C Specification
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
:
// Provided by VK_VERSION_1_0
typedef struct VkPipelineInputAssemblyStateCreateInfo {
VkStructureType sType;
const void* pNext;
VkPipelineInputAssemblyStateCreateFlags flags;
VkPrimitiveTopology topology;
VkBool32 primitiveRestartEnable;
} VkPipelineInputAssemblyStateCreateInfo;
Members
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
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 theindexType
parameter ofvkCmdBindIndexBuffer2KHR
orvkCmdBindIndexBuffer
is equal toVK_INDEX_TYPE_UINT32
, 0xFF whenindexType
is equal toVK_INDEX_TYPE_UINT8_EXT
, or 0xFFFF whenindexType
is equal toVK_INDEX_TYPE_UINT16
. Primitive restart is not allowed for “list” topologies, unless one of the featuresprimitiveTopologyPatchListRestart
(forVK_PRIMITIVE_TOPOLOGY_PATCH_LIST
) orprimitiveTopologyListRestart
(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.
Document Notes
For more information, see the Vulkan Specification
This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.