent"
"RenderType"="Transparent"
}
Cull Off
Blend SrcAlpha OneMinusSrcAlpha
ZWrite Off
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct v2f
{
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float4 vertex : COLOR0;
};
v2f vert (appdata_base v)
{
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = v.texcoord;
o.vertex = v.vertex;
return o;
}
float4 frag (v2f i) : COLOR
{
float dist = length(i.vertex)*3;
float brightness = (1.0/(dist*dist) - 0.1) * 1;
return float4(1,0,0,0.5);
}
ENDCG
}
}
}
Incidentally, this is Copyright Valve, but you can get it for free from the Asset Store - under “TheLabRenderer”.
Shader "Valve/vr_skybox"
{
Properties
{
_Tint( "Tint Color", Color ) = ( .5, .5, .5, .5 )
[Gamma] _Exposure( "Exposure", Range( 0, 8 ) ) = 1.0
_Rotation( "Rotation", Range( 0, 360 ) ) = 0
[NoScaleOffset] _FrontTex( "Front [+Z] (HDR)", 2D) = "grey" {}
[NoScaleOffset] _BackTex( "Back [-Z] (HDR)", 2D) = "grey" {}
[NoScaleOffset] _LeftTex( "Left [+X] (HDR)", 2D) = "grey" {}
[NoScaleOffset] _RightTex( "Right [-X] (HDR)", 2D) = "grey" {}
[NoScaleOffset] _UpTex( "Up [+Y] (HDR)", 2D) = "grey" {}
[NoScaleOffset] _DownTex( "Down [-Y] (HDR)", 2D) = "grey" {}
}
SubShader
{
Tags
{
"Queue"="Background"
"RenderType"="Background"
"PreviewType"="Skybox"
}
Cull Off
ZWrite Off
//doesn't change anything, messed with Zero and One in both spots, no fix
//Blend SrcAlpha OneMinusSrcAlpha
CGINCLUDE
#pragma target 5.0
#pragma only_renderers d3d11
#pragma exclude_renderers gles
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
#include "UnityCG.cginc"
#include "vr_utils.cginc"
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
float4 _Tint;
float _Exposure;
float _Rotation;
#define g_vTint _Tint
#define g_flExposure _Exposure
#define g_flRotation _Rotation
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
float4 RotateAroundYInDegrees( float4 vPositionOs, float flDegrees )
{
float flRadians = flDegrees * UNITY_PI / 180.0;
float flSin, flCos;
sincos( flRadians, flSin, flCos );
float2x2 m = float2x2( flCos, -flSin, flSin, flCos );
return float4( mul( m, vPositionOs.xz ), vPositionOs.yw ).xzyw;
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
struct VS_INPUT
{
float4 vPositionOs : POSITION;
float2 vTexcoord : TEXCOORD0;
};
struct PS_INPUT
{
float4 vPositionPs : SV_POSITION;
float2 vTexcoord : TEXCOORD0;
};
struct PS_OUTPUT
{
float4 vColor : SV_Target0;
};
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
PS_INPUT SkyboxVs( VS_INPUT v )
{
PS_INPUT o;
o.vPositionPs.xyzw = mul( UNITY_MATRIX_MVP, RotateAroundYInDegrees( v.vPositionOs.xyzw, g_flRotation ) );
o.vTexcoord.xy = v.vTexcoord.xy;
return o;
}
//-------------------------------------------------------------------------------------------------------------------------------------------------------------
PS_OUTPUT SkyboxPs( PS_INPUT i, sampler2D faceSampler, float4 faceSamplerDecode )
{
float4 vSkyboxTexel = tex2D( faceSampler, i.vTexcoord.xy ).rgba;
float3 vSkyboxLinearColor = DecodeHDR( vSkyboxTexel.rgba, faceSamplerDecode.rgba );
PS_OUTPUT o;
o.vColor.rgb = saturate( vSkyboxLinearColor.rgb * g_vTint.rgb * unity_ColorSpaceDouble.rgb * g_flExposure );
o.vColor.a = 1.0;
// Dither to fix banding artifacts
o.vColor.rgb += ScreenSpaceDither( i.vPositionPs.xy );
return o;
}
ENDCG
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _FrontTex;
float4 _FrontTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _FrontTex, _FrontTex_HDR ); }
ENDCG
}
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _BackTex;
float4 _BackTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _BackTex, _BackTex_HDR ); }
ENDCG
}
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _LeftTex;
float4 _LeftTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _LeftTex, _LeftTex_HDR ); }
ENDCG
}
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _RightTex;
float4 _RightTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _RightTex, _RightTex_HDR ); }
ENDCG
}
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _UpTex;
float4 _UpTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _UpTex, _UpTex_HDR ); }
ENDCG
}
Pass
{
CGPROGRAM
#pragma vertex SkyboxVs
#pragma fragment MainPs
sampler2D _DownTex;
float4 _DownTex_HDR;
PS_OUTPUT MainPs( PS_INPUT i ) { return SkyboxPs( i, _DownTex, _DownTex_HDR ); }
ENDCG
}
}
}