Making a shadowcaster

Processing Coding Questions
1

So im trying to write a 2d raycaster for the first time, and im having trouble only drawing lines to the closest walls. i cant find what to do next

Code:

Source source;
Ray ray;
Wall[] walls = new Wall[2];

void setup() {
  size(600, 600); 
  frameRate(60);

  source = new Source(new PVector(width/2, height/2));
  walls[0] = new Wall(100, 400, 100, 500);
  walls[1] = new Wall(50, 500, 20, 300);
}

void draw() {
  background(0);


  source.show();
  for (int i = 0; i < walls.length; i++) {
    walls[i].show();
  }

  //Controls
  noCursor();
  source.pos = new PVector(mouseX, mouseY);
}

Ray class:

class Ray {
  PVector pos;
  PVector dir;
  PVector pt;
  boolean ptExist = false;

  Ray (PVector setpos, float  angle) {
    pos = setpos;
    dir = PVector.fromAngle(angle);
  }

  void show() {
    stroke(255);
    push();
    translate(pos.x, pos.y);
    line(0, 0, dir.x * 10, dir.y * 10);
    pop();
    update();
  }

  void update() {
    pos= source.pos;
  }

  void setDir(float x, float y) {
    dir.x = x - pos.x;
    dir.y = y - pos.y;
    dir.normalize();
  }

  void cast(int wall) {
    float x1 = walls[wall].a.x;
    float y1 = walls[wall].a.y;
    float x2 = walls[wall].b.x;
    float y2 = walls[wall].b.y;

    float x3 = pos.x;
    float y3 = pos.y;
    float x4 = pos.x+dir.x;
    float y4 = pos.y+dir.y;

    float den = (x1-x2) * (y3-y4) - (y1-y2) * (x3-x4);
    if (den == 0) {
      return;
    }

    float t = ((x1-x3) * (y3-y4) - (y1-y3) * (x3-x4)) / den;
    float u = -((x1-x2) * (y1-y3) - (y1-y2) * (x1-x3)) / den;

    if (t > 0 && t < 1 && u > 0) {
      pt = new PVector();
      pt.x = x1 + t * (x2-x1);
      pt.y = y1 + t * (y2-y1);

      ptExist = true;
    } else {
      ptExist = false;
    }
  }
}

Source class:

class Source {
  PVector pos;
  PVector closest = new PVector(0, 0);
  float record;
  float heading;
  float fov;
  int i=0;
  Ray[] rays = new Ray[360];

  Source(PVector setpos) {
    pos = setpos;
    heading = 0;
    fov = 45;
    for (float a=0; a < 360; a+=1) {

      rays[i] = new Ray(pos, radians(a));
      i++;
    }
  }


  void look() {
    for (int i=0; i<rays.length; i++) {
      for (int j = 0; j < walls.length; j++) {
        for (int k=0; k<walls.length; k++) {
          record = 10000000;
          rays[i].cast(j);
          PVector pt = rays[i].pt;
          if (rays[i].ptExist) {
            float d = PVector.dist(pos, pt);
            if (d < record) {
              record = d;
              closest = pt;
              record = min(d, record);
            }
          }
        }
      }
      if (closest.x!=0&&closest.y!=0) {
        line(pos.x, pos.y, closest.x, closest.y);
      }
    }
  }

  void show() {
    fill(255);
    noStroke();
    ellipse(pos.x, pos.y, 4, 4);

    for (int i=0; i<rays.length; i++) {
      rays[i].show();
    }
    look();
  }
}

Wall class:

class Wall {
  PVector a;
  PVector b;

  Wall(float x1, float y1, float x2, float y2) {
    a = new PVector(x1, y1);
    b = new PVector(x2, y2);
  }

  void show() {
    stroke(255);
    line(a.x, a.y, b.x, b.y);
  }
}
1 Like
2

please format your code posting by pasting it into the

</> code button

of the editor header menu ( context name: Preformatted text )
it looks like
```
type or paste code here
```

also can use the ``` manually above and below your code.

thank you.

1 Like