UGUI研究院之Mask裁切UI粒子特效或者3D模型（十七）

Shader "Particles/Additive" {
Properties {
	_TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)
	_MainTex ("Particle Texture", 2D) = "white" {}
	_InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
	
	//-------------------add----------------------
	  _MinX ("Min X", Float) = -10
      _MaxX ("Max X", Float) = 10
      _MinY ("Min Y", Float) = -10
      _MaxY ("Max Y", Float) = 10
      //-------------------add----------------------
	
}

Category {
	Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
	Blend SrcAlpha One
	AlphaTest Greater .01
	ColorMask RGB
	Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }
	
	SubShader {
		Pass {
		
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma multi_compile_particles

			#include "UnityCG.cginc"

			sampler2D _MainTex;
			fixed4 _TintColor;
			//-------------------add----------------------
			float _MinX;
            float _MaxX;
            float _MinY;
            float _MaxY;
            //-------------------add----------------------
			
			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
				//-------------------add----------------------
				float3 vpos : TEXCOORD2;
				//-------------------add----------------------
			};
			
			float4 _MainTex_ST;

			v2f vert (appdata_t v)
			{
				v2f o;
				//-------------------add----------------------
				o.vpos = v.vertex.xyz;
				//-------------------add----------------------
				o.vertex = mul(UNITY_MATRIX_MVP, 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);
				return o;
			}

			sampler2D_float _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
				
				//-------------------add----------------------
				 fixed4 c =2.0f * i.color * _TintColor * tex2D(_MainTex, i.texcoord);
				 c.a *= (i.vpos.x >= _MinX );
	           	 c.a *= (i.vpos.x <= _MaxX);
	             c.a *= (i.vpos.y >= _MinY);
	             c.a *= (i.vpos.y <= _MaxY);
                 c.rgb *= c.a;
                return c;
                //-------------------add----------------------
			}
			ENDCG 
		}
	}	
}
}

		Vector3[] corners = new Vector3[4]; 
		RectTransform rectTransform = transform as RectTransform;
		rectTransform.GetWorldCorners (corners);
		minX = corners [0].x;
		minY = corners [0].y;
		maxX = corners [2].x;
		maxY = corners [2].y;

		Material m = GetMaterial (renderer);
		m.SetFloat("_MinX",minX);
		m.SetFloat("_MinY",minY);
		m.SetFloat("_MaxX",maxX);
		m.SetFloat("_MaxY",maxY);

	protected override void OnRectTransformDimensionsChange ()
	{
		base.OnRectTransformDimensionsChange ();
		Change ();//重新再给材质赋裁切参数
	}