// 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, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

// Copyright 2007, Daniel Fontijne, University of Amsterdam -- fontijne@science.uva.nl

#ifdef WIN32
#include <windows.h>
#endif

#include <GL/gl.h>
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>

#include <string>

#include <libgasandbox/e3ga.h>
#include <libgasandbox/e3ga_draw.h>
#include <libgasandbox/e3ga_util.h>
#include <libgasandbox/gl_util.h>
#include <libgasandbox/glut_util.h>
#include <libgasandbox/timing.h>

using namespace e3ga;
using namespace mv_draw;

const char *WINDOW_TITLE = "Geometric Algebra, Chapter 7, Example 1: Reflecting in Vectors";

// GLUT state information
int g_viewportWidth = 800;
int g_viewportHeight = 600;
int g_GLUTmenu;

// mouse position on last call to MouseButton() / MouseMotion()
e3ga::vector g_prevMousePos;

// when true, MouseMotion() will rotate the model
bool g_rotateModel = false;
bool g_rotateModelOutOfPlane = false;

// rotation of the model
rotor g_modelRotor(_rotor(1.0f));

// when dragging vectors: which one, and at what depth:
float g_dragDistance = -1.0f;
int g_dragObject = -1;


// the vector in which we reflect (red)
e3ga::vector g_reflectionVector = _vector(e2);

// the vectors which we reflect (green)
e3ga::vector g_inputVector1 = _vector(e1 + e2);
e3ga::vector g_inputVector2 = _vector(e3);

// the reflected vectors (blue)
e3ga::vector g_reflectedVector1;
e3ga::vector g_reflectedVector2;

// what vectors to draw (bitmap):
int g_drawVectors = 1;




e3ga::vector reflectVector(const e3ga::vector &a, const e3ga::vector &x) {
    // we use a _line_ reflection for this example
    return _vector(a * x * inverse(a));
}

void display() {
    doIntelWarning(); // warn for possible problems with pciking on Intel graphics chipsets

    // update the reflected vectors
    g_reflectedVector1 = reflectVector(g_reflectionVector, g_inputVector1);
    g_reflectedVector2 = reflectVector(g_reflectionVector, g_inputVector2);

    // setup projection & transform for the vectors:
    glViewport(0, 0, g_viewportWidth, g_viewportHeight);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glMatrixMode(GL_PROJECTION);
    const float screenWidth = 1600.0f;
    glLoadIdentity();
    pickLoadMatrix();
    GLpick::g_frustumWidth = 2.0 *  (double)g_viewportWidth / screenWidth;
    GLpick::g_frustumHeight = 2.0 *  (double)g_viewportHeight / screenWidth;
    glFrustum(
        -GLpick::g_frustumWidth / 2.0, GLpick::g_frustumWidth / 2.0,
        -GLpick::g_frustumHeight / 2.0, GLpick::g_frustumHeight / 2.0,
        GLpick::g_frustumNear, GLpick::g_frustumFar);
    glMatrixMode(GL_MODELVIEW);
    glTranslatef(0.0f, 0.0f, -8.0f);


    glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_DEPTH_TEST);
    glPolygonMode(GL_FRONT, GL_FILL);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glLineWidth(2.0f);


    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();

    rotorGLMult(g_modelRotor);

    // draw reflection vector
    if (GLpick::g_pickActive) glLoadName(1);
    glColor3fm(1.0f, 0.0f, 0.0f);
    draw(g_reflectionVector);

    if (g_drawVectors & 1) {
        // draw input vector 1
        if (GLpick::g_pickActive) glLoadName(2);
        glColor3fm(0.0f, 1.0f, 0.0f);
        draw(g_inputVector1);
    }

    if (g_drawVectors & 2) {
        // draw input vector 2
        if (GLpick::g_pickActive) glLoadName(3);
        glColor3fm(0.0f, 1.0f, 0.0f);
        draw(g_inputVector2);
    }

    if (!GLpick::g_pickActive) {
        if ((g_drawVectors & 3) == 3) {
            g_drawState.pushDrawModeOff(OD_ORIENTATION);

            glColor3fm(0.0f, 1.0f, 0.0f);
            draw(g_inputVector1 ^ g_inputVector2);
            glColor3fm(0.0f, 0.0f, 1.0f);
            draw(g_reflectedVector1 ^ g_reflectedVector2);
            g_drawState.popDrawMode();
        }


        if (g_drawVectors & 1) {
            // draw reflected vector 1
            glColor3fm(0.0f, 0.0f, 1.0f);
            draw(g_reflectedVector1);
        }

        if (g_drawVectors & 2) {
            // draw reflected vector 2
            glColor3fm(0.0f, 0.0f, 1.0f);
            draw(g_reflectedVector2);
        }

        // draw stippled line between input and reflection:
        glDisable(GL_LIGHTING);
        glEnable(GL_LINE_STIPPLE);
        int ST = 0xFF00FF >> ((int)(u_timeGet() * 25) % 16);
        glLineStipple(1, ( GLushort)(ST & 0xFFFF));
        glColor3fm(0.5f, 0.5f, 0.5f);

        if (g_drawVectors & 1) {
            glBegin(GL_LINES);
            glVertex3fv(g_reflectedVector1.getC(vector_e1_e2_e3));
            glVertex3fv(g_inputVector1.getC(vector_e1_e2_e3));
            glEnd();
        }

        if (g_drawVectors & 2) {
            glBegin(GL_LINES);
            glVertex3fv(g_reflectedVector2.getC(vector_e1_e2_e3));
            glVertex3fv(g_inputVector2.getC(vector_e1_e2_e3));
            glEnd();
        }

        glDisable(GL_LINE_STIPPLE);
    }


    glPopMatrix();

    if (!GLpick::g_pickActive) {
        glViewport(0, 0, g_viewportWidth, g_viewportHeight);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, g_viewportWidth, 0, g_viewportHeight, -100.0, 100.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        glDisable(GL_LIGHTING);
        glColor3f(1.0f, 1.0f, 1.0f);
        void *font = GLUT_BITMAP_HELVETICA_12;
        renderBitmapString(20, 60, font, "The green vector(s) are reflected in plane orthogonal to the red vector.");
        renderBitmapString(20, 40, font, "Use the left mouse button to drag the (green or red) vectors and orbit the scene.");
        renderBitmapString(20, 20, font, "Use the other mouse buttons to access the popup menu.");
    }

    if (!GLpick::g_pickActive) {
        glutSwapBuffers();
    }
}

void reshape(GLint width, GLint height) {
    g_viewportWidth = width;
    g_viewportHeight = height;

    // redraw viewport
    glutPostRedisplay();
}


e3ga::vector vectorAtDepth(double depth, const e3ga::vector &v2d) {
    if ((GLpick::g_frustumWidth <= 0) || (GLpick::g_frustumHeight <= 0) ||
        (GLpick::g_frustumNear <= 0) || (GLpick::g_frustumFar <= 0)) {
        return e3ga::vector();
    }

    return _vector((depth * (double)v2d.e1() * GLpick::g_frustumWidth) / (g_viewportWidth * GLpick::g_frustumNear) * e1 +
        (depth * (double)v2d.e2() * GLpick::g_frustumHeight) / (g_viewportHeight * GLpick::g_frustumNear) * e2);
}


e3ga::vector mousePosToVector(int x, int y) {
    x -= g_viewportWidth / 2;
    y -= g_viewportHeight / 2;
    return e3ga::_vector((float)x * e3ga::e1 - (float)y * e3ga::e2);
}

void MouseButton(int button, int state, int x, int y) {
    g_rotateModel = false;

    g_prevMousePos = mousePosToVector(x, y);

    g_dragObject = pick(x, g_viewportHeight - y, display, &g_dragDistance);
    if (g_dragObject < 0) {
        e3ga::vector mousePos = mousePosToVector(x, y);
        g_rotateModel = true;
        if ((_Float(norm_e(mousePos)) / _Float(norm_e(g_viewportWidth * e1 + g_viewportHeight * e2))) < 0.2)
            g_rotateModelOutOfPlane = true;
        else g_rotateModelOutOfPlane = false;
    }
}

void MouseMotion(int x, int y) {
    // get mouse position, motion
    e3ga::vector mousePos = mousePosToVector(x, y);
    e3ga::vector motion = _vector(mousePos - g_prevMousePos);
    if (g_rotateModel) {
        // update rotor
        if (g_rotateModelOutOfPlane)
            g_modelRotor = _rotor(e3ga::exp(0.005f * (motion ^ e3ga::e3)) * g_modelRotor);
        else g_modelRotor = _rotor(e3ga::exp(0.00001f * (motion ^ mousePos)) * g_modelRotor);
    }
    else if ((g_dragObject >= 1) && (g_dragObject <= 3)) {
        // add motion to vector:
        e3ga::vector T = vectorAtDepth(g_dragDistance, motion);
        T = _vector(inverse(g_modelRotor) * T * g_modelRotor);
        if (g_dragObject == 1) {
            g_reflectionVector += T;
        }
        else if (g_dragObject == 2) {
            g_inputVector1  += T;
        }
        else if (g_dragObject == 3) {
            g_inputVector2  += T;
        }
    }

    // remember mouse pos for next motion:
    g_prevMousePos = mousePos;

    // redraw viewport
    glutPostRedisplay();
}

void menuCallback(int value) {
    g_drawVectors = value;

    // redraw viewport
    glutPostRedisplay();
}

void Idle() {
    // redraw viewport
    glutPostRedisplay();
}

int main(int argc, char*argv[]) {
    // profiling for Gaigen 2:
    e3ga::g2Profiling::init();

    // GLUT Window Initialization:
    glutInit (&argc, argv);
    glutInitWindowSize(g_viewportWidth, g_viewportHeight);
    glutInitDisplayMode( GLUT_RGB | GLUT_ALPHA | GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow(WINDOW_TITLE);

    // Register callbacks:
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutMouseFunc(MouseButton);
    glutMotionFunc(MouseMotion);
    glutIdleFunc(Idle);

    g_GLUTmenu = glutCreateMenu(menuCallback);
    glutAddMenuEntry("vector mode", 1);
    glutAddMenuEntry("bivector mode", 3);
    glutAttachMenu(GLUT_MIDDLE_BUTTON);
    glutAttachMenu(GLUT_RIGHT_BUTTON);


    glutMainLoop();

    return 0;
}