MRClass/Assets/Mirza Beig/Shaders/Particles/Cutout/AlphaCutoff-Alpha.shader


Shader "Mirza Beig/Particles/Alpha Cutoff/Alpha Blended"
{
	Properties
	{
		_TintColor("Tint Color", Color) = (0.5, 0.5, 0.5, 0.5)

		_MainTex("Particle Texture", 2D) = "white" {}
		_InvFade("Soft Particles Factor", Range(0.01, 8.0)) = 1.0

		_alphaCutoffThreshold("Alpha Cutoff Threshold", Range(-1.0, 1.0)) = 0.125
		[MaterialToggle] _textureBased("Texture Based", Float) = 0.0
	}

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

			Blend SrcAlpha OneMinusSrcAlpha
			AlphaTest Greater .01
			ColorMask RGB
			Cull Off Lighting Off ZWrite Off

			SubShader {
				Pass {

					CGPROGRAM

					#pragma vertex vert
					#pragma fragment frag
					#pragma multi_compile_particles
					#pragma multi_compile_fog

					#include "UnityCG.cginc"

					sampler2D _MainTex;
					fixed4 _TintColor;

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

					struct v2f 
					{
						float4 vertex : SV_POSITION;
						fixed4 color : COLOR;

						float2 texcoord : TEXCOORD0;

		#ifdef SOFTPARTICLES_ON
							float4 projPos : TEXCOORD1;
		#endif

						UNITY_FOG_COORDS(2)
					};

					float4 _MainTex_ST;

					v2f vert(appdata_t v)
					{
						v2f 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);

						return o;
					}

					sampler2D_float _CameraDepthTexture;
					float _InvFade;

					uniform float _alphaCutoffThreshold;
					uniform float _textureBased;

					fixed4 frag(v2f i) : SV_Target
					{
						// Get texture colour.

						float4 texColour = tex2D(_MainTex, i.texcoord);

						// Tint.

						fixed4 colour = _TintColor * texColour;

						#ifdef SOFTPARTICLES_ON

						// Scene depth.

						//float sceneZ = LinearEyeDepth(tex2Dproj(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos)).r);
						float sceneZ = LinearEyeDepth(SAMPLE_DEPTH_TEXTURE_PROJ(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos)));

						// Distance to the camera.

						float partZ = i.projPos.z;

						// Soft particles (soft factor).
						// "Comparing depth values of the particle with depth values of world geometry (in view space)." - Special Effects with Depth (Siggraph, 2011).

						// float softFactor = saturate((depthEye - zEye) * fade)

						// Inverse fade: 0.0f = off.

						float fade = saturate(_InvFade * (sceneZ - partZ));
						colour.a *= fade;

					#endif

						// Input colour.

						colour *= i.color * 2.0f;

						// Alpha test. Automatic cutoff inversion detection.
						// Could use an if-statement, but I think that's slower?

						float alphaCutoffSign = sign(_alphaCutoffThreshold);
						clip(alphaCutoffSign * ((!_textureBased ? colour.a : texColour.a) - _alphaCutoffThreshold * alphaCutoffSign));

						// Fog towards nothing.

						UNITY_APPLY_FOG(i.fogCoord, colour);

						return colour;
					}
					ENDCG
				}
			}
		}
}