Flutter Impeller
capabilities.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_IMPELLER_RENDERER_CAPABILITIES_H_
6 #define FLUTTER_IMPELLER_RENDERER_CAPABILITIES_H_
7 
8 #include <memory>
9 
10 #include "flutter/fml/macros.h"
11 #include "impeller/core/formats.h"
12 
13 namespace impeller {
14 
15 class Capabilities {
16  public:
17  virtual ~Capabilities();
18 
19  /// @brief Whether the context backend supports attaching offscreen MSAA
20  /// color/stencil textures.
21  virtual bool SupportsOffscreenMSAA() const = 0;
22 
23  /// @brief Whether the context backend supports multisampled rendering to
24  /// the on-screen surface without requiring an explicit resolve of
25  /// the MSAA color attachment.
26  virtual bool SupportsImplicitResolvingMSAA() const = 0;
27 
28  /// @brief Whether the context backend supports binding Shader Storage Buffer
29  /// Objects (SSBOs) to pipelines.
30  virtual bool SupportsSSBO() const = 0;
31 
32  /// @brief Whether the context backend supports blitting from a given
33  /// `DeviceBuffer` view to a texture region (via the relevant
34  /// `BlitPass::AddCopy` overloads).
35  virtual bool SupportsBufferToTextureBlits() const = 0;
36 
37  /// @brief Whether the context backend supports blitting from one texture
38  /// region to another texture region (via the relevant
39  /// `BlitPass::AddCopy` overloads).
40  virtual bool SupportsTextureToTextureBlits() const = 0;
41 
42  /// @brief Whether the context backend is able to support pipelines with
43  /// shaders that read from the framebuffer (i.e. pixels that have been
44  /// written by previous draw calls in the current render pass).
45  ///
46  /// Example of reading from the first color attachment in a GLSL
47  /// shader:
48  /// ```
49  /// uniform subpassInput subpass_input;
50  ///
51  /// out vec4 frag_color;
52  ///
53  /// void main() {
54  /// vec4 color = subpassLoad(subpass_input);
55  /// // Invert the colors drawn to the framebuffer.
56  /// frag_color = vec4(vec3(1) - color.rgb, color.a);
57  /// }
58  /// ```
59  virtual bool SupportsFramebufferFetch() const = 0;
60 
61  /// @brief Whether the context backend supports `ComputePass`.
62  virtual bool SupportsCompute() const = 0;
63 
64  /// @brief Whether the context backend supports configuring `ComputePass`
65  /// command subgroups.
66  virtual bool SupportsComputeSubgroups() const = 0;
67 
68  /// @brief Whether the context backend supports binding the current
69  /// `RenderPass` attachments. This is supported if the backend can
70  /// guarantee that attachment textures will not be mutated until the
71  /// render pass has fully completed.
72  ///
73  /// This is possible because many mobile graphics cards track
74  /// `RenderPass` attachment state in intermediary tile memory prior to
75  /// Storing the pass in the heap allocated attachments on DRAM.
76  /// Metal's hazard tracking and Vulkan's barriers are granular enough
77  /// to allow for safely accessing attachment textures prior to storage
78  /// in the same `RenderPass`.
79  virtual bool SupportsReadFromResolve() const = 0;
80 
81  /// @brief Whether the context backend supports `SamplerAddressMode::Decal`.
82  virtual bool SupportsDecalSamplerAddressMode() const = 0;
83 
84  /// @brief Whether the context backend supports allocating
85  /// `StorageMode::kDeviceTransient` (aka "memoryless") textures, which
86  /// are temporary textures kept in tile memory for the duration of the
87  /// `RenderPass` it's attached to.
88  ///
89  /// This feature is especially useful for MSAA and stencils.
90  virtual bool SupportsDeviceTransientTextures() const = 0;
91 
92  /// @brief Returns a supported `PixelFormat` for textures that store
93  /// 4-channel colors (red/green/blue/alpha).
94  virtual PixelFormat GetDefaultColorFormat() const = 0;
95 
96  /// @brief Returns a supported `PixelFormat` for textures that store stencil
97  /// information. May include a depth channel if a stencil-only format
98  /// is not available.
99  virtual PixelFormat GetDefaultStencilFormat() const = 0;
100 
101  /// @brief Returns a supported `PixelFormat` for textures that store both a
102  /// stencil and depth component. This will never return a depth-only
103  /// or stencil-only texture.
104  /// Returns `PixelFormat::kUnknown` if no suitable depth+stencil
105  /// format was found.
106  virtual PixelFormat GetDefaultDepthStencilFormat() const = 0;
107 
108  /// @brief Returns the default pixel format for the alpha bitmap glyph atlas.
109  ///
110  /// Some backends may use Red channel while others use grey. This
111  /// should not have any impact
112  virtual PixelFormat GetDefaultGlyphAtlasFormat() const = 0;
113 
114  protected:
115  Capabilities();
116 
117  Capabilities(const Capabilities&) = delete;
118 
119  Capabilities& operator=(const Capabilities&) = delete;
120 };
121 
123  public:
125 
127 
129 
131 
133 
135 
137 
139 
141 
143 
145 
147 
149 
151 
153 
155 
156  std::unique_ptr<Capabilities> Build();
157 
158  private:
159  bool supports_offscreen_msaa_ = false;
160  bool supports_ssbo_ = false;
161  bool supports_buffer_to_texture_blits_ = false;
162  bool supports_texture_to_texture_blits_ = false;
163  bool supports_framebuffer_fetch_ = false;
164  bool supports_compute_ = false;
165  bool supports_compute_subgroups_ = false;
166  bool supports_read_from_resolve_ = false;
167  bool supports_decal_sampler_address_mode_ = false;
168  bool supports_device_transient_textures_ = false;
169  std::optional<PixelFormat> default_color_format_ = std::nullopt;
170  std::optional<PixelFormat> default_stencil_format_ = std::nullopt;
171  std::optional<PixelFormat> default_depth_stencil_format_ = std::nullopt;
172  std::optional<PixelFormat> default_glyph_atlas_format_ = std::nullopt;
173 
174  CapabilitiesBuilder(const CapabilitiesBuilder&) = delete;
175 
176  CapabilitiesBuilder& operator=(const CapabilitiesBuilder&) = delete;
177 };
178 
179 } // namespace impeller
180 
181 #endif // FLUTTER_IMPELLER_RENDERER_CAPABILITIES_H_
impeller::CapabilitiesBuilder::CapabilitiesBuilder
CapabilitiesBuilder()
impeller::CapabilitiesBuilder::Build
std::unique_ptr< Capabilities > Build()
Definition: capabilities.cc:226
impeller::Capabilities::SupportsReadFromResolve
virtual bool SupportsReadFromResolve() const =0
Whether the context backend supports binding the current RenderPass attachments. This is supported if...
impeller::Capabilities::SupportsOffscreenMSAA
virtual bool SupportsOffscreenMSAA() const =0
Whether the context backend supports attaching offscreen MSAA color/stencil textures.
impeller::Capabilities::SupportsDeviceTransientTextures
virtual bool SupportsDeviceTransientTextures() const =0
Whether the context backend supports allocating StorageMode::kDeviceTransient (aka "memoryless") text...
formats.h
impeller::CapabilitiesBuilder
Definition: capabilities.h:122
impeller::PixelFormat
PixelFormat
The Pixel formats supported by Impeller. The naming convention denotes the usage of the component,...
Definition: formats.h:100
impeller::Capabilities
Definition: capabilities.h:15
impeller::CapabilitiesBuilder::SetSupportsSSBO
CapabilitiesBuilder & SetSupportsSSBO(bool value)
Definition: capabilities.cc:150
impeller::CapabilitiesBuilder::SetSupportsCompute
CapabilitiesBuilder & SetSupportsCompute(bool value)
Definition: capabilities.cc:173
impeller::CapabilitiesBuilder::SetDefaultDepthStencilFormat
CapabilitiesBuilder & SetDefaultDepthStencilFormat(PixelFormat value)
Definition: capabilities.cc:196
impeller::CapabilitiesBuilder::SetDefaultGlyphAtlasFormat
CapabilitiesBuilder & SetDefaultGlyphAtlasFormat(PixelFormat value)
Definition: capabilities.cc:220
impeller::Capabilities::SupportsImplicitResolvingMSAA
virtual bool SupportsImplicitResolvingMSAA() const =0
Whether the context backend supports multisampled rendering to the on-screen surface without requirin...
impeller::CapabilitiesBuilder::SetSupportsFramebufferFetch
CapabilitiesBuilder & SetSupportsFramebufferFetch(bool value)
Definition: capabilities.cc:167
impeller::CapabilitiesBuilder::~CapabilitiesBuilder
~CapabilitiesBuilder()
impeller::CapabilitiesBuilder::SetSupportsComputeSubgroups
CapabilitiesBuilder & SetSupportsComputeSubgroups(bool value)
Definition: capabilities.cc:178
impeller::Capabilities::SupportsBufferToTextureBlits
virtual bool SupportsBufferToTextureBlits() const =0
Whether the context backend supports blitting from a given DeviceBuffer view to a texture region (via...
impeller::Capabilities::Capabilities
Capabilities()
impeller::CapabilitiesBuilder::SetSupportsTextureToTextureBlits
CapabilitiesBuilder & SetSupportsTextureToTextureBlits(bool value)
Definition: capabilities.cc:161
impeller::Capabilities::operator=
Capabilities & operator=(const Capabilities &)=delete
impeller::Capabilities::GetDefaultGlyphAtlasFormat
virtual PixelFormat GetDefaultGlyphAtlasFormat() const =0
Returns the default pixel format for the alpha bitmap glyph atlas.
impeller::Capabilities::GetDefaultStencilFormat
virtual PixelFormat GetDefaultStencilFormat() const =0
Returns a supported PixelFormat for textures that store stencil information. May include a depth chan...
impeller::CapabilitiesBuilder::SetDefaultColorFormat
CapabilitiesBuilder & SetDefaultColorFormat(PixelFormat value)
Definition: capabilities.cc:184
impeller::CapabilitiesBuilder::SetDefaultStencilFormat
CapabilitiesBuilder & SetDefaultStencilFormat(PixelFormat value)
Definition: capabilities.cc:190
impeller::CapabilitiesBuilder::SetSupportsBufferToTextureBlits
CapabilitiesBuilder & SetSupportsBufferToTextureBlits(bool value)
Definition: capabilities.cc:155
impeller::Capabilities::~Capabilities
virtual ~Capabilities()
impeller::CapabilitiesBuilder::SetSupportsDecalSamplerAddressMode
CapabilitiesBuilder & SetSupportsDecalSamplerAddressMode(bool value)
Definition: capabilities.cc:208
impeller::Capabilities::SupportsComputeSubgroups
virtual bool SupportsComputeSubgroups() const =0
Whether the context backend supports configuring ComputePass command subgroups.
impeller::CapabilitiesBuilder::SetSupportsDeviceTransientTextures
CapabilitiesBuilder & SetSupportsDeviceTransientTextures(bool value)
Definition: capabilities.cc:214
impeller::Capabilities::GetDefaultColorFormat
virtual PixelFormat GetDefaultColorFormat() const =0
Returns a supported PixelFormat for textures that store 4-channel colors (red/green/blue/alpha).
impeller::Capabilities::SupportsDecalSamplerAddressMode
virtual bool SupportsDecalSamplerAddressMode() const =0
Whether the context backend supports SamplerAddressMode::Decal.
impeller::Capabilities::SupportsFramebufferFetch
virtual bool SupportsFramebufferFetch() const =0
Whether the context backend is able to support pipelines with shaders that read from the framebuffer ...
impeller::Capabilities::SupportsSSBO
virtual bool SupportsSSBO() const =0
Whether the context backend supports binding Shader Storage Buffer Objects (SSBOs) to pipelines.
impeller
Definition: aiks_blur_unittests.cc:20
impeller::CapabilitiesBuilder::SetSupportsReadFromResolve
CapabilitiesBuilder & SetSupportsReadFromResolve(bool value)
Definition: capabilities.cc:202
impeller::Capabilities::SupportsTextureToTextureBlits
virtual bool SupportsTextureToTextureBlits() const =0
Whether the context backend supports blitting from one texture region to another texture region (via ...
impeller::CapabilitiesBuilder::SetSupportsOffscreenMSAA
CapabilitiesBuilder & SetSupportsOffscreenMSAA(bool value)
Definition: capabilities.cc:145
impeller::Capabilities::GetDefaultDepthStencilFormat
virtual PixelFormat GetDefaultDepthStencilFormat() const =0
Returns a supported PixelFormat for textures that store both a stencil and depth component....
impeller::Capabilities::SupportsCompute
virtual bool SupportsCompute() const =0
Whether the context backend supports ComputePass.