VkPipelineInputAssemblyStateCreateInfo

Drawing can be achieved in two modes:

• Programmable Mesh Shading, the mesh shader assembles primitives, or
• Programmable Primitive Shading, the input primitives are assembled as follows.

Each draw is made up of zero or more vertices and zero or more instances, which are processed by the device and result in the assembly of primitives. Primitives are assembled according to the pInputAssemblyState member of the VkGraphicsPipelineCreateInfo structure, which is of type VkPipelineInputAssemblyStateCreateInfo:

typedef struct VkPipelineInputAssemblyStateCreateInfo {
    VkStructureType sType;
    const void* pNext;
    VkPipelineInputAssemblyStateCreateFlags flags;
    VkPrimitiveTopology topology;
    VkBool32 primitiveRestartEnable;
} VkPipelineInputAssemblyStateCreateInfo;

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• flags is reserved for future use.
• topology is a VkPrimitiveTopology defining the primitive topology, as described below.
• primitiveRestartEnable controls whether a special vertex index value is treated as restarting the assembly of primitives. This enable only applies to indexed draws (vkCmdDrawIndexed, vkCmdDrawMultiIndexedEXT, and vkCmdDrawIndexedIndirect), and the special index value is either 0xFFFFFFFF when the indexType parameter of vkCmdBindIndexBuffer2KHR or vkCmdBindIndexBuffer is equal to VK_INDEX_TYPE_UINT32, 0xFF when indexType is equal to VK_INDEX_TYPE_UINT8_KHR, or 0xFFFF when indexType is equal to VK_INDEX_TYPE_UINT16. Primitive restart is not allowed for list topologies, unless one of the features primitiveTopologyPatchListRestart (for VK_PRIMITIVE_TOPOLOGY_PATCH_LIST) or primitiveTopologyListRestart (for all other list topologies) is enabled.

Restarting the assembly of primitives discards the most recent index values if those elements formed an incomplete primitive, and restarts the primitive assembly using the subsequent indices, but only assembling the immediately following element through the end of the originally specified elements. The primitive restart index value comparison is performed before adding the vertexOffset value to the index value.