Initial Commit

Assets/Scripts/DeltaHoone/Weather_System/Grass/Old/InstancedNonConsumeGrassShader.shader

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+Shader "DBV/Kristo/InstancedGrassShader"
+{
+    Properties {
+        _MainTex("Albedo (RGB)", 2D) = "white" {}
+        _Glossiness("Smoothness", Range(0,1)) = 0.5
+        _Metallic("Metallic", Range(0,1)) = 0.0
+
+        [Space]
+        _ColorA("Color A", Color) = (1,1,1,1)
+        _ColorB("Color B", Color) = (1,1,1,1)
+
+        [Space]
+        _AlphaCutoff ("Alpha cutoff", Range(0,1)) = 0.05
+        }
+    SubShader
+    {
+        Tags { "RenderType"="Instanced" }
+        LOD 200
+        Cull Off
+
+        CGPROGRAM
+        #pragma surface surf Standard vertex:vert //addshadow
+        #pragma multi_compile_instancing
+        #pragma instancing_options procedural:setup
+
+        #pragma target 4.5
+
+        sampler2D _MainTex;
+
+        struct Input{
+            float2 uv_MainTex;
+            };
+
+        struct GrassElement {
+            float3 position;
+            float rotation;
+            float size;
+            float colorBlend;//0-1
+            };
+
+        //Note
+        //StructuredBuffers are good when there are loads of data that needs to be read at different places by different threads
+        //Constant buffers are good when there isent too much data and threads read the same data
+
+        #ifdef UNITY_PROCEDURAL_INSTANCING_ENABLED
+            StructuredBuffer<GrassElement> grassBuffer;
+        #endif
+
+        
+        //https://forum.unity.com/threads/rotating-mesh-in-vertex-shader.501709/
+        float3x3 YRotationMatrix(float degrees) {
+            float alpha = degrees * UNITY_PI / 180.0;
+            float sina, cosa;
+            sincos(alpha, sina, cosa);
+            return float3x3(
+                cosa, 0, -sina,
+                0, 1, 0,
+                sina, 0, cosa);
+            }
+        //USAGE: pos.xyz = mul(YRotationMatrix(degrees),pos.xyz);
+
+        void rotate2D(inout float2 v, float r) {
+            float s, c;
+            sincos(r, s, c);
+            v = float2(v.x * c - v.y * s, v.x * s + v.y * c);
+            }
+
+        half _Glossiness;
+        half _Metallic;
+        fixed4 _ColorA, _ColorB;
+        float _AlphaCutoff;
+
+        void setup () {
+            #ifdef UNITY_PROCEDURAL_INSTANCING_ENABLED
+                GrassElement data = grassBuffer[unity_InstanceID];
+                //Scale the mesh
+                unity_ObjectToWorld._11_21_31_41 = float4(data.size, 0, 0, 0);
+                unity_ObjectToWorld._12_22_32_42 = float4(0, data.size, 0, 0);
+                unity_ObjectToWorld._13_23_33_43 = float4(0, 0, data.size, 0);
+                //position the mesh
+                unity_ObjectToWorld._14_24_34_44 = float4(data.position.xyz, 1);
+                
+                //No idea what this does
+                unity_WorldToObject = unity_ObjectToWorld;
+                unity_WorldToObject._14_24_34 *= -1;
+                unity_WorldToObject._11_22_33 = 1.0f / unity_WorldToObject._11_22_33;
+            #endif
+            }
+
+        void vert (inout appdata_full v) {
+            #ifdef UNITY_PROCEDURAL_INSTANCING_ENABLED
+                GrassElement data = grassBuffer[unity_InstanceID];
+                //Rotate
+                v.vertex.xyz = mul(YRotationMatrix(data.rotation),v.vertex);
+            #endif
+            }
+
+        void surf (Input IN, inout SurfaceOutputStandard o) {
+
+            //Clip the grass
+            fixed4 c = tex2D (_MainTex, IN.uv_MainTex);
+            clip(c.a - _AlphaCutoff);
+
+            #ifdef UNITY_PROCEDURAL_INSTANCING_ENABLED
+                GrassElement data = grassBuffer[unity_InstanceID];
+
+                float blend = data.colorBlend;
+                fixed4 col = blend * _ColorA + (1-blend) * _ColorB;
+            #else
+                fixed4 col = _ColorA;
+            #endif
+
+            // Albedo comes from a texture tinted by color
+            c = c * col;
+            o.Albedo = c.rgb;
+            // Metallic and smoothness come from slider variables
+            o.Metallic = _Metallic;
+            o.Smoothness = _Glossiness;
+            o.Alpha = c.a;
+            }
+        ENDCG
+    }
+    FallBack "Diffuse"
+}