1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef GrGLVertexArray_DEFINED
9#define GrGLVertexArray_DEFINED
10
11#include "GrGpuResource.h"
12#include "GrTypesPriv.h"
13#include "gl/GrGLDefines.h"
14#include "gl/GrGLTypes.h"
15#include "SkTArray.h"
16
17class GrBuffer;
18class GrGLGpu;
19
20/**
21 * This sets and tracks the vertex attribute array state. It is used internally by GrGLVertexArray
22 * (below) but is separate because it is also used to track the state of vertex array object 0.
23 */
24class GrGLAttribArrayState {
25public:
26    explicit GrGLAttribArrayState(int arrayCount = 0) {
27        this->resize(arrayCount);
28    }
29
30    void resize(int newCount) {
31        fAttribArrayStates.resize_back(newCount);
32        this->invalidate();
33    }
34
35    /**
36     * This function enables and sets vertex attrib state for the specified attrib index. It is
37     * assumed that the GrGLAttribArrayState is tracking the state of the currently bound vertex
38     * array object.
39     */
40    void set(GrGLGpu*,
41             int attribIndex,
42             const GrBuffer* vertexBuffer,
43             GrVertexAttribType type,
44             GrGLsizei stride,
45             size_t offsetInBytes,
46             int divisor = 0);
47
48    enum class EnablePrimitiveRestart : bool {
49        kYes = true,
50        kNo = false
51    };
52
53    /**
54     * This function enables the first 'enabledCount' vertex arrays and disables the rest.
55     */
56    void enableVertexArrays(const GrGLGpu*, int enabledCount,
57                            EnablePrimitiveRestart = EnablePrimitiveRestart::kNo);
58
59    void invalidate() {
60        int count = fAttribArrayStates.count();
61        for (int i = 0; i < count; ++i) {
62            fAttribArrayStates[i].invalidate();
63        }
64        fEnableStateIsValid = false;
65    }
66
67    /**
68     * The number of attrib arrays that this object is configured to track.
69     */
70    int count() const { return fAttribArrayStates.count(); }
71
72private:
73    static constexpr int kInvalidDivisor = -1;
74
75    /**
76     * Tracks the state of glVertexAttribArray for an attribute index.
77     */
78    struct AttribArrayState {
79        void invalidate() {
80            fVertexBufferUniqueID.makeInvalid();
81            fDivisor = kInvalidDivisor;
82        }
83
84        GrGpuResource::UniqueID   fVertexBufferUniqueID;
85        GrVertexAttribType        fType;
86        GrGLsizei                 fStride;
87        size_t                    fOffset;
88        int                       fDivisor;
89    };
90
91    SkSTArray<16, AttribArrayState, true> fAttribArrayStates;
92    int fNumEnabledArrays;
93    EnablePrimitiveRestart fPrimitiveRestartEnabled;
94    bool fEnableStateIsValid = false;
95};
96
97/**
98 * This class represents an OpenGL vertex array object. It manages the lifetime of the vertex array
99 * and is used to track the state of the vertex array to avoid redundant GL calls.
100 */
101class GrGLVertexArray {
102public:
103    GrGLVertexArray(GrGLint id, int attribCount);
104
105    /**
106     * Binds this vertex array. If the ID has been deleted or abandoned then nullptr is returned.
107     * Otherwise, the GrGLAttribArrayState that is tracking this vertex array's attrib bindings is
108     * returned.
109     */
110    GrGLAttribArrayState* bind(GrGLGpu*);
111
112    /**
113     * This is a version of the above function that also binds an index buffer to the vertex
114     * array object.
115     */
116    GrGLAttribArrayState* bindWithIndexBuffer(GrGLGpu* gpu, const GrBuffer* indexBuffer);
117
118    GrGLuint arrayID() const { return fID; }
119
120    void invalidateCachedState();
121
122private:
123    GrGLuint                  fID;
124    GrGLAttribArrayState      fAttribArrays;
125    GrGpuResource::UniqueID   fIndexBufferUniqueID;
126};
127
128#endif
129