Question by hm2337 · Jun 04, 2019 at 08:19 PM · c#shader mesh vertex compute shader

Using compute shader, how to take every vertex of a mesh and make a cube spawn and move to each one?

Here is a script I currently have for object Emptsh to use a compute shader for making a point appear on a screen where every vertex on the BoyMesh mesh is.

Now I'm trying to, instead of make simple points appear on screen for each BoyMesh vertex position, spawn cubes from a different position and then have them fly over to each vertex position (one cube per vertex position). Any ideas?

 using UnityEngine;
 using System.Collections;
 
 public class Emptsh : MonoBehaviour
 {
     public BoyMesh BoyMesh;
     public Mesh meshdata;
 
     public ComputeShader cshader;
     public Material mat;
 
     private int kernel;
     private int num4pos;
 
     private ComputeBuffer posbuffer;
     private int num4vertex;
     private ComputeBuffer vertexbuffer;
 
 
     private void meshInfo()
     {
         Vector3[] vertics = meshdata.vertices;
         int[] triangles = meshdata.triangles;
         num4vertex = triangles.Length;
 
         Vector3[] newVertics = new Vector3[num4vertex];
         for (int i = 0; i < num4vertex; ++i)
         {
             newVertics[i] = vertics[triangles[i]];
         }
 
         vertexbuffer = new ComputeBuffer(num4vertex, 12);
         vertexbuffer.SetData(newVertics);
     }
 
     void Start()
     {   
         meshdata = BoyMesh.Mesh;
 
         kernel = cshader.FindKernel("CSMain");
         num4pos = 1; //this determines how many appear
         //num4vertex = ;
         meshInfo();
         //float3 
         posbuffer = new ComputeBuffer(num4pos, 12); 
     }
 
     private void BufferSet()
     {
         cshader.SetBuffer(kernel, "posbuffer", posbuffer); 
         mat.SetBuffer("posbuffer", posbuffer);     
         mat.SetBuffer("vertexbuffer", vertexbuffer);             
     }
 
     private void OnRenderObject()
     {
         BufferSet();
         //1
         cshader.Dispatch(kernel, 1, 1, 1);
         //2
         mat.SetPass(0);
         //3
         Graphics.DrawProceduralNow(MeshTopology.Points, num4vertex, num4pos);      
     }
 
     private void OnDestroy()
     {
         posbuffer.Release();
         vertexbuffer.Release();
     }
 }

And then the shader code:

 Shader "Unlit/cshader4"
 {
     Properties
     {
         _MainTex ("Texture", 2D) = "white" {}
     }
     CGINCLUDE
         #define time _Time.y 
         float3 Rotx(in float3 p,in float a){
             float c,s; float3 q = p;
             c = cos(a); s = sin(a);
             q.y = c * p.y - s * q.z;
             q.z = s * p.y + c * q.z;
             return q;
         }
 
         float random(float id){
             return frac(sin(id)*678.342231);
         }
     ENDCG
     SubShader
     {
         Tags { "RenderType"="Opaque" }
         LOD 100
 
         Pass{
             CGPROGRAM
                 #pragma target 5.0
                 #pragma vertex vert
                 #pragma fragment frag 
                 #include "UnityCG.cginc"
 
                 sampler2D _MainTex;
 
                 StructuredBuffer<float3> vertexbuffer;
                 StructuredBuffer<float3> posbuffer;
                 struct vertIN{
                     uint vID : SV_VertexID;
                     uint ins : SV_InstanceID;
                 };
 
                 struct vertOUT{
                     float4 pos : SV_POSITION;
                 };
 
                 vertOUT vert(vertIN i){
                     vertOUT o = (vertOUT)0;
                         float4 position = float4(vertexbuffer[i.vID],1);
                         position.xyz = Rotx(position.xyz,time*(1+random(i.ins)));
                         position.xyz += posbuffer[i.ins];
                         o.pos = UnityObjectToClipPos(position);
                     return o;
                 }
 
                 fixed4 frag(vertOUT ou):SV_Target{
 
                     return 1;
                 }
             ENDCG
         }
     }
 }

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