/*
 * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * This is a port of the infamous "glxgears" demo to straight EGL
 * Port by Dane Rushton 10 July 2005
 *
 * No command line options.
 * Program runs for 5 seconds then exits, outputing framerate to console
 */
#define MAXFRAME    5
#define PFINISH     1

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

static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
static GLint gear1, gear2, gear3;
static GLfloat angle = 0.0;
static GLuint win_width = 1024;
static GLuint win_height = 512;
static GLuint frames = 0;

/*
 *  Draw a gear wheel.  You'll probably want to call this function when
 *  building a display list since we do a lot of trig here.
 *
 *  Input:  inner_radius - radius of hole at center
 *          outer_radius - radius at center of teeth
 *          width - width of gear
 *          teeth - number of teeth
 *          tooth_depth - depth of tooth
 */
static void gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
                 GLint teeth, GLfloat tooth_depth)
{
    GLint i;
    GLfloat r0, r1, r2;
    GLfloat angle, da;
    GLfloat u, v, len;

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

    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);
    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), 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);
    }
    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);
    }
    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), sin(angle), 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), sin(angle), 0.0);
    }

    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();
}

static void draw(void)
{
#if PFINISH
    fprintf(stderr, "EE CLEAR -----------------------------------------------------\n");
#endif
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
#if PFINISH
    glFinish();
    fprintf(stderr, "EE CLEAR _____________________________________________________\n");
#endif

#if PFINISH
    fprintf(stderr, "EE DRAW ------------------------------------------------------\n");
#endif
    glPushMatrix();
    glRotatef(view_rotx, 1.0, 0.0, 0.0);
    glRotatef(view_roty, 0.0, 1.0, 0.0);
    glRotatef(view_rotz, 0.0, 0.0, 1.0);

    glPushMatrix();
    glTranslatef(-3.0, -2.0, 0.0);
    glRotatef(angle, 0.0, 0.0, 1.0);
    glCallList(gear1);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(3.1, -2.0, 0.0);
    glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
    glCallList(gear2);
    glPopMatrix();

    glPushMatrix();
    glTranslatef(-3.1, 4.2, 0.0);
    glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
    glCallList(gear3);
    glPopMatrix();

    glPopMatrix();
#if PFINISH
    glFinish();
    fprintf(stderr, "EE DRAW ______________________________________________________\n");
#endif

    glutSwapBuffers();

    frames++;
    if (frames >= MAXFRAME) {
        glFinish();
        exit(0);
    }
}

static void idle(void)
{
    static double t0 = -1.;
    double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
    if (t0 < 0.0)
        t0 = t;
    dt = t - t0;
    t0 = t;

    angle += 70.0 * dt;  /* 70 degrees per second */
    angle = fmod(angle, 360.0); /* prevents eventual overflow */

    glutPostRedisplay();
}

/* new window size or exposure */
static void reshape(int width, int height)
{
    GLfloat h = (GLfloat) height / (GLfloat) width;

    glViewport(0, 0, (GLint) width, (GLint) height);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0, 0.0, -40.0);
}


static void init(void)
{
    static GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
    static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
    static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
    static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };

    glLightfv(GL_LIGHT0, GL_POSITION, pos);
    glEnable(GL_CULL_FACE);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_DEPTH_TEST);

    /* make the gears */
    gear1 = glGenLists(1);
    glNewList(gear1, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
    gear(1.0, 4.0, 1.0, 20, 0.7);
    glEndList();

    gear2 = glGenLists(1);
    glNewList(gear2, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
    gear(0.5, 2.0, 2.0, 10, 0.7);
    glEndList();

    gear3 = glGenLists(1);
    glNewList(gear3, GL_COMPILE);
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
    gear(1.3, 2.0, 0.5, 10, 0.7);
    glEndList();

    glEnable(GL_NORMALIZE);
}

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE | GLUT_STENCIL);
    glutInitWindowSize(win_width, win_height);

    glutCreateWindow("glgears");

    glutIdleFunc(idle);
    glutReshapeFunc(reshape);
    glutDisplayFunc(draw);

    init();
    reshape(win_width, win_height);
    glDrawBuffer(GL_BACK);
    glutMainLoop();

    return 0;
}