I am using the following shaders to mask two sprites:
Shader "Sprites/Stencil Mask"
{
Properties
{
[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
_Color ("Tint", Color) = (1,1,1,1)
[MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
}
SubShader
{
Tags
{
"Queue"="Transparent"
"IgnoreProjector"="True"
"RenderType"="Transparent"
"PreviewType"="Plane"
"CanUseSpriteAtlas"="True"
}
Cull Off
Lighting Off
ZWrite Off
Fog { Mode Off }
Blend SrcAlpha OneMinusSrcAlpha
Pass
{
Stencil
{
Ref 1
Comp always
Pass replace
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile DUMMY PIXELSNAP_ON
#include "UnityCG.cginc"
struct appdata_t
{
float4 vertex : POSITION;
float4 color : COLOR;
float2 texcoord : TEXCOORD0;
};
struct v2f
{
float4 vertex : SV_POSITION;
fixed4 color : COLOR;
half2 texcoord : TEXCOORD0;
};
fixed4 _Color;
v2f vert(appdata_t IN)
{
v2f OUT;
OUT.vertex = mul(UNITY_MATRIX_MVP, IN.vertex);
OUT.texcoord = IN.texcoord;
OUT.color = IN.color * _Color;
#ifdef PIXELSNAP_ON
OUT.vertex = UnityPixelSnap (OUT.vertex);
#endif
return OUT;
}
sampler2D _MainTex;
fixed4 frag(v2f IN) : SV_Target
{
fixed4 c = tex2D(_MainTex, IN.texcoord) * IN.color;
if (c.a<0.1) discard; //Most IMPORTANT working Code
c.rgb *= c.a;
return c;
}
ENDCG
}
}
}
Shader "Sprites/Stencil Draw In Mask"
{
Properties
{
[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
_Color ("Tint", Color) = (1,1,1,1)
[MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
}
SubShader
{
Tags
{
"Queue"="Transparent+1" //DON'T FORGET this must be drew later to catch Stencil Ref value.
"IgnoreProjector"="True"
"RenderType"="Transparent"
"PreviewType"="Plane"
"CanUseSpriteAtlas"="True"
}
Cull Off
Lighting Off
ZWrite Off
Fog { Mode Off }
Blend One One
Pass
{
Stencil
{
Ref 1
Comp Equal
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile DUMMY PIXELSNAP_ON
#include "UnityCG.cginc"
struct appdata_t
{
float4 vertex : POSITION;
float4 color : COLOR;
float2 texcoord : TEXCOORD0;
};
struct v2f
{
float4 vertex : SV_POSITION;
fixed4 color : COLOR;
half2 texcoord : TEXCOORD0;
};
fixed4 _Color;
v2f vert(appdata_t IN)
{
v2f OUT;
OUT.vertex = mul(UNITY_MATRIX_MVP, IN.vertex);
OUT.texcoord = IN.texcoord;
OUT.color = IN.color * _Color;
#ifdef PIXELSNAP_ON
OUT.vertex = UnityPixelSnap (OUT.vertex);
#endif
return OUT;
}
sampler2D _MainTex;
fixed4 frag(v2f IN) : SV_Target
{
fixed4 c = tex2D(_MainTex, IN.texcoord) * IN.color;
c.rgb *= c.a;
return c;
}
ENDCG
}
}
}
This worked fine on my iPhone 6S but not on older devices like my iPhone 5 running iOS 7. I read that this was because of the Discard statement and that I should instead set the alpha to zero.
I did this, but then I get an outline around my object. I have tried to disable anti aliasing to troubleshoot, but that did not work.
My new shader (only changed that one line from discard to c.a = 0)
Shader "Sprites/Stencil Mask"
{
Properties
{
[PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
_Color ("Tint", Color) = (1,1,1,1)
[MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
}
SubShader
{
Tags
{
"Queue"="Transparent"
"IgnoreProjector"="True"
"RenderType"="Transparent"
"PreviewType"="Plane"
"CanUseSpriteAtlas"="True"
}
Cull Off
Lighting Off
ZWrite Off
Fog { Mode Off }
Blend SrcAlpha OneMinusSrcAlpha
Pass
{
Stencil
{
Ref 1
Comp always
Pass replace
}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile DUMMY PIXELSNAP_ON
#include "UnityCG.cginc"
struct appdata_t
{
float4 vertex : POSITION;
float4 color : COLOR;
float2 texcoord : TEXCOORD0;
};
struct v2f
{
float4 vertex : SV_POSITION;
fixed4 color : COLOR;
half2 texcoord : TEXCOORD0;
};
fixed4 _Color;
v2f vert(appdata_t IN)
{
v2f OUT;
OUT.vertex = mul(UNITY_MATRIX_MVP, IN.vertex);
OUT.texcoord = IN.texcoord;
OUT.color = IN.color * _Color;
#ifdef PIXELSNAP_ON
OUT.vertex = UnityPixelSnap (OUT.vertex);
#endif
return OUT;
}
sampler2D _MainTex;
fixed4 frag(v2f IN) : SV_Target
{
fixed4 c = tex2D(_MainTex, IN.texcoord) * IN.color;
if (c.a<0.1) c.a = 0; //Most IMPORTANT working Code
c.rgb *= c.a;
return c;
}
ENDCG
}
}
}
results before (with discard):
results after (with c.a=0):
How can I get a clean sprite mask without using discard?
Thank you