QRhiVertexInputBinding Class

Detailed Description

Describes a vertex input binding.

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). Definining 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.