/*
 * 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 <stdlib.h>
#include <math.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glew.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 GLfloat cube_rot = 0.0;
static GLuint gears_fbo, gears_tex;
static GLuint win_width = 1024;
static GLuint win_height = 512;
static GLuint frames = 0;
static GLuint renderbuffers[3];
static GLuint nrenderbuffers = 0;

GLuint generate_simple_fbo(unsigned width, unsigned height)
{
    GLuint fb;
    GLenum status;
    unsigned color, stencil, depth, packed;

    color = stencil = depth = packed = 1;

    /* texture */
    glGenTextures(1, &gears_tex);
    glBindTexture(GL_TEXTURE_2D, gears_tex);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    glGenFramebuffers(1, &fb);
    glBindFramebuffer(GL_FRAMEBUFFER, fb);


    if (color) {
#if 0
        glGenRenderbuffers(1, &renderbuffers[nrenderbuffers]);
        glBindRenderbuffer(GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, width, height);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        nrenderbuffers++;
#else
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, gears_tex, 0);
#endif
    }

    if (stencil) {
        const GLenum format = (packed)
            ? GL_DEPTH24_STENCIL8
            : GL_STENCIL_INDEX8;
        const GLenum attachment = (packed)
            ? GL_DEPTH_STENCIL_ATTACHMENT
            : GL_STENCIL_ATTACHMENT;

        glGenRenderbuffers(1, &renderbuffers[nrenderbuffers]);
        glBindRenderbuffer(GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        glRenderbufferStorage(GL_RENDERBUFFER, format, width, height);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, attachment, GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        nrenderbuffers++;
    }

    if (!packed && depth) {
        glGenRenderbuffers(1, &renderbuffers[nrenderbuffers]);
        glBindRenderbuffer(GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffers[nrenderbuffers]);
        nrenderbuffers++;
    }

    status = glGetError();
    if (status != GL_NO_ERROR) {
        fprintf(stderr, "Unexpected GL error: 0x%x\n", status);
        exit(1);
    }

    /* All of the possible combinations that we can generate are required
     * to be supported by all OpenGL 3.0 implementations, with one
     * exception.  As far as I can tell, implementations are not required
     * to support separate depth and stencil.  That one option is handled
     * specially.
     */
    status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    if (status != GL_FRAMEBUFFER_COMPLETE
        && !(status == GL_FRAMEBUFFER_UNSUPPORTED && stencil && !packed)) {
        fprintf(stderr,
            "Framebuffer %s color, %s stencil (%s) was not "
            "complete: 0x%04x\n",
            color ? "with" : "without",
            stencil ? "with" : "without",
            packed ? "packed" : "separate",
            status);
        exit(1);
    }

    if (status == GL_FRAMEBUFFER_UNSUPPORTED) {
        glDeleteRenderbuffers(nrenderbuffers, renderbuffers);
        glDeleteFramebuffers(1, &fb);
        fprintf(stderr, "Unsupported framebuffer\n");
        exit(1);
    }
    glBindFramebuffer(GL_FRAMEBUFFER, 0);

#if 0
    glClearColor(0.2, 0.4, 0.6, 1.0);
    glClearDepth(0.5);
    glClearStencil(0x7a);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    glFinish();
#endif
    return fb;
}

/*
 *  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_gear(void)
{
#if PFINISH
    fprintf(stderr, "EE CLEAR FBO -------------------------------------------------\n");
#endif
    glBindFramebuffer(GL_FRAMEBUFFER, gears_fbo);
    glClearColor(0.5, 0.5, 0.8, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
#if PFINISH
    fprintf(stderr, "EE CLEAR FBO _________________________________________________\n");
#endif

#if PFINISH
    fprintf(stderr, "EE DRAW FBO --------------------------------------------------\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();
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
#if PFINISH
    fprintf(stderr, "EE DRAW FBO __________________________________________________\n");
#endif
}

static void draw_cube(void)
{
    static const GLfloat texcoords[4][2] = {
        { 0, 0 }, { 1, 0 }, { 1, 1 }, { 0, 1 }
    };
    static const GLfloat vertices[4][2] = {
        { -1, -1 }, { 1, -1 }, { 1, 1 }, { -1, 1 }
    };
    static const GLfloat xforms[6][4] = {
        {   0, 0, 1, 0 },
        {  90, 0, 1, 0 },
        { 180, 0, 1, 0 },
        { 270, 0, 1, 0 },
        {  90, 1, 0, 0 },
        { -90, 1, 0, 0 }
    };
    static const GLfloat mat[4] = { 1.0, 1.0, 0.5, 1.0 };
    float ar;
    GLint i, j;

#if PFINISH
    fprintf(stderr, "EE CLEAR -----------------------------------------------------\n");
#endif
    glClearColor(0.8, 0.5, 0.5, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
#if PFINISH
    fprintf(stderr, "EE CLEAR _____________________________________________________\n");
#endif

#if PFINISH
    fprintf(stderr, "EE DRAW ------------------------------------------------------\n");
#endif
    ar = (float)win_width / win_height;
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-ar, ar, -1.0, 1.0, 5.0, 60.0);
    glMatrixMode(GL_MODELVIEW);
    glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, gears_tex);

    glPushMatrix();
    glRotatef(view_rotx, 1.0, 0.0, 0.0);
    glRotatef(15, 1, 0, 0);
    glRotatef(cube_rot, 0, 1, 0);
    glScalef(4, 4, 4);

    for (i = 0; i < 6; i++) {
        glPushMatrix();
        glRotatef(xforms[i][0], xforms[i][1], xforms[i][2], xforms[i][3]);
        glTranslatef(0, 0, 1.1);
        glBegin(GL_POLYGON);
        glNormal3f(0, 0, 1);
        for (j = 0; j < 4; j++) {
            glTexCoord2fv(texcoords[j]);
            glVertex2fv(vertices[j]);
        }
        glEnd();
        glPopMatrix();
    }
    glPopMatrix();

    glDisable(GL_TEXTURE_2D);
#if PFINISH
    fprintf(stderr, "EE DRAW ______________________________________________________\n");
#endif
}

static void draw(void)
{
#if PFINISH
    fprintf(stderr, "EE FRAME -----------------------------------------------------\n");
#endif
    draw_gear();

    draw_cube();
#if PFINISH
    glFinish();
    fprintf(stderr, "EE FRAME _____________________________________________________\n");
#endif
    glutSwapBuffers();
    frames++;
    if (frames >= MAXFRAME) {
        exit(0);
    }
}

static void idle(void)
{
    static double t0 = -1.;
    double dt, t;

    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 */
    cube_rot = fmod(cube_rot + 15.0 * dt, 360.0);  /* 15 deg/sec */

    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);

    win_width = width;
    win_height = height;
}

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();

    gears_fbo = generate_simple_fbo(512, 512);

    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");

    GLenum err = glewInit();
    if (GLEW_OK != err) {
        fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
        return -1;
    }

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

    init();
    reshape(win_width, win_height);
    glutMainLoop();
    return 0;
}