main.c

#include <stdio.h>
#include <stdlib.h>
#include "screen.h"
#include "ray.h"

// Times a ray can reflect. Higher the more realistic?
int const DEPTH = 20;

// Adjust the amount of characters to be printed.
int const WIDTH = 470;
int const HEIGHT = 320;

// DUE TO LIMITATION OF THE LANGUAGE
//double const ASPECT_RATIO = WIDTH/HEIGHT;
double ASPECT_RATIO = WIDTH/HEIGHT;

double greyscale(vector color) {
  //Definition of Greyscale
  return 0.2126*color.x + 0.7152*color.y + 0.0722*color.z;
}

int main(int argc, char const *argv[]) {
  // Create screen
  screen scr;
  scr.width = WIDTH;
  scr.height = HEIGHT;
  scr.view = createScr(scr.height, scr.width);

  // Convert into unit used in the 3D space
  double viewport_height = 2.0;
  double viewport_width = ASPECT_RATIO * viewport_height;

  // Field of View. Small number to make scene wider
  double focalLength = 1.2;

  // Position of Camera
  vector origin;
  fill_value(&origin, 0, 0, 0);

  // Width element
  vector horizontal;
  fill_value(&horizontal, viewport_width, 0, 0);

  // Height element
  vector vertical;
  fill_value(&vertical, 0, viewport_height, 0);

  // Length element
  vector length;
  fill_value(&length, 0, 0, focalLength);

  char input = '?';

  do {
    vector lower_left_corner;
    //lower_left_corner = origin - (horizontal / 2) - (vertical / 2) - length
    lower_left_corner = subtract_vect(subtract_vect(subtract_vect(origin, div_const(horizontal, 2)), div_const(vertical, 2)), length);

    // Going through every bit of screen.
    for (size_t i = 0; i < scr.height; i++) {
      for (size_t j = 0; j < scr.width; j++) {

        // Determine the direction of each ray
        double u = (double)i / (scr.height - 1);
        double v = (double)j / (scr.width - 1);

        // Create a ray with origin at camera position
        ray r;
        r.orig = origin;

        //By subtracting the origin, the direction become relative.
        //r.dir = lower_left_corner + u*vertical + v*horizontal - origin
        r.dir = subtract_vect(add_vect(lower_left_corner, add_vect(mult_const(vertical, u), mult_const(horizontal, v))), origin);


        vector color = shootRay(r, DEPTH);

        // Convert into greyscale
        scr.view[i][j] = greyscale(mult_const(color, 255 * 0.5));

      }
    }
    printScr(scr);

    /* CAMERA CONTROLS */
    //Note that the direction is global and not relative to current camera position / angle.
    scanf(" %c", &input);

    if (input == 'w') { //Front
      fill_value(&origin, origin.x, origin.y, origin.z - 0.2);

    } else if (input == 's') { //Back
      fill_value(&origin, origin.x, origin.y, origin.z + 0.2);

    } else if (input == 'd') { //Right
      fill_value(&origin, origin.x + 0.2, origin.y, origin.z);

    } else if (input == 'a') { //Left
      fill_value(&origin, origin.x - 0.2, origin.y, origin.z);

    } else if (input == 'A') { //Turn left
      horizontal = rotateY(horizontal, 10);
      vertical = rotateY(vertical, 10);
      length = rotateY(length, 10);

    } else if (input == 'D') { //Turn right
      horizontal = rotateY(horizontal, -10);
      vertical = rotateY(vertical, -10);
      length = rotateY(length, -10);

    } else if (input == 'W') { //Look up
      horizontal = rotateX(horizontal, 10);
      vertical = rotateX(vertical, 10);
      length = rotateX(length, 10);

    } else if (input == 'S') { //Look down
      horizontal = rotateX(horizontal, -10);
      vertical = rotateX(vertical, -10);
      length = rotateX(length, -10);

    } else if (input == 'Q') { //Tilt left
      horizontal = rotateZ(horizontal, 10);
      vertical = rotateZ(vertical, 10);
      length = rotateZ(length, 10);

    } else if (input == 'E') { //Tilt right
      horizontal = rotateZ(horizontal, -10);
      vertical = rotateZ(vertical, -10);
      length = rotateZ(length, -10);
    }

  } while(input != 'q'); //quit

  deleteScr(&scr);
  return 0;
}