1 //
2 // Copyright 2016 Pixar
3 //
4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
7 // Section 6. Trademarks. is deleted and replaced with:
8 //
9 // 6. Trademarks. This License does not grant permission to use the trade
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11 //    and its affiliates, except as required to comply with Section 4(c) of
12 //    the License and to reproduce the content of the NOTICE file.
13 //
14 // You may obtain a copy of the Apache License at
15 //
16 //     http://www.apache.org/licenses/LICENSE-2.0
17 //
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19 // distributed under the Apache License with the above modification is
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24 #ifndef PXR_IMAGING_HD_RENDER_PASS_H
25 #define PXR_IMAGING_HD_RENDER_PASS_H
26 
27 #include "pxr/pxr.h"
28 #include "pxr/imaging/hd/api.h"
29 #include "pxr/imaging/hd/version.h"
30 #include "pxr/imaging/hd/rprimCollection.h"
31 #include "pxr/imaging/hd/task.h"
32 
33 #include <memory>
34 
35 PXR_NAMESPACE_OPEN_SCOPE
36 
37 class HdRenderIndex;
38 class HdSceneDelegate;
39 
40 using HdRenderPassSharedPtr = std::shared_ptr<class HdRenderPass>;
41 using HdRenderPassStateSharedPtr = std::shared_ptr<class HdRenderPassState>;
42 
43 /// \class HdRenderPass
44 ///
45 /// An abstract class representing a single render iteration over a set of prims
46 /// (the HdRprimCollection), for the camera/viewport parameters in
47 /// HdRenderPassState.
48 ///
49 /// Conceptually, a rendering task may be broken down into one or more
50 /// HdRenderPass(es).
51 ///
52 /// An HdRenderPass has two phases, Sync() and Execute(), in line with Hydra's
53 /// execution phases (See HdEngine::Execute)
54 ///
55 /// The base class implementation of Sync() takes care of syncing collection
56 /// changes with the HdRenderIndex via HdDirtyList, and allows derived classes
57 /// to track collection changes (via _MarkCollectionDirty) and sync additional
58 /// resources (via _Sync)
59 ///
60 /// Renderer backends implement _Execute, wherein the HdDrawItem(s) for the
61 /// collection may be consumed via HdRenderIndex::GetDrawItems.
62 /// Typically, the HdRenderPassState argument of _Execute is made available via
63 /// the HdTaskContext.
64 ///
65 /// \note
66 /// Rendering backends are expected to specialize this abstract class, and
67 /// return the specialized object via HdRenderDelegate::CreateRenderPass
68 ///
69 class HdRenderPass
70 {
71 public:
72     HD_API
73     HdRenderPass(HdRenderIndex *index, HdRprimCollection const& collection);
74     HD_API
75     virtual ~HdRenderPass();
76 
77     /// Returns the HdRprimCollection to be drawn by this RenderPass.
GetRprimCollection()78     HdRprimCollection const& GetRprimCollection() const { return _collection; }
79 
80     /// Sets the HdRprimCollection, note that this may invalidate internal
81     /// caches used to accelerate drawing.
82     HD_API
83     void SetRprimCollection(HdRprimCollection const& col);
84 
85     /// Return the render index
GetRenderIndex()86     HdRenderIndex* GetRenderIndex() const { return _renderIndex; }
87 
88     // ---------------------------------------------------------------------- //
89     /// \name Synchronization
90     // ---------------------------------------------------------------------- //
91 
92     /// Sync the render pass resources
93     HD_API
94     void Sync();
95 
96     // ---------------------------------------------------------------------- //
97     /// \name Execution
98     // ---------------------------------------------------------------------- //
99 
100     /// Execute a subset of buckets of this renderpass.
101     HD_API
102     void Execute(HdRenderPassStateSharedPtr const &renderPassState,
103                  TfTokenVector const &renderTags);
104 
105     // ---------------------------------------------------------------------- //
106     /// \name Optional API hooks for progressive rendering
107     // ---------------------------------------------------------------------- //
108 
IsConverged()109     virtual bool IsConverged() const { return true; }
110 
111 protected:
112     /// Virtual API: Execute the buckets corresponding to renderTags;
113     /// renderTags.empty() implies execute everything.
114     virtual void _Execute(HdRenderPassStateSharedPtr const &renderPassState,
115                          TfTokenVector const &renderTags) = 0;
116 
117     /// Optional API: let derived classes mark their collection tracking as dirty.
_MarkCollectionDirty()118     virtual void _MarkCollectionDirty() {}
119 
120     /// Optional API: let derived classes sync data.
_Sync()121     virtual void _Sync() {}
122 
123 private:
124 
125     // Don't allow copies
126     HdRenderPass(const HdRenderPass &) = delete;
127     HdRenderPass &operator=(const HdRenderPass &) = delete;
128 
129     // ---------------------------------------------------------------------- //
130     // \name Change Tracking State
131     // ---------------------------------------------------------------------- //
132     // The renderIndex to which this renderPass belongs
133     // (can't change after construction)
134     HdRenderIndex * const _renderIndex;
135 
136     // ---------------------------------------------------------------------- //
137     // \name Core RenderPass State
138     // ---------------------------------------------------------------------- //
139     HdRprimCollection _collection;
140 };
141 
142 PXR_NAMESPACE_CLOSE_SCOPE
143 
144 #endif //PXR_IMAGING_HD_RENDER_PASS_H
145