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Unity Engine

RenderMeshPrimitives(in RenderParams, Mesh, int, int)

Renders multiple instances of a Mesh using GPU instancing and a custom shader.
Read time 2 minutesLast updated 6 days ago

Definition

  • Type: Method
  • Namespace: UnityEngine
  • Assembly: UnityEngine.CoreModule

RenderMeshPrimitives(RenderParams, Mesh, int, int)

public static void RenderMeshPrimitives(in RenderParams rparams, Mesh mesh, int submeshIndex, int instanceCount = 1)

Parameters

rparams

RenderParams
The parameters Unity uses to render the Mesh primitives.

mesh

Mesh
The Mesh to render.

submeshIndex

int
The index of a submesh Unity renders when the Mesh contains multiple Materials (submeshes). For a Mesh with a single Material, use value 0.

instanceCount

int
The number of instances to render.

Remarks

This method renders multiple instances of the same Mesh, similar to Graphics.RenderMeshIndirect, but provides the number of instances and other rendering command arguments as function arguments.
Use 
SV_InstanceID
semantic in shaders to access the rendered instance.
The following example uses 
RenderMeshPrimitives
to render 10 Mesh instances. The associated Material must use the below custom shader:
using UnityEngine;public class ExampleClass : MonoBehaviour{    public Material material;    public Mesh mesh;    void Update()    {        RenderParams rp = new RenderParams(material);        rp.worldBounds = new Bounds(Vector3.zero, 10000*Vector3.one); // use tighter bounds        rp.matProps = new MaterialPropertyBlock();        rp.matProps.SetMatrix("_ObjectToWorld", Matrix4x4.Translate(new Vector3(-4.5f, 0, 0)));        rp.matProps.SetFloat("_NumInstances", 10.0f);        Graphics.RenderMeshPrimitives(rp, mesh, 0, 10);    }}
Use the following example shader with the above C# example code:
Shader "ExampleShader"{    SubShader    {        Pass        {            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #include "UnityCG.cginc"            struct v2f            {                float4 pos : SV_POSITION;                float4 color : COLOR0;            };            uniform float4x4 _ObjectToWorld;            uniform float _NumInstances;            v2f vert(appdata_base v, uint instanceID : SV_InstanceID)            {                v2f o;                float4 wpos = mul(_ObjectToWorld, v.vertex + float4(instanceID, 0, 0, 0));                o.pos = mul(UNITY_MATRIX_VP, wpos);                o.color = float4(instanceID / _NumInstances, 0.0f, 0.0f, 0.0f);                return o;            }            float4 frag(v2f i) : SV_Target            {                return i.color;            }            ENDCG        }    }}