1//
2// Copyright (c) 2013-2014 The ANGLE Project Authors. All rights reserved.
3// Use of this source code is governed by a BSD-style license that can be
4// found in the LICENSE file.
5//
6// blocklayout.h:
7//   Methods and classes related to uniform layout and packing in GLSL and HLSL.
8//
9
10#ifndef COMMON_BLOCKLAYOUT_H_
11#define COMMON_BLOCKLAYOUT_H_
12
13#include <cstddef>
14#include <vector>
15
16#include "angle_gl.h"
17#include <GLSLANG/ShaderLang.h>
18
19namespace sh
20{
21struct ShaderVariable;
22struct InterfaceBlockField;
23struct Uniform;
24struct Varying;
25struct InterfaceBlock;
26
27struct BlockMemberInfo
28{
29    BlockMemberInfo(int offset, int arrayStride, int matrixStride, bool isRowMajorMatrix)
30        : offset(offset),
31          arrayStride(arrayStride),
32          matrixStride(matrixStride),
33          isRowMajorMatrix(isRowMajorMatrix)
34    {}
35
36    static BlockMemberInfo getDefaultBlockInfo()
37    {
38        return BlockMemberInfo(-1, -1, -1, false);
39    }
40
41    int offset;
42    int arrayStride;
43    int matrixStride;
44    bool isRowMajorMatrix;
45};
46
47class BlockLayoutEncoder
48{
49  public:
50    BlockLayoutEncoder();
51
52    BlockMemberInfo encodeType(GLenum type, unsigned int arraySize, bool isRowMajorMatrix);
53
54    size_t getBlockSize() const { return mCurrentOffset * BytesPerComponent; }
55    size_t getCurrentRegister() const { return mCurrentOffset / ComponentsPerRegister; }
56    size_t getCurrentElement() const { return mCurrentOffset % ComponentsPerRegister; }
57
58    virtual void enterAggregateType() = 0;
59    virtual void exitAggregateType() = 0;
60
61    static const size_t BytesPerComponent = 4u;
62    static const unsigned int ComponentsPerRegister = 4u;
63
64  protected:
65    size_t mCurrentOffset;
66
67    void nextRegister();
68
69    virtual void getBlockLayoutInfo(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int *arrayStrideOut, int *matrixStrideOut) = 0;
70    virtual void advanceOffset(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int arrayStride, int matrixStride) = 0;
71};
72
73// Block layout according to the std140 block layout
74// See "Standard Uniform Block Layout" in Section 2.11.6 of the OpenGL ES 3.0 specification
75
76class Std140BlockEncoder : public BlockLayoutEncoder
77{
78  public:
79    Std140BlockEncoder();
80
81    virtual void enterAggregateType();
82    virtual void exitAggregateType();
83
84  protected:
85    virtual void getBlockLayoutInfo(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int *arrayStrideOut, int *matrixStrideOut);
86    virtual void advanceOffset(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int arrayStride, int matrixStride);
87};
88
89// Block layout packed according to the D3D9 or default D3D10+ register packing rules
90// See http://msdn.microsoft.com/en-us/library/windows/desktop/bb509632(v=vs.85).aspx
91// The strategy should be ENCODE_LOOSE for D3D9 constant blocks, and ENCODE_PACKED
92// for everything else (D3D10+ constant blocks and all attributes/varyings).
93
94class HLSLBlockEncoder : public BlockLayoutEncoder
95{
96  public:
97    enum HLSLBlockEncoderStrategy
98    {
99        ENCODE_PACKED,
100        ENCODE_LOOSE
101    };
102
103    HLSLBlockEncoder(HLSLBlockEncoderStrategy strategy);
104
105    virtual void enterAggregateType();
106    virtual void exitAggregateType();
107    void skipRegisters(unsigned int numRegisters);
108
109    bool isPacked() const { return mEncoderStrategy == ENCODE_PACKED; }
110
111    static HLSLBlockEncoderStrategy GetStrategyFor(ShShaderOutput outputType);
112
113  protected:
114    virtual void getBlockLayoutInfo(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int *arrayStrideOut, int *matrixStrideOut);
115    virtual void advanceOffset(GLenum type, unsigned int arraySize, bool isRowMajorMatrix, int arrayStride, int matrixStride);
116
117    HLSLBlockEncoderStrategy mEncoderStrategy;
118};
119
120// This method returns the number of used registers for a ShaderVariable. It is dependent on the HLSLBlockEncoder
121// class to count the number of used registers in a struct (which are individually packed according to the same rules).
122unsigned int HLSLVariableRegisterCount(const Varying &variable);
123unsigned int HLSLVariableRegisterCount(const Uniform &variable, ShShaderOutput outputType);
124
125}
126
127#endif // COMMON_BLOCKLAYOUT_H_
128