// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)

Shader "Azure[Sky]/BuiltIn/Particles/Multiply"
{
	Properties
	{
		_MainTex ("Particle Texture", 2D) = "white" {}
		_InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
	}

	Category
	{
		Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" "PreviewType"="Plane" }
		Blend Zero SrcColor
		Cull Off Lighting Off ZWrite Off

		SubShader
		{
			Pass {

				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#pragma target 2.0
				#pragma multi_compile_particles
				#pragma multi_compile_fog

				#include "UnityCG.cginc"

				// Azure[Sky] Start: Including the file that contains the methods and functions needed to apply the fog.
				#include "Assets/Azure[Sky] Dynamic Skybox/Shaders/Transparent/AzureFogCore.cginc"
				// Azure[Sky] End.

				sampler2D _MainTex;
				fixed4 _TintColor;

				struct appdata_t {
					float4 vertex : POSITION;
					fixed4 color : COLOR;
					float2 texcoord : TEXCOORD0;
					UNITY_VERTEX_INPUT_INSTANCE_ID
				};

				struct v2f {
					float4 vertex : SV_POSITION;
					fixed4 color : COLOR;
					float2 texcoord : TEXCOORD0;
					UNITY_FOG_COORDS(1)
					#ifdef SOFTPARTICLES_ON
					float4 projPos : TEXCOORD2;
					#endif
					UNITY_VERTEX_OUTPUT_STEREO

					// Azure[Sky] Start: Adding the extra TEXCOORD to store the vertex world position.
					float3 worldPos : TEXCOORD3;
					// Azure[Sky] End.
				};

				float4 _MainTex_ST;

				v2f vert (appdata_t v)
				{
					v2f o;
					UNITY_SETUP_INSTANCE_ID(v);
					UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
					o.vertex = UnityObjectToClipPos(v.vertex);
					#ifdef SOFTPARTICLES_ON
					o.projPos = ComputeScreenPos (o.vertex);
					COMPUTE_EYEDEPTH(o.projPos.z);
					#endif
					o.color = v.color;
					o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
					UNITY_TRANSFER_FOG(o,o.vertex);

					// Azure[Sky] Start: Calculating the vertex world position and storing in the extra TEXCOORD.
					o.worldPos = mul(unity_ObjectToWorld, v.vertex);
					// Azure[Sky] End.

					return o;
				}

				UNITY_DECLARE_DEPTH_TEXTURE(_CameraDepthTexture);
				float _InvFade;

				fixed4 frag (v2f i) : SV_Target
				{
					#ifdef SOFTPARTICLES_ON
					float sceneZ = LinearEyeDepth (SAMPLE_DEPTH_TEXTURE_PROJ(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos)));
					float partZ = i.projPos.z;
					float fade = saturate (_InvFade * (sceneZ-partZ));
					i.color.a *= fade;
					#endif

					half4 prev = i.color * tex2D(_MainTex, i.texcoord);
					fixed4 col = lerp(half4(1,1,1,1), prev, prev.a);
					UNITY_APPLY_FOG_COLOR(i.fogCoord, col, fixed4(1,1,1,1)); // fog towards white due to our blend mode

					// Azure[Sky] Start: Applying the fog in the output color of the fragment shader.
					col = ApplyAzureFog(col, i.worldPos, float4(1,1,1,1)); // fog towards white due to our blend mode
					// Azure[Sky] End:

					return col;
				}
				ENDCG
			}
		}
	}
}