Unity Procedural Instancing材质属性无效问题解决

        在SRP中使用DrawMeshInstancedProcedural之后，发现之前材质里定义的属性都无效了。排查后发现是UnityInstancing.cginc的锅，这里摘抄一下代码：

#if UNITY_INSTANCING_ENABLED
	...
#else
	#ifdef UNITY_PROCEDURAL_INSTANCING_ENABLED
		#define UNITY_INSTANCING_BUFFER_START(buf)
		#define UNITY_INSTANCING_BUFFER_END(arr)
		#define UNITY_DEFINE_INSTANCED_PROP(type, var)      static type var;
	#else
		#define UNITY_INSTANCING_BUFFER_START(buf)          CBUFFER_START(buf)
		#define UNITY_INSTANCING_BUFFER_END(arr)            CBUFFER_END
		#define UNITY_DEFINE_INSTANCED_PROP(type, var)      type var;
	#endif
	...
#endif

        问题出在这一行上：

#define UNITY_DEFINE_INSTANCED_PROP(type, var)      static type var;

    &nb