impeller::CommandBuffer Class Reference

A collection of encoded commands to be submitted to the GPU for execution. A command buffer is obtained from a graphics Context. More...

#include <command_buffer.h>

Inheritance diagram for impeller::CommandBuffer:

Public Types
enum	Status {   Status::kPending,   Status::kError,   Status::kCompleted }
using	CompletionCallback = std::function< void(Status)>

Public Member Functions
virtual	~CommandBuffer ()
virtual bool	IsValid () const =0
virtual void	SetLabel (const std::string &label) const =0
bool	SubmitCommands (const CompletionCallback &callback)
	Schedule the command encoded by render passes within this command buffer on the GPU. The encoding of these commnands is performed immediately on the calling thread. More...
bool	SubmitCommands ()
virtual bool	EncodeAndSubmit (const std::shared_ptr< RenderPass > &render_pass)
	Schedule the command encoded by render passes within this command buffer on the GPU. The enqueing of this buffer is performed immediately but encoding is pushed to a worker thread if possible. More...
virtual bool	EncodeAndSubmit (const std::shared_ptr< BlitPass > &blit_pass, const std::shared_ptr< Allocator > &allocator)
	Schedule the command encoded by blit passes within this command buffer on the GPU. The enqueing of this buffer is performed immediately but encoding is pushed to a worker thread if possible. More...
void	WaitUntilScheduled ()
	Force execution of pending GPU commands. More...
std::shared_ptr< RenderPass >	CreateRenderPass (const RenderTarget &render_target)
	Create a render pass to record render commands into. More...
std::shared_ptr< BlitPass >	CreateBlitPass ()
	Create a blit pass to record blit commands into. More...
std::shared_ptr< ComputePass >	CreateComputePass ()
	Create a compute pass to record compute commands into. More...

Protected Member Functions
	CommandBuffer (std::weak_ptr< const Context > context)
virtual std::shared_ptr< RenderPass >	OnCreateRenderPass (RenderTarget render_target)=0
virtual std::shared_ptr< BlitPass >	OnCreateBlitPass ()=0
virtual bool	OnSubmitCommands (CompletionCallback callback)=0
virtual void	OnWaitUntilScheduled ()=0
virtual std::shared_ptr< ComputePass >	OnCreateComputePass ()=0

Protected Attributes
std::weak_ptr< const Context >	context_

Friends
class	testing::CommandBufferMock

Detailed Description

A collection of encoded commands to be submitted to the GPU for execution. A command buffer is obtained from a graphics Context.

To submit commands to the GPU, acquire a RenderPass from the command buffer and record Commands into that pass. A RenderPass describes the configuration of the various attachments when the command is submitted.

A command buffer is only meant to be used on a single thread. If a frame workload needs to be encoded from multiple threads, set up and record into multiple command buffers. The order of submission of commands encoded in multiple command buffers can be controlled via either the order in which the command buffers were created, or, using the ReserveSpotInQueue command which allows for encoding commands for submission in an order that is different from the encoding order.

Definition at line 45 of file command_buffer.h.

Member Typedef Documentation

CompletionCallback

using impeller::CommandBuffer::CompletionCallback = std::function<void(Status)>

Definition at line 55 of file command_buffer.h.

Member Enumeration Documentation

Status

enum impeller::CommandBuffer::Status

strong

Enumerator
kPending
kError
kCompleted

Definition at line 49 of file command_buffer.h.

                    {
    kPending,
    kError,
    kCompleted,
  };

Constructor & Destructor Documentation

~CommandBuffer()

impeller::CommandBuffer::~CommandBuffer ( )

virtualdefault

CommandBuffer()

impeller::CommandBuffer::CommandBuffer ( std::weak_ptr< const Context >  context )

explicitprotected

Definition at line 14 of file command_buffer.cc.

    : context_(std::move(context)) {}

Member Function Documentation

CreateBlitPass()

std::shared_ptr< BlitPass > impeller::CommandBuffer::CreateBlitPass

(

)

Create a blit pass to record blit commands into.

Returns

A valid blit pass or null.

Definition at line 76 of file command_buffer.cc.

                                                      {
  auto pass = OnCreateBlitPass();
  if (pass && pass->IsValid()) {
    pass->SetLabel("BlitPass");
    return pass;
  }
  return nullptr;
}

References OnCreateBlitPass().

CreateComputePass()

std::shared_ptr< ComputePass > impeller::CommandBuffer::CreateComputePass

(

)

Create a compute pass to record compute commands into.

Returns

A valid compute pass or null.

Definition at line 85 of file command_buffer.cc.

                                                            {
  if (!IsValid()) {
    return nullptr;
  }
  auto pass = OnCreateComputePass();
  if (pass && pass->IsValid()) {
    pass->SetLabel("ComputePass");
    return pass;
  }
  return nullptr;
}

References IsValid(), and OnCreateComputePass().

CreateRenderPass()

std::shared_ptr< RenderPass > impeller::CommandBuffer::CreateRenderPass

(

const RenderTarget &

render_target

)

Create a render pass to record render commands into.

Parameters

[in]

render_target

The description of the render target this pass will target.

Returns

A valid render pass or null.

Definition at line 66 of file command_buffer.cc.

                                       {
  auto pass = OnCreateRenderPass(render_target);
  if (pass && pass->IsValid()) {
    pass->SetLabel("RenderPass");
    return pass;
  }
  return nullptr;
}

References OnCreateRenderPass().

EncodeAndSubmit() [1/2]

bool impeller::CommandBuffer::EncodeAndSubmit ( const std::shared_ptr< BlitPass > &  blit_pass, const std::shared_ptr< Allocator > &  allocator  )

virtual

Schedule the command encoded by blit passes within this command buffer on the GPU. The enqueing of this buffer is performed immediately but encoding is pushed to a worker thread if possible.

A command buffer may only be committed once.

Definition at line 52 of file command_buffer.cc.

                                               {
  TRACE_EVENT0("impeller", "CommandBuffer::EncodeAndSubmit");
  if (!blit_pass->IsValid() || !IsValid()) {
    return false;
  }
  if (!blit_pass->EncodeCommands(allocator)) {
    return false;
  }
 
  return SubmitCommands(nullptr);
}

References IsValid(), and SubmitCommands().

EncodeAndSubmit() [2/2]

bool impeller::CommandBuffer::EncodeAndSubmit ( const std::shared_ptr< RenderPass > &  render_pass )

virtual

Schedule the command encoded by render passes within this command buffer on the GPU. The enqueing of this buffer is performed immediately but encoding is pushed to a worker thread if possible.

A command buffer may only be committed once.

Definition at line 39 of file command_buffer.cc.

                                                  {
  TRACE_EVENT0("impeller", "CommandBuffer::EncodeAndSubmit");
  if (!render_pass->IsValid() || !IsValid()) {
    return false;
  }
  if (!render_pass->EncodeCommands()) {
    return false;
  }
 
  return SubmitCommands(nullptr);
}

References IsValid(), and SubmitCommands().

IsValid()

virtual bool impeller::CommandBuffer::IsValid ( ) const

pure virtual

Referenced by CreateComputePass(), EncodeAndSubmit(), and SubmitCommands().

OnCreateBlitPass()

virtual std::shared_ptr<BlitPass> impeller::CommandBuffer::OnCreateBlitPass ( )

protectedpure virtual

Referenced by CreateBlitPass().

OnCreateComputePass()

virtual std::shared_ptr<ComputePass> impeller::CommandBuffer::OnCreateComputePass ( )

protectedpure virtual

Referenced by CreateComputePass().

OnCreateRenderPass()

virtual std::shared_ptr<RenderPass> impeller::CommandBuffer::OnCreateRenderPass ( RenderTarget  render_target )

protectedpure virtual

Referenced by CreateRenderPass().

OnSubmitCommands()

virtual bool impeller::CommandBuffer::OnSubmitCommands ( CompletionCallback  callback )

protectedpure virtual

Referenced by SubmitCommands().

OnWaitUntilScheduled()

virtual void impeller::CommandBuffer::OnWaitUntilScheduled ( )

protectedpure virtual

Referenced by WaitUntilScheduled().

SetLabel()

virtual void impeller::CommandBuffer::SetLabel ( const std::string &  label ) const

pure virtual

SubmitCommands() [1/2]

bool impeller::CommandBuffer::SubmitCommands

(

)

Definition at line 31 of file command_buffer.cc.

                                   {
  return SubmitCommands(nullptr);
}

Referenced by EncodeAndSubmit().

SubmitCommands() [2/2]

bool impeller::CommandBuffer::SubmitCommands

(

const CompletionCallback &

callback

)

Schedule the command encoded by render passes within this command buffer on the GPU. The encoding of these commnands is performed immediately on the calling thread.

A command buffer may only be committed once.

Parameters

[in]

callback

The completion callback.

Definition at line 19 of file command_buffer.cc.

                                                                     {
  TRACE_EVENT0("impeller", "CommandBuffer::SubmitCommands");
  if (!IsValid()) {
    // Already committed or was never valid. Either way, this is caller error.
    if (callback) {
      callback(Status::kError);
    }
    return false;
  }
  return OnSubmitCommands(callback);
}

References IsValid(), kError, and OnSubmitCommands().

WaitUntilScheduled()

void impeller::CommandBuffer::WaitUntilScheduled

(

)

Force execution of pending GPU commands.

Definition at line 35 of file command_buffer.cc.

                                       {
  return OnWaitUntilScheduled();
}

References OnWaitUntilScheduled().

Friends And Related Function Documentation

testing::CommandBufferMock

friend class testing::CommandBufferMock

friend

Definition at line 46 of file command_buffer.h.

Member Data Documentation

context_

std::weak_ptr<const Context> impeller::CommandBuffer::context_

protected

Definition at line 130 of file command_buffer.h.

---

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

• impeller/renderer/command_buffer.h
• impeller/renderer/command_buffer.cc