/* Creates a bicycle object.  Demonstrates affine transforms.

Note on the objects used: glutSolidTorus is drawn in the xy plane 
from its center; twSolidCylinder is centered in the xz plane and is
drawn downward from y = 0.

Written by Caroline Geiersbach and Scott D. Anderson
scott.anderson@acm.org
Summer 2003
*/

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

//colors used
twTriple tireColor = {0.1,0.1,0.1};
twTriple frameColor = {0.2,0,0.6};

//draws one tire and its spokes
void drawTire() {
  int i;
  glPushMatrix();
  twColor(tireColor,0.9,50.0);
  glutSolidTorus(0.3,3.0,30,30); 
  for(i=0;i<12;i++) {  //spokes
    glRotatef(30,0,0,1);
    twSolidCylinder(0.03,0.03,3.0,10,10);
  }
  glPopMatrix();
}

//draws handlebars
void drawHandlebar() {
  glPushMatrix();
  twSolidCylinder(0.2,0.2,3,20,20);
  glRotatef(90,1,0,0);
  glTranslatef(0,3,0);
  twSolidCylinder(0.2,0.2,6,20,20);
  glPopMatrix();
}

//draws seat
void drawSeat() {
  glPushMatrix();
  twSolidCylinder(0.2,0.2,2,20,20); //post
  glRotatef(90,0,0,1);
  glScalef(0.5,1,1);                //flatten seat (y-direction)
  twSolidCylinder(1,0.2,2.5,20,20); //seat
  glPopMatrix();
}

//used three times in the bicycle, oriented downwards (y-direction)
void parallelBars(GLfloat length) {
  glPushMatrix();
  glTranslatef(0,0,0.5);
  twSolidCylinder(0.1,0.1,length,20,20);
  glTranslatef(0,0,-1);
  twSolidCylinder(0.1,0.1,length,20,20);
  //connect the bars
  glRotatef(-90,1,0,0);
  twSolidCylinder(0.1,0.1,1,20,20);
  glTranslatef(0,0,-length);
  twSolidCylinder(0.1,0.1,1,20,20);
  glPopMatrix();
}

void frame() {
  twColor(frameColor,0.9,100);
  //draw center bar
  glPushMatrix();
  glTranslatef(-5,0,0);
  glRotatef(90,0,0,1);
  twSolidCylinder(0.2,0.2,10,20,20); 
  glPopMatrix();
  //draw back frame
  glPushMatrix();
  glTranslatef(-5,0,0);
  GLfloat angle = atan(2.0/5.0)*180/M_PI;
  glRotatef(-angle,0,0,1);
  parallelBars(sqrt(29));
  glRotatef(angle*2,0,0,1);
  twSolidCylinder(0.2,0.2,sqrt(29),20,20);
  glPopMatrix();
  //draw front frame
  glPushMatrix();
  glTranslatef(5,0,0);
  glRotatef(angle,0,0,1);
  parallelBars(sqrt(29));
  GLfloat angle2 = atan(8.0/5.0)*180/M_PI;
  glRotatef(-angle2-angle,0,0,1);
  twSolidCylinder(0.2,0.2,sqrt(89),20,20);
  glPopMatrix();
}

void drawBicycle() {
 //draw back tire
  glPushMatrix();
  glTranslatef(-7,-5,0); 
  drawTire();
  twColor(frameColor,0.9,100); //return to frame color
  glRotatef(90,0,0,1);
  parallelBars(4);
  glPopMatrix();
  //draw front tire
  glPushMatrix();
  glTranslatef(7,-5,0);
  drawTire();
  glPopMatrix();
  //draw frame
  frame();
  //draw handlebars
  glPushMatrix();
  glTranslatef(5,3,0);
  drawHandlebar();
  glPopMatrix();
  //draw seat
  glPushMatrix();
  glTranslatef(-5,2,0);
  drawSeat();
  glPopMatrix();
}

void display(void) {
    twDisplayInit();
    twCamera(); // sets up camera based on bounding box coords.
    glEnable(GL_LIGHTING);
    twLighting2();
    drawBicycle();
    glutSwapBuffers();  
}

int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  twInitWindowSize(650,650);
  glutCreateWindow(argv[0]);
  twBoundingBox(-11,11,-9,5,-4,4);
  twMainInit(); 
  glutDisplayFunc(display);
  glutMainLoop();
  return 0;
}