src/dawn/native/opengl/ContextEGL.cpp

// Copyright 2022 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
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// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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#include "src/dawn/native/opengl/ContextEGL.h"

#include <array>
#include <memory>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

#include "absl/container/flat_hash_set.h"
#include "absl/strings/str_split.h"
#include "src/dawn/native/opengl/DisplayEGL.h"
#include "src/dawn/native/opengl/UtilsEGL.h"

#ifndef EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE
#define EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE 0x33AF
#endif

// https://chromium.googlesource.com/angle/angle/+/main/extensions/EGL_ANGLE_create_context_backwards_compatible.txt
#ifndef EGL_CONTEXT_OPENGL_BACKWARDS_COMPATIBLE_ANGLE
#define EGL_CONTEXT_OPENGL_BACKWARDS_COMPATIBLE_ANGLE 0x3483
#endif

// https://chromium.googlesource.com/angle/angle.git/+/refs/heads/chromium/5996/extensions/EGL_ANGLE_create_context_extensions_enabled.txt
#ifndef EGL_EXTENSIONS_ENABLED_ANGLE
#define EGL_EXTENSIONS_ENABLED_ANGLE 0x345F
#endif

// https://chromium.googlesource.com/angle/angle/+/main/extensions/EGL_ANGLE_context_virtualization.txt
#ifndef EGL_CONTEXT_VIRTUALIZATION_GROUP_ANGLE
#define EGL_CONTEXT_VIRTUALIZATION_GROUP_ANGLE 0x3481
#endif

// https://chromium.googlesource.com/angle/angle/+/main/extensions/EGL_ANGLE_create_context_webgl_compatibility.txt
#ifndef EGL_CONTEXT_HARDENED_ANGLE
#define EGL_CONTEXT_HARDENED_ANGLE 0x34F8
#endif

// https://chromium.googlesource.com/angle/angle/+/main/extensions/ANGLE_request_extension.txt
#ifndef GL_REQUESTABLE_EXTENSIONS_ANGLE
#define GL_REQUESTABLE_EXTENSIONS_ANGLE 0x93A8
#endif

namespace dawn::native::opengl {

namespace {

thread_local ContextEGL* gCurrentContextInScope = nullptr;

MaybeError MakeContextCurrent(DisplayEGL* display, const ContextEGL::ContextState& state) {
    if (display->egl->GetCurrentContext() != state.context ||
        display->egl->GetCurrentSurface(EGL_DRAW) != state.drawSurface ||
        display->egl->GetCurrentSurface(EGL_READ) != state.readSurface) {
        EGLBoolean success = display->egl->MakeCurrent(display->GetDisplay(), state.drawSurface,

                                                       state.readSurface, state.context);

        return CheckEGL(display->egl.get(), static_cast<EGLBoolean>(success == EGL_TRUE),
                        "eglMakeCurrent");
    }
    return {};
}

}  // namespace

// static
ResultOrError<std::unique_ptr<ContextEGL>> ContextEGL::Create(Ref<DisplayEGL> display,
                                                              wgpu::BackendType backend,
                                                              bool useRobustness,
                                                              bool disableEGL15Robustness,
                                                              bool useANGLETextureSharing,
                                                              bool forceES31AndMinExtensions,
                                                              bool bindContextOnlyDuringUse,
                                                              EGLint angleVirtualizationGroup) {
    auto context =
        std::unique_ptr<ContextEGL>(new ContextEGL(std::move(display), bindContextOnlyDuringUse));
    DAWN_TRY(context->Initialize(
        backend, /*useRobustness=*/useRobustness, /*disableEGL15Robustness=*/disableEGL15Robustness,
        /*useANGLETextureSharing=*/useANGLETextureSharing,
        /*forceES31AndMinExtensions=*/forceES31AndMinExtensions, angleVirtualizationGroup));
    return std::move(context);
}

ContextEGL::ContextEGL(Ref<DisplayEGL> display, bool bindContextOnlyDuringUse)
    : mDisplay(std::move(display)), mBindContextOnlyDuringUse(bindContextOnlyDuringUse) {}

ContextEGL::~ContextEGL() {
    if (mOffscreenSurface != EGL_NO_SURFACE) {
        mDisplay->egl->DestroySurface(mDisplay->GetDisplay(), mOffscreenSurface);
        mOffscreenSurface = EGL_NO_SURFACE;
    }
    if (mState.context != EGL_NO_CONTEXT) {
        if (mState.context == mDisplay->egl->GetCurrentContext()) {
            mDisplay->egl->MakeCurrent(mDisplay->GetDisplay(), EGL_NO_SURFACE, EGL_NO_SURFACE,
                                       EGL_NO_CONTEXT);
        }
        mDisplay->egl->DestroyContext(mDisplay->GetDisplay(), mState.context);
        mState.context = EGL_NO_CONTEXT;
    }
}

MaybeError ContextEGL::Initialize(wgpu::BackendType backend,
                                  bool useRobustness,
                                  bool disableEGL15Robustness,
                                  bool useANGLETextureSharing,
                                  bool forceES31AndMinExtensions,
                                  EGLint angleVirtualizationGroup) {
    const EGLFunctions& egl = mDisplay->egl.get();

    // Unless EGL_KHR_no_config is present, we need to choose an EGLConfig on context creation that
    // will lock the EGLContext to be use with a single kind of color buffer. In that case the
    // display should only list one kind of color buffer as potentially supported.
    EGLConfig contextConfig = kNoConfig;
    if (!egl.HasExt(EGLExt::NoConfigContext)) {
        DAWN_ASSERT(mDisplay->GetPotentialSurfaceFormats().size() == 1);
        wgpu::TextureFormat format = mDisplay->GetPotentialSurfaceFormats()[0];

        contextConfig = mDisplay->ChooseConfig(EGL_WINDOW_BIT, format);
        if (contextConfig == kNoConfig) {
            return DAWN_UNRECOVERABLE_ERROR(
                "Couldn't find an EGLConfig rendering to a window for %s.", format);
        }
    }

    DAWN_TRY(CheckEGL(egl, egl.BindAPI(mDisplay->GetAPIEnum()), "eglBindAPI"));

    absl::InlinedVector<EGLint, 10> attribs;
    auto AddAttrib = [&](EGLint attrib, EGLint value) {
        attribs.push_back(attrib);
        attribs.push_back(value);
    };

    if (egl.HasExt(EGLExt::CreateContext)) {
        switch (backend) {
            case wgpu::BackendType::OpenGLES:
                AddAttrib(EGL_CONTEXT_MAJOR_VERSION, 3);
                AddAttrib(EGL_CONTEXT_MINOR_VERSION, 1);
                break;
            case wgpu::BackendType::OpenGL:
                AddAttrib(EGL_CONTEXT_MAJOR_VERSION, 4);
                AddAttrib(EGL_CONTEXT_MINOR_VERSION, 4);
                break;
            default:
                DAWN_UNREACHABLE();
        }
    } else {
        // Without EGL 1.5 or EGL_KHR_create_context we have to request ES 2.0 or above and see what
        // context version we end up getting.
        AddAttrib(EGL_CONTEXT_CLIENT_VERSION, 2);
    }

    if (useRobustness) {
        DAWN_ASSERT(egl.HasExt(EGLExt::CreateContextRobustness));
        // EGL_EXT_create_context_robustness is promoted to 1.5 but with a different enum value.
        // PowerVR advertises EGL 1.5, but only supports the old enum value.
        if (egl.GetMinorVersion() >= 5 && !disableEGL15Robustness) {
            AddAttrib(EGL_CONTEXT_OPENGL_ROBUST_ACCESS, EGL_TRUE);
        } else {
            AddAttrib(EGL_CONTEXT_OPENGL_ROBUST_ACCESS_EXT, EGL_TRUE);
        }
    }

    if (useANGLETextureSharing) {
        DAWN_ASSERT(egl.HasExt(EGLExt::DisplayTextureShareGroup));
        AddAttrib(EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE, EGL_TRUE);
    }

    mForceES31AndMinExtensions = forceES31AndMinExtensions;
    if (forceES31AndMinExtensions) {
        if (egl.HasExt(EGLExt::ANGLECreateContextBackwardsCompatible)) {
            AddAttrib(EGL_CONTEXT_OPENGL_BACKWARDS_COMPATIBLE_ANGLE, EGL_FALSE);
        }
        if (egl.HasExt(EGLExt::ANGLECreateContextExtensionsEnabled)) {
            AddAttrib(EGL_EXTENSIONS_ENABLED_ANGLE, EGL_FALSE);
        }
    }

    if (egl.HasExt(EGLExt::ANGLEContextVirtualization)) {
        AddAttrib(EGL_CONTEXT_VIRTUALIZATION_GROUP_ANGLE, angleVirtualizationGroup);
    }

    if (egl.HasExt(EGLExt::ANGLECreateContextWebGLCompatibility)) {
        AddAttrib(EGL_CONTEXT_HARDENED_ANGLE, EGL_TRUE);
    }

    // The attrib list is finished with an EGL_NONE tag.
    attribs.push_back(EGL_NONE);

    mState.context =
        egl.CreateContext(mDisplay->GetDisplay(), contextConfig, EGL_NO_CONTEXT, attribs.data());
    DAWN_TRY(CheckEGL(egl, mState.context != EGL_NO_CONTEXT, "eglCreateContext"));

    // When EGL_KHR_surfaceless_context is not supported, we need to create a pbuffer to act
    // as an offscreen surface.
    if (!egl.HasExt(EGLExt::SurfacelessContext)) {
        // The first potential surface format is always a good choice to find the config. Either we
        // only support this one and the context will be compatible with the pbuffer, or
        // EGL_KHR_no_config_context is supported and the context is compatible with any config.
        wgpu::TextureFormat format = mDisplay->GetPotentialSurfaceFormats()[0];

        EGLConfig pbufferConfig = mDisplay->ChooseConfig(EGL_PBUFFER_BIT, format);
        if (pbufferConfig == kNoConfig) {
            return DAWN_UNRECOVERABLE_ERROR(
                "Couldn't find an EGLConfig rendering to a window for %s.", format);
        }

        EGLint pbufferAttribs[] = {
            EGL_WIDTH,  1,  //
            EGL_HEIGHT, 1,  //
            EGL_NONE,
        };
        mOffscreenSurface =
            egl.CreatePbufferSurface(mDisplay->GetDisplay(), pbufferConfig, pbufferAttribs);
        DAWN_TRY(
            CheckEGL(egl, mOffscreenSurface != EGL_NO_SURFACE, "Creating the offscreen surface."));
    }

    return {};
}

// Request compat mode required extensions explicitly when mForceES31AndMinExtensions is true
void ContextEGL::RequestRequiredExtensionsExplicitly() {
    if (!mForceES31AndMinExtensions) {
        return;
    }

    const EGLFunctions& egl = mDisplay->egl.get();
    // Copied from third_party/angle/include/GLES/gl.h
    typedef void(KHRONOS_APIENTRY * PFNGLREQUESTEXTENSIONANGLEPROC)(const GLchar* name);

    auto proc = egl.GetProcAddress("glRequestExtensionANGLE");
    if (!proc) {
        return;
    }

    auto glRequestExtension = reinterpret_cast<PFNGLREQUESTEXTENSIONANGLEPROC>(proc);

    // Requesting an extension that isn't requestable generates a GL error, so only request the
    // extensions listed in GL_REQUESTABLE_EXTENSIONS_ANGLE.
    typedef const GLubyte*(KHRONOS_APIENTRY * PFNGLGETSTRINGPROC)(GLenum name);
    auto getStringProc = egl.GetProcAddress("glGetString");
    if (!getStringProc) {
        return;
    }
    auto glGetString = reinterpret_cast<PFNGLGETSTRINGPROC>(getStringProc);
    const char* rawRequestableExtensions =
        reinterpret_cast<const char*>(glGetString(GL_REQUESTABLE_EXTENSIONS_ANGLE));
    if (rawRequestableExtensions == nullptr) {
        return;
    }
    absl::flat_hash_set<std::string_view> requestableExtensions =
        absl::StrSplit(rawRequestableExtensions, " ");

    // src/dawn/native/opengl/supported_extensions.json
    constexpr std::array kExtensions = {
        "GL_OES_texture_stencil8",
        "GL_EXT_texture_compression_s3tc",
        "GL_EXT_texture_compression_s3tc_srgb",
        "GL_OES_EGL_image",
        "GL_EXT_texture_format_BGRA8888",
        "GL_APPLE_texture_format_BGRA8888",
        "GL_EXT_color_buffer_float",
        "GL_EXT_color_buffer_half_float",
        "GL_EXT_multisampled_render_to_texture",
    };
    for (const char* extension : kExtensions) {
        if (requestableExtensions.contains(extension)) {
            glRequestExtension(extension);
        }
    }
}

bool ContextEGL::IsInScopedMakeCurrent() const {
    // TODO(451928481): This should ideally check `eglGetCurrentContext() == mState.context`,
    // but that is not possible until all legacy call sites are updated to use
    // `ScopedMakeCurrent` instead of `DeprecatedMakeCurrent`. This thread-local tracks if the
    // context was made current via a scope and can be removed after the refactor.
    return gCurrentContextInScope == this;
}

bool ContextEGL::IsNotCurrentOnAnotherThread() const {
#if defined(DAWN_ENABLE_ASSERTS)
    return mCurrentThread == std::thread::id() || mCurrentThread == std::this_thread::get_id();
#else
    // For non-assert builds, assuming not current on another thread.
    // This function is intended to be used by DAWN_ASSERT.
    return true;
#endif
}

void ContextEGL::DeprecatedMakeCurrent() {
    IgnoreErrors(MakeContextCurrent(mDisplay.Get(), mState));
}

// ScopedSetCurrentSurface

[[nodiscard]] ContextEGL::ScopedSetCurrentSurface ContextEGL::SetCurrentSurfaceScope(
    EGLSurface surface) {
    return {this, surface};
}

ContextEGL::ScopedSetCurrentSurface::ScopedSetCurrentSurface(ContextEGL* context,
                                                             EGLSurface surface)
    : mContext(context) {
    mContext->mState.drawSurface = surface;
    mContext->mState.readSurface = surface;
}

ContextEGL::ScopedSetCurrentSurface::~ScopedSetCurrentSurface() {
    mContext->mState.drawSurface = mContext->mOffscreenSurface;
    mContext->mState.readSurface = mContext->mOffscreenSurface;
}

// ContextState

bool ContextEGL::ContextState::operator==(const ContextState& other) const {
    return context == other.context && drawSurface == other.drawSurface &&
           readSurface == other.readSurface;
}

bool ContextEGL::ContextState::operator!=(const ContextState& other) const {
    return !(*this == other);
}

// ScopedMakeCurrent

ContextEGL::ScopedMakeCurrent::ScopedMakeCurrent(ContextEGL* context) : mContext(context) {}

ContextEGL::ScopedMakeCurrent::ScopedMakeCurrent(ScopedMakeCurrent&& src)
    : mContext(std::move(src.mContext)),
      mPrevState(std::move(src.mPrevState)),
      mLock(std::move(src.mLock)) {
    src.mContext = nullptr;
}

ContextEGL::ScopedMakeCurrent& ContextEGL::ScopedMakeCurrent::operator=(ScopedMakeCurrent&& src) {
    if (&src == this) {
        return *this;
    }
    mContext = std::move(src.mContext);
    src.mContext = nullptr;
    mPrevState = std::move(src.mPrevState);
    mLock = std::move(src.mLock);
    return *this;
}

ContextEGL::ScopedMakeCurrent::~ScopedMakeCurrent() {
    auto result = End();
    DAWN_ASSERT(result.IsSuccess());
    IgnoreErrors(std::move(result));
}

MaybeError ContextEGL::ScopedMakeCurrent::Initialize() {
    if (!mContext) {
        return {};
    }
    mLock = std::unique_lock<std::mutex>(mContext->mExclusiveMakeCurrentMutex);

    mPrevState.context = mContext->mDisplay->egl->GetCurrentContext();
    mPrevState.drawSurface = mContext->mDisplay->egl->GetCurrentSurface(EGL_DRAW);
    mPrevState.readSurface = mContext->mDisplay->egl->GetCurrentSurface(EGL_READ);

    // Assert that the context is not current on another thread.
    DAWN_ASSERT(mContext->IsNotCurrentOnAnotherThread());

    if (mPrevState != mContext->mState) {
        auto result = MakeContextCurrent(mContext->mDisplay.Get(), mContext->mState);
        if (DAWN_UNLIKELY(result.IsError())) {
            mContext = nullptr;
            return result;
        }
    }

#if defined(DAWN_ENABLE_ASSERTS)
    mContext->mCurrentThread = std::this_thread::get_id();
#endif

    gCurrentContextInScope = mContext;
    return {};
}

MaybeError ContextEGL::ScopedMakeCurrent::End() {
    if (!mContext) {
        return {};
    }

    MaybeError result;
    if (mContext->mBindContextOnlyDuringUse && mPrevState != mContext->mState) {
        // Unmake current this context so that other threads can use it.
        result = MakeContextCurrent(mContext->mDisplay.Get(), mPrevState);

#if defined(DAWN_ENABLE_ASSERTS)
        mContext->mCurrentThread = {};
#endif
    }
    gCurrentContextInScope = nullptr;
    mContext = nullptr;
    return result;
}

ResultOrError<ContextEGL::ScopedMakeCurrent> ContextEGL::MakeCurrent() {
    ScopedMakeCurrent scopedMakeCurrent(IsInScopedMakeCurrent() ? nullptr : this);
    DAWN_TRY(scopedMakeCurrent.Initialize());
    return std::move(scopedMakeCurrent);
}

}  // namespace dawn::native::opengl