src/dawn/native/opengl/ContextEGL.cpp

// Copyright 2022 The Dawn & Tint Authors
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#include "dawn/native/opengl/ContextEGL.h"

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

#include "dawn/native/opengl/DisplayEGL.h"
#include "dawn/native/opengl/UtilsEGL.h"

#ifndef EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE
#define EGL_DISPLAY_TEXTURE_SHARE_GROUP_ANGLE 0x33AF
#endif

namespace dawn::native::opengl {

// static
ResultOrError<std::unique_ptr<ContextEGL>> ContextEGL::Create(const DisplayEGL* display,
                                                              wgpu::BackendType backend,
                                                              bool useRobustness,
                                                              bool useANGLETextureSharing) {
    auto context = std::make_unique<ContextEGL>(display);
    DAWN_TRY(context->Initialize(backend, useRobustness, useANGLETextureSharing));
    return std::move(context);
}

ContextEGL::ContextEGL(const DisplayEGL* display) : mDisplay(display) {}

ContextEGL::~ContextEGL() {
    if (mContext != EGL_NO_CONTEXT) {
        mDisplay->egl.DestroyContext(mDisplay->GetDisplay(), mContext);
        mContext = EGL_NO_CONTEXT;
    }
}

MaybeError ContextEGL::Initialize(wgpu::BackendType backend,
                                  bool useRobustness,
                                  bool useANGLETextureSharing) {
    const EGLFunctions& egl = mDisplay->egl;

    // Since we're creating a surfaceless context, the only thing we really care
    // about is the RENDERABLE_TYPE.
    EGLint configAttribs[] = {EGL_RENDERABLE_TYPE, mDisplay->GetAPIBit(), EGL_NONE};

    EGLint numConfig;
    EGLConfig config;
    DAWN_TRY(CheckEGL(
        egl, egl.ChooseConfig(mDisplay->GetDisplay(), configAttribs, &config, 1, &numConfig),
        "eglChooseConfig"));

    DAWN_INVALID_IF(numConfig == 0, "eglChooseConfig returned zero configs");

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

    int major, minor;
    switch (backend) {
        case wgpu::BackendType::OpenGLES:
            major = 3;
            minor = 1;
            break;
        case wgpu::BackendType::OpenGL:
            major = 4;
            minor = 4;
            break;
        default:
            DAWN_UNREACHABLE();
    }

    std::vector<EGLint> attribs{
        EGL_CONTEXT_MAJOR_VERSION,
        major,
        EGL_CONTEXT_MINOR_VERSION,
        minor,
    };

    if (useRobustness) {
        DAWN_ASSERT(egl.HasExt(EGLExt::CreateContextRobustness));
        // EGL_EXT_create_context_robustness is promoted to 1.5 but with a different enum value.
        if (egl.GetMinorVersion() >= 5) {
            attribs.push_back(EGL_CONTEXT_OPENGL_ROBUST_ACCESS);
        } else {
            attribs.push_back(EGL_CONTEXT_OPENGL_ROBUST_ACCESS_EXT);
        }
        attribs.push_back(EGL_TRUE);
    }

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

    attribs.push_back(EGL_NONE);

    mContext = egl.CreateContext(mDisplay->GetDisplay(), config, EGL_NO_CONTEXT, attribs.data());
    return CheckEGL(egl, mContext != EGL_NO_CONTEXT, "eglCreateContext");
}

void ContextEGL::MakeCurrent() {
    EGLBoolean success =
        mDisplay->egl.MakeCurrent(mDisplay->GetDisplay(), EGL_NO_SURFACE, EGL_NO_SURFACE, mContext);
    IgnoreErrors(CheckEGL(mDisplay->egl, success == EGL_TRUE, "eglMakeCurrent"));
}

}  // namespace dawn::native::opengl