1//
2// Copyright (c) 2002-2012 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
7#include "compiler/translator/VersionGLSL.h"
8
9static const int GLSL_VERSION_110 = 110;
10static const int GLSL_VERSION_120 = 120;
11
12// We need to scan for the following:
13// 1. "invariant" keyword: This can occur in both - vertex and fragment shaders
14//    but only at the global scope.
15// 2. "gl_PointCoord" built-in variable: This can only occur in fragment shader
16//    but inside any scope.
17// 3. Call to a matrix constructor with another matrix as argument.
18//    (These constructors were reserved in GLSL version 1.10.)
19// 4. Arrays as "out" function parameters.
20//    GLSL spec section 6.1.1: "When calling a function, expressions that do
21//    not evaluate to l-values cannot be passed to parameters declared as
22//    out or inout."
23//    GLSL 1.1 section 5.8: "Other binary or unary expressions,
24//    non-dereferenced arrays, function names, swizzles with repeated fields,
25//    and constants cannot be l-values."
26//    GLSL 1.2 relaxed the restriction on arrays, section 5.8: "Variables that
27//    are built-in types, entire structures or arrays... are all l-values."
28//
29// TODO(alokp): The following two cases of invariant decalaration get lost
30// during parsing - they do not get carried over to the intermediate tree.
31// Handle these cases:
32// 1. When a pragma is used to force all output variables to be invariant:
33//    - #pragma STDGL invariant(all)
34// 2. When a previously decalared or built-in variable is marked invariant:
35//    - invariant gl_Position;
36//    - varying vec3 color; invariant color;
37//
38TVersionGLSL::TVersionGLSL(sh::GLenum type)
39    : mVersion(GLSL_VERSION_110)
40{
41}
42
43void TVersionGLSL::visitSymbol(TIntermSymbol *node)
44{
45    if (node->getSymbol() == "gl_PointCoord")
46        updateVersion(GLSL_VERSION_120);
47}
48
49bool TVersionGLSL::visitAggregate(Visit, TIntermAggregate *node)
50{
51    bool visitChildren = true;
52
53    switch (node->getOp())
54    {
55      case EOpSequence:
56        // We need to visit sequence children to get to global or inner scope.
57        visitChildren = true;
58        break;
59      case EOpDeclaration:
60        {
61            const TIntermSequence &sequence = *(node->getSequence());
62            TQualifier qualifier = sequence.front()->getAsTyped()->getQualifier();
63            if ((qualifier == EvqInvariantVaryingIn) ||
64                (qualifier == EvqInvariantVaryingOut))
65            {
66                updateVersion(GLSL_VERSION_120);
67            }
68            break;
69        }
70      case EOpInvariantDeclaration:
71        updateVersion(GLSL_VERSION_120);
72        break;
73      case EOpParameters:
74        {
75            const TIntermSequence &params = *(node->getSequence());
76            for (TIntermSequence::const_iterator iter = params.begin();
77                 iter != params.end(); ++iter)
78            {
79                const TIntermTyped *param = (*iter)->getAsTyped();
80                if (param->isArray())
81                {
82                    TQualifier qualifier = param->getQualifier();
83                    if ((qualifier == EvqOut) || (qualifier ==  EvqInOut))
84                    {
85                        updateVersion(GLSL_VERSION_120);
86                        break;
87                    }
88                }
89            }
90            // Fully processed. No need to visit children.
91            visitChildren = false;
92            break;
93        }
94      case EOpConstructMat2:
95      case EOpConstructMat3:
96      case EOpConstructMat4:
97        {
98            const TIntermSequence &sequence = *(node->getSequence());
99            if (sequence.size() == 1)
100            {
101                TIntermTyped *typed = sequence.front()->getAsTyped();
102                if (typed && typed->isMatrix())
103                {
104                    updateVersion(GLSL_VERSION_120);
105                }
106            }
107            break;
108        }
109      default:
110        break;
111    }
112
113    return visitChildren;
114}
115
116void TVersionGLSL::updateVersion(int version)
117{
118    mVersion = std::max(version, mVersion);
119}
120
121