Version: 2021.2
LanguageEnglish
  • C#

Graphics.RenderMeshPrimitives

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Declaration

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

Parameters

rparams The parameters Unity uses to render the Mesh primitives.
mesh The Mesh to render.
submeshIndex 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 The number of instances to render.

Description

Renders multiple instances of a Mesh using GPU instancing and a custom shader.

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 } } }