One tone transparent blending

Hello everyone!
How to mix transparent sprites to achieve something like this?

I think i tried all variants "Blend SrcFactor DstFactor" and result almost in all cases like this(Darkest color in place where sprite overlayed each other).

I do the first picture with 2 cameras and this shader, bud it's creepy.

Code (csharp):

1.  
2. Shader "Unlit/TransparentAlphatestShadow"
3. {
4. Properties
5. {
6.     _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
7.     _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
8.     _Alpha ("Alpha", Range(0,1)) = 0.5
9. }
10.  
11. SubShader
12. {
13.     Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
14.    
15.     ZWrite On
16.     ColorMask 0
17.    
18.     Pass
19.     {
20.         CGPROGRAM
21.             #pragma vertex vert
22.             #pragma fragment frag
23.            
24.             #include "UnityCG.cginc"
25.  
26.             struct appdata_t
27.             {
28.                 float4 vertex : POSITION;
29.                 float2 texcoord : TEXCOORD0;
30.             };
31.  
32.             struct v2f
33.             {
34.                 float4 vertex : SV_POSITION;
35.                 half2 texcoord : TEXCOORD0;
36.             };
37.  
38.             sampler2D _MainTex;
39.             float4 _MainTex_ST;
40.             fixed _Cutoff;
41.            
42.             v2f vert (appdata_t v)
43.             {
44.                 v2f o;
45.                 o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
46.                 o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
47.                 return o;
48.             }
49.            
50.             fixed4 frag (v2f i) : COLOR
51.             {
52.                 fixed4 col = tex2D(_MainTex, i.texcoord);
53.                 clip(col.a - _Cutoff);
54.                 return 0;
55.             }
56.         ENDCG
57.     }
58.  
59.  
60.     ZWrite Off
61.     Blend DstAlpha OneMinusSrcAlpha
62.    
63.     ColorMask rgba
64.    
65.     Pass
66.     {      
67.         CGPROGRAM
68.             #pragma vertex vert
69.             #pragma fragment frag
70.            
71.             #include "UnityCG.cginc"
72.  
73.             struct appdata_t {
74.                 float4 vertex : POSITION;
75.                 float2 texcoord : TEXCOORD0;
76.             };
77.  
78.             struct v2f {
79.                 float4 vertex : SV_POSITION;
80.                 half2 texcoord : TEXCOORD0;
81.             };
82.  
83.             sampler2D _MainTex;
84.             float4 _MainTex_ST;
85.             fixed _Cutoff;
86.             fixed _Alpha;
87.            
88.             v2f vert (appdata_t v)
89.             {
90.                 v2f o;
91.                 o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
92.                 o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
93.                 return o;
94.             }
95.            
96.             fixed4 frag (v2f i) : COLOR
97.             {
98.                 fixed4 col = tex2D(_MainTex, i.texcoord);
99.                 return fixed4(0, 0, 0, _Alpha*step(0, col.a - _Cutoff));
100.             }
101.         ENDCG
102.     }
103. }
104.  
105. }
106.  

Have any way to get one tone transparent shadows without render to texture?
Thanks in advance!

 

Two cameras is a reasonable solution to the issue. If you want a single camera solution, and have pro, you can use the stencil buffer to avoid writing to the framebuffer in an area that has already been written to.

 

kru, thank you very much. It's good reason to learn how stencil stuff work.

 

You know.. you could also simply turn on ZWrite and set ZTest to LEqual

 

Dolkar, I can't understand mechanism of this method. May you explain little more detailed?
upd
Nevermind, I got it. Thank you!