vkCmdSetBlendConstants(3)

# vkCmdSetBlendConstants(3) Manual Page

## Name

vkCmdSetBlendConstants - Set the values of blend constants

## C Specification

To dynamically set and change the blend constants, call:

    // Provided by VK_VERSION_1_0
    void vkCmdSetBlendConstants(
        VkCommandBuffer                             commandBuffer,
        const float                                 blendConstants[4]);

## Parameters

- `commandBuffer` is the command buffer into which the command will be recorded.

- `blendConstants` is a pointer to an array of four values specifying the Rc, Gc, Bc, and Ac components of the blend constant color used in blending, depending on the blend factor.

## Description

This command sets blend constants for subsequent drawing commands when when drawing using shader objects, or the graphics pipeline is created with VK_DYNAMIC_STATE_BLEND_CONSTANTS set in VkPipelineDynamicStateCreateInfo::`pDynamicStates`. Otherwise, this state is specified by the VkPipelineColorBlendStateCreateInfo::`blendConstants` values used to create the currently active pipeline.

Valid Usage (Implicit)

- VUID-vkCmdSetBlendConstants-commandBuffer-parameter
  `commandBuffer` must be a valid VkCommandBuffer handle

- VUID-vkCmdSetBlendConstants-commandBuffer-recording
  `commandBuffer` must be in the recording state

- VUID-vkCmdSetBlendConstants-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support VK_QUEUE_GRAPHICS_BIT operations

- VUID-vkCmdSetBlendConstants-videocoding
  This command must only be called outside of a video coding scope

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 | Video Coding Scope | Supported Queue Types | Command Type
--- | --- | --- | --- | ---
Primary Secondary | Both | Outside | VK_QUEUE_GRAPHICS_BIT | State

Conditional Rendering

vkCmdSetBlendConstants is not affected by conditional rendering

## See Also

VK_VERSION_1_0, VkCommandBuffer

## 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 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0