boolean inflight = false;
float speed = 20;
float hspeed;
float vspeed;
float voldspeed;
float vnewspeed;
float angle = 65;
float deltaa = 3;
float deltas = 2;
float angler;
float lastangler= 0;
float g = 1;
float posx = 100;
float posy = 5;
float groundlevel = 300;
PFont font;
float targetx, targety,targetw,targeth;
float cannonx = 100;
boolean targetok = true;

void setup() {
 	background(102,255,255);
size(800,400);
font = createFont("Ariel",15);
 	 textFont(font);
 	 fill(255,0,250);
   	text("Speed ",330,50);
        text(int(speed),390,50);
        text("Angle ",460,50);
         text(int(angle),500,50);
text("Mouse on red arrow to fire. Left or right arrow keys to change speed. Up or down change angle.",10,80);
createtarget();
positioncannon();
//positionball();
frameRate(6);
}

void draw() {
 	 if (inflight) {
 background(102,255,255);  //comment this line to see arc
 		 fill(255,0,250);
 		  text("Speed ",330,50);
        text(int(speed),390,50);
        text("Angle ",460,50);
         text(int(angle),500,50);
 		  if (targetok) {
  			 drawtarget();
  		 }
  		positioncannon();
 		advanceball();
 	 }
   }
 
void positioncannon(){
 	 fill(40,200,0);
 	 rect(0,groundlevel,800,100);
 	 fill(255,0,0);
  	triangle(700,groundlevel+10,750,groundlevel+50,700,groundlevel+90);
angler = -PI*angle/180;
pushMatrix();
 	translate(cannonx,groundlevel);
 	rotate(angler);
stroke(0,0,0);
 	fill(240);
 	rect(0,0,100,10);
}

void positionball() {
 	 fill(51,0,102);
 	 ellipse(posx,posy,10,10);
 }

void advanceball() {
  	popMatrix();
 	 voldspeed = vnewspeed;
  	vnewspeed = voldspeed + g;
  	vspeed = .5*(voldspeed + vnewspeed);
  	posx = posx + hspeed;
 	 posy = posy + vspeed;
 	 if (posy>=groundlevel) {
   		 inflight = false;
 	 }
  if (hittarget(posx,posy)) {
    		explodetarget();
   		 inflight = false;
 	 }
else {
     		positionball();
 	 }
}

void mousePressed() {
  	if (ontriangle()) {
  		angler = -PI*angle/180;
 		 hspeed = speed * cos(angler);
 		 vnewspeed = speed * sin(angler);
 		 voldspeed = vnewspeed;
 		 posx = cannonx + 100*cos(angler);
 		 posy = groundlevel + 100*sin(angler);
 		 inflight = true;
 		 targetok = true;
 	 }
}

void createtarget() {
  	targetx = 600;
 	 targety = groundlevel-100;
 	 targetw = 30;
 	 targeth = 100;
 	 drawtarget();
}

void drawtarget() {
  	fill(250,250,0);
 	 rect(targetx,targety,targetw,targeth);
}

boolean hittarget(float posx,float posy) {
 	 if ((posx>targetx)&&(posx<(targetx+targetw))&&(posy>targety)&&(posy<(targety+targeth))){
    		return true;}
   	 else {
  		return false;
   	 }
}

void explodetarget() {
 	 targetok = false;
 	 fill(102,255,255);
 noStroke();
 	 rect(targetx,targety,targetw+1,targeth);
  	fill(0,0,0);
  quad(targetx-50,groundlevel+10,targetx,groundlevel-50,targetx+targetw,groundlevel-60,targetx+targetw+30,groundlevel+5);
}
boolean ontriangle() {
  // sloppy test to determine if mouse is over the triangle
  if ((mouseX>700)&&(mouseX<750)&&(mouseY>(groundlevel+10))&&(mouseY<(groundlevel+90)))
     {return true;}
  else {
    return false;}
  }

void keyPressed() {
  if (keyCode==UP) {
      angle +=deltaa;
  }
  if (keyCode==DOWN) {
      angle -=deltaa;
  }
   if (keyCode==RIGHT) {
      speed +=deltas;
  }
  if (keyCode==LEFT) {
      speed -=deltas;
  }
  //fill(102,255,255);
  //noStroke();
  //rect(330,30,200,30);
   background(102,255,255); 
  fill(255,0,250);
  text("Speed ",330,50);
        text(int(speed),390,50);
        text("Angle ",460,50);
         text(int(angle),500,50);
         positioncannon();
         
         popMatrix();
         drawtarget();
}