- Qt 6.8
- Qt GUI
- C++ Classes
- QRhiVertexInputBinding
- Qt 6.8.0 Reference Documentation

# QRhiVertexInputBinding Class

Describes a vertex input binding. More...

Header: | #include <QRhiVertexInputBinding>
CMake: | find_package(Qt6 REQUIRED COMPONENTS Gui) target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake: | QT += gui
Since: | Qt 6.6

- List of all members, including inherited members

## Public Types

enum | Classification { PerVertex, PerInstance }

## Public Functions

| QRhiVertexInputBinding()
| QRhiVertexInputBinding(quint32 stride, QRhiVertexInputBinding::Classification cls = PerVertex, quint32 stepRate = 1)
QRhiVertexInputBinding::Classification | classification() const
quint32 | instanceStepRate() const
void | setClassification(QRhiVertexInputBinding::Classification c)
void | setInstanceStepRate(quint32 rate)
void | setStride(quint32 s)
quint32 | stride() const

## Related Non-Members

size_t | qHash(const QRhiVertexInputBinding &v, size_t seed = 0)
bool | operator!=(const QRhiVertexInputBinding &a, const QRhiVertexInputBinding &b)
bool | operator==(const QRhiVertexInputBinding &a, const QRhiVertexInputBinding &b)

## Detailed Description

Specifies the stride (in bytes, must be a multiple of 4), the classification and optionally the instance step rate.

As an example, assume a vertex shader with the following inputs:

     layout(location = 0) in vec4 position;
     layout(location = 1) in vec2 texcoord;

Now let's assume also that 3 component vertex positions `(x, y, z)` and 2 component texture coordinates `(u, v)` are provided in a non-interleaved format in a buffer (or separate buffers even). Defining two bindings could then be done like this:

     QRhiVertexInputLayout inputLayout;
     inputLayout.setBindings({
         { 3 * sizeof(float) },
         { 2 * sizeof(float) }
     });

Only the stride is interesting here since instancing is not used. The binding number is given by the index of the QRhiVertexInputBinding element in the bindings vector of the QRhiVertexInputLayout.

Once a graphics pipeline with this vertex input layout is bound, the vertex inputs could be set up like the following for drawing a cube with 36 vertices, assuming we have a single buffer with first the positions and then the texture coordinates:

     const QRhiCommandBuffer::VertexInput vbufBindings[] = {
         { cubeBuf, 0 },
         { cubeBuf, 36 * 3 * sizeof(float) }
     };
     cb->setVertexInput(0, 2, vbufBindings);

Note how the index defined by `startBinding + i`, where `i` is the index in the second argument of setVertexInput(), matches the index of the corresponding entry in the `bindings` vector of the QRhiVertexInputLayout.

Note: the stride must always be a multiple of 4.

Note: This is a RHI API with limited compatibility guarantees, see QRhi for details.

See also QRhiCommandBuffer::setVertexInput().

## Member Type Documentation

### enum QRhiVertexInputBinding::Classification

Describes the input data classification.

Constant | Value | Description
--- | --- | ---
`QRhiVertexInputBinding::PerVertex` | `0` | Data is per-vertex
`QRhiVertexInputBinding::PerInstance` | `1` | Data is per-instance

## Member Function Documentation

### `[constexpr noexcept]` QRhiVertexInputBinding::QRhiVertexInputBinding()

Constructs a default vertex input binding description.

### QRhiVertexInputBinding::QRhiVertexInputBinding(quint32 stride, QRhiVertexInputBinding::Classification cls = PerVertex, quint32 stepRate = 1)

Constructs a vertex input binding description with the specified stride, classification cls, and instance step rate stepRate.

Note: stepRate other than 1 is only supported when QRhi::CustomInstanceStepRate is reported to be supported.

### QRhiVertexInputBinding::Classification QRhiVertexInputBinding::classification() const

Returns the input data classification.

See also setClassification().

### quint32 QRhiVertexInputBinding::instanceStepRate() const

Returns the instance step rate.

See also setInstanceStepRate().

### void QRhiVertexInputBinding::setClassification(QRhiVertexInputBinding::Classification c)

Sets the input data classification c. By default this is set to PerVertex.

See also classification().

### void QRhiVertexInputBinding::setInstanceStepRate(quint32 rate)

Sets the instance step rate. By default this is set to 1.

See also instanceStepRate().

### void QRhiVertexInputBinding::setStride(quint32 s)

Sets the stride to s.

See also stride().

### quint32 QRhiVertexInputBinding::stride() const

Returns the stride in bytes.

See also setStride().

## Related Non-Members

### `[noexcept]` size_t qHash(const QRhiVertexInputBinding &v, size_t seed = 0)

Returns the hash value for v, using seed to seed the calculation.

### `[noexcept]` bool operator!=(const QRhiVertexInputBinding &a, const QRhiVertexInputBinding &b)

Returns `false` if the values in the two QRhiVertexInputBinding objects a and b are equal; otherwise returns `true`.

### `[noexcept]` bool operator==(const QRhiVertexInputBinding &a, const QRhiVertexInputBinding &b)

Returns `true` if the values in the two QRhiVertexInputBinding objects a and b are equal.