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impeller::ContextMTL Class Referencefinal

`#include <context_mtl.h>`

Inheritance diagram for impeller::ContextMTL:

## Public Member Functions
| ~ContextMTL () override
BackendType | GetBackendType () const override
| Get the graphics backend of an Impeller context. More...
id< MTLDevice > | GetMTLDevice () const
std::string | DescribeGpuModel () const override
bool | IsValid () const override
| Determines if a context is valid. If the caller ever receives an invalid context, they must discard it and construct a new context. There is no recovery mechanism to repair a bad context. More...
std::shared_ptr< Allocator > | GetResourceAllocator () const override
| Returns the allocator used to create textures and buffers on the device. More...
std::shared_ptr< ShaderLibrary > | GetShaderLibrary () const override
| Returns the library of shaders used to specify the programmable stages of a pipeline. More...
std::shared_ptr< SamplerLibrary > | GetSamplerLibrary () const override
| Returns the library of combined image samplers used in shaders. More...
std::shared_ptr< PipelineLibrary > | GetPipelineLibrary () const override
| Returns the library of pipelines used by render or compute commands. More...
std::shared_ptr< CommandBuffer > | CreateCommandBuffer () const override
| Create a new command buffer. Command buffers can be used to encode graphics, blit, or compute commands to be submitted to the device. More...
std::shared_ptr< CommandQueue > | GetCommandQueue () const override
| Return the graphics queue for submitting command buffers. More...
const std::shared_ptr< const Capabilities > & | GetCapabilities () const override
| Get the capabilities of Impeller context. All optionally supported feature of the platform, client-rendering API, and device can be queried using the `Capabilities`. More...
RuntimeStageBackend | GetRuntimeStageBackend () const override
| Retrieve the runtime stage for this context type. More...
void | SetCapabilities (const std::shared_ptr< const Capabilities > &capabilities)
bool | UpdateOffscreenLayerPixelFormat (PixelFormat format) override
void | Shutdown () override
| Force all pending asynchronous work to finish. This is achieved by deleting all owned concurrent message loops. More...
id< MTLCommandBuffer > | CreateMTLCommandBuffer (const std::string &label) const
std::shared_ptr< const fml::SyncSwitch > | GetIsGpuDisabledSyncSwitch () const
void | StoreTaskForGPU (const fml::closure &task, const fml::closure &failure) override
void | FlushTasksAwaitingGPU ()
Public Member Functions inherited from impeller::Context
virtual | ~Context ()
| Destroys an Impeller context. More...
virtual void | InitializeCommonlyUsedShadersIfNeeded () const
virtual void | DisposeThreadLocalCachedResources ()
virtual bool | EnqueueCommandBuffer (std::shared_ptr< CommandBuffer > command_buffer)
| Enqueue command_buffer for submission by the end of the frame. More...
virtual bool | FlushCommandBuffers ()
| Flush all pending command buffers. More...
virtual bool | AddTrackingFence (const std::shared_ptr< Texture > &texture) const
virtual std::shared_ptr< const IdleWaiter > | GetIdleWaiter () const
virtual void | ResetThreadLocalState () const
virtual bool | SubmitOnscreen (std::shared_ptr< CommandBuffer > cmd_buffer)
| Submit the command buffer that renders to the onscreen surface. More...
const Flags & | GetFlags () const

## Static Public Member Functions
static std::shared_ptr< ContextMTL > | Create (const Flags &flags, const std::vector< std::string > &shader_library_paths, std::shared_ptr< const fml::SyncSwitch > is_gpu_disabled_sync_switch)
static std::shared_ptr< ContextMTL > | Create (const Flags &flags, const std::vector< std::shared_ptr< fml::Mapping >> &shader_libraries_data, std::shared_ptr< const fml::SyncSwitch > is_gpu_disabled_sync_switch, const std::string &label, std::optional< PixelFormat > pixel_format_override=std::nullopt)
static std::shared_ptr< ContextMTL > | Create (const Flags &flags, id< MTLDevice > device, id< MTLCommandQueue > command_queue, const std::vector< std::shared_ptr< fml::Mapping >> &shader_libraries_data, std::shared_ptr< const fml::SyncSwitch > is_gpu_disabled_sync_switch, const std::string &label)
Static Public Member Functions inherited from impeller::BackendCast< ContextMTL, Context >
static ContextMTL & | Cast (Context &base)
static const ContextMTL & | Cast (const Context &base)
static ContextMTL * | Cast (Context *base)
static const ContextMTL * | Cast (const Context *base)

## Additional Inherited Members
Public Types inherited from impeller::Context
enum class | BackendType { kMetal , kOpenGLES , kVulkan }
Static Public Attributes inherited from impeller::Context
static constexpr int32_t | kMaxTasksAwaitingGPU = 64
Protected Member Functions inherited from impeller::Context
| Context (const Flags &flags)
Protected Attributes inherited from impeller::Context
Flags | flags_
std::vector< std::function< void()> > | per_frame_task_

## Detailed Description

Definition at line 65 of file context_mtl.h.

## Constructor & Destructor Documentation

## ◆ ~ContextMTL()

impeller::ContextMTL::~ContextMTL | ( |  | ) |
| override

Definition at line 301 of file context_mtl.mm.

301 {
302 is_gpu_disabled_sync_switch_->RemoveObserver(sync_switch_observer_.get());
303 }

## Member Function Documentation

## ◆ Create() [1/3]

std::shared_ptr< ContextMTL > impeller::ContextMTL::Create | ( | const Flags & | flags,
|  | const std::vector< std::shared_ptr< fml::Mapping >> & | shader_libraries_data,
|  | std::shared_ptr< const fml::SyncSwitch > | is_gpu_disabled_sync_switch,
|  | const std::string & | label,
|  | std::optional< PixelFormat > | pixel_format_override = `std::nullopt`
| ) |  |
| static

Definition at line 259 of file context_mtl.mm.

264 {
265 auto device = CreateMetalDevice();
266 auto command_queue = CreateMetalCommandQueue(device);
267 if (!command_queue) {
268 return nullptr;
269 }
270 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
271 flags, device, command_queue,
272 MTLShaderLibraryFromFileData(device, shader_libraries_data,
273 library_label),
274 std::move(is_gpu_disabled_sync_switch), pixel_format_override));
275 if (!context->IsValid()) {
276 FML_LOG(ERROR) << "Could not create Metal context.";
277 return nullptr;
278 }
279 return context;
280 }
impeller::MTLShaderLibraryFromFileData
static NSArray< id< MTLLibrary > > * MTLShaderLibraryFromFileData(id< MTLDevice > device, const std::vector< std::shared_ptr< fml::Mapping >> &libraries_data, const std::string &label)
Definition: context_mtl.mm:182
impeller::CreateMetalDevice
static id< MTLDevice > CreateMetalDevice()
Definition: context_mtl.mm:225
impeller::CreateMetalCommandQueue
static id< MTLCommandQueue > CreateMetalCommandQueue(id< MTLDevice > device)
Definition: context_mtl.mm:229

References impeller::CreateMetalCommandQueue(), impeller::CreateMetalDevice(), and impeller::MTLShaderLibraryFromFileData().

## ◆ Create() [2/3]

std::shared_ptr< ContextMTL > impeller::ContextMTL::Create | ( | const Flags & | flags,
|  | const std::vector< std::string > & | shader_library_paths,
|  | std::shared_ptr< const fml::SyncSwitch > | is_gpu_disabled_sync_switch
| ) |  |
| static

Definition at line 239 of file context_mtl.mm.

242 {
243 auto device = CreateMetalDevice();
244 auto command_queue = CreateMetalCommandQueue(device);
245 if (!command_queue) {
246 return nullptr;
247 }
248 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
249 flags, device, command_queue,
250 MTLShaderLibraryFromFilePaths(device, shader_library_paths),
251 std::move(is_gpu_disabled_sync_switch)));
252 if (!context->IsValid()) {
253 FML_LOG(ERROR) << "Could not create Metal context.";
254 return nullptr;
255 }
256 return context;
257 }
impeller::MTLShaderLibraryFromFilePaths
static NSArray< id< MTLLibrary > > * MTLShaderLibraryFromFilePaths(id< MTLDevice > device, const std::vector< std::string > &libraries_paths)
Definition: context_mtl.mm:159

References impeller::CreateMetalCommandQueue(), impeller::CreateMetalDevice(), and impeller::MTLShaderLibraryFromFilePaths().

Referenced by impeller::interop::ContextMTL::Create(), and impeller::PlaygroundImplMTL::PlaygroundImplMTL().

## ◆ Create() [3/3]

std::shared_ptr< ContextMTL > impeller::ContextMTL::Create | ( | const Flags & | flags,
|  | id< MTLDevice > | device,
|  | id< MTLCommandQueue > | command_queue,
|  | const std::vector< std::shared_ptr< fml::Mapping >> & | shader_libraries_data,
|  | std::shared_ptr< const fml::SyncSwitch > | is_gpu_disabled_sync_switch,
|  | const std::string & | label
| ) |  |
| static

Definition at line 282 of file context_mtl.mm.

288 {
289 auto context = std::shared_ptr<ContextMTL>(
290 new ContextMTL(flags, device, command_queue,
291 MTLShaderLibraryFromFileData(device, shader_libraries_data,
292 library_label),
293 std::move(is_gpu_disabled_sync_switch)));
294 if (!context->IsValid()) {
295 FML_LOG(ERROR) << "Could not create Metal context.";
296 return nullptr;
297 }
298 return context;
299 }

References impeller::MTLShaderLibraryFromFileData().

## ◆ CreateCommandBuffer()

std::shared_ptr< CommandBuffer > impeller::ContextMTL::CreateCommandBuffer | ( |  | ) | const
| override virtual

Create a new command buffer. Command buffers can be used to encode graphics, blit, or compute commands to be submitted to the device.

A command buffer can only be used on a single thread. Multi-threaded render, blit, or compute passes must create a new command buffer on each thread.

Returns
  A new command buffer.

Implements impeller::Context.

Definition at line 335 of file context_mtl.mm.

335 {
336 return CreateCommandBufferInQueue(command_queue_);
337 }

Referenced by impeller::SurfaceMTL::PreparePresent().

## ◆ CreateMTLCommandBuffer()

id< MTLCommandBuffer > impeller::ContextMTL::CreateMTLCommandBuffer | ( | const std::string & | label | ) | const

Definition at line 390 of file context_mtl.mm.

391 {
392 auto buffer = [command_queue_ commandBuffer];
393 if (!label.empty()) {
394 [buffer setLabel:@(label.data())];
395 }
396 return buffer;
397 }

Referenced by impeller::SurfaceMTL::Present().

## ◆ DescribeGpuModel()

std::string impeller::ContextMTL::DescribeGpuModel | ( |  | ) | const
| override virtual

Implements impeller::Context.

Definition at line 310 of file context_mtl.mm.

310 {
311 return std::string([[device_ name] UTF8String]);
312 }

## ◆ FlushTasksAwaitingGPU()

void impeller::ContextMTL::FlushTasksAwaitingGPU | ( |  | ) |

Definition at line 425 of file context_mtl.mm.

425 {
426 std::deque<PendingTasks> tasks_awaiting_gpu;
427 {
428 Lock lock(tasks_awaiting_gpu_mutex_);
429 std::swap(tasks_awaiting_gpu, tasks_awaiting_gpu_);
430 }
431 std::vector<PendingTasks> tasks_to_queue;
432 for (const auto& task : tasks_awaiting_gpu) {
433 is_gpu_disabled_sync_switch_->Execute(fml::SyncSwitch::Handlers()
434 .SetIfFalse([&] { task.task(); })
435 .SetIfTrue([&] {
436 // Lost access to the GPU
437 // immediately after it was
438 // activated. This may happen if
439 // the app was quickly
440 // foregrounded/backgrounded
441 // from a push notification.
442 // Store the tasks on the
443 // context again.
444 tasks_to_queue.push_back(task);
445 }));
446 }
447 if (!tasks_to_queue.empty()) {
448 Lock lock(tasks_awaiting_gpu_mutex_);
449 tasks_awaiting_gpu_.insert(tasks_awaiting_gpu_.end(),
450 tasks_to_queue.begin(), tasks_to_queue.end());
451 }
452 }

## ◆ GetBackendType()

Context::BackendType impeller::ContextMTL::GetBackendType | ( |  | ) | const
| override virtual

Get the graphics backend of an Impeller context.

            This is useful for cases where a renderer needs to track and
            lookup backend-specific resources, like shaders or uniform
            layout information.

            It's not recommended to use this as a substitute for
            per-backend capability checking. Instead, check for specific
            capabilities via `GetCapabilities()`.

Returns
  The graphics backend of the `Context`.

Implements impeller::Context.

Definition at line 305 of file context_mtl.mm.

305 {
306 return Context::BackendType::kMetal;
307 }
impeller::Context::BackendType::kMetal
@ kMetal

## ◆ GetCapabilities()

const std::shared_ptr< const Capabilities > & impeller::ContextMTL::GetCapabilities | ( |  | ) | const
| override virtual

Get the capabilities of Impeller context. All optionally supported feature of the platform, client-rendering API, and device can be queried using the `Capabilities`.

Returns
  The capabilities. Can never be `nullptr` for a valid context.

Implements impeller::Context.

Definition at line 375 of file context_mtl.mm.

375 {
376 return device_capabilities_;
377 }

## ◆ GetCommandQueue()

std::shared_ptr< CommandQueue > impeller::ContextMTL::GetCommandQueue | ( |  | ) | const
| override virtual

Return the graphics queue for submitting command buffers.

Implements impeller::Context.

Definition at line 464 of file context_mtl.mm.

464 {
465 return command_queue_ip_;
466 }

## ◆ GetIsGpuDisabledSyncSwitch()

std::shared_ptr< const fml::SyncSwitch > impeller::ContextMTL::GetIsGpuDisabledSyncSwitch | ( |  | ) | const

Definition at line 348 of file context_mtl.mm.

349 {
350 return is_gpu_disabled_sync_switch_;
351 }

## ◆ GetMTLDevice()

id< MTLDevice > impeller::ContextMTL::GetMTLDevice | ( |  | ) | const

Definition at line 371 of file context_mtl.mm.

371 {
372 return device_;
373 }

Referenced by impeller::PlaygroundImplMTL::PlaygroundImplMTL().

## ◆ GetPipelineLibrary()

std::shared_ptr< PipelineLibrary > impeller::ContextMTL::GetPipelineLibrary | ( |  | ) | const
| override virtual

Returns the library of pipelines used by render or compute commands.

Returns
  The pipeline library. Can never be `nullptr` for a valid context.

Implements impeller::Context.

Definition at line 325 of file context_mtl.mm.

325 {
326 return pipeline_library_;
327 }

## ◆ GetResourceAllocator()

std::shared_ptr< Allocator > impeller::ContextMTL::GetResourceAllocator | ( |  | ) | const
| override virtual

Returns the allocator used to create textures and buffers on the device.

Returns
  The resource allocator. Can never be `nullptr` for a valid context.

Implements impeller::Context.

Definition at line 367 of file context_mtl.mm.

367 {
368 return resource_allocator_;
369 }

## ◆ GetRuntimeStageBackend()

RuntimeStageBackend impeller::ContextMTL::GetRuntimeStageBackend | ( |  | ) | const
| override virtual

Retrieve the runtime stage for this context type.

This is used by the engine shell and other subsystems for loading the correct shader types.

Implements impeller::Context.

Definition at line 469 of file context_mtl.mm.

469 {
470 return RuntimeStageBackend::kMetal;
471 }
impeller::RuntimeStageBackend::kMetal
@ kMetal

References impeller::kMetal.

## ◆ GetSamplerLibrary()

std::shared_ptr< SamplerLibrary > impeller::ContextMTL::GetSamplerLibrary | ( |  | ) | const
| override virtual

Returns the library of combined image samplers used in shaders.

Returns
  The sampler library. Can never be `nullptr` for a valid context.

Implements impeller::Context.

Definition at line 330 of file context_mtl.mm.

330 {
331 return sampler_library_;
332 }

## ◆ GetShaderLibrary()

std::shared_ptr< ShaderLibrary > impeller::ContextMTL::GetShaderLibrary | ( |  | ) | const
| override virtual

Returns the library of shaders used to specify the programmable stages of a pipeline.

Returns
  The shader library. Can never be `nullptr` for a valid context.

Implements impeller::Context.

Definition at line 320 of file context_mtl.mm.

320 {
321 return shader_library_;
322 }

## ◆ IsValid()

bool impeller::ContextMTL::IsValid | ( |  | ) | const
| override virtual

Determines if a context is valid. If the caller ever receives an invalid context, they must discard it and construct a new context. There is no recovery mechanism to repair a bad context.

It is convention in Impeller to never return an invalid context from a call that returns an pointer to a context. The call implementation performs validity checks itself and return a null context instead of a pointer to an invalid context.

How a context goes invalid is backend specific. It could happen due to device loss, or any other unrecoverable error.

Returns
  If the context is valid.

Implements impeller::Context.

Definition at line 315 of file context_mtl.mm.

315 {
316 return is_valid_;
317 }

## ◆ SetCapabilities()

void impeller::ContextMTL::SetCapabilities | ( | const std::shared_ptr< const Capabilities > & | capabilities | ) |

Definition at line 379 of file context_mtl.mm.

380 {
381 device_capabilities_ = capabilities;
382 }

## ◆ Shutdown()

void impeller::ContextMTL::Shutdown | ( |  | ) |
| override virtual

Force all pending asynchronous work to finish. This is achieved by deleting all owned concurrent message loops.

Implements impeller::Context.

Definition at line 340 of file context_mtl.mm.

340 {}

## ◆ StoreTaskForGPU()

void impeller::ContextMTL::StoreTaskForGPU | ( | const fml::closure & | task,
|  | const fml::closure & | failure
| ) |  |
| override virtual

Stores a task on the `ContextMTL` that is awaiting access for the GPU.

The task will be executed in the event that the GPU access has changed to being available or that the task has been canceled. The task should operate with the `SyncSwitch` to make sure the GPU is accessible.

If the queue of pending tasks is cleared without GPU access, then the failure callback will be invoked and the primary task function will not

Threadsafe.

`task` will be executed on the platform thread.

Reimplemented from impeller::Context.

Definition at line 399 of file context_mtl.mm.

400 {
401 std::vector<PendingTasks> failed_tasks;
402 {
403 Lock lock(tasks_awaiting_gpu_mutex_);
404 tasks_awaiting_gpu_.push_back(PendingTasks{task, failure});
405 int32_t failed_task_count =
406 tasks_awaiting_gpu_.size() - kMaxTasksAwaitingGPU;
407 if (failed_task_count > 0) {
408 failed_tasks.reserve(failed_task_count);
409 failed_tasks.insert(failed_tasks.end(),
410 std::make_move_iterator(tasks_awaiting_gpu_.begin()),
411 std::make_move_iterator(tasks_awaiting_gpu_.begin() +
412 failed_task_count));
413 tasks_awaiting_gpu_.erase(
414 tasks_awaiting_gpu_.begin(),
415 tasks_awaiting_gpu_.begin() + failed_task_count);
416 }
417 }
418 for (const PendingTasks& task : failed_tasks) {
419 if (task.failure) {
420 task.failure();
421 }
422 }
423 }
impeller::Context::kMaxTasksAwaitingGPU
static constexpr int32_t kMaxTasksAwaitingGPU
Definition: context.h:61

## ◆ UpdateOffscreenLayerPixelFormat()

bool impeller::ContextMTL::UpdateOffscreenLayerPixelFormat | ( | PixelFormat | format | ) |
| override virtual

Reimplemented from impeller::Context.

Definition at line 385 of file context_mtl.mm.

385 {
386 device_capabilities_ = InferMetalCapabilities(device_, format);
387 return true;
388 }
impeller::InferMetalCapabilities
static std::unique_ptr< Capabilities > InferMetalCapabilities(id< MTLDevice > device, PixelFormat color_format)
Definition: context_mtl.mm:64

References impeller::InferMetalCapabilities().

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

- impeller/renderer/backend/metal/context_mtl.h
- impeller/renderer/backend/metal/context_mtl.mm