/********************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright (C) 2010 Martin Gräßlin <kde@martin-graesslin.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/

// This file is included in scene_opengl.cpp
//#include "scene_opengl.h"
#include <QX11Info>

EGLDisplay dpy;
EGLConfig config;
EGLSurface surface;
EGLContext ctx;

SceneOpenGL::SceneOpenGL( Workspace* ws )
    : Scene( ws )
    , init_ok( false )
    , selfCheckDone( true )
    {
    if( !initRenderingContext() )
        return;

    initEGL();
    if (!hasGLExtension("EGL_KHR_image_pixmap")) {
        kError(1212) << "Required extension EGL_KHR_image_pixmap not found, disabling compositing";
        return;
    }
    initGL();
    if (!hasGLExtension("GL_OES_EGL_image")) {
        kError(1212) << "Required extension GL_OES_EGL_image not found, disabling compositing";
        return;
    }
    debug = qstrcmp( qgetenv( "KWIN_GL_DEBUG" ), "1" ) == 0;
    if (!ShaderManager::instance()->isValid()) {
        kError( 1212 ) << "Shaders not valid, ES compositing not possible";
        return;
    }
    ShaderManager::instance()->pushShader(ShaderManager::SimpleShader);

    if( checkGLError( "Init" ))
        {
        kError( 1212 ) << "OpenGL compositing setup failed";
        return; // error
        }
    init_ok = true;
    }

SceneOpenGL::~SceneOpenGL()
    {
    foreach( Window* w, windows )
        delete w;
    // do cleanup after initBuffer()
    eglMakeCurrent( dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT );
    eglDestroyContext( dpy, ctx );
    eglDestroySurface( dpy, surface );
    eglTerminate( dpy );
    eglReleaseThread();
    SceneOpenGL::EffectFrame::cleanup();
    checkGLError( "Cleanup" );
    }

bool SceneOpenGL::initTfp()
    {
    return false;
    }

bool SceneOpenGL::initRenderingContext()
    {
    dpy = eglGetDisplay( display() );
    if( dpy == EGL_NO_DISPLAY )
        return false;
    EGLint major, minor;
    if( eglInitialize( dpy, &major, &minor ) == EGL_FALSE )
        return false;
    eglBindAPI( EGL_OPENGL_ES_API );
    initBufferConfigs();
    if( !wspace->createOverlay() )
        {
        kError( 1212 ) << "Could not get overlay window";
        return false;
        }
    surface = eglCreateWindowSurface( dpy, config, wspace->overlayWindow(), 0 );

    const EGLint context_attribs[] = {
        EGL_CONTEXT_CLIENT_VERSION, 2,
        EGL_NONE
    };

    ctx = eglCreateContext( dpy, config, EGL_NO_CONTEXT, context_attribs );
    if( ctx == EGL_NO_CONTEXT )
        return false;
    if( eglMakeCurrent( dpy, surface, surface, ctx ) == EGL_FALSE )
        return false;
    kDebug( 1212 ) << "EGL version: " << major << "." << minor;
    EGLint error = eglGetError();
    if( error != EGL_SUCCESS )
        {
        kWarning( 1212 ) << "Error occurred while creating context " << error;
        return false;
        }
    return true;
    }

bool SceneOpenGL::initBuffer()
    {
    return false;
    }

bool SceneOpenGL::initBufferConfigs()
    {
    const EGLint config_attribs[] = {
        EGL_SURFACE_TYPE,         EGL_WINDOW_BIT,
        EGL_RED_SIZE,             1,
        EGL_GREEN_SIZE,           1,
        EGL_BLUE_SIZE,            1,
        EGL_ALPHA_SIZE,           0,
        EGL_RENDERABLE_TYPE,      EGL_OPENGL_ES2_BIT,
        EGL_CONFIG_CAVEAT,        EGL_NONE,
        EGL_NONE,
    };

    EGLint count;
    EGLConfig configs[1024];
    eglChooseConfig(dpy, config_attribs, configs, 1024, &count);

    EGLint visualId = XVisualIDFromVisual((Visual*)QX11Info::appVisual());

    config = configs[0];
    for (int i = 0; i < count; i++)
        {
        EGLint val;
        eglGetConfigAttrib(dpy, configs[i], EGL_NATIVE_VISUAL_ID, &val);
        if (visualId == val)
            {
            config = configs[i];
            break;
            }
        }
    return true;
    }

bool SceneOpenGL::initDrawableConfigs()
    {
    return false;
    }

void SceneOpenGL::selfCheckSetup()
    {
    // not used in EGL
    }

bool SceneOpenGL::selfCheckFinish()
    {
    // not used in EGL
    return true;
    }

// the entry function for painting
void SceneOpenGL::paint( QRegion damage, ToplevelList toplevels )
    {
    QTime t = QTime::currentTime();
    foreach( Toplevel* c, toplevels )
        {
        assert( windows.contains( c ));
        stacking_order.append( windows[ c ] );
        }
    grabXServer();
    int mask = 0;
    paintScreen( &mask, &damage ); // call generic implementation
    ungrabXServer(); // ungrab before flushBuffer(), it may wait for vsync
    if( wspace->overlayWindow()) // show the window only after the first pass, since
        wspace->showOverlay();   // that pass may take long
    lastRenderTime = t.elapsed();
    flushBuffer( mask, damage );
    // do cleanup
    stacking_order.clear();
    checkGLError( "PostPaint" );
    }

void SceneOpenGL::waitSync()
    {
    // not used in EGL
    }

void SceneOpenGL::flushBuffer( int mask, QRegion damage )
    {
    glFlush();
    if( mask & PAINT_SCREEN_REGION )
        {
        // TODO: implement me properly
        eglSwapBuffers( dpy, surface );
        }
    else
        {
        eglSwapBuffers( dpy, surface );
        }
    eglWaitGL();
    // TODO: remove for wayland
    XFlush( display());
    }

void SceneOpenGL::paintGenericScreen(int mask, ScreenPaintData data)
{
    if (mask & PAINT_SCREEN_TRANSFORMED) {
        // apply screen transformations
        QMatrix4x4 screenTransformation;
        screenTransformation.translate(data.xTranslate, data.yTranslate, data.zTranslate);
        if (data.rotation) {
            screenTransformation.translate(data.rotation->xRotationPoint, data.rotation->yRotationPoint, data.rotation->zRotationPoint);
            // translate to rotation point, rotate, translate back
            qreal xAxis = 0.0;
            qreal yAxis = 0.0;
            qreal zAxis = 0.0;
            switch (data.rotation->axis) {
                case RotationData::XAxis:
                    xAxis = 1.0;
                    break;
                case RotationData::YAxis:
                    yAxis = 1.0;
                    break;
                case RotationData::ZAxis:
                    zAxis = 1.0;
                    break;
            }
            screenTransformation.rotate(data.rotation->angle, xAxis, yAxis, zAxis);
            screenTransformation.translate(-data.rotation->xRotationPoint, -data.rotation->yRotationPoint, -data.rotation->zRotationPoint);
        }
        screenTransformation.scale(data.xScale, data.yScale, data.zScale);
        GLShader *shader = ShaderManager::instance()->pushShader(ShaderManager::GenericShader);
        shader->setUniform("screenTransformation", screenTransformation);
    } else if ((mask & PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS) || (mask & PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS_WITHOUT_FULL_REPAINTS)) {
        GLShader *shader = ShaderManager::instance()->pushShader(ShaderManager::GenericShader);
        shader->setUniform("screenTransformation", QMatrix4x4());
    }
    Scene::paintGenericScreen(mask, data);
    if ((mask & PAINT_SCREEN_TRANSFORMED) ||
        (mask & PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS) ||
        (mask & PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS_WITHOUT_FULL_REPAINTS)) {
        ShaderManager::instance()->popShader();
    }
}

void SceneOpenGL::paintBackground(QRegion region)
{
    PaintClipper pc(region);
    if (!PaintClipper::clip()) {
        glClearColor(0, 0, 0, 1);
        glClear(GL_COLOR_BUFFER_BIT);
        return;
    }
    if (pc.clip() && pc.paintArea().isEmpty())
        return; // no background to paint
    QVector<float> verts;
    for (PaintClipper::Iterator iterator; !iterator.isDone(); iterator.next()) {
        QRect r = iterator.boundingRect();
        verts << r.x() + r.width() << r.y();
        verts << r.x() << r.y();
        verts << r.x() << r.y() + r.height();
        verts << r.x() << r.y() + r.height();
        verts << r.x() + r.width() << r.y() + r.height();
        verts << r.x() + r.width() << r.y();
    }
    GLVertexBuffer vbo(GLVertexBuffer::Static);
    vbo.setUseColor(true);
    vbo.setUseShader(true);
    vbo.setData(verts.count() / 2, 2, verts.data(), NULL);
    ShaderManager::instance()->pushShader(ShaderManager::ColorShader);
    vbo.render(GL_TRIANGLES);
    ShaderManager::instance()->popShader();
}

//****************************************
// SceneOpenGL::Texture
//****************************************

void SceneOpenGL::Texture::init()
    {
    findTarget();
    }

void SceneOpenGL::Texture::release()
    {
    mTexture = None;
    }

void SceneOpenGL::Texture::findTarget()
    {
    mTarget = GL_TEXTURE_2D;
    }

bool SceneOpenGL::Texture::load( const Pixmap& pix, const QSize& size,
    int depth, QRegion region )
    {
    Q_UNUSED(size)
    Q_UNUSED(depth)
    Q_UNUSED(region)
    if( mTexture == None )
        {
        createTexture();
        bind();
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        const EGLint attribs[] = {
            EGL_IMAGE_PRESERVED_KHR, EGL_TRUE,
            EGL_NONE
        };
        EGLImageKHR image = eglCreateImageKHR(dpy, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
                                (EGLClientBuffer)pix, attribs);
        glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, (GLeglImageOES)image);
        eglDestroyImageKHR( dpy, image );
        unbind();
        checkGLError("load texture");
        }
    return true;
    }

void SceneOpenGL::Texture::bind()
    {
    GLTexture::bind();
    }

void SceneOpenGL::Texture::unbind()
    {
    GLTexture::unbind();
    }