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    [plugin] Ruby Raytracer

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    • AdamBA Offline
      AdamB
      last edited by

      Because I evidently have waay too much time on my hands, I offer for your delectation...

      A pure Ruby raytracer

      It has Depth-of-field (using jittered samples), 3 fixed materials, (sky, checkerboard and chrome) and font rendering - of sorts!

      There are a couple of constants you can edit:

      REZ for image size
      SAMPLES for number of jittered samples per pixel

      (I started from a micro raytracer written in C and transmogrified it into our chosen language and twiddled it a bit.)

      Enjoy - Thea will be quaking in their boots. πŸ˜‰


      raytrace.rb

      Developer of LightUp Click for website

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      • Chris FullmerC Offline
        Chris Fullmer
        last edited by

        Sounds cool Adam, I've got a render cooking in the background as we speak! πŸ˜„

        Lately you've been tan, suspicious for the winter.
        All my Plugins I've written

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        • Mike LuceyM Offline
          Mike Lucey
          last edited by

          Thanks Adam.

          Chris, can you show the results and original and anything else we might learn from?

          Support us so we can support you! Upgrade to Premium Membership!

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          • thomthomT Offline
            thomthom
            last edited by

            God heavens! Ruby raytracer ... πŸ˜† do you also race snails on your spare time? πŸ˜„


            Lost track of how long this took to render. :D

            Thomas Thomassen β€” SketchUp Monkey & Coding addict
            List of my plugins and link to the CookieWare fund

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            • MarianM Offline
              Marian
              last edited by

              Does it need a lot of resources? It just hangs for me after I point out the output file, it just stays at line 0 out of 512.

              http://marian87.deviantart.com/

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              • thomthomT Offline
                thomthom
                last edited by

                @marian said:

                Does it need a lot of resources? It just hangs for me after I point out the output file, it just stays at line 0 out of 512.

                Yes, it's a raytrace render - taking a long time. I set the resolution down to 256 and it still took a long time. The SketchUp UI stops updating as well - like when you do a large Sandbox operation.

                Thomas Thomassen β€” SketchUp Monkey & Coding addict
                List of my plugins and link to the CookieWare fund

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                • MarianM Offline
                  Marian
                  last edited by

                  I guess I won't have much use for it then πŸ˜›

                  http://marian87.deviantart.com/

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                  • A Offline
                    Aerilius
                    last edited by

                    And it seems to render a "built-in" model, not actually my SketchUp model (that's probably why it is called a "micro raytracer"). When I change the numbers in G, the balls shift.

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                    • thomthomT Offline
                      thomthom
                      last edited by

                      There is a reason this is posted in the Developers section, not the Plugins section. πŸ˜‰

                      Thomas Thomassen β€” SketchUp Monkey & Coding addict
                      List of my plugins and link to the CookieWare fund

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                      • AdamBA Offline
                        AdamB
                        last edited by

                        Guys, guys

                        Its a 100 lines of Ruby that manages to do image file writing, blurry depth of field, a point light and multiple materials!
                        How on earth do you think it would be a full raytracer! 😲

                        However, if you're interested in raytracing, its very simple and you can play around with it to learn about this area of graphics.

                        The G[] array contains a Bitmap of 32x10 stored as 10 integers.

                        In function T(), I test the primary ray against an infinite plane and if hit return position+surface normal+materialID (Line 36).
                        I run through each bit of the bitmap and where this is '1' bits, I trace a reflective Sphere returning a surface position+normal+materiaID. (Line 54)

                        The Scene function S(), traces the primary ray into the scene (Line 70) and colors the pixels depending on material m, and a single pointlight (Line 77). Try changing the position of the light.

                        The color for the infinite plane is chosen based on a mod function of position. Line 83 controls the scale of chequers.

                        The main function "raytrace" starts at line 93 and takes care of generating primary rays, and writing out an PPM image file.

                        Adam

                        Developer of LightUp Click for website

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                        • thomthomT Offline
                          thomthom
                          last edited by

                          Thanks for the breakdown Adam. πŸ‘

                          Thomas Thomassen β€” SketchUp Monkey & Coding addict
                          List of my plugins and link to the CookieWare fund

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                          • T Offline
                            tomasz
                            last edited by

                            Thanks for the sample code and the explanation.
                            I wasn't aware that a Raytracer can be written in such a small piece of code!! 😲

                            @adamb said:

                            Thea will be quaking in their boots. πŸ˜‰
                            πŸ˜†

                            Author of [Thea Render for SketchUp](http://www.thearender.com/sketchup)

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                            • A Offline
                              Aerilius
                              last edited by

                              I edited and reduced some lines. Hope nobody minds...
                              (it's just what I thought would work, I've not yet looked at other raytracing source codes)

                              
                              module RubyRaytracer
                              
                              class Geom;;Vector3d
                                def sc(s)
                                  Geom;;Vector3d.new(x*s,y*s,z*s)
                                end
                                def sc!(s)
                                  self.x *= s
                                  self.y *= s
                                  self.z *= s
                                  self
                                end
                              end
                              
                              def self.v(x,y,z)
                                Geom;;Vector3d.new(x,y,z)
                              end
                              
                              # @lights; position, color, intensity, radius of light source
                              @lights = [ [[1000,1000,1000],[255,255,255],300,10], [[-20,23,15],[255,0,0],50,0], [[-5.5,8,15],[0,0,255],50,0] ]
                              @groundcolor = v(180,160,120)
                              @skycolor = v(180,200,255)
                              @skycolor2 = v(140,160,220)
                              @rez = 256
                              @samples = 8
                              
                              def self.cast_ray(o, d)
                                hit = @model.raytest([o,d],false)
                                return (d.z<0)? @groundcolor.sc(1+0.5*d.z) ; @skycolor.sc(1-2*d.z)+@skycolor2.sc(2*d.z) if hit == nil || (f = hit[1].last).class != Sketchup;;Face
                                p = hit[0]
                                n = f.normal
                                rd = (d - n.sc( 2*(d%n)/(n.length**2) )).normalize # reflected ray on face
                                m = (d%n<0)? f.material ; (f.back_material||f.material)
                                a = (m!=nil)? m.alpha ; 1 # opacity; I use this parameter for reflectivity
                                lc = v(0,0,0) # light color
                                @lights.each{|lt| # loop over all light sources
                                  l = Geom;;Point3d.new(lt[0].collect{|x| x+lt[3]*rand()}) # light position +/- light radius for smooth shadows
                                  ld = (p.vector_to(l)).normalize # vector to light source
                                  s = ( x=@model.raytest([p,ld]); x!=nil && x[0].on_line?([p,l]) )? 0.5 ; 1 # occlusion test for shadows
                                  i = lt[2]/(4*Math;;PI*ld.length)**2 # light intensity decreases with distance
                                  h = 0.25+0.75*[(1 - 2*Math.acos( n%ld )/Math;;PI),0].max # shading
                                  lc += v(*lt[1]).sc(i*s*h)
                                }
                                c = (m!=nil)? v( *((m.materialType>0)? m.texture.average_color ; m.color).to_a.slice(0,3) ) ; v(255,255,255) # color of face
                                new_color = (lc - v(255,255,255) + c).sc(a)
                                # new_color += self.cast_ray(p,d).sc(1-a) if a<1 # uncomment this for transparency
                                new_color += self.cast_ray(p,rd).sc(1-a) if a<1 # reflectivity
                                return new_color
                              end #def cast_ray
                              
                              # credits to AdamB, http://forums.sketchucation.com/viewtopic.php?f=180&t=40989#p363271
                              def self.raytrace(filename=nil, width=@rez, samples=@samples)
                                @model = Sketchup.active_model
                                @lights[0] = [ @model.shadow_info["SunDirection"].sc(1000000).to_a, [255,255,255], 300, 100000] # SketchUp sun
                              
                                filename = UI.savepanel("Save Raytrace Image", "","output.ppm") unless filename
                                File.open(filename, "wb") {|f|
                                  vw = Sketchup.active_model.active_view
                                  height = (width*vw.vpheight/vw.vpwidth).to_i
                                  f.printf("P6 #{width} #{height} 255\n")
                              
                                  fov = vw.field_of_view.degrees
                                  e = vw.camera.eye
                                  o = v(e.x, e.y, e.z)
                                  t = vw.camera.target - e
                                  g = v(t.x, t.y, t.z).normalize
                                  
                                  a = (v(0,0,1).cross(g)).normalize.sc(fov / height)
                                  b = (g.cross(a)).normalize.sc(fov / height) 
                                  c = a.sc(-width*0.5)+b.sc(-height*0.5)+g
                                  
                                  for y1 in 0...height
                                    y = height - 1 - y1
                                    Sketchup.set_status_text "raytrace; line #{y1} of #{height}"
                                    for x1 in 0...width
                                      x = width - 1 - x1
                                      p = v(0,0,0)
                                      for r in 1..samples
                                        p += self.cast_ray(Geom;;Point3d.new(o.to_a), (a.sc(x+rand())+b.sc(y+rand())+c))
                                      end
                                      p = p.sc(1/samples.to_f)
                                      p = p.to_a.collect{|x| if x>255;255;elsif x<0;0;else;x.to_i;end}
                                      f.printf("%c%c%c", *p)
                                    end
                                  end
                                  Sketchup.set_status_text "Finished #{filename}"
                                }
                              end
                              
                              end #module RubyRaytracer
                              
                              if( not file_loaded?(__FILE__) )
                                menu=UI.menu("Plugins")
                                menu.add_item("Raytrace the model!") { RubyRaytracer.raytrace }
                                file_loaded(__FILE__)
                              end
                              
                              
                              
                              #100
                              
                              

                              output.png

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                              • thomthomT Offline
                                thomthom
                                last edited by

                                It renders the SketchUp scene?

                                Thomas Thomassen β€” SketchUp Monkey & Coding addict
                                List of my plugins and link to the CookieWare fund

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                                • A Offline
                                  Aerilius
                                  last edited by

                                  Well, instead of the hard-coded materials and G-Bitmap, it does a raytest() in the model and takes the material of the face that the ray hits (+ shading from normal etc). That is all, but when it's repeated for every pixel, the result is impressive.
                                  Nevertheless, it's still slow πŸ˜‰

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                                  • AdamBA Offline
                                    AdamB
                                    last edited by

                                    Thats pretty cool. Its it it much slower?

                                    Just FYI, I test LightUp raytests in a mode that gives realtime raytracing of your scene as you look around!

                                    Adam

                                    Developer of LightUp Click for website

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                                    • N Offline
                                      notareal
                                      last edited by

                                      @unknownuser said:

                                      Thanks for the sample code and the explanation.
                                      I wasn't aware that a Raytracer can be written in such a small piece of code!! 😲
                                      πŸ˜†

                                      Quite tiny indeed... there are others too, like
                                      http://tog.acm.org/resources/GraphicsGems/gemsiv/minray/

                                      Welcome to try [Thea Render](http://www.thearender.com/), Thea support | [kerkythea.net](http://www.kerkythea.net/) -team member

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