DecalShaders.md

Decal shader

Decal shaders covers the area of where their mesh is rendered on top of the existing geometry without adding new geometry.

Unlit Decal shader

Shader "MageQuest/DecalUnlitShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
		_Color("Color", Color) = (1, 1, 1, 1)
    }

    SubShader
    {
		Tags {
			"Queue" = "Transparent"
			"IgnoreProjector" = "True"
			"RenderType" = "Transparent"
			"ForceNoShadowCasting" = "True"
		}

        Pass
        {
			Fog { Mode Off }
			ZWrite Off
			Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM
			#pragma target 3.0
            #pragma vertex vert
            #pragma fragment frag
			#pragma exclude_renderers nomrt

            #include "UnityCG.cginc"

            struct v2f
            {
				float4 pos : SV_POSITION;
				half2 uv : TEXCOORD0;
				float4 screenUV : TEXCOORD1;
				float3 ray : TEXCOORD2;
				half3 orientation : TEXCOORD3;
            };

            sampler2D _MainTex;
			fixed4 _Color;

			sampler2D _CameraDepthTexture;

            v2f vert (appdata_base v)
            {
                v2f o;
				UNITY_INITIALIZE_OUTPUT(v2f, o);
				o.pos = UnityObjectToClipPos(v.vertex);
				o.screenUV = ComputeScreenPos(o.pos);
				o.ray = UnityObjectToViewPos(v.vertex).xyz * float3(-1, -1, 1);
				o.orientation = mul((float3x3)unity_ObjectToWorld, float3(0, 1, 0));
				o.uv = v.texcoord;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
				i.ray = i.ray * (_ProjectionParams.z / i.ray.z);
				float2 uv = i.screenUV.xy / i.screenUV.w;
				float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, uv);
				depth = Linear01Depth(depth);
				float4 vpos = float4(i.ray * depth, 1);
				float3 wpos = mul(unity_CameraToWorld, vpos).xyz;
				float3 opos = mul(unity_WorldToObject, float4(wpos, 1)).xyz;

				clip(float3(0.5, 0.5, 0.5) - abs(opos.xyz));

				i.uv = (opos.xz + 0.5);

                fixed4 col = tex2D(_MainTex, i.uv) * _Color;
                return col;
            }
            ENDCG
        }
    }
}