foreword
Today we will implement a relatively simple and practical shader effect – 2D Sprite shadow effect
final effect:
Preparation:
Open unity to create a new 2D scene, import a 2D character picture and a transparent picture (used to receive shadows), modify the picture Texture Type to Sprite type,
Drag the 2D character sprite map to the scene, then drag the transparent map to the character sprite map node, name it shadow, use it to receive the shadow and then create a new material ball, drag it to the shadow node, shader select the shadow we will create. shader.
The scene is as follows:
Implementation idea:
In fact, it is very simple, just pass the texture of the character to the shadow shader, and change the rgb of the pixel whose alpha value is greater than 0 to black.
Shaders:
<pre>
// ---------------------------【2D Sprite Shadow】---------------- -----------
Shader
"lcl/shader2D/playerShadow"
{<!-- -->
// ---------------------------【Subshader】---------------- -----------
SubShader
{<!-- -->
// No culling or depth
Cull Off ZWrite Off ZTest Always
// turn on transparency
Blend SrcAlpha OneMinusSrcAlpha
// set up the render queue
Tags
{<!-- -->
"Queue"
=
"Transparent"
"RenderType"
=
"Opaque"
}
// --------------------------【Channel 1】----------------- ----------
pass
{<!-- -->
CGPROGRAM
#
pragma
vertex vert
#
pragma
fragment frag
#include
"UnityCG.cginc"
structure
appdata
{<!-- -->
float4
vertex
:
POSITION
;
float2
uv
:
TEXCOORD0
;
}
;
structure
v2f
{<!-- -->
float2
uv
:
TEXCOORD0
;
float4
vertex
:
SV_POSITION
;
}
;
// get vertex shader
v2f
vert
(
appdata
v
)
{<!-- -->
v2f
o
;
o
.
vertex
=
UnityObjectToClipPos
(
v
.
vertex
)
;
o
.
uv
=
v
.
uv
;
o
.
uv
.
the y
=
1
-
o
.
uv
.
the y
;
return
o
;
}
//Get the character texture and pass it through c#
sampler2D
_PlayerTex
;
// Fragment shader acquisition
fixed4
frag
(
v2f
i
)
:
SV_Target
{<!-- -->
// Sample the passed texture
fixed4
col
=
tex2D
(
_PlayerTex
,
i
.
uv
)
;
// Here use step instead of if
// When the transparency value is greater than 1, it will appear black (ie shadow)
col
.
rgb
=
1
-
step
(
0
,
col
.
a
)
;
return
col
;
}
ENDCG
}
}
}
C#:
<pre>
using
UnityEngine
;
public
class
playerShadow
:
Mono Behavior
{<!-- -->
public
GameObject
shadow
;
void
start
(
)
{<!-- -->
if
(
!
shadow
)
{<!-- -->
return
;
}
// Get the texture and pass it to the shader
var
shadowMat
=
shadow
.
GetComponent
<
SpriteRenderer
>
(
)
.
material
;
var
playerTex
=
GetComponent
<
SpriteRenderer
>
(
)
.
sprites
.
texture
;
shadowMat
.
SetTexture
(
"_PlayerTex"
,
playerTex
)
;
}
}
Finally, drag the c# script to the character node, drag the shadow to the shadow variable, and click to run
final effect:
at last
Finally welcome to my
GitHub
Star, thank you! There are some special effect demos that I usually realize in the process of learning unity shader.