ray.rb

# 1. とりあえず色を出す

IMAGE_WIDTH = 256
IMAGE_HEIGHT = 256
IMAGE_DEPTH = 256

class Vec
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
  attr_reader :x, :y, :z

  def vnormalize!
    len = vlength()
    if len > 1.0e-17
      r_len = 1.0 / len
      @x *= r_len
      @y *= r_len
      @z *= r_len
    end
    self
  end

  def vlength
    Math.sqrt(@x * @x + @y * @y + @z * @z)
  end
end

class Ray
  def initialize(origin, dir)
    @origin, @dir = origin, dir
  end
  attr_reader :dir
end

puts("P3")
puts("#{IMAGE_WIDTH} #{IMAGE_HEIGHT}")
puts("#{IMAGE_DEPTH-1}")

# t: 0 ~ 1
def color(t)
  t = 0 if t < 0
  t = 1 if t > 1
  ret = IMAGE_DEPTH * t.to_f
  return (ret == IMAGE_DEPTH ? (IMAGE_DEPTH-1) : ret).to_i
end

IMAGE_HEIGHT.times do |row|
  IMAGE_WIDTH.times do |col|
    x = col.to_f / (IMAGE_WIDTH / 2) - 1.0
    y = (IMAGE_HEIGHT-row).to_f / (IMAGE_HEIGHT / 2) - 1.0

    ray = Ray.new(Vec.new(0.0, 0.0, 5.0),
                  Vec.new(x, y, -1.0).vnormalize!)
    #p x: x, y: y, dir: ray.dir
    r, g, b = color(ray.dir.x), color(ray.dir.y), color(ray.dir.z)
    print("#{r} #{g} #{b} ")
  end
end

ray2.rb

# 2. 白い円を出す

IMAGE_WIDTH = 256
IMAGE_HEIGHT = 256
IMAGE_DEPTH = 256

class Vec
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
  attr_reader :x, :y, :z

  def vsub(b)
    Vec.new(@x - b.x, @y - b.y, @z - b.z)
  end

  def vdot(b)
    @x * b.x + @y * b.y + @z * b.z
  end

  def vnormalize!
    len = vlength()
    if len > 1.0e-17
      r_len = 1.0 / len
      @x *= r_len
      @y *= r_len
      @z *= r_len
    end
    self
  end

  def vlength
    Math.sqrt(@x * @x + @y * @y + @z * @z)
  end
end

class Ray
  def initialize(origin, dir)
    @origin, @dir = origin, dir
  end
  attr_reader :origin, :dir
end

class Sphere
  def initialize(radius, position, color)
    @radius, @position, @color = radius, position, color
  end
  attr_reader :radius, :position, :color

  def intersect?(ray)
    rs = ray.origin.vsub(@position)
    b = rs.vdot(ray.dir)
    c = rs.vdot(rs) - @radius * @radius
    d = b * b - c
    return d > 0 && (-b - Math.sqrt(d)) > 0
  end
end

puts("P3")
puts("#{IMAGE_WIDTH} #{IMAGE_HEIGHT}")
puts("#{IMAGE_DEPTH-1}")

# t: 0 ~ 1
def color(t)
  t = 0 if t < 0
  t = 1 if t > 1
  ret = IMAGE_DEPTH * t.to_f
  return (ret == IMAGE_DEPTH ? (IMAGE_DEPTH-1) : ret).to_i
end

def print_col(c)
  print("#{color(c.x)} #{color(c.y)} #{color(c.z)} ")
end

BLACK = Vec.new(0, 0, 0)
sphere = Sphere.new(1.0, Vec.new(0, 0, 0), Vec.new(1, 1, 1))

IMAGE_HEIGHT.times do |row|
  IMAGE_WIDTH.times do |col|
    x = col.to_f / (IMAGE_WIDTH / 2) - 1.0
    y = (IMAGE_HEIGHT-row).to_f / (IMAGE_HEIGHT / 2) - 1.0

    ray = Ray.new(Vec.new(0.0, 0.0, 5.0),
                  Vec.new(x, y, -1.0).vnormalize!)
    c = if sphere.intersect?(ray) 
          sphere.color
        else
          BLACK
        end
    print_col(c)
  end
end

ray3.rb

# 3. 球に影をつける

IMAGE_WIDTH = 256
IMAGE_HEIGHT = 256
IMAGE_DEPTH = 256

class Vec
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
  attr_reader :x, :y, :z

  def vadd(b)
    Vec.new(@x + b.x, @y + b.y, @z + b.z)
  end

  def vsub(b)
    Vec.new(@x - b.x, @y - b.y, @z - b.z)
  end

  def vmul(t)
    Vec.new(@x * t, @y * t, @z * t)
  end

  def vdot(b)
    @x * b.x + @y * b.y + @z * b.z
  end

  def vnormalize!
    len = vlength()
    if len > 1.0e-17
      r_len = 1.0 / len
      @x *= r_len
      @y *= r_len
      @z *= r_len
    end
    self
  end

  def vlength
    Math.sqrt(@x * @x + @y * @y + @z * @z)
  end
end

class Ray
  def initialize(origin, dir)
    @origin, @dir = origin, dir
  end
  attr_reader :origin, :dir
end

# 交点
class Isect
  def initialize(hit=false)
    @hit = hit
    @hit_point = Vec.new(0, 0, 0)
    @normal = Vec.new(0, 0, 0)
    @color = Vec.new(0, 0, 0)
  end
  attr_accessor :hit, :hit_point, :normal, :color
end

class Sphere
  def initialize(radius, position, color)
    @radius, @position, @color = radius, position, color
  end
  attr_reader :radius, :position, :color

  def intersection(ray)
    rs = ray.origin.vsub(@position)
    b = rs.vdot(ray.dir)
    c = rs.vdot(rs) - @radius * @radius
    d = b * b - c
    if d > 0 && (t = -b - Math.sqrt(d)) > 0
      i = Isect.new(true)
      i.hit_point = ray.origin.vadd(ray.dir.vmul(t))
      i.normal = i.hit_point.vsub(@position).vnormalize!
      d = clamp(Vec.new(1, 1, 1).vnormalize!.vdot(i.normal), 0.1, 1.0)
      i.color = @color.vmul(d)
    else
      i = Isect.new(false)
    end
    i
  end
end

puts("P3")
puts("#{IMAGE_WIDTH} #{IMAGE_HEIGHT}")
puts("#{IMAGE_DEPTH-1}")

def clamp(t, min, max)
  if t < min
    min
  elsif t > max
    max
  else
    t
  end
end

# t: 0 ~ 1
def color(t)
  t = 0 if t < 0
  t = 1 if t > 1
  ret = IMAGE_DEPTH * t.to_f
  return (ret == IMAGE_DEPTH ? (IMAGE_DEPTH-1) : ret).to_i
end

def print_col(c)
  print("#{color(c.x)} #{color(c.y)} #{color(c.z)} ")
end

BLACK = Vec.new(0, 0, 0)
sphere = Sphere.new(1.0, Vec.new(0, 0, 0), Vec.new(1, 1, 1))

IMAGE_HEIGHT.times do |row|
  IMAGE_WIDTH.times do |col|
    x = col.to_f / (IMAGE_WIDTH / 2) - 1.0
    y = (IMAGE_HEIGHT-row).to_f / (IMAGE_HEIGHT / 2) - 1.0

    ray = Ray.new(Vec.new(0.0, 0.0, 5.0),
                  Vec.new(x, y, -1.0).vnormalize!)
    i = sphere.intersection(ray) 
    print_col(i.color)
  end
end

ray4.rb

# 4. 床を出す

IMAGE_WIDTH = 256
IMAGE_HEIGHT = 256
IMAGE_DEPTH = 256

class Vec
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
  attr_reader :x, :y, :z

  def vadd(b)
    Vec.new(@x + b.x, @y + b.y, @z + b.z)
  end

  def vsub(b)
    Vec.new(@x - b.x, @y - b.y, @z - b.z)
  end

  def vmul(t)
    Vec.new(@x * t, @y * t, @z * t)
  end

  def vdot(b)
    @x * b.x + @y * b.y + @z * b.z
  end

  def vnormalize!
    len = vlength()
    if len > 1.0e-17
      r_len = 1.0 / len
      @x *= r_len
      @y *= r_len
      @z *= r_len
    end
    self
  end

  def vlength
    Math.sqrt(@x * @x + @y * @y + @z * @z)
  end
end

class Ray
  def initialize(origin, dir)
    @origin, @dir = origin, dir
  end
  attr_reader :origin, :dir
end

# 交点
class Isect
  def initialize(hit=false)
    @hit = hit
    @hit_point = Vec.new(0, 0, 0)
    @normal = Vec.new(0, 0, 0)
    @color = Vec.new(0, 0, 0)
    @distance = 1.0e+30
  end
  attr_accessor :hit, :hit_point, :normal, :color, :distance
end

class Sphere
  def initialize(radius, position, color)
    @radius, @position, @color = radius, position, color
  end
  attr_reader :radius, :position, :color

  def intersect!(ray, isect)
    rs = ray.origin.vsub(@position)
    b = rs.vdot(ray.dir)
    c = rs.vdot(rs) - (@radius * @radius)
    d = b * b - c
    if d > 0 
      t = -b - Math.sqrt(d)
      if t > 0 && t < isect.distance
        isect.hit_point = ray.origin.vadd(ray.dir.vmul(t))
        isect.normal = isect.hit_point.vsub(@position).vnormalize!
        isect.color = @color.vmul(clamp(LIGHT.vdot(isect.normal), 0.1, 1.0))
        isect.distance = t
      end
    end
  end
end

class Plane
  def initialize(position, normal, color)
    @position, @normal, @color = position, normal, color
  end

  def intersect!(ray, isect)
    d = -(@position.vdot(@normal))
    v = ray.dir.vdot(@normal)
    t = -(ray.origin.vdot(@normal) + d) / v
    if t > 0 && t < isect.distance
      isect.hit_point = ray.origin.vadd(ray.dir.vmul(t))
      isect.normal = @normal
      d = clamp(LIGHT.vdot(isect.normal), 0.1, 1.0)
      m = isect.hit_point.x % 2
      n = isect.hit_point.z % 2
      d *= 0.5 if ((m > 1 && n > 1) || (m < 1 && n < 1))
      f = 1.0 - [isect.hit_point.z.abs, 25.0].min * 0.04
      isect.color = @color.vmul(d * f)
      isect.distance = t
    end
  end
end

def clamp(t, min, max)
  if t < min
    min
  elsif t > max
    max
  else
    t
  end
end

# t: 0 ~ 1
def color(t)
  t = 0 if t < 0
  t = 1 if t > 1
  ret = IMAGE_DEPTH * t.to_f
  return (ret == IMAGE_DEPTH ? (IMAGE_DEPTH-1) : ret).to_i
end

def print_col(c)
  print("#{color(c.x)} #{color(c.y)} #{color(c.z)} ")
end

BLACK = Vec.new(0, 0, 0)
LIGHT = Vec.new(0.577, 0.577, 0.577)

puts("P3")
puts("#{IMAGE_WIDTH} #{IMAGE_HEIGHT}")
puts("#{IMAGE_DEPTH-1}")

plane = Plane.new(Vec.new(0, -1, 0), Vec.new(0, 1, 0), Vec.new(1, 1, 1))
t = 0
sphere1 = Sphere.new(0.5, Vec.new( 0.0, -0.5, Math.sin(0)), Vec.new(1, 0, 0))
sphere2 = Sphere.new(1.0, Vec.new( 2.0,  0.0, Math.cos(t*0.666)), Vec.new(0, 1, 0))
sphere3 = Sphere.new(1.5, Vec.new(-2.0,  0.5, Math.cos(t*0.333)), Vec.new(0, 0, 1))

IMAGE_HEIGHT.times do |row|
  IMAGE_WIDTH.times do |col|
    x = col.to_f / (IMAGE_WIDTH / 2) - 1.0
    y = (IMAGE_HEIGHT-row).to_f / (IMAGE_HEIGHT / 2) - 1.0

    ray = Ray.new(Vec.new(0.0, 2.0, 6.0),
                  Vec.new(x, y, -1.0).vnormalize!)
    i = Isect.new(false)
    sphere1.intersect!(ray, i) 
    sphere2.intersect!(ray, i) 
    sphere3.intersect!(ray, i) 
    plane.intersect!(ray, i)
    print_col(i.color)
  end
end

ray5.rb

# 5. 反射させる

IMAGE_WIDTH = 512
IMAGE_HEIGHT = 512
IMAGE_DEPTH = 256

class Vec
  def initialize(x, y, z)
    @x, @y, @z = x, y, z
  end
  attr_reader :x, :y, :z

  def vadd(b)
    Vec.new(@x + b.x, @y + b.y, @z + b.z)
  end

  def vsub(b)
    Vec.new(@x - b.x, @y - b.y, @z - b.z)
  end

  def vmul(t)
    Vec.new(@x * t, @y * t, @z * t)
  end

  def vmulti(b)
    Vec.new(@x * b.x, @y * b.y, @z * b.z)
  end

  def vdot(b)
    @x * b.x + @y * b.y + @z * b.z
  end

  def vcross(b)
    Vec.new(@y * b.z - @z * b.y,
            @z * b.x - @x * b.z,
            @x * b.y - @y * b.x)
  end

  def vnormalize!
    len = vlength()
    if len > 1.0e-17
      r_len = 1.0 / len
      @x *= r_len
      @y *= r_len
      @z *= r_len
    end
    self
  end

  def vlength
    Math.sqrt(@x * @x + @y * @y + @z * @z)
  end

  def reflect(normal)
    self.vadd(normal.vmul(-2 * normal.vdot(self)))
  end
end

class Ray
  def initialize(origin, dir)
    @origin, @dir = origin, dir
  end
  attr_reader :origin, :dir
end

# 交点
class Isect
  def initialize()
    @hit = 0
    @hit_point = Vec.new(0, 0, 0)
    @normal = Vec.new(0, 0, 0)
    @color = Vec.new(0, 0, 0)
    @distance = 1.0e+30
    @ray_dir = Vec.new(0, 0, 0)
  end
  attr_accessor :hit, :hit_point, :normal, :color, :distance, :ray_dir
end

class Sphere
  def initialize(radius, position, color)
    @radius, @position, @color = radius, position, color
  end
  attr_reader :radius, :position, :color

  def intersect!(ray, isect)
    rs = ray.origin.vsub(@position)
    b = rs.vdot(ray.dir)
    c = rs.vdot(rs) - (@radius * @radius)
    d = b * b - c
    t = -b - Math.sqrt(d.abs)
    if d > 0 && t > EPS && t < isect.distance
      isect.hit_point = ray.origin.vadd(ray.dir.vmul(t))
      isect.normal = isect.hit_point.vsub(@position).vnormalize!
      isect.color = @color.vmul(clamp(LIGHT.vdot(isect.normal), 0.1, 1.0))
      isect.distance = t
      isect.hit += 1
      isect.ray_dir = ray.dir
    end
  end
end

class Plane
  def initialize(position, normal, color)
    @position, @normal, @color = position, normal, color
  end

  def intersect!(ray, isect)
    d = -(@position.vdot(@normal))
    v = ray.dir.vdot(@normal)
    t = -(ray.origin.vdot(@normal) + d) / v
    if t > EPS && t < isect.distance
      isect.hit_point = ray.origin.vadd(ray.dir.vmul(t))
      isect.normal = @normal
      d = clamp(LIGHT.vdot(isect.normal), 0.1, 1.0)
      m = isect.hit_point.x % 2
      n = isect.hit_point.z % 2
      d *= 0.5 if ((m > 1 && n > 1) || (m < 1 && n < 1))
      f = 1.0 - [isect.hit_point.z.abs, 25.0].min * 0.04
      isect.color = @color.vmul(d * f)
      isect.distance = t
      isect.hit += 1
      isect.ray_dir = ray.dir
    end
  end
end

def clamp(t, min, max)
  if t < min
    min
  elsif t > max
    max
  else
    t
  end
end

# t: 0 ~ 1
def color(t)
  t = 0 if t < 0
  t = 1 if t > 1
  ret = IMAGE_DEPTH * t.to_f
  return (ret == IMAGE_DEPTH ? (IMAGE_DEPTH-1) : ret).to_i
end

def print_col(c)
  print("#{color(c.x)} #{color(c.y)} #{color(c.z)} ")
end

# 光の方向
LIGHT = Vec.new(0.577, 0.577, 0.577)
EPS = 0.0001
# 最大反射回数
MAX_REF = 4

PLANE = Plane.new(Vec.new(0, -1, 0), Vec.new(0, 1, 0), Vec.new(1, 1, 1))
t = 0
SPHERE1 = Sphere.new(0.5, Vec.new( 0.0, -0.5, Math.sin(0)), Vec.new(1, 0, 0))
SPHERE2 = Sphere.new(1.0, Vec.new( 2.0,  0.0, Math.cos(t*0.666)), Vec.new(0, 1, 0))
SPHERE3 = Sphere.new(1.5, Vec.new(-2.0,  0.5, Math.cos(t*0.333)), Vec.new(0, 0, 1))

def intersect!(ray, i)
  SPHERE1.intersect!(ray, i) 
  SPHERE2.intersect!(ray, i) 
  SPHERE3.intersect!(ray, i) 
  PLANE.intersect!(ray, i)
end

puts("P3")
puts("#{IMAGE_WIDTH} #{IMAGE_HEIGHT}")
puts("#{IMAGE_DEPTH-1}")


IMAGE_HEIGHT.times do |row|
  IMAGE_WIDTH.times do |col|
    x = col.to_f / (IMAGE_WIDTH / 2) - 1.0
    y = (IMAGE_HEIGHT-row).to_f / (IMAGE_HEIGHT / 2) - 1.0

    ray = Ray.new(Vec.new(0.0, 2.0, 6.0),
                  Vec.new(x, y, -1.0).vnormalize!)
    i = Isect.new
    intersect!(ray, i)
    if i.hit > 0
      dest_col = i.color
      temp_col = Vec.new(1, 1, 1).vmulti(i.color)
      (1...MAX_REF).each do |j|
        q = Ray.new(i.hit_point.vadd(i.normal.vmul(EPS)),
                    i.ray_dir.reflect(i.normal))
        intersect!(q, i)
        if i.hit > j
          dest_col = dest_col.vadd(temp_col.vmulti(i.color))
          temp_col = temp_col.vmulti(i.color)
        end
      end
    else
      dest_col = Vec.new(ray.dir.y, ray.dir.y, ray.dir.y)
    end
    print_col(dest_col)
  end
end