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Simple Billboard shader for Unity
Shader "Unlit/Billboard"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" "DisableBatching" = "True" }
ZWrite Off
Blend SrcAlpha OneMinusSrcAlpha
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 pos : SV_POSITION;
};
sampler2D _MainTex;
float4 _MainTex_ST;
v2f vert (appdata v)
{
v2f o;
o.pos = UnityObjectToClipPos(v.vertex);
o.uv = v.uv.xy;
// billboard mesh towards camera
float3 vpos = mul((float3x3)unity_ObjectToWorld, v.vertex.xyz);
float4 worldCoord = float4(unity_ObjectToWorld._m03, unity_ObjectToWorld._m13, unity_ObjectToWorld._m23, 1);
float4 viewPos = mul(UNITY_MATRIX_V, worldCoord) + float4(vpos, 0);
float4 outPos = mul(UNITY_MATRIX_P, viewPos);
o.pos = outPos;
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
// sample the texture
fixed4 col = tex2D(_MainTex, i.uv);
// apply fog
UNITY_APPLY_FOG(i.fogCoord, col);
return col;
}
ENDCG
}
}
}
@MuhammadFaizanKhan
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The direction is not towards the camera further it is only billboard the mesh not its collider

@c6burns
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c6burns commented Nov 27, 2018

The direction is not towards the camera further it is only billboard the mesh not its collider

How could a shader program (which executes on the GPU as part of the graphics pipeline) possibly access and manipulate the physics collider data??? Short answer: it can't

@MBurtsev
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Shader "Custom/Billboard"
{
	Properties
	{
	   _MainTex("Texture Image", 2D) = "white" {}
	   _ScaleX("Scale X", Float) = 1.0
	   _ScaleY("Scale Y", Float) = 1.0
	}
	SubShader
	{
		Tags {"Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent"}
		ZWrite Off
		Blend SrcAlpha OneMinusSrcAlpha

		Pass
		{
			CGPROGRAM

			#pragma vertex vert  
			#pragma fragment frag

			// User-specified uniforms            
			uniform sampler2D _MainTex;
			uniform float _ScaleX;
			uniform float _ScaleY;

			struct vertexInput
			{
				float4 vertex : POSITION;
				float4 tex : TEXCOORD0;
			};
			struct vertexOutput
			{
				float4 pos : SV_POSITION;
				float4 tex : TEXCOORD0;
			};

			vertexOutput vert(vertexInput input)
			{
				vertexOutput output;

				output.pos = mul(UNITY_MATRIX_P,
				mul(UNITY_MATRIX_MV, float4(0.0, 0.0, 0.0, 1.0))
				+ float4(input.vertex.x, input.vertex.y, 0.0, 0.0)
				* float4(_ScaleX, _ScaleY, 1.0, 1.0));

				output.tex = input.tex;

				return output;
			}

			float4 frag(vertexOutput input) : COLOR
			{
				return tex2D(_MainTex, float2(input.tex.xy));
			}

			ENDCG
		}
	}
}

@AnthonyisMedia
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I don't know why but Unity said there was an error on one line in your code. Might be because I'm using unity 2017.

Instead of UNITY_TRANSFER_FOG(o,o.vertex);

I believe it should be: UNITY_TRANSFER_FOG(o,o.pos);

Shader "Unlit/Billboard"
{
	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
	}
	SubShader
	{	

		Tags{ "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" "DisableBatching" = "True" }

		ZWrite Off
		Blend SrcAlpha OneMinusSrcAlpha

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			// make fog work
			#pragma multi_compile_fog

			#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				UNITY_FOG_COORDS(1)
				float4 pos : SV_POSITION;
			};

			sampler2D _MainTex;
			float4 _MainTex_ST;
		
			v2f vert (appdata v)
			{
				v2f o;
				o.pos = UnityObjectToClipPos(v.vertex);
				o.uv = v.uv.xy;

				// billboard mesh towards camera
				float3 vpos = mul((float3x3)unity_ObjectToWorld, v.vertex.xyz);
				float4 worldCoord = float4(unity_ObjectToWorld._m03, unity_ObjectToWorld._m13, unity_ObjectToWorld._m23, 1);
				float4 viewPos = mul(UNITY_MATRIX_V, worldCoord) + float4(vpos, 0);
				float4 outPos = mul(UNITY_MATRIX_P, viewPos);

				o.pos = outPos;

				UNITY_TRANSFER_FOG(o,o.pos);
				return o;
			}
		
			fixed4 frag (v2f i) : SV_Target
			{
				// sample the texture
				fixed4 col = tex2D(_MainTex, i.uv);
				// apply fog
				UNITY_APPLY_FOG(i.fogCoord, col);
				return col;
			}
			ENDCG
		}
	} 
}

@wmcnamara
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wmcnamara commented May 25, 2021

Hi!

If its no trouble, could you help explain these two calculations you perform here?

float4 viewPos = mul(UNITY_MATRIX_V, worldCoord) + float4(vpos, 0);
float4 outPos = mul(UNITY_MATRIX_P, viewPos);

I'm having a bit of trouble understanding what exactly is going on with it.

@morm91
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morm91 commented Jun 20, 2022

Hi !
Thanks, this shader was exactly what I was looking for, but does anyone know why it doesn't work with flipped sprites ? (either with flipX or scale.x = -1)

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