require 'bundler/setup'
require 'opengl'
require 'glut'
require './opengl_getbitmap'
include Gl, Glut

def init
  glClearColor(0, 0, 0, 1)
end

def line(x1, y1, x2, y2)
  glBegin(GL_LINES)
    glVertex2d(x1, y1)
    glVertex2d(x2, y2)
  glEnd
  BitMap.gl_capture("./picture/img#{@counter}.bmp")
  glFlush
  @counter += 1
end

display = proc do
  @counter = 1
  glClear(GL_COLOR_BUFFER_BIT)
  glColor3f(0, 1, 0)
  -1.step(1, 0.1) do |x|
    line(x, 1, -x, -1)
  end
end

glutInit
glutInitWindowSize(170, 170)
glutInitWindowPosition(200, 100)
glutCreateWindow
glutDisplayFunc(display)
init
glutMainLoop