Flutter Impeller
command.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_COMMAND_H_
6 #define FLUTTER_IMPELLER_RENDERER_COMMAND_H_
7 
8 #include <cstdint>
9 #include <memory>
10 #include <optional>
11 #include <string>
12 
14 #include "impeller/core/formats.h"
15 #include "impeller/core/sampler.h"
17 #include "impeller/core/texture.h"
18 #include "impeller/geometry/rect.h"
20 
21 namespace impeller {
22 
23 template <class T>
24 class Resource {
25  public:
26  using ResourceType = T;
28 
29  Resource() {}
30 
31  Resource(const ShaderMetadata* metadata, ResourceType p_resource)
32  : resource(p_resource), metadata_(metadata) {}
33 
34  const ShaderMetadata* GetMetadata() const {
35  return dynamic_metadata_ ? dynamic_metadata_.get() : metadata_;
36  }
37 
38  static Resource MakeDynamic(std::unique_ptr<ShaderMetadata> metadata,
39  ResourceType p_resource) {
40  return Resource(std::move(metadata), p_resource);
41  }
42 
43  private:
44  Resource(std::unique_ptr<ShaderMetadata> metadata, ResourceType p_resource)
45  : resource(p_resource), dynamic_metadata_(std::move(metadata)) {}
46 
47  // Static shader metadata (typically generated by ImpellerC).
48  const ShaderMetadata* metadata_ = nullptr;
49 
50  // Dynamically generated shader metadata.
51  std::unique_ptr<const ShaderMetadata> dynamic_metadata_ = nullptr;
52 };
53 
56 
57 /// @brief combines the texture, sampler and sampler slot information.
63 };
64 
65 //------------------------------------------------------------------------------
66 /// @brief An object used to specify work to the GPU along with references
67 /// to resources the GPU will used when doing said work.
68 ///
69 /// To construct a valid command, follow these steps:
70 /// * Specify a valid pipeline.
71 /// * Specify vertex information via a call `BindVertices`
72 /// * Specify any stage bindings.
73 /// * (Optional) Specify a debug label.
74 ///
75 /// Command can be created frequently and on demand. The resources
76 /// referenced in commands views into buffers managed by other
77 /// allocators and resource managers.
78 ///
79 struct Command {
80  //----------------------------------------------------------------------------
81  /// The pipeline to use for this command.
82  ///
84 
85  /// An offset into render pass storage where bound buffers/texture metadata is
86  /// stored.
89 
90 #ifdef IMPELLER_DEBUG
91  //----------------------------------------------------------------------------
92  /// The debugging label to use for the command.
93  ///
94  std::string label;
95 #endif // IMPELLER_DEBUG
96 
97  //----------------------------------------------------------------------------
98  /// The reference value to use in stenciling operations. Stencil configuration
99  /// is part of pipeline setup and can be read from the pipelines descriptor.
100  ///
101  /// @see `Pipeline`
102  /// @see `PipelineDescriptor`
103  ///
104  uint32_t stencil_reference = 0u;
105  //----------------------------------------------------------------------------
106  /// The offset used when indexing into the vertex buffer.
107  ///
108  uint64_t base_vertex = 0u;
109  //----------------------------------------------------------------------------
110  /// The viewport coordinates that the rasterizer linearly maps normalized
111  /// device coordinates to.
112  /// If unset, the viewport is the size of the render target with a zero
113  /// origin, znear=0, and zfar=1.
114  ///
115  std::optional<Viewport> viewport;
116  //----------------------------------------------------------------------------
117  /// The scissor rect to use for clipping writes to the render target. The
118  /// scissor rect must lie entirely within the render target.
119  /// If unset, no scissor is applied.
120  ///
121  std::optional<IRect> scissor;
122  //----------------------------------------------------------------------------
123  /// The number of instances of the given set of vertices to render. Not all
124  /// backends support rendering more than one instance at a time.
125  ///
126  /// @warning Setting this to more than one will limit the availability of
127  /// backends to use with this command.
128  ///
129  size_t instance_count = 1u;
130 
131  //----------------------------------------------------------------------------
132  /// An offset and range of vertex buffers bound for this draw call.
133  ///
134  /// The vertex buffers are stored on the render pass object.
136 
137  //----------------------------------------------------------------------------
138  /// The index buffer binding used by the vertex shader stage.
140 
141  //----------------------------------------------------------------------------
142  /// The number of elements to draw. When only a vertex buffer is set, this is
143  /// the vertex count. When an index buffer is set, this is the index count.
144  size_t element_count = 0u;
145 
146  //----------------------------------------------------------------------------
147  /// The type of indices in the index buffer. The indices must be tightly
148  /// packed in the index buffer.
150 
151  bool IsValid() const { return pipeline && pipeline->IsValid(); }
152 };
153 
154 } // namespace impeller
155 
156 #endif // FLUTTER_IMPELLER_RENDERER_COMMAND_H_
virtual bool IsValid() const =0
static Resource MakeDynamic(std::unique_ptr< ShaderMetadata > metadata, ResourceType p_resource)
Definition: command.h:38
const ShaderMetadata * GetMetadata() const
Definition: command.h:34
Resource(const ShaderMetadata *metadata, ResourceType p_resource)
Definition: command.h:31
ResourceType resource
Definition: command.h:27
A wrapper around a raw ptr that adds additional unopt mode only checks.
Definition: raw_ptr.h:15
Definition: comparable.h:95
An object used to specify work to the GPU along with references to resources the GPU will used when d...
Definition: command.h:79
Range bound_textures
Definition: command.h:88
uint64_t base_vertex
Definition: command.h:108
uint32_t stencil_reference
Definition: command.h:104
BufferView index_buffer
The index buffer binding used by the vertex shader stage.
Definition: command.h:139
std::optional< Viewport > viewport
Definition: command.h:115
Range vertex_buffers
Definition: command.h:135
Range bound_buffers
Definition: command.h:87
PipelineRef pipeline
Definition: command.h:83
std::optional< IRect > scissor
Definition: command.h:121
IndexType index_type
Definition: command.h:149
size_t element_count
Definition: command.h:144
bool IsValid() const
Definition: command.h:151
size_t instance_count
Definition: command.h:129
Metadata required to bind a combined texture and sampler.
Definition: shader_types.h:98
combines the texture, sampler and sampler slot information.
Definition: command.h:58
raw_ptr< const Sampler > sampler
Definition: command.h:62
SampledImageSlot slot
Definition: command.h:59
TextureResource texture
Definition: command.h:61