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1. To move your object towards a location,provided targeted location and current location, you can suppose your current location origin and then get the relative position of the target location in polar coordinate.
2. This will give you the direction you need to travel.
3. Given the speed you want the object to travel,

4. Stepped example : (Click mouse to step, Hold down to see the hint, More content under demo 1, please scroll down to view Keynote 0)

   Processing
   Height 600 Width 600
   final int appwidth = 600; final int appheight = 600; final float stepsize = 10; targetedobject myobject; class targetedobject { // This is the object to move int mcurrentx, mcurrenty; // This will store the current location of the object int mtargetx, mtargety; // This will store the target location of the object int mtargetx_t, mtargety_t; // Step travel float mrotation; // This is the current orientation of this object float thisstep; boolean demostep; targetedobject( int x, int y, int r ) { // Initialize with coordinate and orientation mcurrentx = x; mtargetx = x; mcurrenty = y; mtargety = y; mrotation = r; demostep = false; } void updatedraw() { //Draws the shape pushMatrix(); translate( mcurrentx, mcurrenty ); rotate( mrotation ); noStroke(); fill( 255, 0, 0 ); ellipse(0, 0, 40, 40); noFill(); stroke(255); strokeWeight(5); line( -10, 0, 10, 0 ); line( 10, 0, 5, -5 ); line( 10, 0, 5, 5 ); popMatrix(); this.drawhelper(); } void drawhelper() { if ( this.demostep ) { //Need draw float textx, texty; noFill(); strokeWeight(3); stroke( 0, 255, 255, 192 ); line( this.mcurrentx, this.mcurrenty, this.mtargetx, this.mtargety ); line( this.mtargetx, this.mcurrenty, this.mtargetx, this.mtargety ); line( this.mcurrentx, this.mcurrenty, this.mtargetx, this.mcurrenty ); textSize(24); textAlign(CENTER, BOTTOM); noStroke(); fill(255); textx = (this.mtargetx + this.mcurrentx) / 2; texty = this.mcurrenty; text( "X2 - X1", textx, texty ); textAlign(LEFT, CENTER); textx = this.mtargetx; texty = (this.mtargety + this.mcurrenty) / 2; text( "Y2 - Y1", textx, texty ); textAlign(CENTER, CENTER); textx = (this.mtargetx + this.mcurrentx) / 2; texty = (this.mtargety + this.mcurrenty) / 2; text( "L", textx, texty ); } } void startstep(int x, int y) { float targetlength; float temprotation; this.demostep = true; this.mtargetx = x; this.mtargety = y; targetlength = sqrt( pow( this.mtargetx - this.mcurrentx, 2 ) + pow( this.mtargety - this.mcurrenty, 2 ) ); //Get the target distance if (targetlength <= 0.5) { this.mrotation = 0; return; //Do not move } if (targetlength > stepsize) { //Calculate step size this.thisstep = stepsize; } else { this.thisstep = targetlength; } temprotation = acos( (this.mtargetx - this.mcurrentx) / targetlength ); if ( this.mtargety > this.mcurrenty ) { //> 180 degrees this.mrotation = temprotation; }else{ this.mrotation = 2 * PI - temprotation; } // Calculate the step target this.mtargetx_t = (int)(this.thisstep * cos(this.mrotation)); this.mtargety_t = (int)(this.thisstep * sin(this.mrotation)); } void endstep() { this.demostep = false; this.mcurrentx += this.mtargetx_t; this.mcurrenty += this.mtargety_t; } } void setup() { size(appwidth, appheight); background(0); myobject = new targetedobject( width / 2, height / 2, 0 ); } void draw() { background(0); myobject.updatedraw(); } void mousePressed() { if (mouseButton == LEFT) { myobject.startstep(mouseX, mouseY); } } void mouseReleased() { if ( myobject.demostep ) { myobject.endstep(); } }

5. Anchor
   keynote00 keynote00

   Processingcode
   title Key note
   //Get the target distance targetlength = sqrt( pow( this.mtargetx - this.mcurrentx, 2 ) + pow( this.mtargety - this.mcurrenty, 2 ) ); //Arc cosin adjacent side divide by Hypotenuse //OR arc sin subtense divide by Hypotenuse //Not using tangent to avoid Divide by Zero temprotation = acos( (this.mtargetx - this.mcurrentx) / targetlength ); //In this case, we are using cosin, so for the angle > 180 which means that //targety is under currend y if ( this.mtargety > this.mcurrenty ) { //> 180 degrees this.mrotation = temprotation; }else{ this.mrotation = 2 * PI - temprotation; } //Now that we have the rotation, we recalculate the x and y we need to travel this.mtargetx_t = (int)(this.thisstep * cos(this.mrotation)); this.mtargety_t = (int)(this.thisstep * sin(this.mrotation)); //Finally, move the object this.mcurrentx += this.mtargetx_t; this.mcurrenty += this.mtargety_t;

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