## C Specification

Drawing can be achieved in two modes:

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:

// Provided by VK_VERSION_1_0
typedef struct VkPipelineInputAssemblyStateCreateInfo {
VkStructureType                            sType;
const void*                                pNext;
VkPipelineInputAssemblyStateCreateFlags    flags;
VkPrimitiveTopology                        topology;
VkBool32                                   primitiveRestartEnable;
} VkPipelineInputAssemblyStateCreateInfo;

## Members

• sType is the type of 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 vkCmdBindIndexBuffer is equal to VK_INDEX_TYPE_UINT32, 0xFF when indexType is equal to VK_INDEX_TYPE_UINT8_EXT, 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.

## Description

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.

Valid Usage
• VUID-VkPipelineInputAssemblyStateCreateInfo-topology-06252
If topology is VK_PRIMITIVE_TOPOLOGY_POINT_LIST, VK_PRIMITIVE_TOPOLOGY_LINE_LIST, VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST, VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY or VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY, and primitiveRestartEnable is VK_TRUE, the primitiveTopologyListRestart feature must be enabled

• VUID-VkPipelineInputAssemblyStateCreateInfo-topology-06253
If topology is VK_PRIMITIVE_TOPOLOGY_PATCH_LIST, and primitiveRestartEnable is VK_TRUE, the primitiveTopologyPatchListRestart feature must be enabled

• VUID-VkPipelineInputAssemblyStateCreateInfo-topology-00429
If the geometry shaders feature is not enabled, topology must not be any of VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY, VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY, VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY or VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY

• VUID-VkPipelineInputAssemblyStateCreateInfo-topology-00430
If the tessellation shaders feature is not enabled, topology must not be VK_PRIMITIVE_TOPOLOGY_PATCH_LIST

• VUID-VkPipelineInputAssemblyStateCreateInfo-triangleFans-04452
If the VK_KHR_portability_subset extension is enabled, and VkPhysicalDevicePortabilitySubsetFeaturesKHR::triangleFans is VK_FALSE, topology must not be VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN

Valid Usage (Implicit)
• VUID-VkPipelineInputAssemblyStateCreateInfo-sType-sType
sType must be VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO

• VUID-VkPipelineInputAssemblyStateCreateInfo-pNext-pNext
pNext must be NULL

flags must be 0

• VUID-VkPipelineInputAssemblyStateCreateInfo-topology-parameter
topology must be a valid VkPrimitiveTopology value