hello all,

I am working on a steering simulation for a car.

So far the car moves (cursor up and down) and the tires turn (cursor left and right)

But I don't know how to apply the angle of my wheel      car.wheelAngle    to the cars movement?

Any hints? Important parts are bold in the code below.

At the moment, I apply the cars gobal angle car.angleCar (compared to north (or east)) to its movement but I don't know how to integrate car.wheelAngle into this.

Thanks!!!

Greetings, Chrisir  



// see http://www.asawicki.info/Mirror/Car%20Physics%20for%20Games/Car%20Physics%20for%20Games.html

//
// one car of class Car
Car car;
//
// ---------------------------------------------------------------
//
void setup()
{
  // init
  size(800, 600);
  car = new Car();
} // func
//
//
void draw()
{
  background(255);
  car.display();
  car.drive();
  text("cursor: drive and steer, space: stop, mouse: steer", 10, height-20);
} // func
//

// =====================================================================

void keyPressed () {
  if (key==CODED)
    keyPressedCoded();
  else
    keyPressedUnCoded();
}// func

void keyPressedCoded() {
  switch (keyCode) {
  case UP:
    println ("up");
    car.xspeed=1;
    break;
  case DOWN:
    car.xspeed=-1;
    break;

  case LEFT:
    car.wheelAngle++;
    break;
  case RIGHT:
    car.wheelAngle--;
    break;
  } // switch
}// func

void keyPressedUnCoded() {
  //
  switch (key) {
  case ' ':
    // spacee = stop
    car.xspeed=0;
    // car.yspeed=0;
    break;
  default:
    break;
  } // switch
} // func

// =====================================================================

void mouseMoved() {
  float value = mouseX;
  car.wheelAngle = map(mouseX, 0, width, -60, 60);
  if (value > 255) {
    value = 0;
  }
}

// =====================================================================

class Car {

  // the car itself
  float xpos;
  float ypos;
  float w, h;
  float xspeed;
  //float yspeed;
  color c;
  float angleCar=12;
  // 4 tires
  float tireOffsetX, tireOffsetY; // position as offset from car center 
  float tireW, tireH;  // size
  float L = tireOffsetX*2;        // the dist between tires front and rear
  // wheel
  //PImage imgWheel;
  float wheelAngle = 0;

  //
  Car() {
    // constr
    xpos = width/2;
    ypos = height/2;
    w=70;
    h=25;
    // speed = stop
    xspeed = 0;
    //yspeed = 0;
    c = color(255);
    tireW=19;
    tireH=11;
    tireOffsetX=w/2;
    tireOffsetY=h/2+5;
    //imgWheel=loadImage("wheel.jpg");
  } // constr

  void display() {
    // display car
    pushMatrix();
    rectMode(CENTER);
    translate(xpos, ypos);
    rotate(radians (angleCar));  //
    // the car itself
    fill(c);
    rect(0, 0, w, h);
    //
    //
    // the tires
    // rear tires
    fill(255, 2, 2);
    //rect(xpos-tireOffsetX, ypos-tireOffsetY, tireW, tireH);
    oneTire(-tireOffsetX, tireOffsetY, 0 );
    oneTire(-tireOffsetX, -tireOffsetY, 0 );

    // front tires
    oneTire(tireOffsetX, tireOffsetY, -radians (wheelAngle)/3);
    oneTire(tireOffsetX, -tireOffsetY, -radians (wheelAngle)/3);
    //rect(xpos-tireOffsetX, ypos+tireOffsetY, tireW, tireH);
    popMatrix();
    //
    // wheel - upper left corner
    pushMatrix();
    imageMode(CENTER);
    translate(120, 120);
    rotate(-radians (wheelAngle));
    //    image (imgWheel, 11, 11);
    popMatrix();
  }

  void oneTire ( float xpos1, float ypos1, float angleTire ) {
    // front tire with steering
    pushMatrix();
    translate(xpos1, ypos1);
    rotate(angleTire);
    rect(0, 0, tireW, tireH);   
    popMatrix();
  }
  // 
  void drive() {
    xpos = xspeed * cos (radians(angleCar)) + xpos;
    ypos = xspeed * sin (radians(angleCar)) + ypos;
    if (xpos > width) {
      xpos = 0;
    } // if
    //
    // check walls
    if (xpos < 0) {
      xpos = width;
    } // if
    if (ypos > height) {
      ypos = 0;
    } // if
    if (ypos < 0) {
      ypos = height;
    } // if
  } // func
  //
} // class

// =====================================================================