零時，Unity小實驗 GS部分（一）

@author 小道

發現Unity用來作一些小的渲染實驗嗨挺方便。（N年前了，又從新打開試試）

1、Scene視圖 ，對齊相機到視圖

這個UE是自帶了，Unity發現沒，就寫了，有點醜將就。主要用來後面實驗方便點

 

 

public class CameraEditor_Tool

{

[MenuItem("DZEditorTool/DZCameraTool/Align/SceneView")]

    static void AlignToSceneView()

    {

if(Selection.gameObjects.Length >0)

{

Camera viewCame = Selection.gameObjects[0].GetComponent<Camera>();

if( viewCame != null)

{

Camera cas = UnityEditor.SceneView.lastActiveSceneView.camera;

if(cas == null || cas == viewCame)

return;

Transform camT = cas.transform;

viewCame.gameObject.transform.position = camT.position;

viewCame.gameObject.transform.LookAt(camT.position + camT.forward*10);

}

}

    }

 

 

 

    [InitializeOnLoadMethod]

     static void StartInitializeOnLoadMethod()

     {

     EditorApplication.hierarchyWindowItemOnGUI += OnHierarchyGUI;

     }

 

     static void OnHierarchyGUI(int instanceID, Rect selectionRect)

     {

     if (Event.current != null && selectionRect.Contains(Event.current.mousePosition)

     && Event.current.button == 1 && Event.current.type <= EventType.MouseUp)

     {

     GameObject selectedGameObject = EditorUtility.InstanceIDToObject(instanceID) as GameObject;

             //這裏能夠判斷selectedGameObject的條件

     if (selectedGameObject&&selectedGameObject.GetComponent<Camera>()!=null)

     {

                Vector2 mousePosition = Event.current.mousePosition;

 

                EditorUtility.DisplayPopupMenu(new Rect(mousePosition.x, mousePosition.y, 0, 0), "DZEditorTool/",null);

     Event.current.Use();

     }          

     }

     }

}

 

2、計算着色器

------Unreal中Shader自己不是很麻煩，主要是按框架寫套路麻煩就懶了

 

原理簡單，只是試試自己（該Shader轉的，其實不少Shader和算法自己是已經存在，看完改改哦）

 

 

Shader "RenderStudio/Geo/Geo_ParticleExp_Beta"

{

Properties

{

    //細分相關變量

    _Level("Level",int)=0

    _DispDir("Displacement Direction",Vector)=(0,0,0)

    _uVelScale("VelScale",float)=2

    //粒子化特效相關變量

        _Speed("Speed",Range(0,1))=1

        _ShaderStartTime("Shader Start Time",float)=0

        _FinalColor("Final Color",color)=(1,1,1,1)

}

SubShader

{

        Tags{"RenderType"="Transparent" "Queue" = "Transparent"}

LOD 100

 

Pass

{

   Blend SrcAlpha OneMinusSrcAlpha // use alpha blending

    cull off

CGPROGRAM

#pragma vertex vert

#pragma fragment frag

#pragma geometry geom

 

#include "UnityCG.cginc"

//CPU輸入變量

////細分相關變量

uniform int _Level;

            uniform float3 _DispDir;

            uniform float _uVelScale;

            ////粒子化特效相關變量

            uniform float _Speed;           //粒子位移速度

            uniform float _ShaderStartTime; //粒子化起始時間

            uniform fixed4 _FinalColor;     //粒子顏色

            //內部變量

            float3 V0, V1, V2;

            float3 CG;

            float unityTime;

struct appdata

{

float4 vertex : POSITION;

float3 normal:NORMAL;

};

 

struct v2g

{

float4 vertex : SV_POSITION;

fixed4 color:COLOR;

float3 normal:NORMAL;

};

struct g2f

{

float4 vertex : SV_POSITION;

fixed4 color:COLOR;

};

 

v2g vert (appdata v)

{

v2g o;

o.vertex = v.vertex;

o.normal=UnityObjectToWorldNormal(v.normal);

return o;

}

[maxvertexcount(120)]//v2g input[3]

void geom(inout PointStream<g2f> OutputStream,triangle v2g input[3])

{

float time_SinceBirth=(unityTime-_ShaderStartTime)*0.1f;

            g2f o = (g2f)0;

             V1 = (input[1].vertex - input[0].vertex).xyz;

             V2 = (input[2].vertex - input[0].vertex).xyz;

             V0 = input[0].vertex.xyz;

             CG=(input[0].vertex.xyz + input[1].vertex.xyz+ input[2].vertex.xyz)/3.0f;

             int numLayers =1<<_Level;     //2^_Level

             float dt = 1.0f / float( numLayers );

float t = 1.0f;

for( int it = 0; it < numLayers; it++ )

             {

                float smax = 1.0f - t;

                int nums = it + 1;

                float ds = smax / float( nums - 1 );

                float s = 0;

                for( int is = 0; is < nums; is++ )

                {

                    float3 v = V0 + s*V1 + t*V2;

                    float3 vel = _uVelScale * ( v - CG );

                    v = CG + vel*(_Speed*time_SinceBirth+1.0f) + 0.5f*_DispDir.xyz*sin(it*is)*(_Speed*time_SinceBirth)*(_Speed*time_SinceBirth);

                    o.vertex = UnityObjectToClipPos(float4( v, 1.0f ));

                    o.color=_FinalColor;

                    o.color.w=1.0f-smoothstep(0,1.0f,time_SinceBirth);

                    OutputStream.Append(o);

                 s += ds;

             }

                t -= dt;

             }

}

fixed4 frag (g2f i) : SV_Target

{

          return i.color;

}

ENDCG

}

}

}