supported uint8_index_type

inc/hgl/graph/VK.h

@@ -138,8 +138,9 @@ inline const uint32_t GetMipLevel(const VkExtent3D &ext)
 /**
  * 索引类型,等同于VkIndexType
  */
-enum IndexType:uint
+enum IndexType:int
 {
+    AUTO=-1,
     U16=0,
     U32,
     U8=VK_INDEX_TYPE_UINT8_EXT,
@@ -147,6 +148,11 @@ enum IndexType:uint
     ERR=VK_INDEX_TYPE_MAX_ENUM
 };
 
+inline const bool IsIndexType(const IndexType it)
+{
+    return it>=U16&&it<=U8;
+}
+
 //Push Constant max-lengths:
 //
 //    256 bytes:  nvidia,arm

inc/hgl/graph/VKDevice.h

@@ -117,6 +117,9 @@ public: //Buffer相关
     VBO *           CreateVBO   (VkFormat format, uint32_t count,const void *data,    SharingMode sm=SharingMode::Exclusive);
     VBO *           CreateVBO   (VkFormat format, uint32_t count,                     SharingMode sm=SharingMode::Exclusive){return CreateVBO(format,count,nullptr,sm);}
 
+    const IndexType GetIndexType(const VkDeviceSize &vertex_count)const;     ///<求一个合适的索引类型
+    const bool      CheckIndexType(const IndexType,const VkDeviceSize &vertex_count)const;     ///<检测一个索引类型是否合适
+
     IndexBuffer *   CreateIBO   (IndexType type,  uint32_t count,const void *  data,  SharingMode sm=SharingMode::Exclusive);
     IndexBuffer *   CreateIBO8  (                 uint32_t count,const void *  data,  SharingMode sm=SharingMode::Exclusive){return CreateIBO(IndexType::U8,  count,(void *)data,sm);}
     IndexBuffer *   CreateIBO16 (                 uint32_t count,const uint16 *data,  SharingMode sm=SharingMode::Exclusive){return CreateIBO(IndexType::U16, count,(void *)data,sm);}

inc/hgl/graph/VKDeviceAttribute.h

@@ -39,6 +39,8 @@ struct GPUDeviceAttribute
     VkSurfaceTransformFlagBitsKHR       preTransform;
     VkCompositeAlphaFlagBitsKHR         compositeAlpha  =VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
 
+    bool                                uint8_index_type=false;
+
     VkDevice                            device          =VK_NULL_HANDLE;
     VkCommandPool                       cmd_pool        =VK_NULL_HANDLE;