/********************************************************************************
* FaceTrackNoIR		This program is a private project of the some enthusiastic	*
*					gamers from Holland, who don't like to pay much for			*
*					head-tracking.												*
*																				*
* Copyright (C) 2010	Wim Vriend (Developing)									*
*						Ron Hendriks (Researching and Testing)					*
*																				*
* Homepage																		*
*																				*
* 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 3 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.																	*
*																				*
* Adopted this widget from the 'textures' sample of the Nokia Qt toolkit.		*
*																				*
* You should have received a copy of the GNU General Public License along		*
* with this program; if not, see <http://www.gnu.org/licenses/>.				*
*********************************************************************************/

#include <QtGui>
#include <QtOpenGL>

#include "glwidget.h"
#include <QWidget>

GLWidget::GLWidget(QWidget *parent, QGLWidget *shareWidget)
    : QGLWidget(parent, shareWidget)
{
#if !defined(_WIN32)
    setAttribute(Qt::WA_NativeWindow, true);
#endif
    clearColor = Qt::black;
    xRot = 0;
    yRot = 0;
    zRot = 0;

#ifdef QT_OPENGL_ES_2
    program = 0;
#endif
}

GLWidget::~GLWidget()
{
}

QSize GLWidget::minimumSizeHint() const
{
    return QSize(60, 60);
}

QSize GLWidget::sizeHint() const
{
    return QSize(90, 90);
}

void GLWidget::rotateBy(int xAngle, int yAngle, int zAngle)
{
    xRot = xAngle;
    yRot = yAngle;
    zRot = zAngle;
    updateGL();
}

void GLWidget::setClearColor(const QColor &color)
{
    clearColor = color;
    updateGL();
}

void GLWidget::initializeGL()
{
    makeObject();

    glDisable(GL_DEPTH_TEST);
    glEnable(GL_CULL_FACE);
#ifndef QT_OPENGL_ES_2
    glEnable(GL_TEXTURE_2D);
#endif

#ifdef QT_OPENGL_ES_2

#define PROGRAM_VERTEX_ATTRIBUTE 0
#define PROGRAM_TEXCOORD_ATTRIBUTE 1

    QGLShader *vshader = new QGLShader(QGLShader::Vertex, this);
    const char *vsrc =
        "attribute highp vec4 vertex;\n"
        "attribute mediump vec4 texCoord;\n"
        "varying mediump vec4 texc;\n"
        "uniform mediump mat4 matrix;\n"
        "void main(void)\n"
        "{\n"
        "    gl_Position = matrix * vertex;\n"
        "    texc = texCoord;\n"
        "}\n";
    vshader->compileSourceCode(vsrc);

    QGLShader *fshader = new QGLShader(QGLShader::Fragment, this);
    const char *fsrc =
        "uniform sampler2D texture;\n"
        "varying mediump vec4 texc;\n"
        "void main(void)\n"
        "{\n"
        "    gl_FragColor = texture2D(texture, texc.st);\n"
        "}\n";
    fshader->compileSourceCode(fsrc);

    program = new QGLShaderProgram(this);
    program->addShader(vshader);
    program->addShader(fshader);
    program->bindAttributeLocation("vertex", PROGRAM_VERTEX_ATTRIBUTE);
    program->bindAttributeLocation("texCoord", PROGRAM_TEXCOORD_ATTRIBUTE);
    program->link();

    program->bind();
    program->setUniformValue("texture", 0);
#else
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
    glTexCoordPointer(2, GL_FLOAT, 0, texCoords.constData());
#endif
}

void GLWidget::paintGL()
{
    glClearColor(0, 0, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

#if 1

    glLoadIdentity();
    glTranslatef(0.0f, 0.0f, -10.0f);

	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
    glRotatef(-1.0f * zRot, 0.0f, 0.0f, 1.0f);

#else

    QMatrix4x4 m;
    m.ortho(-0.5f, +0.5f, +0.5f, -0.5f, 4.0f, 15.0f);
    m.translate(0.0f, 0.0f, -10.0f);
    m.rotate(xRot / 16.0f, 1.0f, 0.0f, 0.0f);
    m.rotate(yRot / 16.0f, 0.0f, 1.0f, 0.0f);
    m.rotate(zRot / 16.0f, 0.0f, 0.0f, 1.0f);

    program->setUniformValue("matrix", m);
    program->enableAttributeArray(PROGRAM_VERTEX_ATTRIBUTE);
    program->enableAttributeArray(PROGRAM_TEXCOORD_ATTRIBUTE);
    program->setAttributeArray
        (PROGRAM_VERTEX_ATTRIBUTE, vertices.constData());
    program->setAttributeArray
        (PROGRAM_TEXCOORD_ATTRIBUTE, texCoords.constData());

#endif

    for (int i = 0; i < 6; ++i) {
        glBindTexture(GL_TEXTURE_2D, textures[i]);
        glDrawArrays(GL_TRIANGLE_FAN, i * 4, 4);
    }
    glFlush();
}

void GLWidget::resizeGL(int width, int height)
{
    int side = qMin(width, height);
    glViewport((width - side) / 2, (height - side) / 2, side, side);

#if !defined(QT_OPENGL_ES_2)
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
#ifndef QT_OPENGL_ES
    glOrtho(-0.5, +0.5, +0.5, -0.5, 4.0, 15.0);
#else
    glOrthof(-0.5, +0.5, +0.5, -0.5, 4.0, 15.0);
#endif
    glMatrixMode(GL_MODELVIEW);
#endif
}

void GLWidget::makeObject()
{
    static const int coords[6][4][3] = {
        { { +1, -1, -1 }, { -1, -1, -1 }, { -1, +1, -1 }, { +1, +1, -1 } },
        { { +1, +1, -1 }, { -1, +1, -1 }, { -1, +1, +1 }, { +1, +1, +1 } },
        { { +1, -1, +1 }, { +1, -1, -1 }, { +1, +1, -1 }, { +1, +1, +1 } },
        { { -1, -1, -1 }, { -1, -1, +1 }, { -1, +1, +1 }, { -1, +1, -1 } },
        { { +1, -1, +1 }, { -1, -1, +1 }, { -1, -1, -1 }, { +1, -1, -1 } },
        { { -1, -1, +1 }, { +1, -1, +1 }, { +1, +1, +1 }, { -1, +1, +1 } }
    };

    for (int j=0; j < 6; ++j) {
        textures[j] = bindTexture
            (QPixmap(QString(":/images/side%1.png").arg(j + 1)), GL_TEXTURE_2D);
    }

    for (int i = 0; i < 6; ++i) {
        for (int j = 0; j < 4; ++j) {
            texCoords.append
                (QVector2D(j == 0 || j == 3, j == 0 || j == 1));
            vertices.append
                (QVector3D(0.4 * coords[i][j][0], 0.4 * coords[i][j][1],
                           0.02 * coords[i][j][2]));
        }
    }
}