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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
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...

## Static Public Member Functions
static std::shared_ptr< ContextMTL > | Create (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 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 (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 | BackendType { BackendType::kMetal, BackendType::kOpenGLES, BackendType::kVulkan }
Static Public Attributes inherited from impeller::Context
static constexpr int32_t | kMaxTasksAwaitingGPU = 10
Protected Member Functions inherited from impeller::Context
| Context ()
Protected Attributes inherited from impeller::Context
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 285 of file context_mtl.mm.

285 {
286 is_gpu_disabled_sync_switch_->RemoveObserver(sync_switch_observer_.get());
287 }

## Member Function Documentation

## ◆ Create() [1/3]

std::shared_ptr< ContextMTL > impeller::ContextMTL::Create | ( | 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 245 of file context_mtl.mm.

249 {
250 auto device = CreateMetalDevice();
251 auto command_queue = CreateMetalCommandQueue(device);
252 if (!command_queue) {
253 return nullptr;
254 }
255 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
256 device, command_queue,
257 MTLShaderLibraryFromFileData(device, shader_libraries_data,
258 library_label),
259 std::move(is_gpu_disabled_sync_switch), pixel_format_override));
260 if (!context->IsValid()) {
261 FML_LOG(ERROR) << "Could not create Metal context.";
262 return nullptr;
263 }
264 return context;
265 }

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

## ◆ Create() [2/3]

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

Definition at line 226 of file context_mtl.mm.

228 {
229 auto device = CreateMetalDevice();
230 auto command_queue = CreateMetalCommandQueue(device);
231 if (!command_queue) {
232 return nullptr;
233 }
234 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
235 device, command_queue,
236 MTLShaderLibraryFromFilePaths(device, shader_library_paths),
237 std::move(is_gpu_disabled_sync_switch)));
238 if (!context->IsValid()) {
239 FML_LOG(ERROR) << "Could not create Metal context.";
240 return nullptr;
241 }
242 return context;
243 }

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

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

## ◆ Create() [3/3]

std::shared_ptr< ContextMTL > impeller::ContextMTL::Create | ( | 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 267 of file context_mtl.mm.

272 {
273 auto context = std::shared_ptr<ContextMTL>(
274 new ContextMTL(device, command_queue,
275 MTLShaderLibraryFromFileData(device, shader_libraries_data,
276 library_label),
277 std::move(is_gpu_disabled_sync_switch)));
278 if (!context->IsValid()) {
279 FML_LOG(ERROR) << "Could not create Metal context.";
280 return nullptr;
281 }
282 return context;
283 }

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 319 of file context_mtl.mm.

319 {
320 return CreateCommandBufferInQueue(command_queue_);
321 }

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

## ◆ CreateMTLCommandBuffer()

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

Definition at line 374 of file context_mtl.mm.

375 {
376 auto buffer = [command_queue_ commandBuffer];
377 if (!label.empty()) {
378 [buffer setLabel:@(label.data())];
379 }
380 return buffer;
381 }

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

## ◆ DescribeGpuModel()

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

Implements impeller::Context.

Definition at line 294 of file context_mtl.mm.

294 {
295 return std::string([[device_ name] UTF8String]);
296 }

## ◆ 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 289 of file context_mtl.mm.

289 {
290 return Context::BackendType::kMetal;
291 }

## ◆ 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 359 of file context_mtl.mm.

359 {
360 return device_capabilities_;
361 }

## ◆ 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 430 of file context_mtl.mm.

430 {
431 return command_queue_ip_;
432 }

## ◆ GetIsGpuDisabledSyncSwitch()

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

Definition at line 332 of file context_mtl.mm.

333 {
334 return is_gpu_disabled_sync_switch_;
335 }

## ◆ GetMTLDevice()

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

Definition at line 355 of file context_mtl.mm.

355 {
356 return device_;
357 }

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 309 of file context_mtl.mm.

309 {
310 return pipeline_library_;
311 }

## ◆ 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 351 of file context_mtl.mm.

351 {
352 return resource_allocator_;
353 }

## ◆ 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 435 of file context_mtl.mm.

435 {
436 return RuntimeStageBackend::kMetal;
437 }

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 314 of file context_mtl.mm.

314 {
315 return sampler_library_;
316 }

## ◆ 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 304 of file context_mtl.mm.

304 {
305 return shader_library_;
306 }

## ◆ 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 299 of file context_mtl.mm.

299 {
300 return is_valid_;
301 }

## ◆ SetCapabilities()

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

Definition at line 363 of file context_mtl.mm.

364 {
365 device_capabilities_ = capabilities;
366 }

## ◆ 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 324 of file context_mtl.mm.

324 {}

## ◆ 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 383 of file context_mtl.mm.

384 {
385 std::vector<PendingTasks> failed_tasks;
386 {
387 Lock lock(tasks_awaiting_gpu_mutex_);
388 tasks_awaiting_gpu_.push_back(PendingTasks{task, failure});
389 int32_t failed_task_count =
390 tasks_awaiting_gpu_.size() - kMaxTasksAwaitingGPU;
391 if (failed_task_count > 0) {
392 failed_tasks.reserve(failed_task_count);
393 failed_tasks.insert(failed_tasks.end(),
394 std::make_move_iterator(tasks_awaiting_gpu_.begin()),
395 std::make_move_iterator(tasks_awaiting_gpu_.begin() +
396 failed_task_count));
397 tasks_awaiting_gpu_.erase(
398 tasks_awaiting_gpu_.begin(),
399 tasks_awaiting_gpu_.begin() + failed_task_count);
400 }
401 }
402 for (const PendingTasks& task : failed_tasks) {
403 if (task.failure) {
404 task.failure();
405 }
406 }
407 }

## ◆ UpdateOffscreenLayerPixelFormat()

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

Reimplemented from impeller::Context.

Definition at line 369 of file context_mtl.mm.

369 {
370 device_capabilities_ = InferMetalCapabilities(device_, format);
371 return true;
372 }

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

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:169
impeller::CreateMetalCommandQueue
static id< MTLCommandQueue > CreateMetalCommandQueue(id< MTLDevice > device)
Definition: context_mtl.mm:216
impeller::CreateMetalDevice
static id< MTLDevice > CreateMetalDevice()
Definition: context_mtl.mm:212
impeller::InferMetalCapabilities
static std::unique_ptr< Capabilities > InferMetalCapabilities(id< MTLDevice > device, PixelFormat color_format)
Definition: context_mtl.mm:55
impeller::Context::BackendType::kMetal
@ kMetal
impeller::MTLShaderLibraryFromFilePaths
static NSArray< id< MTLLibrary > > * MTLShaderLibraryFromFilePaths(id< MTLDevice > device, const std::vector< std::string > &libraries_paths)
Definition: context_mtl.mm:146
impeller::RuntimeStageBackend::kMetal
@ kMetal
impeller::Context::kMaxTasksAwaitingGPU
static constexpr int32_t kMaxTasksAwaitingGPU
Definition: context.h:60