Saves a Codea mesh item as a PLY object

CSGBox.ply

ply
format ascii 1.0
comment Written by WritePLY - a Codea LUA project by Antonio Ciolino
element vertex 36
property float x
property float y
property float z
property uchar red
property uchar green
property uchar blue
property uchar alpha
element face 12
property list uchar int vertex_index
end_header
-1 -1 1 237 83 100 255 
1 -1 1 150 73 100 255
1 1 1 226 138 100 255
-1 -1 1 214 94 100 255 
1 1 1 154 66 100 255
-1 1 1 245 133 100 255
1 -1 1 186 105 100 255 
1 -1 -1 172 61 100 255
1 1 -1 249 126 100 255
1 -1 1 162 116 100 255 
1 1 -1 199 60 100 255
1 1 1 238 116 100 255
1 -1 -1 150 125 100 255 
-1 -1 -1 226 61 100 255
-1 1 -1 215 106 100 255
1 -1 -1 153 133 100 255 
-1 1 -1 244 66 100 255
1 1 -1 187 94 100 255
-1 -1 -1 171 138 100 255 
-1 -1 1 249 73 100 255
-1 1 1 163 84 100 255
-1 -1 -1 198 139 100 255 
-1 1 1 238 82 100 255
-1 1 -1 150 74 100 255
-1 1 1 225 138 100 255 
1 1 1 216 93 100 255
1 1 -1 153 66 100 255
-1 1 1 244 134 100 255 
1 1 -1 188 104 100 255
-1 1 -1 170 61 100 255
-1 -1 -1 249 126 100 255 
1 -1 -1 163 115 100 255
1 -1 1 197 60 100 255
-1 -1 -1 239 117 100 255 
1 -1 1 150 125 100 255
-1 -1 1 224 61 100 255
3 0 1 2
3 3 4 5
3 6 7 8
3 9 10 11
3 12 13 14
3 15 16 17
3 18 19 20
3 21 22 23
3 24 25 26
3 27 28 29
3 30 31 32
3 33 34 35

Example.txt

    w = WritePLY("Saving a mesh")
    result = w:Save(yourmesh)

ReadPLY.lua

--
-- ReadPLY.lua
-- This file will need some work to operate standalone; 
-- it is part of the HTTPLoader library, but extracted here for JVM38's use.
-- 
ReadPLY = class()


--
function ReadPLY:init()
    self.renderitems={}   -- assigned later...
--    self.plyFileName=file 
    self.ParsedFile = nil
    self.texcoords = {}

end
    
function ReadPLY:draw()
    -- draw all of the renderitems in this mesh()
    if (self.renderitems~=nil) then
        for k,v in pairs(self.renderitems) do
            v:draw()
        end
    end
end

--For hack's sake, pass the PLY file string here. obj is the PLY string for this example.
function ReadPLY:ProcessObject(obj)
    self.ParsedFile=obj
    self:ProcessScene(self)  
    --log("string parsing done.")
end

function ReadPLY:ProcessScene()
    self:ProcessSceneHeader()
    self:ProcessSceneBody()
end
function ReadPLY:ProcessSceneHeader()
    elements={}        -- elements of this file
    endheader = string.find(self.ParsedFile, "end_header")
    header = string.sub(self.ParsedFile, 1, endheader-1)        
    body = string.sub(self.ParsedFile, endheader+11, 999999)
        
     -- make a table to interpret the header. this is the guide to read the file.   
    for token in string.gmatch(header, "[^\r\n]+") do
        -- pack each string and process
        -- special case find the texture file if it exists
        i= string.find(token, "comment TextureFile")
        if (i~=nil) then
            texture=string.sub(token, string.find(token, "comment TextureFile")+20, 99)
--AC: Commented out need HTTPLoader for this.
            --if (string.find(texture,"http://")~=nil) then
            --    self.d:Add(texture, DEFERRED_TEXTURE, ignoreCache)
            --else
                --self.d:Add("Documents:"..texture, DEFERRED_TEXTURE,ignoreCache)
            --    self.d:Add(self.d.rootPath..texture, DEFERRED_TEXTURE,ignoreCache)
            --end
            --log("Deferred loading "..self.d.files[1].file) --texture)
        end
        
        i=string.find(token,"element")
        if (i~=nil) then
                --we have a new element
                tbl = split(token, " ")
                entry= { name=tbl[2], value=tbl[3], properties={}, lines={} }
                table.insert(elements, entry)
        end
        i=string.find(token, "property")
        if (i~=nil) then
            tbl = split(token, " ")
            indexed = 0
            if tbl[2] == "list" then 
                -- this data is a lookup list. unused, we are hardcoding our lookups
                --against texcoords and faces.
                -- later we should deal with uchar, list data
                indexed = 1
            end
            prop = { property=tbl[table.maxn(tbl)], index=indexed}
            table.insert(entry.properties, prop)
        end  
    end  
end

function ReadPLY:ProcessSceneBody()
   self.newItem=mesh()    
    local pcolor={}        --color array, if defined, per vertex. not the packed color obj 
    local tx = {}            --texture coordindates, if ddefined
    local vertices={}       --data that gets sent to mesh triangles of point data
    local points = {}        --stores points, eventaully used to build vertices
    local colors={}
    local texcoord={}
    
    -- read through the body string using the header as a guide
    -- all elements have a value
    --lines=split(body, "[^\r\n]") failed!

    lines=GetTable(body, "[^\r\n]+") 

    offset=0
    for k,v in pairs(elements) do
        tmp = {}        --clar my temp table
        -- get value number of lines and process
        for i=1, v.value do
            table.insert(tmp, lines[i+offset])
        end
        offset=v.value
        v.lines = tmp
        --process verts these are points?
        if v.name=="vertex" then

            for lk, lv in pairs(v.lines) do 
                pt = vec3(0,0,0)
                items=GetTable(lv, "[^%s]+") --"([-+]?[0-9]*\.?[0-9]+)")

                --for k,v in pairs(items) do  --needss to be aa case stmt later
                pt.x=items[1]+0
                pt.y=items[2]+0
                pt.z=items[3]+0
                if(#items>3) then  --hack!!
                    --colors of the verts go here
                    r = items[4]+0
                    g = items[5]+0
                    b = items[6]+0
                      --  a = items[7]+0
                end
                --end    

                table.insert(points, pt)
                if (#items >3) then 
                    table.insert(pcolor, color(r,g,b,255))
                end
                pt = vec3(0,0,0)
                
            end
        end

        if v.name=="face" then
            --takes us from points to triangles...we pack these into the mesh!
            for lk, lv in pairs(v.lines) do 
                items=GetTable(lv, "[^%s]+")
                fv={}
                out={}
                vtx =vec3(0,0,0)
                --todo: read the structure data...
                --vertex_indices portion. 3 0 1 2

                vtx = items[2]+1
                table.insert(vertices, points[vtx])
                table.insert(colors, pcolor[vtx])
                
                vtx = items[3]+1
                table.insert(vertices, points[vtx])
                table.insert(colors, pcolor[vtx])
                
                vtx = items[4]+1
                table.insert(vertices, points[vtx])
                table.insert(colors, pcolor[vtx])

                --if we have teturecoords, read then here.
                if (#items > 4) then
                    uv=vec2(items[6], items[7])
                    table.insert(texcoord, uv)
                    uv=vec2(items[8], items[9])
                    table.insert(texcoord, uv)
                    uv=vec2(items[10], items[11])
                    table.insert(texcoord, uv)
                end
            end
        end  
    end
        
    --log ("final points "..#points)
    --log ("final verts "..#vertices)
    --log ("final colors "..#colors)
    --log ("final texcoord "..#texcoord) 
    
    self.newItem.vertices=vertices  -- a vec3 of points
   if (#colors>1) then  self.newItem.colors=colors  end
   if (#texcoord> 1) then
        self.newItem.texCoords=texcoord  
        self.newItem:setColors(255,255,255,255)  --IF WE HAVE A TEXTURE, IGNORE COLOR FOR NOW
    end
    --put new shape in a table for later rendering
   --table.insert(self.renderitems, self.newItem)
   return self.newItem              --  <==-- this is the mesh

    -- if we have urls to load, do so...
    --if (#self.d.files>0) then
    --    log("Loading texture...")
    --    self.d:LoadAll(self.newItem)
    --end
    
end

WritePLY.lua

--
-- WritePLY.lua
--
WritePLY = class()

function WritePLY:init(comment)
    -- load a mesh object and write it as a simple PLY. we are not going to do 
    -- textures.
    --if a comment is wanted, add it during object creation or edit it while instance exists.
    self.comment = comment 
end

function WritePLY:Save(obj)
    startheader  = "ply\r\nformat ascii 1.0\r\n"
    comments = "comment Written by WritePLY - a Codea LUA project by Antonio Ciolino " 
    if (self.comment ~=nil) then 
    comments = comments .. self.comment 
    end
    comments = comments .. "\r\n"
    meta1 = "element vertex "
    meta2 = "property float x\r\nproperty float y\r\nproperty float z\r\n"
    meta2 = meta2 .. "property uchar red\r\nproperty uchar green\r\n"
    meta2 = meta2 .. "property uchar blue\r\nproperty uchar alpha\r\n"
    meta3 = "element face "
    meta4 = "property list uchar int vertex_index\r\n"
    endheader = "end_header\r\n" 
    
    --modify meta1 and meta3
    
    pointlist = {} 
    colorlist = {}
    verts = ""
    faces = ""
    colors = obj.colors
    for x=1, #obj.vertices do         --these are locations in space. 3 of them make a face
        v = obj:vertex(x)
        pt = v.x .. " " .. v.y .. " " ..v.z  --a triplet of points
        c = colors[x]
        clr = math.floor(c.r*255) .. " " .. 
            math.floor(c.g*255) .. " " ..
            math.floor(c.b*255) .. " " .. 
            math.floor(c.a*255)
        table.insert(pointlist, pt)    --add to a table to index later. THIS IS A FACE.
        table.insert(colorlist, clr)    --store the color of the vertex.
    end
    
    meta1 = meta1 .. #obj.vertices .. "\r\n"
    
    for x=1, #pointlist,3 do
        verts = verts .. tostring(pointlist[x]) .. " " .. tostring(colorlist[x]) .. " \r\n" ..
        tostring(pointlist[x+1]) .. " " .. tostring(colorlist[x+1]) .. "\r\n" .. 
        tostring(pointlist[x+2]) .. " " .. tostring(colorlist[x+2]) .. "\r\n"
        --ply files are zero based for indices
        idx = x-1
        faces = faces ..  "3 " .. tostring(idx) .. " " ..
        tostring(idx+1) .. " " .. 
        tostring(idx+2) .. "\r\n"
    end
    meta3 = meta3 .. #pointlist / 3 .. "\r\n"
    
    header = startheader ..comments .. meta1 ..meta2 .. meta3 .. meta4 .. endheader
    output = header .. verts .. faces 
    return output   
    
end