/*****************************************************************
  example0.cpp
  by Dave Pape
  17 Feb 2003

*****************************************************************/
#include <stdlib.h>
#include <math.h>
#include <unistd.h>
#include <stdio.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <dms/Util.h>

void drawEverything(void);
void key(unsigned char k, int x, int y);
void specialkey(int k, int x, int y);
void idle(void);

GLfloat cameraPos[3] = {0, 0, 10};
GLfloat cameraXrot = 0, cameraYrot = 0;
GLfloat cameraFovy = 45.0;


int main(int argc, char *argv[])
    {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(512,512);
    glutCreateWindow(argv[0]);
    
    glutDisplayFunc(drawEverything);
    glutKeyboardFunc(key);
    glutSpecialFunc(specialkey);
    glutIdleFunc(idle);
    
    glutMainLoop();
    return 0;
    }


void initLight(void)
    {
    GLfloat position[] = { -5, 4, 1, 0 };
    GLfloat color[] = {1, 1, 1, 1};
    glEnable(GL_LIGHT0);
    glLightfv(GL_LIGHT0, GL_POSITION, position);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, color);
    }


void drawFloorMesh(int columns,int rows)
    {
    int i,j;
    GLfloat x,z;
    GLfloat green[] = {0, 0.8, 0, 1};
    GLfloat black[] = {0, 0, 0, 1};
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
    glMaterialfv(GL_FRONT, GL_SPECULAR, black);
    glNormal3f(0.0, 1.0, 0.0);
    for (j = 0; j < rows; j++)
        {
        glBegin(GL_TRIANGLE_STRIP);
        for (i = 0; i < columns; i++)
            {
            x = (((float)i) / columns) * 40.0 - 20.0;
            z = (((float)j) / rows) * 40.0 - 20.0;
            glVertex3f(x, -2.0, z);
            z = (((float)j+1) / rows) * 40.0 - 20.0;
            glVertex3f(x, -2.0, z);
            }
        glEnd();
        }
    }


void drawTeapot(void)
    {
    GLfloat red[] = {0.8, 0, 0, 1};
    GLfloat white[] = {1, 1, 1, 1};
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
    glMaterialfv(GL_FRONT, GL_SPECULAR, white);
    glMaterialf(GL_FRONT, GL_SHININESS, 90.0);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glPushMatrix();
     glTranslatef(2.0, 4.0, -1.0);
     glRotatef(dms::currentTime() * 30.0, 0.0, 1.0, 0.0);
     glutSolidTeapot(2.0);
    glPopMatrix();
    glDisable(GL_BLEND);
    }


void drawPedestal(void)
    {
    static GLUquadricObj * quadric = NULL;
    GLfloat grey[4] = { 0.6, 0.6, 0.6, 1 };
    GLfloat white[4] = { 1, 1, 1, 1 };
    if (!quadric)
        quadric = gluNewQuadric();
    glMaterialfv(GL_FRONT, GL_AMBIENT, grey);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, grey);
    glMaterialfv(GL_FRONT, GL_SPECULAR, white);
    glMaterialf(GL_FRONT, GL_SHININESS, 30.0);
    glPushMatrix();
     glTranslatef(2.0, -2.0, -1.0);
     glRotatef(-90.0, 1.0, 0.0, 0.0);
     gluCylinder(quadric, 4.0, 4.0, 4.0, 16, 1);
     glTranslatef(0.0, 0.0, 4.0);
     gluDisk(quadric, 0.0, 4.0, 16, 1);
    glPopMatrix();
    }


void drawBall(void)
    {
    GLfloat cyan[] = {0, 1, 1, 1};
    GLfloat black[] = {0, 0, 0, 1};
    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, cyan);
    glMaterialfv(GL_FRONT, GL_SPECULAR, black);
    glPushMatrix();
     glTranslatef(-10.0, fabs(sin(dms::currentTime())) * 3.0, -15.0);
     glutSolidSphere(2.0, 16, 8);
    glPopMatrix();
    }


void drawEverything(void)
    {
    glClearColor(0.5, 0.7, 1.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(cameraFovy, 1.0, 1.0, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glRotatef(-cameraXrot, 1.0, 0.0, 0.0);
    glRotatef(-cameraYrot, 0.0, 1.0, 0.0);
    glTranslatef(-cameraPos[0], -cameraPos[1], -cameraPos[2]);
    
    glEnable(GL_LIGHTING);
    initLight();

    drawFloorMesh(32,32);
    drawTeapot();
    drawPedestal();
    drawBall();

    glDisable(GL_LIGHTING);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    
    glDisable(GL_DEPTH_TEST);
    glColor3f(0.2, 0.1, 0.0);
    glBegin(GL_QUADS);
     glVertex2f(0.0, 0.0);
     glVertex2f(1.0, 0.0);
     glVertex2f(1.0, 0.05);
     glVertex2f(0.0, 0.05);
    glEnd();
    glColor3f(1.0, 1.0, 0.0);
    glRasterPos2f(0.4, 0.01);
    dms::drawString("example0");

    glutSwapBuffers();

    dms::checkGLError("end-of-frame");
    }


void key(unsigned char k, int x, int y)
    {
    if (k == 27)
        exit(0);
    glutPostRedisplay();
    }


void specialkey(int k, int x, int y)
    {
    if (k == GLUT_KEY_LEFT)
        cameraYrot += 3;
    else if (k == GLUT_KEY_RIGHT)
        cameraYrot -= 3;
    else if (k == GLUT_KEY_UP)
        cameraXrot += 2;
    else if (k == GLUT_KEY_DOWN)
        cameraXrot -= 2;
    else if (k == GLUT_KEY_HOME)
        cameraPos[2] -= 0.25;
    else if (k == GLUT_KEY_END)
        cameraPos[2] += 0.25;
    else if (k == GLUT_KEY_PAGE_UP)
        cameraFovy -= 1;
    else if (k == GLUT_KEY_PAGE_DOWN)
        cameraFovy += 1;
    glutPostRedisplay();
    }


void idle(void)
    {
    glutPostRedisplay();
    }