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 "impeller/core/formats.h"
11 
12 namespace impeller {
13 
14 class Capabilities {
15  public:
16  virtual ~Capabilities();
17 
18  /// @brief Whether the context backend supports attaching offscreen MSAA
19  /// color/stencil textures.
20  virtual bool SupportsOffscreenMSAA() const = 0;
21 
22  /// @brief Whether the context backend supports multisampled rendering to
23  /// the on-screen surface without requiring an explicit resolve of
24  /// the MSAA color attachment.
25  virtual bool SupportsImplicitResolvingMSAA() const = 0;
26 
27  /// @brief Whether the context backend supports binding Shader Storage Buffer
28  /// Objects (SSBOs) to pipelines.
29  virtual bool SupportsSSBO() const = 0;
30 
31  /// @brief Whether the context backend supports blitting from one texture
32  /// region to another texture region (via the relevant
33  /// `BlitPass::AddCopy` overloads).
34  virtual bool SupportsTextureToTextureBlits() const = 0;
35 
36  /// @brief Whether the context backend is able to support pipelines with
37  /// shaders that read from the framebuffer (i.e. pixels that have been
38  /// written by previous draw calls in the current render pass).
39  ///
40  /// Example of reading from the first color attachment in a GLSL
41  /// shader:
42  /// ```
43  /// uniform subpassInput subpass_input;
44  ///
45  /// out vec4 frag_color;
46  ///
47  /// void main() {
48  /// vec4 color = subpassLoad(subpass_input);
49  /// // Invert the colors drawn to the framebuffer.
50  /// frag_color = vec4(vec3(1) - color.rgb, color.a);
51  /// }
52  /// ```
53  virtual bool SupportsFramebufferFetch() const = 0;
54 
55  /// @brief Whether the context backend supports `ComputePass`.
56  virtual bool SupportsCompute() const = 0;
57 
58  /// @brief Whether the context backend supports configuring `ComputePass`
59  /// command subgroups.
60  virtual bool SupportsComputeSubgroups() const = 0;
61 
62  /// @brief Whether the context backend supports binding the current
63  /// `RenderPass` attachments. This is supported if the backend can
64  /// guarantee that attachment textures will not be mutated until the
65  /// render pass has fully completed.
66  ///
67  /// This is possible because many mobile graphics cards track
68  /// `RenderPass` attachment state in intermediary tile memory prior to
69  /// Storing the pass in the heap allocated attachments on DRAM.
70  /// Metal's hazard tracking and Vulkan's barriers are granular enough
71  /// to allow for safely accessing attachment textures prior to storage
72  /// in the same `RenderPass`.
73  virtual bool SupportsReadFromResolve() const = 0;
74 
75  /// @brief Whether the context backend supports `SamplerAddressMode::Decal`.
76  virtual bool SupportsDecalSamplerAddressMode() const = 0;
77 
78  /// @brief Whether the context backend supports allocating
79  /// `StorageMode::kDeviceTransient` (aka "memoryless") textures, which
80  /// are temporary textures kept in tile memory for the duration of the
81  /// `RenderPass` it's attached to.
82  ///
83  /// This feature is especially useful for MSAA and stencils.
84  virtual bool SupportsDeviceTransientTextures() const = 0;
85 
86  /// @brief Whether the primitive type TriangleFan is supported by the backend.
87  virtual bool SupportsTriangleFan() const = 0;
88 
89  /// @brief Whether primitive restart is supported.
90  virtual bool SupportsPrimitiveRestart() 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.
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
113 
114  /// @brief Return the maximum size of a render pass attachment.
115  ///
116  /// Note that this may be smaller than the maximum allocatable texture size.
118 
119  /// @brief Whether the XR formats are supported on this device.
120  ///
121  /// This is only ever true for iOS and macOS devices. We may need
122  /// to revisit this API when approaching wide gamut rendering for
123  /// Vulkan and GLES.
124  virtual bool SupportsExtendedRangeFormats() const = 0;
125 
126  /// @brief The minimum alignment of uniform value offsets in bytes.
127  virtual size_t GetMinimumUniformAlignment() const = 0;
128 
129  protected:
131 
132  Capabilities(const Capabilities&) = delete;
133 
135 };
136 
138  public:
140 
142 
144 
146 
148 
150 
152 
154 
156 
158 
160 
162 
164 
166 
168 
170 
172 
174 
176 
177  std::unique_ptr<Capabilities> Build();
178 
179  private:
180  bool supports_offscreen_msaa_ = false;
181  bool supports_ssbo_ = false;
182  bool supports_texture_to_texture_blits_ = false;
183  bool supports_framebuffer_fetch_ = false;
184  bool supports_compute_ = false;
185  bool supports_compute_subgroups_ = false;
186  bool supports_read_from_resolve_ = false;
187  bool supports_decal_sampler_address_mode_ = false;
188  bool supports_device_transient_textures_ = false;
189  bool supports_triangle_fan_ = false;
190  bool supports_extended_range_formats_ = false;
191  std::optional<PixelFormat> default_color_format_ = std::nullopt;
192  std::optional<PixelFormat> default_stencil_format_ = std::nullopt;
193  std::optional<PixelFormat> default_depth_stencil_format_ = std::nullopt;
194  std::optional<PixelFormat> default_glyph_atlas_format_ = std::nullopt;
195  std::optional<ISize> default_maximum_render_pass_attachment_size_ =
196  std::nullopt;
197  size_t minimum_uniform_alignment_ = 256;
198 
199  CapabilitiesBuilder(const CapabilitiesBuilder&) = delete;
200 
201  CapabilitiesBuilder& operator=(const CapabilitiesBuilder&) = delete;
202 };
203 
204 } // namespace impeller
205 
206 #endif // FLUTTER_IMPELLER_RENDERER_CAPABILITIES_H_
CapabilitiesBuilder & SetDefaultColorFormat(PixelFormat value)
CapabilitiesBuilder & SetSupportsComputeSubgroups(bool value)
CapabilitiesBuilder & SetMinimumUniformAlignment(size_t value)
CapabilitiesBuilder & SetSupportsTextureToTextureBlits(bool value)
CapabilitiesBuilder & SetDefaultStencilFormat(PixelFormat value)
CapabilitiesBuilder & SetSupportsDeviceTransientTextures(bool value)
CapabilitiesBuilder & SetSupportsTriangleFan(bool value)
CapabilitiesBuilder & SetSupportsFramebufferFetch(bool value)
CapabilitiesBuilder & SetSupportsDecalSamplerAddressMode(bool value)
CapabilitiesBuilder & SetSupportsOffscreenMSAA(bool value)
CapabilitiesBuilder & SetSupportsSSBO(bool value)
CapabilitiesBuilder & SetMaximumRenderPassAttachmentSize(ISize size)
CapabilitiesBuilder & SetSupportsExtendedRangeFormats(bool value)
CapabilitiesBuilder & SetDefaultGlyphAtlasFormat(PixelFormat value)
CapabilitiesBuilder & SetSupportsCompute(bool value)
std::unique_ptr< Capabilities > Build()
CapabilitiesBuilder & SetDefaultDepthStencilFormat(PixelFormat value)
CapabilitiesBuilder & SetSupportsReadFromResolve(bool value)
virtual PixelFormat GetDefaultStencilFormat() const =0
Returns a supported PixelFormat for textures that store stencil information. May include a depth chan...
virtual size_t GetMinimumUniformAlignment() const =0
The minimum alignment of uniform value offsets in bytes.
virtual bool SupportsOffscreenMSAA() const =0
Whether the context backend supports attaching offscreen MSAA color/stencil textures.
virtual bool SupportsImplicitResolvingMSAA() const =0
Whether the context backend supports multisampled rendering to the on-screen surface without requirin...
virtual bool SupportsFramebufferFetch() const =0
Whether the context backend is able to support pipelines with shaders that read from the framebuffer ...
virtual bool SupportsDecalSamplerAddressMode() const =0
Whether the context backend supports SamplerAddressMode::Decal.
virtual bool SupportsReadFromResolve() const =0
Whether the context backend supports binding the current RenderPass attachments. This is supported if...
virtual bool SupportsTriangleFan() const =0
Whether the primitive type TriangleFan is supported by the backend.
virtual bool SupportsComputeSubgroups() const =0
Whether the context backend supports configuring ComputePass command subgroups.
Capabilities(const Capabilities &)=delete
virtual PixelFormat GetDefaultGlyphAtlasFormat() const =0
Returns the default pixel format for the alpha bitmap glyph atlas.
virtual bool SupportsPrimitiveRestart() const =0
Whether primitive restart is supported.
virtual PixelFormat GetDefaultColorFormat() const =0
Returns a supported PixelFormat for textures that store 4-channel colors (red/green/blue/alpha).
virtual ISize GetMaximumRenderPassAttachmentSize() const =0
Return the maximum size of a render pass attachment.
virtual bool SupportsDeviceTransientTextures() const =0
Whether the context backend supports allocating StorageMode::kDeviceTransient (aka "memoryless") text...
Capabilities & operator=(const Capabilities &)=delete
virtual bool SupportsCompute() const =0
Whether the context backend supports ComputePass.
virtual bool SupportsExtendedRangeFormats() const =0
Whether the XR formats are supported on this device.
virtual bool SupportsSSBO() const =0
Whether the context backend supports binding Shader Storage Buffer Objects (SSBOs) to pipelines.
virtual PixelFormat GetDefaultDepthStencilFormat() const =0
Returns a supported PixelFormat for textures that store both a stencil and depth component....
virtual bool SupportsTextureToTextureBlits() const =0
Whether the context backend supports blitting from one texture region to another texture region (via ...
int32_t value
PixelFormat
The Pixel formats supported by Impeller. The naming convention denotes the usage of the component,...
Definition: formats.h:99