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

Copyright (C) 2009 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/>.

Based on Compiz Fusion cube gear plugin by Dennis Kasprzyk:
    http://gitweb.compiz-fusion.org/?p=fusion/plugins/gears;a=blob;f=gears.c;hb=HEAD
Which is based on glxgears.c by Brian Paul:
    http://cvsweb.xfree86.org/cvsweb/xc/programs/glxgears/glxgears.c
*********************************************************************/

#include "gears.h"
#include "../cube/cube_proxy.h"

#include <math.h>

#include <GL/gl.h>

namespace KWin
{

KWIN_EFFECT(gears, GearsEffect)
KWIN_EFFECT_SUPPORTED(gears, GearsEffect::supported())

GearsEffect::GearsEffect()
    : CubeInsideEffect()
    , m_active(false)
    , m_contentRotation(0.0f)
    , m_angle(0.0f)
{
    CubeEffectProxy* proxy =
        static_cast<CubeEffectProxy*>(effects->getProxy("cube"));
    if (proxy)
        proxy->registerCubeInsideEffect(this);
}

GearsEffect::~GearsEffect()
{
    CubeEffectProxy* proxy =
        static_cast<CubeEffectProxy*>(effects->getProxy("cube"));
    if (proxy)
        proxy->unregisterCubeInsideEffect(this);
}

bool GearsEffect::supported()
{
    return effects->compositingType() == OpenGLCompositing;
}

void GearsEffect::prePaintScreen(ScreenPrePaintData& data, int time)
{
    if (m_active) {
        m_contentRotation += time * 360.0f / 20000.0f;
        if (m_contentRotation > 360.0f)
            m_contentRotation -= 360.0f;
        m_angle += time * 360.0f / 8000.0f;
        if (m_angle > 360.0f)
            m_angle -= 360.0f;
    }
    effects->prePaintScreen(data, time);
}

void GearsEffect::postPaintScreen()
{
    if (m_active) {
        effects->addRepaintFull();
    }
    effects->postPaintScreen();
}


void GearsEffect::paint()
{
    if (m_active) {
        paintGears();
    }
}

void GearsEffect::setActive(bool active)
{
    m_active = active;
    if (active)
        initGears();
    else
        endGears();
}

void GearsEffect::gear(float inner_radius, float outer_radius, float width, int teeth, float tooth_depth)
{
    GLint i;
    GLfloat r0, r1, r2, maxr2, minr2;
    GLfloat angle, da;
    GLfloat u, v, len;

    r0 = inner_radius;
    r1 = outer_radius - tooth_depth / 2.0;
    maxr2 = r2 = outer_radius + tooth_depth / 2.0;
    minr2 = r2;

    da = 2.0 * M_PI / teeth / 4.0;

    glShadeModel(GL_FLAT);

    glNormal3f(0.0, 0.0, 1.0);

    /* draw front face */
    glBegin(GL_QUAD_STRIP);

    for (i = 0; i <= teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;
        glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
        glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);

        if (i < teeth) {
            glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
            glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
        }
    }

    glEnd();

    /* draw front sides of teeth */
    glBegin(GL_QUADS);

    for (i = 0; i < teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;

        glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
        glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
        glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
        glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
        r2 = minr2;
    }

    r2 = maxr2;

    glEnd();

    glNormal3f(0.0, 0.0, -1.0);

    /* draw back face */
    glBegin(GL_QUAD_STRIP);

    for (i = 0; i <= teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;
        glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
        glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);

        if (i < teeth) {
            glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
            glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
        }
    }

    glEnd();

    /* draw back sides of teeth */
    glBegin(GL_QUADS);
    da = 2.0 * M_PI / teeth / 4.0;

    for (i = 0; i < teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;

        glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
        glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
        glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
        glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
        r2 = minr2;
    }

    r2 = maxr2;

    glEnd();

    /* draw outward faces of teeth */
    glBegin(GL_QUAD_STRIP);

    for (i = 0; i < teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;

        glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
        glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
        u = r2 * cos(angle + da) - r1 * cos(angle);
        v = r2 * sin(angle + da) - r1 * sin(angle);
        len = sqrt(u * u + v * v);
        u /= len;
        v /= len;
        glNormal3f(v, -u, 0.0);
        glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
        glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
        glNormal3f(cos(angle + 1.5 * da), sin(angle + 1.5 * da), 0.0);
        glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
        glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
        u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
        v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
        glNormal3f(v, -u, 0.0);
        glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
        glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
        glNormal3f(cos(angle + 3.5 * da), sin(angle + 3.5 * da), 0.0);
        r2 = minr2;
    }

    r2 = maxr2;

    glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
    glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);

    glEnd();

    glShadeModel(GL_SMOOTH);

    /* draw inside radius cylinder */
    glBegin(GL_QUAD_STRIP);

    for (i = 0; i <= teeth; ++i) {
        angle = i * 2.0 * M_PI / teeth;
        glNormal3f(-cos(angle), -sin(angle), 0.0);
        glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
        glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
    }
    glEnd();
}

void GearsEffect::paintGears()
{
    static GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
    QRect rect = effects->clientArea(FullArea, effects->activeScreen(), effects->currentDesktop());

    glPushMatrix();
    // invert scale
    float fovy = 60.0f;
    float zNear = 0.1f;
    float ymax = zNear * tan(fovy  * M_PI / 360.0f);
    float ymin = -ymax;
    float xmin =  ymin;
    float xmax = ymax;
    float scaleFactor = 1.1 * tan(fovy * M_PI / 360.0f) / ymax;
    glScalef(1.0f / ((xmax - xmin)*scaleFactor / displayWidth()), 1.0f / (-(ymax - ymin)*scaleFactor / displayHeight()), 1000.0f);

    glPushAttrib(GL_COLOR_BUFFER_BIT | GL_TEXTURE_BIT | GL_ENABLE_BIT | GL_LIGHTING_BIT);

    glDisable(GL_BLEND);

    glPushMatrix();

    // content rotation requires depth test - so disabled
//     glRotatef( m_contentRotation, 0.0, 1.0, 0.0 );

    glScalef(0.05, 0.05, 0.05);

    glEnable(GL_NORMALIZE);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT1);
    glDisable(GL_COLOR_MATERIAL);

    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    glPushMatrix();
    glTranslatef(-3.0, -2.0, 0.0);
    glRotatef(m_angle, 0.0, 0.0, 1.0);
    glCallList(m_gear1);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(3.1, -2.0, 0.0);
    glRotatef(-2.0 * m_angle - 9.0, 0.0, 0.0, 1.0);
    glCallList(m_gear2);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(-3.1, 4.2, 0.0);
    glRotatef(-2.0 * m_angle - 25.0, 0.0, 0.0, 1.0);
    glCallList(m_gear3);
    glPopMatrix();

    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, white);

    glPopMatrix();

    glDisable(GL_LIGHT1);
    glDisable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);

    glDisable(GL_LIGHTING);

    glPopMatrix();
    glPopAttrib();
}

void GearsEffect::initGears()
{
    static GLfloat pos[4]         = { 5.0f, 5.0f, 10.0f, 0.0f };
    static GLfloat red[4]         = { 0.8f, 0.1f, 0.0f, 1.0f };
    static GLfloat green[4]       = { 0.0f, 0.8f, 0.2f, 1.0f };
    static GLfloat blue[4]        = { 0.2f, 0.2f, 1.0f, 1.0f };
    static GLfloat ambientLight[] = { 0.3f, 0.3f, 0.3f, 0.3f };
    static GLfloat diffuseLight[] = { 0.5f, 0.5f, 0.5f, 0.5f };

    glLightfv(GL_LIGHT1, GL_AMBIENT, ambientLight);
    glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuseLight);
    glLightfv(GL_LIGHT1, GL_POSITION, pos);

    m_gear1 = glGenLists(1);
    glNewList(m_gear1, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
    gear(1.0f, 4.0f, 1.0f, 20, 0.7f);
    glEndList();

    m_gear2 = glGenLists(1);
    glNewList(m_gear2, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
    gear(0.5f, 2.0f, 2.0f, 10, 0.7f);
    glEndList();

    m_gear3 = glGenLists(1);
    glNewList(m_gear3, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
    gear(1.3f, 2.0f, 0.5f, 10, 0.7f);
    glEndList();
}

void GearsEffect::endGears()
{
    glDeleteLists(m_gear1, 1);
    glDeleteLists(m_gear2, 1);
    glDeleteLists(m_gear3, 1);
}

} // namespace