summaryrefslogtreecommitdiffstats
path: root/gfx/angle/checkout/src/libANGLE/VertexAttribute.cpp
blob: f525addbba46cbfd0312dff10d468dd4e3f6277a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
//
// Copyright 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// Implementation of the state classes for mananging GLES 3.1 Vertex Array Objects.
//

#include "libANGLE/VertexAttribute.h"

namespace gl
{

// [OpenGL ES 3.1] (November 3, 2016) Section 20 Page 361
// Table 20.2: Vertex Array Object State
VertexBinding::VertexBinding() : VertexBinding(0) {}

VertexBinding::VertexBinding(GLuint boundAttribute) : mStride(16u), mDivisor(0), mOffset(0)
{
    mBoundAttributesMask.set(boundAttribute);
}

VertexBinding::VertexBinding(VertexBinding &&binding)
{
    *this = std::move(binding);
}

VertexBinding::~VertexBinding() {}

VertexBinding &VertexBinding::operator=(VertexBinding &&binding)
{
    if (this != &binding)
    {
        mStride              = binding.mStride;
        mDivisor             = binding.mDivisor;
        mOffset              = binding.mOffset;
        mBoundAttributesMask = binding.mBoundAttributesMask;
        std::swap(binding.mBuffer, mBuffer);
    }
    return *this;
}

void VertexBinding::onContainerBindingChanged(const Context *context, int incr) const
{
    if (mBuffer.get())
        mBuffer->onNonTFBindingChanged(incr);
}

VertexAttribute::VertexAttribute(GLuint bindingIndex)
    : enabled(false),
      format(&angle::Format::Get(angle::FormatID::R32G32B32A32_FLOAT)),
      pointer(nullptr),
      relativeOffset(0),
      vertexAttribArrayStride(0),
      bindingIndex(bindingIndex),
      mCachedElementLimit(0)
{}

VertexAttribute::VertexAttribute(VertexAttribute &&attrib)
    : enabled(attrib.enabled),
      format(attrib.format),
      pointer(attrib.pointer),
      relativeOffset(attrib.relativeOffset),
      vertexAttribArrayStride(attrib.vertexAttribArrayStride),
      bindingIndex(attrib.bindingIndex),
      mCachedElementLimit(attrib.mCachedElementLimit)
{}

VertexAttribute &VertexAttribute::operator=(VertexAttribute &&attrib)
{
    if (this != &attrib)
    {
        enabled                 = attrib.enabled;
        format                  = attrib.format;
        pointer                 = attrib.pointer;
        relativeOffset          = attrib.relativeOffset;
        vertexAttribArrayStride = attrib.vertexAttribArrayStride;
        bindingIndex            = attrib.bindingIndex;
        mCachedElementLimit     = attrib.mCachedElementLimit;
    }
    return *this;
}

void VertexAttribute::updateCachedElementLimit(const VertexBinding &binding)
{
    Buffer *buffer = binding.getBuffer().get();
    if (!buffer)
    {
        mCachedElementLimit = 0;
        return;
    }

    angle::CheckedNumeric<GLint64> bufferSize(buffer->getSize());
    angle::CheckedNumeric<GLint64> bufferOffset(binding.getOffset());
    angle::CheckedNumeric<GLint64> attribOffset(relativeOffset);
    angle::CheckedNumeric<GLint64> attribSize(ComputeVertexAttributeTypeSize(*this));

    // (buffer.size - buffer.offset - attrib.relativeOffset - attrib.size) / binding.stride
    angle::CheckedNumeric<GLint64> elementLimit =
        (bufferSize - bufferOffset - attribOffset - attribSize);

    // Use the special integer overflow value if there was a math error.
    if (!elementLimit.IsValid())
    {
        static_assert(kIntegerOverflow < 0, "Unexpected value");
        mCachedElementLimit = kIntegerOverflow;
        return;
    }

    mCachedElementLimit = elementLimit.ValueOrDie();
    if (mCachedElementLimit < 0)
    {
        return;
    }

    if (binding.getStride() == 0)
    {
        // Special case for a zero stride. If we can fit one vertex we can fit infinite vertices.
        mCachedElementLimit = std::numeric_limits<GLint64>::max();
        return;
    }

    angle::CheckedNumeric<GLint64> bindingStride(binding.getStride());
    elementLimit /= bindingStride;

    if (binding.getDivisor() > 0)
    {
        // For instanced draws, the element count is floor(instanceCount - 1) / binding.divisor.
        angle::CheckedNumeric<GLint64> bindingDivisor(binding.getDivisor());
        elementLimit *= bindingDivisor;

        // We account for the floor() part rounding by adding a rounding constant.
        elementLimit += bindingDivisor - 1;
    }

    mCachedElementLimit = elementLimit.ValueOrDefault(kIntegerOverflow);
}

size_t ComputeVertexAttributeStride(const VertexAttribute &attrib, const VertexBinding &binding)
{
    // In ES 3.1, VertexAttribPointer will store the type size in the binding stride.
    // Hence, rendering always uses the binding's stride.
    return attrib.enabled ? binding.getStride() : 16u;
}

// Warning: you should ensure binding really matches attrib.bindingIndex before using this function.
GLintptr ComputeVertexAttributeOffset(const VertexAttribute &attrib, const VertexBinding &binding)
{
    return attrib.relativeOffset + binding.getOffset();
}

size_t ComputeVertexBindingElementCount(GLuint divisor, size_t drawCount, size_t instanceCount)
{
    // For instanced rendering, we draw "instanceDrawCount" sets of "vertexDrawCount" vertices.
    //
    // A vertex attribute with a positive divisor loads one instanced vertex for every set of
    // non-instanced vertices, and the instanced vertex index advances once every "mDivisor"
    // instances.
    if (instanceCount > 0 && divisor > 0)
    {
        // When instanceDrawCount is not a multiple attrib.divisor, the division must round up.
        // For instance, with 5 non-instanced vertices and a divisor equal to 3, we need 2 instanced
        // vertices.
        return (instanceCount + divisor - 1u) / divisor;
    }

    return drawCount;
}

}  // namespace gl