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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...
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 std::function< void()> &task) override
Public Member Functions inherited from impeller::Context
virtual | ~Context ()
| Destroys an Impeller context. More...
virtual void | InitializeCommonlyUsedShadersIfNeeded () const

## 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)
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 }
Public Attributes inherited from impeller::Context
CaptureContext | capture
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 35 of file context_mtl.h.

## Constructor & Destructor Documentation

## ◆ ~ContextMTL()

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

Definition at line 277 of file context_mtl.mm.

277 {
278 is_gpu_disabled_sync_switch_->RemoveObserver(sync_switch_observer_.get());
279 }

## 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
| ) |  |
| static

Definition at line 238 of file context_mtl.mm.

241 {
242 auto device = CreateMetalDevice();
243 auto command_queue = CreateMetalCommandQueue(device);
244 if (!command_queue) {
245 return nullptr;
246 }
247 auto context = std::shared_ptr<ContextMTL>(
248 new ContextMTL(device, command_queue,
249 MTLShaderLibraryFromFileData(device, shader_libraries_data,
250 library_label),
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 }

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 219 of file context_mtl.mm.

221 {
222 auto device = CreateMetalDevice();
223 auto command_queue = CreateMetalCommandQueue(device);
224 if (!command_queue) {
225 return nullptr;
226 }
227 auto context = std::shared_ptr<ContextMTL>(new ContextMTL(
228 device, command_queue,
229 MTLShaderLibraryFromFilePaths(device, shader_library_paths),
230 std::move(is_gpu_disabled_sync_switch)));
231 if (!context->IsValid()) {
232 FML_LOG(ERROR) << "Could not create Metal context.";
233 return nullptr;
234 }
235 return context;
236 }

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

## ◆ 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 259 of file context_mtl.mm.

264 {
265 auto context = std::shared_ptr<ContextMTL>(
266 new ContextMTL(device, command_queue,
267 MTLShaderLibraryFromFileData(device, shader_libraries_data,
268 library_label),
269 std::move(is_gpu_disabled_sync_switch)));
270 if (!context->IsValid()) {
271 FML_LOG(ERROR) << "Could not create Metal context.";
272 return nullptr;
273 }
274 return context;
275 }

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 311 of file context_mtl.mm.

311 {
312 return CreateCommandBufferInQueue(command_queue_);
313 }

## ◆ CreateMTLCommandBuffer()

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

Definition at line 366 of file context_mtl.mm.

367 {
368 auto buffer = [command_queue_ commandBuffer];
369 if (!label.empty()) {
370 [buffer setLabel:@(label.data())];
371 }
372 return buffer;
373 }

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

## ◆ DescribeGpuModel()

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

Implements impeller::Context.

Definition at line 286 of file context_mtl.mm.

286 {
287 return std::string([[device_ name] UTF8String]);
288 }

## ◆ 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 281 of file context_mtl.mm.

281 {
282 return Context::BackendType::kMetal;
283 }

## ◆ 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 351 of file context_mtl.mm.

351 {
352 return device_capabilities_;
353 }

## ◆ 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 400 of file context_mtl.mm.

400 {
401 return command_queue_ip_;
402 }

## ◆ GetIsGpuDisabledSyncSwitch()

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

Definition at line 324 of file context_mtl.mm.

325 {
326 return is_gpu_disabled_sync_switch_;
327 }

## ◆ GetMTLDevice()

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

Definition at line 347 of file context_mtl.mm.

347 {
348 return device_;
349 }

## ◆ 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 301 of file context_mtl.mm.

301 {
302 return pipeline_library_;
303 }

## ◆ 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 343 of file context_mtl.mm.

343 {
344 return resource_allocator_;
345 }

## ◆ 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 306 of file context_mtl.mm.

306 {
307 return sampler_library_;
308 }

## ◆ 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 296 of file context_mtl.mm.

296 {
297 return shader_library_;
298 }

## ◆ 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 291 of file context_mtl.mm.

291 {
292 return is_valid_;
293 }

## ◆ SetCapabilities()

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

Definition at line 355 of file context_mtl.mm.

356 {
357 device_capabilities_ = capabilities;
358 }

## ◆ 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 316 of file context_mtl.mm.

316 {}

## ◆ StoreTaskForGPU()

void impeller::ContextMTL::StoreTaskForGPU | ( | const std::function< void()> & | task | ) |
| 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.

Threadsafe.

`task` will be executed on the platform thread.

Reimplemented from impeller::Context.

Definition at line 375 of file context_mtl.mm.

375 {
376 tasks_awaiting_gpu_.emplace_back(task);
377 while (tasks_awaiting_gpu_.size() > kMaxTasksAwaitingGPU) {
378 tasks_awaiting_gpu_.front()();
379 tasks_awaiting_gpu_.pop_front();
380 }
381 }

## ◆ UpdateOffscreenLayerPixelFormat()

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

Reimplemented from impeller::Context.

Definition at line 361 of file context_mtl.mm.

361 {
362 device_capabilities_ = InferMetalCapabilities(device_, format);
363 return true;
364 }

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:162
impeller::CreateMetalCommandQueue
static id< MTLCommandQueue > CreateMetalCommandQueue(id< MTLDevice > device)
Definition: context_mtl.mm:209
impeller::CreateMetalDevice
static id< MTLDevice > CreateMetalDevice()
Definition: context_mtl.mm:205
impeller::InferMetalCapabilities
static std::unique_ptr< Capabilities > InferMetalCapabilities(id< MTLDevice > device, PixelFormat color_format)
Definition: context_mtl.mm:53
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:139
impeller::Context::kMaxTasksAwaitingGPU
static constexpr int32_t kMaxTasksAwaitingGPU
Definition: context.h:60