Added new clouds shader

Assets/dbl-world/materials/environment/CloudsShader.shader

@@ -0,0 +1,61 @@
+Shader "Custom/CloudsShader"
+{
+    Properties
+    {
+        _MainTex("Texture", 2D) = "white" {}
+        _ScrollSpeed("Scroll Speed", Vector) = (0.1, 0.1, 0, 0)
+        _Color("Tint Color", Color) = (1,1,1,1)
+    }
+
+    SubShader
+    {
+        Tags { "Queue"="Transparent" "RenderType"="Transparent" }
+        Blend One One // Additive blending
+        ZWrite Off
+        Cull Off
+
+        Pass
+        {
+            CGPROGRAM
+            #pragma vertex vert
+            #pragma fragment frag
+
+            sampler2D _MainTex;
+            float4 _MainTex_ST;
+            float4 _ScrollSpeed;
+            float4 _Color;
+
+            struct appdata
+            {
+                float4 vertex : POSITION;
+                float2 uv : TEXCOORD0;
+            };
+
+            struct v2f
+            {
+                float2 uv : TEXCOORD0;
+                float4 vertex : SV_POSITION;
+            };
+
+            v2f vert(appdata v)
+            {
+                v2f o;
+                o.vertex = UnityObjectToClipPos(v.vertex);
+
+                // Scroll UVs over time
+                float2 scroll = _ScrollSpeed.xy * _Time.y;
+                o.uv = v.uv + scroll;
+
+                return o;
+            }
+
+            fixed4 frag(v2f i) : SV_Target
+            {
+                fixed4 tex = tex2D(_MainTex, i.uv) * _Color;
+                return tex;
+            }
+            ENDCG
+        }
+    }
+    FallBack "Unlit/Transparent"
+}