// Basé sur :
// CC-BY Edouard.Thiel@univ-amu.fr - 22/01/2019

#include "glarea.h"
#include <QDebug>
#include <QSurfaceFormat>
#include <QMatrix4x4>



GLArea::GLArea(QWidget *parent) :
    QOpenGLWidget(parent)
{
    QSurfaceFormat sf;
    sf.setDepthBufferSize(24);
    sf.setSamples(16);
    setFormat(sf);

    setEnabled(true);                   // événements clavier et souris
    setFocusPolicy(Qt::StrongFocus);    // accepte focus
    setFocus();                         // donne le focus
}


GLArea::~GLArea()
{
    makeCurrent();
    doneCurrent();
}


void GLArea::initializeGL()
{
    initializeOpenGLFunctions();
    glClearColor(0.5f,0.5f,1.0f,1.0f);
    glEnable(GL_DEPTH_TEST);
	emit onInit((QOpenGLExtraFunctions *) this);
}


void GLArea::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
    windowRatio = float(w) / h;
}


void GLArea::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Matrice de projection
    QMatrix4x4 projectionMatrix;
    projectionMatrix.perspective(45.0f, windowRatio, 1.0f, 1000.0f);

    // Matrice de vue (caméra)
    QMatrix4x4 viewMatrix;
    viewMatrix.translate(xPos, yPos, zPos);
    viewMatrix.rotate(xRot, 1, 0, 0);
    viewMatrix.rotate(yRot, 0, 1, 0);
    viewMatrix.rotate(zRot, 0, 0, 1);

	emit onPaint((QOpenGLExtraFunctions *) this,
				 projectionMatrix,
				 viewMatrix);
}


void GLArea::keyPressEvent(QKeyEvent *ev)
{
    float da = 1.0f;

    switch(ev->key()) {
        case Qt::Key_A :
            xRot -= da;
            update();
            break;

        case Qt::Key_Q :
            xRot += da;
            update();
            break;

        case Qt::Key_Z :
            yRot -= da;
            update();
            break;

        case Qt::Key_S :
            yRot += da;
            update();
            break;

        case Qt::Key_E :
            zRot -= da;
            update();
            break;

        case Qt::Key_D :
            zRot += da;
            update();
            break;
    }
}


void GLArea::keyReleaseEvent(QKeyEvent *ev)
{
    qDebug() << __FUNCTION__ << ev->text();
}


void GLArea::mousePressEvent(QMouseEvent *ev)
{
    lastPos = ev->pos();
}


void GLArea::mouseReleaseEvent(QMouseEvent *ev)
{
    qDebug() << __FUNCTION__ << ev->x() << ev->y() << ev->button();
}


void GLArea::mouseMoveEvent(QMouseEvent *ev)
{
    int dx = ev->x() - lastPos.x();
    int dy = ev->y() - lastPos.y();

    if (ev->buttons() & Qt::LeftButton) {
        xRot += dy;
        yRot += dx;
        update();
    } else if (ev->buttons() & Qt::RightButton) {
        xPos += dx/10.0f;
        yPos -= dy/10.0f;
        update();
    } else if (ev->buttons() & Qt::MidButton) {
        xPos += dx/10.0f;
        zPos += dy;
        update();
    }

    lastPos = ev->pos();
}