## 14.2. Vertex Input Interface

When the vertex stage is present in a pipeline, the vertex shader input variables form an interface with the vertex input attributes. The vertex shader input variables are matched by the `Location` and `Component` decorations to the vertex input attributes specified in the `pVertexInputState` member of the `VkGraphicsPipelineCreateInfo` structure.

The vertex shader input variables listed by `OpEntryPoint` with the `Input` storage class form the vertex input interface. These variables must be identified with a `Location` decoration and can also be identified with a `Component` decoration.

For the purposes of interface matching: variables declared without a `Component` decoration are considered to have a `Component` decoration of zero. The number of available vertex input locations is given by the `maxVertexInputAttributes` member of the `VkPhysicalDeviceLimits` structure.

See Section 20.1.1, “Attribute Location and Component Assignment” for details.

All vertex shader inputs declared as above must have a corresponding attribute and binding in the pipeline.