render.py

        ## Make sure Preview directory exists and is empty
        if not os.path.isdir(preview_dir):
            os.mkdir(preview_dir)

        iniPrevFile=os.path.join(preview_dir, "Preview.ini")
        inputPrevFile=os.path.join(preview_dir, "Preview.pov")
        outputPrevFile=os.path.join(preview_dir, texPrevName)
        ##################### ini ##########################################
        fileIni=open("%s"%iniPrevFile,"w")
        fileIni.write('Version=3.7\n')
        fileIni.write('Input_File_Name="%s"\n'%inputPrevFile)
        fileIni.write('Output_File_Name="%s.png"\n'%outputPrevFile)
        fileIni.write('Library_Path="%s"\n' % preview_dir)
        fileIni.write('Width=256\n')
        fileIni.write('Height=256\n')
        fileIni.write('Pause_When_Done=0\n')
        fileIni.write('Output_File_Type=N\n')
        fileIni.write('Output_Alpha=1\n')
        fileIni.write('Antialias=on\n')
        fileIni.write('Sampling_Method=2\n')
        fileIni.write('Antialias_Depth=3\n')
        fileIni.write('-d\n')
        fileIni.close()
        ##################### pov ##########################################
        filePov=open("%s"%inputPrevFile,"w")
        PATname = "PAT_"+string_strip_hyphen(bpy.path.clean_name(tex.name))
        filePov.write("#declare %s = \n"%PATname)
        filePov.write(shading.exportPattern(tex, string_strip_hyphen))

        filePov.write("#declare Plane =\n")
        filePov.write("mesh {\n")
        filePov.write("    triangle {<-2.021,-1.744,2.021>,<-2.021,-1.744,-2.021>,<2.021,-1.744,2.021>}\n")
        filePov.write("    triangle {<-2.021,-1.744,-2.021>,<2.021,-1.744,-2.021>,<2.021,-1.744,2.021>}\n")
        filePov.write("    texture{%s}\n"%PATname)
        filePov.write("}\n")
        filePov.write("object {Plane}\n")
        filePov.write("light_source {\n")
        filePov.write("    <0,4.38,-1.92e-07>\n")
        filePov.write("    color rgb<4, 4, 4>\n")
        filePov.write("    parallel\n")
        filePov.write("    point_at  <0, 0, -1>\n")
        filePov.write("}\n")
        filePov.write("camera {\n")
        filePov.write("    location  <0, 0, 0>\n")
        filePov.write("    look_at  <0, 0, -1>\n")
        filePov.write("    right <-1.0, 0, 0>\n")
        filePov.write("    up <0, 1, 0>\n")
        filePov.write("    angle  96.805211\n")
        filePov.write("    rotate  <-90.000003, -0.000000, 0.000000>\n")
        filePov.write("    translate <0.000000, 0.000000, 0.000000>\n")
        filePov.write("}\n")
        filePov.close()
        ##################### end write ##########################################

        pov_binary = PovrayRender._locate_binary()
        
        if sys.platform[:3] == "win":
            p1=subprocess.Popen(["%s"%pov_binary,"/EXIT","%s"%iniPrevFile],
                stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
        else:
            p1=subprocess.Popen(["%s"%pov_binary,"-d","%s"%iniPrevFile],
                stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
        p1.wait()

        tex.use_nodes = True
        tree = tex.node_tree
        links = tree.links
        for n in tree.nodes:
            tree.nodes.remove(n)
        im = tree.nodes.new("TextureNodeImage")  
        pathPrev="%s.png"%outputPrevFile
        im.image = bpy.data.images.load(pathPrev)
        name=pathPrev
        name=name.split("/")
        name=name[len(name)-1]
        im.name = name  
        im.location = 200,200
        previewer = tree.nodes.new('TextureNodeOutput')    
        previewer.label = "Preview"
        previewer.location = 400,400
        links.new(im.outputs[0],previewer.inputs[0])
        #tex.type="IMAGE" # makes clip extend possible
        #tex.extension="CLIP"
        return {'FINISHED'}