## 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_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.

Valid Usage
• The current render pass must be compatible with the renderPass member of the VkGraphicsPipelineCreateInfo structure specified when creating the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS.

• The subpass index of the current render pass must be equal to the subpass member of the VkGraphicsPipelineCreateInfo structure specified when creating the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS.

• For each set n that is statically used by the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS, a descriptor set must have been bound to n at VK_PIPELINE_BIND_POINT_GRAPHICS, with a VkPipelineLayout that is compatible for set n, with the VkPipelineLayout used to create the current VkPipeline, as described in ../../html/vkspec.html#descriptorsets-compatibility

• For each push constant that is statically used by the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS, a push constant value must have been set for VK_PIPELINE_BIND_POINT_GRAPHICS, with a VkPipelineLayout that is compatible for push constants, with the VkPipelineLayout used to create the current VkPipeline, as described in ../../html/vkspec.html#descriptorsets-compatibility

• Descriptors in each bound descriptor set, specified via vkCmdBindDescriptorSets, must be valid if they are statically used by the bound VkPipeline object, specified via vkCmdBindPipeline

• All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

• For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in ../../html/vkspec.html#fxvertex-input

• A valid graphics pipeline must be bound to the current command buffer with VK_PIPELINE_BIND_POINT_GRAPHICS

• If the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS requires any dynamic state, that state must have been set on the current command buffer

• (indexSize * (firstIndex + indexCount) + offset) must be less than or equal to the size of the bound index buffer, with indexSize being based on the type specified by indexType, where the index buffer, indexType, and offset are specified via vkCmdBindIndexBuffer

• Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

• If any VkSampler object that is accessed from a shader by the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS uses unnormalized coordinates, it must not be used to sample from any VkImage with a VkImageView of the type VK_IMAGE_VIEW_TYPE_3D, VK_IMAGE_VIEW_TYPE_CUBE, VK_IMAGE_VIEW_TYPE_1D_ARRAY, VK_IMAGE_VIEW_TYPE_2D_ARRAY or VK_IMAGE_VIEW_TYPE_CUBE_ARRAY, in any shader stage

• If any VkSampler object that is accessed from a shader by the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS uses unnormalized coordinates, it must not be used with any of the SPIR-V OpImageSample* or OpImageSparseSample* instructions with ImplicitLod, Dref or Proj in their name, in any shader stage

• If any VkSampler object that is accessed from a shader by the VkPipeline bound to VK_PIPELINE_BIND_POINT_GRAPHICS uses unnormalized coordinates, it must not be used with any of the SPIR-V OpImageSample* or OpImageSparseSample* instructions that includes a LOD bias or any offset values, in any shader stage

• If the robust buffer access feature is not enabled, and any shader stage in the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS accesses a uniform buffer, it must not access values outside of the range of that buffer specified in the bound descriptor set

• If the robust buffer access feature is not enabled, and any shader stage in the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS accesses a storage buffer, it must not access values outside of the range of that buffer specified in the bound descriptor set

• If a VkImageView is sampled with VK_FILTER_LINEAR as a result of this command, then the image view’s format features must contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT.

• Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

• If a VkImageView is sampled with VK_FILTER_CUBIC_IMG as a result of this command, then the image view’s format features must contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG.

• Any VkImageView being sampled with VK_FILTER_CUBIC_IMG as a result of this command must not have a VkImageViewType of VK_IMAGE_VIEW_TYPE_3D, VK_IMAGE_VIEW_TYPE_CUBE, or VK_IMAGE_VIEW_TYPE_CUBE_ARRAY

• If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::maxMultiviewInstanceIndex.

• If commandBuffer is an unprotected command buffer, and any pipeline stage in the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS reads from or writes to any image or buffer, that image or buffer must not be a protected image or protected buffer.

• If commandBuffer is a protected command buffer, and any pipeline stage in the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS writes to any image or buffer, that image or buffer must not be an unprotected image or unprotected buffer.

• If commandBuffer is a protected command buffer, and any pipeline stage other than the framebuffer-space pipeline stages in the VkPipeline object bound to VK_PIPELINE_BIND_POINT_GRAPHICS reads from or writes to any image or buffer, the image or buffer must not be a protected image or protected buffer.

• If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::sampleLocationsEnable set to VK_TRUE and the current subpass has a depth/stencil attachment, then that attachment must have been created with the VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT bit set

• Any VkImage created with a VkImageCreateInfo::flags containing VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV sampled as a result of this command must only be sampled using a VkSamplerAddressMode of VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE.

Valid Usage (Implicit)
• commandBuffer must be a valid VkCommandBuffer handle

• commandBuffer must be in the recording state

• The VkCommandPool that commandBuffer was allocated from must support graphics operations

• This command must only be called inside of a render pass instance

Host Synchronization
• Host access to commandBuffer must be externally synchronized

• Host access to the VkCommandPool that commandBuffer was allocated from must be externally synchronized

Command Properties
Command Buffer Levels Render Pass Scope Supported Queue Types Pipeline Type

Primary
Secondary

Inside

Graphics

Graphics