Open source signal processing for art

• community
• software
• contact

• rubyk
• mimas
• download
• oscit
• liboscit
• dub

rubyk

latest blog entries

• OpenCV bindings with Lua

  Geeez I’ve been waiting for this one. Finally after 39 hours work non-stop (I feel drunk) and the creation of a new ruby gem called Dub (Doxygen based Ubiquitous Binder which generates 10'018 lines of code that compile without a warning, I can PLAY with OpenCV in Rubyk.

  The only source for images right now is the video signal, but that quite fun already.

  

  If you want to reproduce the stupid rotating cube with your own face on it, heres the code:

  (It is also an example in examples/GLLua/opencv.lua)

  Rk patch

  # run from build directory with
  # ./rubyk ../examples/GLLua/opencv.rk
  win = GLWindow()
  cv = GLLua("../examples/GLLua/opencv.lua")
  win => cv
  video = VideoIn()
  video => video~cv
  m = Metro(3000)
  m => win

  Lua code

  The code has been updated to use the new texture based rendering.

  require('cv')
  
  -- size must be a power of 2
  size  = cv.Size(128,128)
  res   = res   or cv.Mat()
  
  n = n or 0
  x = x or 0
  y = y or 0
  z = z or 0
  
  function video(frame)
    cv.resize(frame, res, size, 0, 0, cv.INTER_LINEAR)
    frame_changed = true
  
    n = n + math.pi / 300
    x = math.cos(n / 0.9) * 360 / math.pi
    y = math.sin(n / 0.7) * 360 / math.pi
    z = math.sin(n) * 360 / math.pi
  end
  inlet('video', MatrixIO('send me images'))
  
  function draw()
    gl.Clear( "COLOR_BUFFER_BIT, DEPTH_BUFFER_BIT")
    --gl.ClearDepth(1.0)
    gl.MatrixMode("MODELVIEW")
    gl.LoadIdentity()
  
    if frame_changed then
      rk.makeTexture(res, tex)
      frame_changed = false
    end
  
    gl.Translate(0.0, 0.0, -6.0)
  
    gl.Rotate(x, 1.0, 0.0, 0.0)
    gl.Rotate(y, 0.0, 1.0, 0.0)
    gl.Rotate(z, 0.0, 0.0, 1.0)
  
    gl.Color(0.5,0.5,0.0)--,0.3)
    gl.LineWidth(1.0)
    glut.WireCube(2.6)
  
    gl.Color(0.5,0.5,0.0,0.1)
    glut.SolidCube(2.6)
  
    -- simples way to draw a texture
    gl.Translate(0.0, 0.0, -1.5)
    -- do not forget to set a color or nothing will be drawn
    gl.Color(1,1,1,0.5)
    rk.drawTexture(tex, 1.3, 1.3, -1.3, -1.3)
  end
  
  function resize(width, height)
    textures = textures or gl.GenTextures(1)
    tex = textures[1]
  
    gl.Enable("BLEND")
    gl.Disable("DEPTH_TEST") -- not working ???
    gl.BlendFunc("SRC_ALPHA", "ONE_MINUS_SRC_ALPHA")
  
    gl.Enable("TEXTURE_2D")
  
    gl.Enable("LINE_SMOOTH")
    -- Select the projection matrix
    gl.MatrixMode("PROJECTION")
    -- reset
    gl.LoadIdentity()
    -- Calculate the aspect ratio of the view
    gl.Perspective(
      45.0,             -- Field of view angle
      width / height,   -- Aspect ration
      1.0,              -- zNear
      100.0             -- zFar
    )
  
    view.width  = width
    view.height = height
  end
  

  2010-03-03 - tagged: Lua, OpenCV, OpenGL - comments (0)

• playing with the new GLLua class

  Creating Bezier curves with lua and displaying them with OpenGL (GLLua object):

  

  And here is the code that evaluates the curves and color transitions along the paths:

  for t = 0,1.0,(1.0/resolution) do
    ta = (1-t)^3
    tb = 3 * t * (1-t)^2
    tc = 3 * (1-t) * t^2
    td = t^3
  
    gl.Color(
      c1.r * (1-t) + c4.r * t,
      c1.v * (1-t) + c4.v * t,
      c1.b * (1-t) + c4.b * t
    )
    gl.Vertex(
      ta * p1[1] + tb * p2[1] + tc * p3[1] + td * p4[1],
      ta * p1[2] + tb * p2[2] + tc * p3[2] + td * p4[2],
      ta * p1[3] + tb * p2[3] + tc * p3[3] + td * p4[3]
    )
  end

  2010-02-21 - tagged: Lua, OpenGL - comments (0)