[Unity优化]GPU instancing

参考链接：

https://happyfire.blog.csdn.net/article/details/124861373?spm=1001.2101.3001.6661.1&utm_medium=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-1-124861373-blog-124758706.235%5Ev38%5Epc_relevant_sort_base2&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7ERate-1-124861373-blog-124758706.235%5Ev38%5Epc_relevant_sort_base2&utm_relevant_index=1

 

GPU instancing的官方介绍：

https://docs.unity3d.com/cn/current/Manual/GPUInstancing.html

 

GPU instancing可以批量绘制大量相同mesh相同材质的物体，是一种减少drawcall的手段，支持阴影和多光源，比较适合用于绘制草、树

与动态和静态合批不同的是，GPU instancing并不通过合并网格来减少drawcall，而是提交一个网格让gpu绘制很多遍，可以对实例化后的网格进行坐标、旋转、缩放的操作

 

开启条件：

1.shader要支持GPU instancing，具体见：

https://docs.unity3d.com/cn/current/Manual/gpu-instancing-shader.html

例如：

Shader "Custom/SimplestInstancedShader"
{
    Properties
    {
        _Color("Color", Color) = (1, 1, 1, 1)
    }

    SubShader
    {
        Tags { "RenderType" = "Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_instancing
            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f
            {
                float4 vertex : SV_POSITION;
                UNITY_VERTEX_INPUT_INSTANCE_ID // use this to access instanced properties in the fragment shader.
            };

            UNITY_INSTANCING_BUFFER_START(Props)
                UNITY_DEFINE_INSTANCED_PROP(float4, _Color)
            UNITY_INSTANCING_BUFFER_END(Props)

            v2f vert(appdata v)
            {
                v2f o;

                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_TRANSFER_INSTANCE_ID(v, o);
                o.vertex = UnityObjectToClipPos(v.vertex);
                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(i);
                return UNITY_ACCESS_INSTANCED_PROP(Props, _Color);
            }
            ENDCG
        }
    }
}

 

2.材质要勾选Enable GPU Instancing

 

注意点：

1.SRP Batch的优先级高于GPU Instancing，可以使用MaterialPropertyBlock打破SRP Batch

 

2.GPU Instancing不支持SkinnedMeshRenderer