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ios_context.h
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef FLUTTER_SHELL_PLATFORM_DARWIN_IOS_IOS_CONTEXT_H_
6 #define FLUTTER_SHELL_PLATFORM_DARWIN_IOS_IOS_CONTEXT_H_
7
8 #include <memory>
9
10 #include "flutter/common/graphics/gl_context_switch.h"
11 #include "flutter/common/graphics/msaa_sample_count.h"
12 #include "flutter/common/graphics/texture.h"
13 #include "flutter/fml/concurrent_message_loop.h"
14 #include "flutter/fml/macros.h"
15 #include "flutter/fml/platform/darwin/scoped_nsobject.h"
16 #include "flutter/fml/synchronization/sync_switch.h"
17 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterTexture.h"
18 #import "flutter/shell/platform/darwin/ios/rendering_api_selection.h"
19 #include "third_party/skia/include/gpu/GrDirectContext.h"
20
21 namespace impeller {
22 class Context;
23 } // namespace impeller
24
25 namespace flutter {
26
27 //------------------------------------------------------------------------------
28 /// @brief Manages the lifetime of the on-screen and off-screen rendering
29 /// contexts on iOS. On-screen contexts are used by Flutter for
30 /// rendering into the surface. The lifecycle of this context may be
31 /// tied to the lifecycle of the surface. On the other hand, the
32 /// lifecycle of the off-screen context it tied to that of the
33 /// platform view. This one object used to manage both context
34 /// because GPU handles may need to be shared between the two
35 /// context. To achieve this, context may need references to one
36 /// another at creation time. This one object manages the creation,
37 /// use and collection of both contexts in a client rendering API
38 /// agnostic manner.
39 ///
40 class IOSContext {
41 public:
42 //----------------------------------------------------------------------------
43 /// @brief Create an iOS context object capable of creating the on-screen
44 /// and off-screen GPU context for use by Skia.
45 ///
46 /// In case the engine does not support the specified client
47 /// rendering API, this a `nullptr` may be returned.
48 ///
49 /// @param[in] api A client rendering API supported by the
50 /// engine/platform.
51 /// @param[in] backend A client rendering backend supported by the
52 /// engine/platform.
53 /// @param[in] msaa_samples
54 /// The number of MSAA samples to use. Only supplied to
55 /// Skia, must be either 0, 1, 2, 4, or 8.
56 ///
57 /// @return A valid context on success. `nullptr` on failure.
58 ///
59 static std::unique_ptr<IOSContext> Create(
60 IOSRenderingAPI api,
61 IOSRenderingBackend backend,
62 MsaaSampleCount msaa_samples,
63 const std::shared_ptr<const fml::SyncSwitch>& is_gpu_disabled_sync_switch);
64
65 //----------------------------------------------------------------------------
66 /// @brief Collects the context object. This must happen on the thread on
67 /// which this object was created.
68 ///
69 virtual ~IOSContext();
70
71 //----------------------------------------------------------------------------
72 /// @brief Get the rendering backend used by this context.
73 ///
74 /// @return The rendering backend.
75 ///
76 virtual IOSRenderingBackend GetBackend() const;
77
78 //----------------------------------------------------------------------------
79 /// @brief Create a resource context for use on the IO task runner. This
80 /// resource context is used by Skia to upload texture to
81 /// asynchronously and collect resources that are no longer needed
82 /// on the render task runner.
83 ///
84 /// @attention Client rendering APIs for which a GrDirectContext cannot be realized
85 /// (software rendering), this method will always return null.
86 ///
87 /// @return A non-null Skia context on success. `nullptr` on failure.
88 ///
89 virtual sk_sp<GrDirectContext> CreateResourceContext() = 0;
90
91 //----------------------------------------------------------------------------
92 /// @brief When using client rendering APIs whose contexts need to be
93 /// bound to a specific thread, the engine will call this method
94 /// to give the on-screen context a chance to bind to the current
95 /// thread.
96 ///
97 /// @attention Client rendering APIs that have no-concept of thread local
98 /// bindings (anything that is not OpenGL) will always return
99 /// `true`.
100 ///
101 /// @attention Client rendering APIs for which a GrDirectContext cannot be created
102 /// (software rendering) will always return `false`.
103 ///
104 /// @attention This binds the on-screen context to the current thread. To
105 /// bind the off-screen context to the thread, use the
106 /// `ResoruceMakeCurrent` method instead.
107 ///
108 /// @attention Only one context may be bound to a thread at any given time.
109 /// Making a binding on a thread, clears the old binding.
110 ///
111 /// @return A GLContextResult that represents the result of the method.
112 /// The GetResult() returns a bool that indicates If the on-screen context could be
113 /// bound to the current
114 /// thread.
115 ///
116 virtual std::unique_ptr<GLContextResult> MakeCurrent() = 0;
117
118 //----------------------------------------------------------------------------
119 /// @brief Creates an external texture proxy of the appropriate client
120 /// rendering API.
121 ///
122 /// @param[in] texture_id The texture identifier
123 /// @param[in] texture The texture
124 ///
125 /// @return The texture proxy if the rendering backend supports embedder
126 /// provided external textures.
127 ///
128 virtual std::unique_ptr<Texture> CreateExternalTexture(
129 int64_t texture_id,
130 fml::scoped_nsobject<NSObject<FlutterTexture>> texture) = 0;
131
132 //----------------------------------------------------------------------------
133 /// @brief Accessor for the Skia context associated with IOSSurfaces and
134 /// the raster thread.
135 /// @details There can be any number of resource contexts but this is the
136 /// one context that will be used by surfaces to draw to the
137 /// screen from the raster thread.
138 /// @returns `nullptr` on failure.
139 /// @attention The software context doesn't have a Skia context, so this
140 /// value will be nullptr.
141 /// @see For contexts which are used for offscreen work like loading
142 /// textures see IOSContext::CreateResourceContext.
143 ///
144 virtual sk_sp<GrDirectContext> GetMainContext() const = 0;
145
146 virtual std::shared_ptr<impeller::Context> GetImpellerContext() const;
147
148 MsaaSampleCount GetMsaaSampleCount() const { return msaa_samples_; }
149
150 protected:
151 explicit IOSContext(MsaaSampleCount msaa_samples);
152
153 private:
154 MsaaSampleCount msaa_samples_ = MsaaSampleCount::kNone;
155 FML_DISALLOW_COPY_AND_ASSIGN(IOSContext);
156 };
157
158 } // namespace flutter
159
160 #endif // FLUTTER_SHELL_PLATFORM_DARWIN_IOS_IOS_CONTEXT_H_
flutter::IOSContext::~IOSContext
virtual ~IOSContext()
Collects the context object. This must happen on the thread on which this object was created.
FlutterTexture.h
flutter::IOSContext::GetMsaaSampleCount
MsaaSampleCount GetMsaaSampleCount() const
Definition: ios_context.h:148
flutter::IOSContext::IOSContext
IOSContext(MsaaSampleCount msaa_samples)
Definition: ios_context.mm:18
flutter::IOSContext::Create
static std::unique_ptr< IOSContext > Create(IOSRenderingAPI api, IOSRenderingBackend backend, MsaaSampleCount msaa_samples, const std::shared_ptr< const fml::SyncSwitch > &is_gpu_disabled_sync_switch)
Create an iOS context object capable of creating the on-screen and off-screen GPU context for use by ...
Definition: ios_context.mm:22
flutter::IOSContext
Manages the lifetime of the on-screen and off-screen rendering contexts on iOS. On-screen contexts ar...
Definition: ios_context.h:40
flutter::IOSRenderingBackend
IOSRenderingBackend
Definition: rendering_api_selection.h:19
flutter
Definition: accessibility_bridge.h:28
flutter::IOSRenderingAPI
IOSRenderingAPI
Definition: rendering_api_selection.h:14
flutter::IOSContext::MakeCurrent
virtual std::unique_ptr< GLContextResult > MakeCurrent()=0
When using client rendering APIs whose contexts need to be bound to a specific thread,...
flutter::IOSContext::GetBackend
virtual IOSRenderingBackend GetBackend() const
Get the rendering backend used by this context.
Definition: ios_context.mm:51
flutter::IOSContext::GetMainContext
virtual sk_sp< GrDirectContext > GetMainContext() const =0
Accessor for the Skia context associated with IOSSurfaces and the raster thread.
rendering_api_selection.h
flutter::IOSContext::CreateResourceContext
virtual sk_sp< GrDirectContext > CreateResourceContext()=0
Create a resource context for use on the IO task runner. This resource context is used by Skia to upl...
texture_id
int64_t texture_id
Definition: texture_registrar_unittests.cc:24
impeller
Definition: ios_context.h:21
flutter::IOSContext::CreateExternalTexture
virtual std::unique_ptr< Texture > CreateExternalTexture(int64_t texture_id, fml::scoped_nsobject< NSObject< FlutterTexture >> texture)=0
Creates an external texture proxy of the appropriate client rendering API.
flutter::IOSContext::GetImpellerContext
virtual std::shared_ptr< impeller::Context > GetImpellerContext() const
Definition: ios_context.mm:55