Unity NGUI UIPanel下对粒子的剪裁
Posted JohnRey
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转:http://www.cnblogs.com/jietian331/p/5075487.html
使用 unity 做游戏开发时,有时需要在scroll view下使用粒子,但粒子是不会被 UIPanel 所裁剪的,本人提供了脚本 ParticleSystemClipper,用来处理这种情况。思路是,通过 UIPanel 的 finalClipRegion 换算成 unity3d 世界坐标系中的区域,然后传递到粒子的 shader 中进行裁剪。代码如下:
using System; using UnityEngine; [RequireComponent(typeof(UIPanel))] public class ParticleSystemClipper : MonoBehaviour { const string ShaderName = "Bleach/Particles Additive Area Clip"; const float ClipInterval = 0.5f; UIPanel m_targetPanel; Shader m_shader; void Start() { // find panel m_targetPanel = GetComponent<UIPanel>(); if (m_targetPanel == null) throw new ArgumentNullException("Cann\'t find the right UIPanel"); if (m_targetPanel.clipping != UIDrawCall.Clipping.SoftClip) throw new InvalidOperationException("Don\'t need to clip"); m_shader = Shader.Find(ShaderName); if (!IsInvoking("Clip")) InvokeRepeating("Clip", 0, ClipInterval); } Vector4 CalcClipArea() { var clipRegion = m_targetPanel.finalClipRegion; Vector4 nguiArea = new Vector4() { x = clipRegion.x - clipRegion.z / 2, y = clipRegion.y - clipRegion.w / 2, z = clipRegion.x + clipRegion.z / 2, w = clipRegion.y + clipRegion.w / 2 }; var uiRoot = LuaUtils.UIRoot.GetComponent<UIRoot>(); var pos = m_targetPanel.transform.position - uiRoot.transform.position; float h = 2; float temp = h / uiRoot.manualHeight; return new Vector4() { x = pos.x + nguiArea.x * temp, y = pos.y + nguiArea.y * temp, z = pos.x + nguiArea.z * temp, w = pos.y + nguiArea.w * temp }; } void Clip() { Vector4 clipArea = CalcClipArea(); var particleSystems = this.GetComponentsInChildren<ParticleSystem>(); for (int i = 0; i < particleSystems.Length; i++) { var ps = particleSystems[i]; var mat = ps.renderer.material; if (mat.shader.name != ShaderName) mat.shader = m_shader; mat.SetVector("_Area", clipArea); } } void OnDestroy() { CancelInvoke("Clip"); } }
对应的shader 代码如下:
Shader "Bleach/Particles Additive Area Clip" { Properties { _TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5) _MainTex ("Particle Texture", 2D) = "white" {} _Area ("Area", Vector) = (0,0,1,1) } 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; float4 _Area; struct appdata_t { float4 vertex : POSITION; fixed4 color : COLOR; float2 texcoord : TEXCOORD0; }; struct v2f { float4 vertex : SV_POSITION; fixed4 color : COLOR; float2 texcoord : TEXCOORD0; float2 worldPos : TEXCOORD1; }; float4 _MainTex_ST; v2f vert (appdata_t v) { v2f o; o.vertex = mul(UNITY_MATRIX_MVP, v.vertex); o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex); o.color = v.color; o.worldPos = mul(_Object2World, v.vertex).xy; return o; } fixed4 frag (v2f i) : SV_Target { bool inArea = i.worldPos.x >= _Area.x && i.worldPos.x <= _Area.z && i.worldPos.y >= _Area.y && i.worldPos.y <= _Area.w; return inArea? 2.0f * i.color * _TintColor * tex2D(_MainTex, i.texcoord) : fixed4(0,0,0,0); } ENDCG } } } }
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