C Specification
To record an indexed draw, call:
void vkCmdDrawIndexed(
VkCommandBuffer commandBuffer,
uint32_t indexCount,
uint32_t instanceCount,
uint32_t firstIndex,
int32_t vertexOffset,
uint32_t firstInstance);
Parameters
-
commandBuffer
is the command buffer into which the command is recorded. -
indexCount
is the number of vertices to draw. -
instanceCount
is the number of instances to draw. -
firstIndex
is the base index within the index buffer. -
vertexOffset
is the value added to the vertex index before indexing into the vertex buffer. -
firstInstance
is the instance ID of the first instance to draw.
Description
When the command is executed, primitives are assembled using the current
primitive topology and indexCount
vertices whose indices are retrieved
from the index buffer.
The index buffer is treated as an array of tightly packed unsigned integers
of size defined by the vkCmdBindIndexBuffer::indexType
parameter
with which the buffer was bound.
The first vertex index is at an offset of firstIndex
* indexSize
+ offset
within the bound index buffer, where offset
is the
offset specified by vkCmdBindIndexBuffer
and indexSize
is the
byte size of the type specified by indexType
.
Subsequent index values are retrieved from consecutive locations in the
index buffer.
Indices are first compared to the primitive restart value, then zero
extended to 32 bits (if the indexType
is
VK_INDEX_TYPE_UINT8_EXT
or
VK_INDEX_TYPE_UINT16
) and have vertexOffset
added to them,
before being supplied as the vertexIndex
value.
The primitives are drawn instanceCount
times with instanceIndex
starting with firstInstance
and increasing sequentially for each
instance.
The assembled primitives execute the bound graphics pipeline.
See Also
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.
Copyright
Copyright (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.