magnum/src/Magnum/Platform/WindowlessWindowsEglApplication.cpp

/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022 Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

#include "WindowlessWindowsEglApplication.h"

#include <Corrade/Utility/Assert.h>
#include <Corrade/Utility/Debug.h>

#include "Magnum/GL/Version.h"

#include "Implementation/Egl.h"

#ifndef EGL_KHR_create_context_no_error
#define EGL_CONTEXT_OPENGL_NO_ERROR_KHR 0x31B3
#endif

namespace Magnum { namespace Platform {

WindowlessWindowsEglContext::WindowlessWindowsEglContext(const Configuration& configuration, GLContext* const magnumContext) {
    /** @todo device selection and skipping of eglInitialize()/Terminate() the
        same way as with WindowlessEglContext */

    /* Register the window class (if not yet done) */
    WNDCLASSW wc;
    if(!GetClassInfoW(GetModuleHandleW(nullptr), L"Magnum Windowless Application", &wc)) {
        wc = WNDCLASSW{
            0,
            DefWindowProcW,
            0,
            0,
            GetModuleHandleW(nullptr),
            nullptr,
            nullptr,
            HBRUSH(COLOR_BACKGROUND),
            nullptr,
            L"Magnum Windowless Application"
        };

        if(!RegisterClassW(&wc)) {
            Error() << "Platform::WindowlessWglContext: cannot create window class:" << GetLastError();
            return;
        }
    }

    /* Create the window */
    _window = CreateWindowW(wc.lpszClassName, L"Magnum Windowless Application",
        WS_OVERLAPPEDWINDOW, 0, 0, 32, 32, 0, 0, wc.hInstance, 0);

    /* Initialize */
    _display = eglGetDisplay(GetDC(_window));
    if(!eglInitialize(_display, nullptr, nullptr)) {
        Error() << "Platform::WindowlessWindowsEglApplication::tryCreateContext(): cannot initialize EGL:" << Implementation::eglErrorString(eglGetError());
        return;
    }

    const EGLenum api =
        #ifndef MAGNUM_TARGET_GLES
        EGL_OPENGL_API
        #else
        EGL_OPENGL_ES_API
        #endif
        ;
    if(!eglBindAPI(api)) {
        Error() << "Platform::WindowlessWindowsEglApplication::tryCreateContext(): cannot bind EGL API:" << Implementation::eglErrorString(eglGetError());
        return;
    }

    /* Choose EGL config */
    static const EGLint attribs[] = {
        EGL_RED_SIZE, 1,
        EGL_GREEN_SIZE, 1,
        EGL_BLUE_SIZE, 1,
        EGL_DEPTH_SIZE, 1,
        #ifndef MAGNUM_TARGET_GLES
        EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
        #elif defined(MAGNUM_TARGET_GLES3)
        EGL_RENDERABLE_TYPE, EGL_OPENGL_ES3_BIT,
        #elif defined(MAGNUM_TARGET_GLES2)
        EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
        #else
        #error unsupported OpenGL edition
        #endif
        EGL_NONE
    };
    EGLint configCount;
    EGLConfig config;
    if(!eglChooseConfig(_display, attribs, &config, 1, &configCount)) {
        Error() << "Platform::WindowlessWindowsEglApplication::tryCreateContext(): cannot get EGL visual config:" << Implementation::eglErrorString(eglGetError());
        return;
    }

    if(!configCount) {
        Error() << "Platform::WindowlessWindowsEglApplication::tryCreateContext(): no matching EGL visual config available";
        return;
    }

    /* Request debug context if GpuValidation is enabled either via the
       configuration or via command-line */
    Configuration::Flags flags = configuration.flags();
    if((flags & Configuration::Flag::GpuValidation) || (magnumContext && magnumContext->configurationFlags() & GL::Context::Configuration::Flag::GpuValidation))
        flags |= Configuration::Flag::Debug;
    else if((flags & Configuration::Flag::GpuValidationNoError) || (magnumContext && magnumContext->configurationFlags() & GL::Context::Configuration::Flag::GpuValidationNoError))
        flags |= Configuration::Flag::NoError;

    /** @todo needs a growable DynamicArray with disabled alloc or somesuch */
    EGLint attributes[7] = {
        #ifdef MAGNUM_TARGET_GLES
        EGL_CONTEXT_CLIENT_VERSION,
            #ifdef MAGNUM_TARGET_GLES3
            3,
            #elif defined(MAGNUM_TARGET_GLES2)
            2,
            #else
            #error unsupported OpenGL ES version
            #endif
        #endif
        /* Mask out the upper 32bits used for other flags */
        EGL_CONTEXT_FLAGS_KHR, EGLint(UnsignedLong(flags) & 0xffffffffu),

        /* The rest is added optionally */
        EGL_NONE, EGL_NONE, /* EGL_CONTEXT_OPENGL_NO_ERROR_KHR */
        EGL_NONE
    };

    std::size_t nextAttribute = 4;
    CORRADE_INTERNAL_ASSERT(attributes[nextAttribute] == EGL_NONE);

    if(flags & Configuration::Flag::NoError) {
        attributes[nextAttribute++] = EGL_CONTEXT_OPENGL_NO_ERROR_KHR;
        attributes[nextAttribute++] = true;
    }

    CORRADE_INTERNAL_ASSERT(nextAttribute < Containers::arraySize(attributes));

    if(!(_context = eglCreateContext(_display, config, configuration.sharedContext(), attributes))) {
        Error() << "Platform::WindowlessWindowsEglContext: cannot create EGL context:" << Implementation::eglErrorString(eglGetError());
        return;
    }

    if(!(_surface = eglCreateWindowSurface(_display, config, _window, nullptr)))
        Error() << "Platform::WindowlessWindowsEglContext: cannot create window surface:" << Implementation::eglErrorString(eglGetError());
}

WindowlessWindowsEglContext::WindowlessWindowsEglContext(WindowlessWindowsEglContext&& other) noexcept: _window{other._window}, _display{other._display}, _surface{other._surface}, _context{other._context} {
    other._window = {};
    other._display = {};
    other._surface = {};
    other._context = {};
}

WindowlessWindowsEglContext::~WindowlessWindowsEglContext() {
    if(_context) eglDestroyContext(_display, _context);
    if(_surface) eglDestroySurface(_display, _surface);
    if(_display) eglTerminate(_display);
    if(_window) DestroyWindow(_window);
}

WindowlessWindowsEglContext& WindowlessWindowsEglContext::operator=(WindowlessWindowsEglContext&& other) noexcept {
    using std::swap;
    swap(other._window, _window);
    swap(other._display, _display);
    swap(other._surface, _surface);
    swap(other._context, _context);
    return *this;
}

bool WindowlessWindowsEglContext::makeCurrent() {
    if(eglMakeCurrent(_display, _surface, _surface, _context))
        return true;

    Error() << "Platform::WindowlessWindowsEglContext::makeCurrent(): cannot make context current:" << GetLastError();
    return false;
}

bool WindowlessWindowsEglContext::release() {
    if(eglMakeCurrent(_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT))
        return true;

    Error() << "Platform::WindowlessWindowsEglApplication::release(): cannot release current context:" << GetLastError();
    return false;
}

WindowlessWindowsEglContext::Configuration::Configuration() {
    GL::Context::Configuration::addFlags(GL::Context::Configuration::Flag::Windowless);
}

#ifndef DOXYGEN_GENERATING_OUTPUT
WindowlessWindowsEglApplication::WindowlessWindowsEglApplication(const Arguments& arguments): WindowlessWindowsEglApplication{arguments, Configuration{}} {}
#endif

WindowlessWindowsEglApplication::WindowlessWindowsEglApplication(const Arguments& arguments, const Configuration& configuration): WindowlessWindowsEglApplication{arguments, NoCreate} {
    createContext(configuration);
}

WindowlessWindowsEglApplication::WindowlessWindowsEglApplication(const Arguments& arguments, NoCreateT): _glContext{NoCreate}, _context{NoCreate, arguments.argc, arguments.argv} {}

void WindowlessWindowsEglApplication::createContext() { createContext({}); }

void WindowlessWindowsEglApplication::createContext(const Configuration& configuration) {
    if(!tryCreateContext(configuration)) std::exit(1);
}

bool WindowlessWindowsEglApplication::tryCreateContext(const Configuration& configuration) {
    CORRADE_ASSERT(_context.version() == Version::None, "Platform::WindowlessWindowsEglApplication::tryCreateContext(): context already created", false);

    WindowlessWindowsEglContext glContext{configuration, &_context};
    if(!glContext.isCreated() || !glContext.makeCurrent() || !_context.tryCreate(configuration))
        return false;

    _glContext = std::move(glContext);
    return true;
}

WindowlessWindowsEglApplication::~WindowlessWindowsEglApplication() = default;

}}