Errors in SpaceShip Game

Processing Coding Questions
1

I’ve been programming a 3D game where a ship avoids spikes on a terrain of triangle sectors. I’ve been having two major problems with the game so far. 1) the triangle sector terrain seems to be moving slowly downwards and eventually off-screen, but it seems I’m not changing a z value anywhere. Second, I cannot properly track collisions between the ship and the spikes. I’m not sure if this is because of translations or how I drew the spikes. Code:



int cols, rows;
int scl = 20;
int w = 2000;
int h = 1600;
Ship ship;
ArrayList<Spikes> spikes;
color g;
color s;
float flying = 0;
float score = 0;
float[][] terrain;
boolean gameStart;
boolean gameOver;

void setup() {
  size(600, 600, P3D);
  cols = w / scl;
  rows = h/ scl;
  terrain = new float[cols][rows];
  g = color(156,111,81);
  s = color(0);
  ship = new Ship(1000,1100,50);
  spikes = new ArrayList<Spikes>();
  gameStart = true;
  gameOver = false;
}


void draw() {
  if(gameOver == true){
    background(255);
    text("GAME OVER",width/2,height/2);
  }
  if( gameStart == true){
  flying -= 0.1;
  
  
  for (int y = 0; y < rows; y++) {
    for (int x = 0; x < cols; x++) {
       terrain[x][y] = flying;
      
    }
  } 



  background(0);
  textSize(50);
  fill(255);
  text(frameCount, 50,50);
  stroke(s);
  fill(g);
  score += 0.01;
  translate(width/2, height/2+50);
  rotateX(PI/3);
  translate(-w/2, -h/2);
  for (int y = 0; y < rows-1; y++) {
    beginShape(TRIANGLE_STRIP);
    for (int x = 0; x < cols; x++) {
      vertex(x*scl, y*scl, terrain[x][y]);
      vertex(x*scl, (y+1)*scl, terrain[x][y+1]);
    }
    endShape();
  }
  
 
 for( int i = 0; i < 6; i++){
  spikes.add(new Spikes(random(300,1500),500,50));
  spikes.get(i).render();
  spikes.get(i).move();
 }
  ship.render();
  ship.move();

  }
}

class Ship{
  float x;
  float y;
  float z;
 
  
  Ship(float _x, float _y, float _z){
    x = _x;
    y = _y;
    z = _z;
  }
  void render(){
    translate(x,y,z);
    fill(160);
    stroke(0);
    
     beginShape(TRIANGLES);
     scale(0.6);
      vertex(-50,0,25);
      vertex(-150,100,25);
      vertex(0,100,25);
      
      vertex(50,0,25);
      vertex(150,100,25);
      vertex(0,100,25);
      
       vertex(-50,0,-25);
      vertex(-150,100,-25);
      vertex(0,100,-25);
      
      vertex(50,0,-25);
      vertex(150,100,-25);
      vertex(0,100,-25);
      
      vertex(-50,0,25);
      vertex(50,0,25);
      vertex(0,-300,25);
      
      vertex(-50,0,25);
      vertex(50,0,25);
      vertex(0,100,25);
      
      vertex(-150,100,25);
      vertex(150,100,25);
      vertex(-150,100,-25);
      
      vertex(150,100,25);
      vertex(-150,100,-25);
      vertex(150,100,-25);
      
       vertex(-150,100,25);
      vertex(150,100,25);
      vertex(150,100,-25);
      
       vertex(50,0,25);
       vertex(50,0,-25);
        vertex(0,-300,-25);
        
        vertex(50,0,25);
       vertex(0,-300,25);
        vertex(0,-300,-25);
        
        vertex(-50,0,25);
       vertex(-50,0,-25);
        vertex(0,-300,-25);
        
        vertex(-50,0,25);
       vertex(0,-300,25);
        vertex(0,-300,-25);
       
        vertex(-50,0,25);
      vertex(-50,0,-25);
      vertex(-150,100,25);
      
        vertex(50,0,25);
      vertex(50,0,-25);
      vertex(150,100,25);
      
endShape(); 
  }
  void move(){
    if(keyPressed && keyCode == LEFT){
      x-=3;
    }
     if(keyPressed && keyCode == RIGHT){
      x+=3;
    }
     if(keyPressed && keyCode == UP){
      y-=3;
    }
     if(keyPressed && keyCode == DOWN){
      y+=3;
    }
  }
}

class Spikes{
  float x;
  float y;
  float z;
 
  
  Spikes(float _x, float _y, float _z){
    x = _x;
    x = random(300,1500);
    y = _y;
    z = _z;
  }
  void render(){
    translate(x,y,z);
    fill(0);
    stroke(255);
   
    beginShape(TRIANGLES);
    
    vertex(100,-300,-100);
    vertex(150,-350,-100);
    vertex(100,-300,200);
    
    vertex(100,-300,-100);
    vertex(50,-350,-100);
    vertex(100,-300,200);
    
    endShape();
   translate(-x,-y,-z);
   
  }
  void move(){
    y+=4;
    if(y>1810){
      x = random(300,1500);
      y = 600;
    }
    if(x + 5 >= ship.x && x - 5 <= ship.x && y + 5 >= ship.y && y - 5 <= ship.y){
      gameStart = false;
      gameOver = true;
  }
 }
}
2
  1. Yes, your triangle grid is lowering! Look at the Z coordinate for your grid:
  for (int y = 0; y < rows-1; y++) {
    beginShape(TRIANGLE_STRIP);
    for (int x = 0; x < cols; x++) {
      vertex(x*scl, y*scl, terrain[x][y]);
      vertex(x*scl, (y+1)*scl, terrain[x][y+1]);
    }
    endShape();
  }

The Z positions are in the terrain[x][y] array. Are those values changing? Well, they are getting assigned:

  for (int y = 0; y < rows; y++) {
    for (int x = 0; x < cols; x++) {
       terrain[x][y] = flying;
      
    }
  }

They get assigned the value of flying. Does THAT value change? YES IT DOES!

  if( gameStart == true){
  flying -= 0.1;

You’re subtracting 0.1 from it every frame. Which is why the floor lowers slowly. It seems like that last line should be an assignment, not a decrementation. Like this:

  if( gameStart == true){
  flying = 0.1;

It is a small change but it stops the floor from sinking.

3
  1. This is a hard problem. I suggest you ignore the Z coordinates of everything and imagine your game as a 2D version seen from a bird’s-eye view. This turns your spikes into diamonds, and your ship into several triangles. What does a collision look like in this simplified 2D version?

Consider:

WhyCrash
WhyCrash557×565 6.23 KB

4

Thank you! I tried ignoring Z coordinates and basically doing the same drawing an invisible collision box around each spike. I think my problem is either, the x value in my spike class isn’t truly the x value of any spike in the program, or the ship.x value is not the true x value for the ship (and vice versa for y values).