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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 = 1024
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 294 of file context_mtl.mm.

294 {
295 is_gpu_disabled_sync_switch_->RemoveObserver(sync_switch_observer_.get());
296 }

## 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 252 of file context_mtl.mm.

257 {
258 auto device = CreateMetalDevice();
259 auto command_queue = CreateMetalCommandQueue(device);
260 if (!command_queue) {
261 return nullptr;
262 }
263 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
264 flags, device, command_queue,
265 MTLShaderLibraryFromFileData(device, shader_libraries_data,
266 library_label),
267 std::move(is_gpu_disabled_sync_switch), pixel_format_override));
268 if (!context->IsValid()) {
269 FML_LOG(ERROR) << "Could not create Metal context.";
270 return nullptr;
271 }
272 return context;
273 }
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:175
impeller::CreateMetalDevice
static id< MTLDevice > CreateMetalDevice()
Definition: context_mtl.mm:218
impeller::CreateMetalCommandQueue
static id< MTLCommandQueue > CreateMetalCommandQueue(id< MTLDevice > device)
Definition: context_mtl.mm:222

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 232 of file context_mtl.mm.

235 {
236 auto device = CreateMetalDevice();
237 auto command_queue = CreateMetalCommandQueue(device);
238 if (!command_queue) {
239 return nullptr;
240 }
241 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
242 flags, device, command_queue,
243 MTLShaderLibraryFromFilePaths(device, shader_library_paths),
244 std::move(is_gpu_disabled_sync_switch)));
245 if (!context->IsValid()) {
246 FML_LOG(ERROR) << "Could not create Metal context.";
247 return nullptr;
248 }
249 return context;
250 }
impeller::MTLShaderLibraryFromFilePaths
static NSArray< id< MTLLibrary > > * MTLShaderLibraryFromFilePaths(id< MTLDevice > device, const std::vector< std::string > &libraries_paths)
Definition: context_mtl.mm:152

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 275 of file context_mtl.mm.

281 {
282 auto context = std::shared_ptr<ContextMTL>(
283 new ContextMTL(flags, device, command_queue,
284 MTLShaderLibraryFromFileData(device, shader_libraries_data,
285 library_label),
286 std::move(is_gpu_disabled_sync_switch)));
287 if (!context->IsValid()) {
288 FML_LOG(ERROR) << "Could not create Metal context.";
289 return nullptr;
290 }
291 return context;
292 }

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 328 of file context_mtl.mm.

328 {
329 return CreateCommandBufferInQueue(command_queue_);
330 }

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

## ◆ CreateMTLCommandBuffer()

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

Definition at line 383 of file context_mtl.mm.

384 {
385 auto buffer = [command_queue_ commandBuffer];
386 if (!label.empty()) {
387 [buffer setLabel:@(label.data())];
388 }
389 return buffer;
390 }

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

## ◆ DescribeGpuModel()

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

Implements impeller::Context.

Definition at line 303 of file context_mtl.mm.

303 {
304 return std::string([[device_ name] UTF8String]);
305 }

## ◆ FlushTasksAwaitingGPU()

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

Definition at line 418 of file context_mtl.mm.

418 {
419 std::deque<PendingTasks> tasks_awaiting_gpu;
420 {
421 Lock lock(tasks_awaiting_gpu_mutex_);
422 std::swap(tasks_awaiting_gpu, tasks_awaiting_gpu_);
423 }
424 std::vector<PendingTasks> tasks_to_queue;
425 for (const auto& task : tasks_awaiting_gpu) {
426 is_gpu_disabled_sync_switch_->Execute(fml::SyncSwitch::Handlers()
427 .SetIfFalse([&] { task.task(); })
428 .SetIfTrue([&] {
429 // Lost access to the GPU
430 // immediately after it was
431 // activated. This may happen if
432 // the app was quickly
433 // foregrounded/backgrounded
434 // from a push notification.
435 // Store the tasks on the
436 // context again.
437 tasks_to_queue.push_back(task);
438 }));
439 }
440 if (!tasks_to_queue.empty()) {
441 Lock lock(tasks_awaiting_gpu_mutex_);
442 tasks_awaiting_gpu_.insert(tasks_awaiting_gpu_.end(),
443 tasks_to_queue.begin(), tasks_to_queue.end());
444 }
445 }

## ◆ 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 298 of file context_mtl.mm.

298 {
299 return Context::BackendType::kMetal;
300 }
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 368 of file context_mtl.mm.

368 {
369 return device_capabilities_;
370 }

## ◆ 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 457 of file context_mtl.mm.

457 {
458 return command_queue_ip_;
459 }

## ◆ GetIsGpuDisabledSyncSwitch()

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

Definition at line 341 of file context_mtl.mm.

342 {
343 return is_gpu_disabled_sync_switch_;
344 }

## ◆ GetMTLDevice()

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

Definition at line 364 of file context_mtl.mm.

364 {
365 return device_;
366 }

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 318 of file context_mtl.mm.

318 {
319 return pipeline_library_;
320 }

## ◆ 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 360 of file context_mtl.mm.

360 {
361 return resource_allocator_;
362 }

## ◆ 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 462 of file context_mtl.mm.

462 {
463 return RuntimeStageBackend::kMetal;
464 }
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 323 of file context_mtl.mm.

323 {
324 return sampler_library_;
325 }

## ◆ 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 313 of file context_mtl.mm.

313 {
314 return shader_library_;
315 }

## ◆ 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 308 of file context_mtl.mm.

308 {
309 return is_valid_;
310 }

## ◆ SetCapabilities()

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

Definition at line 372 of file context_mtl.mm.

373 {
374 device_capabilities_ = capabilities;
375 }

## ◆ 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 333 of file context_mtl.mm.

333 {}

## ◆ 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 392 of file context_mtl.mm.

393 {
394 std::vector<PendingTasks> failed_tasks;
395 {
396 Lock lock(tasks_awaiting_gpu_mutex_);
397 tasks_awaiting_gpu_.push_back(PendingTasks{task, failure});
398 int32_t failed_task_count =
399 tasks_awaiting_gpu_.size() - kMaxTasksAwaitingGPU;
400 if (failed_task_count > 0) {
401 failed_tasks.reserve(failed_task_count);
402 failed_tasks.insert(failed_tasks.end(),
403 std::make_move_iterator(tasks_awaiting_gpu_.begin()),
404 std::make_move_iterator(tasks_awaiting_gpu_.begin() +
405 failed_task_count));
406 tasks_awaiting_gpu_.erase(
407 tasks_awaiting_gpu_.begin(),
408 tasks_awaiting_gpu_.begin() + failed_task_count);
409 }
410 }
411 for (const PendingTasks& task : failed_tasks) {
412 if (task.failure) {
413 task.failure();
414 }
415 }
416 }
impeller::Context::kMaxTasksAwaitingGPU
static constexpr int32_t kMaxTasksAwaitingGPU
Definition: context.h:79

## ◆ UpdateOffscreenLayerPixelFormat()

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

Reimplemented from impeller::Context.

Definition at line 378 of file context_mtl.mm.

378 {
379 device_capabilities_ = InferMetalCapabilities(device_, format);
380 return true;
381 }
impeller::InferMetalCapabilities
static std::unique_ptr< Capabilities > InferMetalCapabilities(id< MTLDevice > device, PixelFormat color_format)
Definition: context_mtl.mm:52

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