TranslatorGLSL.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
src/compiler/translator/TranslatorGLSL.cpp
//
// Copyright 2002 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.
//

#include "compiler/translator/TranslatorGLSL.h"

#include "angle_gl.h"
#include "compiler/translator/BuiltInFunctionEmulatorGLSL.h"
#include "compiler/translator/ExtensionGLSL.h"
#include "compiler/translator/OutputGLSL.h"
#include "compiler/translator/VersionGLSL.h"
#include "compiler/translator/tree_ops/EmulatePrecision.h"
#include "compiler/translator/tree_ops/RewriteTexelFetchOffset.h"
#include "compiler/translator/tree_ops/RewriteUnaryMinusOperatorFloat.h"

namespace sh
{

TranslatorGLSL::TranslatorGLSL(sh::GLenum type, ShShaderSpec spec, ShShaderOutput output)
    : TCompiler(type, spec, output)
{}

void TranslatorGLSL::initBuiltInFunctionEmulator(BuiltInFunctionEmulator *emu,
                                                 ShCompileOptions compileOptions)
{
    if (compileOptions & SH_EMULATE_ABS_INT_FUNCTION)
    {
        InitBuiltInAbsFunctionEmulatorForGLSLWorkarounds(emu, getShaderType());
    }

    if (compileOptions & SH_EMULATE_ISNAN_FLOAT_FUNCTION)
    {
        InitBuiltInIsnanFunctionEmulatorForGLSLWorkarounds(emu, getShaderVersion());
    }

    if (compileOptions & SH_EMULATE_ATAN2_FLOAT_FUNCTION)
    {
        InitBuiltInAtanFunctionEmulatorForGLSLWorkarounds(emu);
    }

    int targetGLSLVersion = ShaderOutputTypeToGLSLVersion(getOutputType());
    InitBuiltInFunctionEmulatorForGLSLMissingFunctions(emu, getShaderType(), targetGLSLVersion);
}

void TranslatorGLSL::translate(TIntermBlock *root,
                               ShCompileOptions compileOptions,
                               PerformanceDiagnostics * /*perfDiagnostics*/)
{
    TInfoSinkBase &sink = getInfoSink().obj;

    // Write GLSL version.
    writeVersion(root);

    // Write extension behaviour as needed
    writeExtensionBehavior(root, compileOptions);

    // Write pragmas after extensions because some drivers consider pragmas
    // like non-preprocessor tokens.
    writePragma(compileOptions);

    // If flattening the global invariant pragma, write invariant declarations for built-in
    // variables. It should be harmless to do this twice in the case that the shader also explicitly
    // did this. However, it's important to emit invariant qualifiers only for those built-in
    // variables that are actually used, to avoid affecting the behavior of the shader.
    if ((compileOptions & SH_FLATTEN_PRAGMA_STDGL_INVARIANT_ALL) != 0 &&
        getPragma().stdgl.invariantAll &&
        !sh::RemoveInvariant(getShaderType(), getShaderVersion(), getOutputType(), compileOptions))
    {
        ASSERT(wereVariablesCollected());

        switch (getShaderType())
        {
            case GL_VERTEX_SHADER:
                sink << "invariant gl_Position;\n";

                // gl_PointSize should be declared invariant in both ESSL 1.00 and 3.00 fragment
                // shaders if it's statically referenced.
                conditionallyOutputInvariantDeclaration("gl_PointSize");
                break;
            case GL_FRAGMENT_SHADER:
                // The preprocessor will reject this pragma if it's used in ESSL 3.00 fragment
                // shaders, so we can use simple logic to determine whether to declare these
                // variables invariant.
                conditionallyOutputInvariantDeclaration("gl_FragCoord");
                conditionallyOutputInvariantDeclaration("gl_PointCoord");
                break;
            default:
                // Currently not reached, but leave this in for future expansion.
                ASSERT(false);
                break;
        }
    }

    if ((compileOptions & SH_REWRITE_TEXELFETCHOFFSET_TO_TEXELFETCH) != 0)
    {
        sh::RewriteTexelFetchOffset(root, getSymbolTable(), getShaderVersion());
    }

    if ((compileOptions & SH_REWRITE_FLOAT_UNARY_MINUS_OPERATOR) != 0)
    {
        sh::RewriteUnaryMinusOperatorFloat(root);
    }

    bool precisionEmulation =
        getResources().WEBGL_debug_shader_precision && getPragma().debugShaderPrecision;

    if (precisionEmulation)
    {
        EmulatePrecision emulatePrecision(&getSymbolTable());
        root->traverse(&emulatePrecision);
        emulatePrecision.updateTree();
        emulatePrecision.writeEmulationHelpers(sink, getShaderVersion(), getOutputType());
    }

    // Write emulated built-in functions if needed.
    if (!getBuiltInFunctionEmulator().isOutputEmpty())
    {
        sink << "// BEGIN: Generated code for built-in function emulation\n\n";
        sink << "#define emu_precision\n\n";
        getBuiltInFunctionEmulator().outputEmulatedFunctions(sink);
        sink << "// END: Generated code for built-in function emulation\n\n";
    }

    // Write array bounds clamping emulation if needed.
    getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);

    // Declare gl_FragColor and glFragData as webgl_FragColor and webgl_FragData
    // if it's core profile shaders and they are used.
    if (getShaderType() == GL_FRAGMENT_SHADER)
    {
        const bool mayHaveESSL1SecondaryOutputs =
            IsExtensionEnabled(getExtensionBehavior(), TExtension::EXT_blend_func_extended) &&
            getShaderVersion() == 100;
        const bool declareGLFragmentOutputs = IsGLSL130OrNewer(getOutputType());

        bool hasGLFragColor          = false;
        bool hasGLFragData           = false;
        bool hasGLSecondaryFragColor = false;
        bool hasGLSecondaryFragData  = false;

        for (const auto &outputVar : mOutputVariables)
        {
            if (declareGLFragmentOutputs)
            {
                if (outputVar.name == "gl_FragColor")
                {
                    ASSERT(!hasGLFragColor);
                    hasGLFragColor = true;
                    continue;
                }
                else if (outputVar.name == "gl_FragData")
                {
                    ASSERT(!hasGLFragData);
                    hasGLFragData = true;
                    continue;
                }
            }
            if (mayHaveESSL1SecondaryOutputs)
            {
                if (outputVar.name == "gl_SecondaryFragColorEXT")
                {
                    ASSERT(!hasGLSecondaryFragColor);
                    hasGLSecondaryFragColor = true;
                    continue;
                }
                else if (outputVar.name == "gl_SecondaryFragDataEXT")
                {
                    ASSERT(!hasGLSecondaryFragData);
                    hasGLSecondaryFragData = true;
                    continue;
                }
            }
        }
        ASSERT(!((hasGLFragColor || hasGLSecondaryFragColor) &&
                 (hasGLFragData || hasGLSecondaryFragData)));
        if (hasGLFragColor)
        {
            sink << "out vec4 webgl_FragColor;\n";
        }
        if (hasGLFragData)
        {
            sink << "out vec4 webgl_FragData[gl_MaxDrawBuffers];\n";
        }
        if (hasGLSecondaryFragColor)
        {
            sink << "out vec4 angle_SecondaryFragColor;\n";
        }
        if (hasGLSecondaryFragData)
        {
            sink << "out vec4 angle_SecondaryFragData[" << getResources().MaxDualSourceDrawBuffers
                 << "];\n";
        }
    }

    if (getShaderType() == GL_COMPUTE_SHADER)
    {
        EmitWorkGroupSizeGLSL(*this, sink);
    }

    if (getShaderType() == GL_GEOMETRY_SHADER_EXT)
    {
        WriteGeometryShaderLayoutQualifiers(
            sink, getGeometryShaderInputPrimitiveType(), getGeometryShaderInvocations(),
            getGeometryShaderOutputPrimitiveType(), getGeometryShaderMaxVertices());
    }

    // Write translated shader.
    TOutputGLSL outputGLSL(sink, getArrayIndexClampingStrategy(), getHashFunction(), getNameMap(),
                           &getSymbolTable(), getShaderType(), getShaderVersion(), getOutputType(),
                           compileOptions);

    root->traverse(&outputGLSL);
}

bool TranslatorGLSL::shouldFlattenPragmaStdglInvariantAll()
{
    // Required when outputting to any GLSL version greater than 1.20, but since ANGLE doesn't
    // translate to that version, return true for the next higher version.
    return IsGLSL130OrNewer(getOutputType());
}

bool TranslatorGLSL::shouldCollectVariables(ShCompileOptions compileOptions)
{
    return (compileOptions & SH_FLATTEN_PRAGMA_STDGL_INVARIANT_ALL) ||
           TCompiler::shouldCollectVariables(compileOptions);
}

void TranslatorGLSL::writeVersion(TIntermNode *root)
{
    TVersionGLSL versionGLSL(getShaderType(), getPragma(), getOutputType());
    root->traverse(&versionGLSL);
    int version = versionGLSL.getVersion();
    // We need to write version directive only if it is greater than 110.
    // If there is no version directive in the shader, 110 is implied.
    if (version > 110)
    {
        TInfoSinkBase &sink = getInfoSink().obj;
        sink << "#version " << version << "\n";
    }
}

void TranslatorGLSL::writeExtensionBehavior(TIntermNode *root, ShCompileOptions compileOptions)
{
    TInfoSinkBase &sink                   = getInfoSink().obj;
    const TExtensionBehavior &extBehavior = getExtensionBehavior();
    for (const auto &iter : extBehavior)
    {
        if (iter.second == EBhUndefined)
        {
            continue;
        }

        if (getOutputType() == SH_GLSL_COMPATIBILITY_OUTPUT)
        {
            // For GLSL output, we don't need to emit most extensions explicitly,
            // but some we need to translate in GL compatibility profile.
            if (iter.first == TExtension::EXT_shader_texture_lod)
            {
                sink << "#extension GL_ARB_shader_texture_lod : " << GetBehaviorString(iter.second)
                     << "\n";
            }

            if (iter.first == TExtension::EXT_draw_buffers)
            {
                sink << "#extension GL_ARB_draw_buffers : " << GetBehaviorString(iter.second)
                     << "\n";
            }

            if (iter.first == TExtension::EXT_geometry_shader)
            {
                sink << "#extension GL_ARB_geometry_shader4 : " << GetBehaviorString(iter.second)
                     << "\n";
            }
        }

        const bool isMultiview =
            (iter.first == TExtension::OVR_multiview) || (iter.first == TExtension::OVR_multiview2);
        if (isMultiview)
        {
            EmitMultiviewGLSL(*this, compileOptions, iter.second, sink);
        }

        // Support ANGLE_texture_multisample extension on GLSL300
        if (getShaderVersion() >= 300 && iter.first == TExtension::ANGLE_texture_multisample &&
            getOutputType() < SH_GLSL_330_CORE_OUTPUT)
        {
            sink << "#extension GL_ARB_texture_multisample : " << GetBehaviorString(iter.second)
                 << "\n";
        }
    }

    // GLSL ES 3 explicit location qualifiers need to use an extension before GLSL 330
    if (getShaderVersion() >= 300 && getOutputType() < SH_GLSL_330_CORE_OUTPUT &&
        getShaderType() != GL_COMPUTE_SHADER)
    {
        sink << "#extension GL_ARB_explicit_attrib_location : require\n";
    }

    // Need to enable gpu_shader5 to have index constant sampler array indexing
    if (getOutputType() != SH_ESSL_OUTPUT && getOutputType() < SH_GLSL_400_CORE_OUTPUT &&
        getShaderVersion() == 100)
    {
        // Don't use "require" on to avoid breaking WebGL 1 on drivers that silently
        // support index constant sampler array indexing, but don't have the extension or
        // on drivers that don't have the extension at all as it would break WebGL 1 for
        // some users.
        sink << "#extension GL_ARB_gpu_shader5 : enable\n";
    }

    TExtensionGLSL extensionGLSL(getOutputType());
    root->traverse(&extensionGLSL);

    for (const auto &ext : extensionGLSL.getEnabledExtensions())
    {
        sink << "#extension " << ext << " : enable\n";
    }
    for (const auto &ext : extensionGLSL.getRequiredExtensions())
    {
        sink << "#extension " << ext << " : require\n";
    }
}

void TranslatorGLSL::conditionallyOutputInvariantDeclaration(const char *builtinVaryingName)
{
    if (isVaryingDefined(builtinVaryingName))
    {
        TInfoSinkBase &sink = getInfoSink().obj;
        sink << "invariant " << builtinVaryingName << ";\n";
    }
}

}  // namespace sh
kc3-lang/angle/src/compiler/translator/TranslatorGLSL.cpp

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kc3-lang/angle /src/compiler/translator/TranslatorGLSL.cpp
