impeller::HostBuffer Class Reference

#include <host_buffer.h>

Classes
struct	TestStateQuery
	Test only internal state. More...

Public Types
using	EmplaceProc = std::function< void(uint8_t *buffer)>

Public Member Functions
virtual	~HostBuffer ()
void	SetLabel (std::string label)
template<class UniformType , class = std::enable_if_t<std::is_standard_layout_v<UniformType>>>
BufferView	EmplaceUniform (const UniformType &uniform)
	Emplace uniform data onto the host buffer. Ensure that backend specific uniform alignment requirements are respected. More...
template<class StorageBufferType , class = std::enable_if_t<std::is_standard_layout_v<StorageBufferType>>>
BufferView	EmplaceStorageBuffer (const StorageBufferType &buffer)
	Emplace storage buffer data onto the host buffer. Ensure that backend specific uniform alignment requirements are respected. More...
template<class BufferType , class = std::enable_if_t<std::is_standard_layout_v<BufferType>>>
BufferView	Emplace (const BufferType &buffer, size_t alignment=0)
	Emplace non-uniform data (like contiguous vertices) onto the host buffer. More...
BufferView	Emplace (const void *buffer, size_t length, size_t align)
BufferView	Emplace (size_t length, size_t align, const EmplaceProc &cb)
	Emplaces undefined data onto the managed buffer and gives the caller a chance to update it using the specified callback. The buffer is guaranteed to have enough space for length bytes. It is the responsibility of the caller to not exceed the bounds of the buffer returned in the EmplaceProc. More...
void	Reset ()
	Resets the contents of the HostBuffer to nothing so it can be reused. More...
TestStateQuery	GetStateForTest ()
	Retrieve internal buffer state for test expectations. More...

Static Public Member Functions
static std::shared_ptr< HostBuffer >	Create (const std::shared_ptr< Allocator > &allocator)

Detailed Description

The host buffer class manages one more 1024 Kb blocks of device buffer allocations.

These are reset per-frame.

Definition at line 28 of file host_buffer.h.

Member Typedef Documentation

EmplaceProc

using impeller::HostBuffer::EmplaceProc = std::function<void(uint8_t* buffer)>

Definition at line 107 of file host_buffer.h.

Constructor & Destructor Documentation

~HostBuffer()

impeller::HostBuffer::~HostBuffer ( )

virtualdefault

Member Function Documentation

Create()

std::shared_ptr< HostBuffer > impeller::HostBuffer::Create ( const std::shared_ptr< Allocator > &  allocator )

static

Definition at line 20 of file host_buffer.cc.

                                               {
  return std::shared_ptr<HostBuffer>(new HostBuffer(allocator));
}

Emplace() [1/3]

template<class BufferType , class = std::enable_if_t<std::is_standard_layout_v<BufferType>>>

BufferView impeller::HostBuffer::Emplace ( const BufferType &  buffer, size_t  alignment = 0  )

inline

Emplace non-uniform data (like contiguous vertices) onto the host buffer.

Parameters

[in]	buffer	The buffer data.
[in]	alignment	Minimum alignment of the data being emplaced.

Template Parameters

BufferType

The type of the buffer data.

Returns

The buffer view.

Definition at line 95 of file host_buffer.h.

                                                         {
    return Emplace(reinterpret_cast<const void*>(&buffer),   // buffer
                   sizeof(BufferType),                       // size
                   std::max(alignment, alignof(BufferType))  // alignment
    );
  }

Emplace() [2/3]

BufferView impeller::HostBuffer::Emplace	(	const void *	buffer,
		size_t	length,
		size_t	align
	)

Definition at line 41 of file host_buffer.cc.

                                             {
  auto [range, device_buffer] = EmplaceInternal(buffer, length, align);
  if (!device_buffer) {
    return {};
  }
  return BufferView{std::move(device_buffer), range};
}

Emplace() [3/3]

BufferView impeller::HostBuffer::Emplace	(	size_t	length,
		size_t	align,
		const EmplaceProc &	cb
	)

Emplaces undefined data onto the managed buffer and gives the caller a chance to update it using the specified callback. The buffer is guaranteed to have enough space for length bytes. It is the responsibility of the caller to not exceed the bounds of the buffer returned in the EmplaceProc.

Parameters

[in]

cb

A callback that will be passed a ptr to the underlying host buffer.

Returns

The buffer view.

Definition at line 59 of file host_buffer.cc.

                                                      {
  auto [range, device_buffer] = EmplaceInternal(length, align, cb);
  if (!device_buffer) {
    return {};
  }
  return BufferView{std::move(device_buffer), range};
}

EmplaceStorageBuffer()

template<class StorageBufferType , class = std::enable_if_t<std::is_standard_layout_v<StorageBufferType>>>

BufferView impeller::HostBuffer::EmplaceStorageBuffer ( const StorageBufferType &  buffer )

inline

Emplace storage buffer data onto the host buffer. Ensure that backend specific uniform alignment requirements are respected.

Parameters

[in]

uniform

The storage buffer to emplace onto the buffer.

Template Parameters

StorageBufferType

The type of the shader storage buffer.

Returns

The buffer view.

Definition at line 72 of file host_buffer.h.

                                       {
    const auto alignment =
        std::max(alignof(StorageBufferType), DefaultUniformAlignment());
    return Emplace(&buffer,                    // buffer
                   sizeof(StorageBufferType),  // size
                   alignment                   // alignment
    );
  }

EmplaceUniform()

template<class UniformType , class = std::enable_if_t<std::is_standard_layout_v<UniformType>>>

BufferView impeller::HostBuffer::EmplaceUniform ( const UniformType &  uniform )

inline

Emplace uniform data onto the host buffer. Ensure that backend specific uniform alignment requirements are respected.

Parameters

[in]

uniform

The uniform struct to emplace onto the buffer.

Template Parameters

UniformType

The type of the uniform struct.

Returns

The buffer view.

Definition at line 50 of file host_buffer.h.

                                                                      {
    const auto alignment =
        std::max(alignof(UniformType), DefaultUniformAlignment());
    return Emplace(reinterpret_cast<const void*>(&uniform),  // buffer
                   sizeof(UniformType),                      // size
                   alignment                                 // alignment
    );
  }

GetStateForTest()

HostBuffer::TestStateQuery impeller::HostBuffer::GetStateForTest

(

)

Retrieve internal buffer state for test expectations.

Definition at line 69 of file host_buffer.cc.

                                                     {
  return HostBuffer::TestStateQuery{
      .current_frame = frame_index_,
      .current_buffer = current_buffer_,
      .total_buffer_count = device_buffers_[frame_index_].size(),
  };
}

Reset()

void impeller::HostBuffer::Reset

(

)

Resets the contents of the HostBuffer to nothing so it can be reused.

Definition at line 195 of file host_buffer.cc.

                       {
  // When resetting the host buffer state at the end of the frame, check if
  // there are any unused buffers and remove them.
  while (device_buffers_[frame_index_].size() > current_buffer_ + 1) {
    device_buffers_[frame_index_].pop_back();
  }
 
  offset_ = 0u;
  current_buffer_ = 0u;
  frame_index_ = (frame_index_ + 1) % kHostBufferArenaSize;
}

SetLabel()

void impeller::HostBuffer::SetLabel

(

std::string

label

)

Definition at line 37 of file host_buffer.cc.

                                         {
  label_ = std::move(label);
}

---

The documentation for this class was generated from the following files:

• impeller/core/host_buffer.h
• impeller/core/host_buffer.cc