vkCmdPushConstants

To update push constants, call:

void vkCmdPushConstants(
    VkCommandBuffer commandBuffer,
    VkPipelineLayout layout,
    VkShaderStageFlags stageFlags,
    uint32_t offset,
    uint32_t size,
    const void* pValues);

• commandBuffer is the command buffer in which the push constant update will be recorded.
• layout is the pipeline layout used to program the push constant updates.
• stageFlags is a bitmask of VkShaderStageFlagBits specifying the shader stages that will use the push constants in the updated range.
• offset is the start offset of the push constant range to update, in units of bytes.
• size is the size of the push constant range to update, in units of bytes.
• pValues is a pointer to an array of size bytes containing the new push constant values.

When a command buffer begins recording, all push constant values are undefined:. Reads of undefined: push constant values by the executing shader return undefined: values.

Push constant values can be updated incrementally, causing shader stages in stageFlags to read the new data from pValues for push constants modified by this command, while still reading the previous data for push constants not modified by this command. When a bound pipeline command is issued, the bound pipeline’s layout must be compatible with the layouts used to set the values of all push constants in the pipeline layout’s push constant ranges, as described in Pipeline Layout Compatibility. Binding a pipeline with a layout that is not compatible with the push constant layout does not disturb the push constant values.