Menu
▾
▴
Re: [FreeWRL] Expanding on Dougs answer to Re: EAI documentation question
|
From: Dave J. <dav...@go...> - 2010-05-10 12:39:29
|
On 10 May 2010 16:29, John A. Stewart <ale...@cr...> wrote:
> Doug; once again you are 100% correct. You get the gold star! ;-)
>
> I'm going to add a bit to Doug's comments.
>
>
>>> So, given I know that the node type of a node is 76, how do I find out
>>> the names of all the fields for that type of node?
>
> There are some interesting tables and functions that are generated by the initial Perl code (run perl VRMLC.pm).
>
> All nodes have a node type.
>
> eg:
>
> struct X3D_Shape *myShape = (struct X3D_Shape *) createNewX3DNode(NODE_Shape);
>
> the "myShape->_nodeType" field will be the int equivalent of "NODE_Shape".
>
> The function "stringNodeType(myShape->_nodeType)" will return a pointer to a string, so you can use this in a printf ("%s",) type of call easily.
>
>> const int *NODE_OFFSETS[] = {
>> OFFSETS_Anchor, <<<<< this is element [0] on line 5115
>> ....
>> OFFSETS_Material, <<<<< this is element [76] on line 5115 + 76 = 5191
>>
>> I do the go-to-definition trick on OFFSETS_Material and it takes me to generatedCode.c L3653
>
>
> Yes, so, if you wanted to see what the fields of your Shape node are, as Doug notes:
>
> int * fieldOffsetsPtr = (int *) NODE_OFFSETS[myShape->_nodeType];
>
>
>> const int OFFSETS_Material[] = {
>> (int) FIELDNAMES_transparency, (int) offsetof (struct X3D_Material, transparency), (int) FIELDTYPE_SFFloat, (int) KW_inputOutput, (int) (SPEC_VRML | SPEC_X3D30 | SPEC_X3D31 | SPEC_X3D32 | SPEC_X3D33),
>> ...
>> -1, -1, -1, -1, -1};
>>
>> It appears to be a table of field names for Material. The -1,-1,-1,-1,-1 is obviously a sentinal value so if you are looping through fields you know when you're done.
>
>
> Ok - the info for each field is grouped into groups of 5 integers. You know when you are at the end of the fields for that node when you hit the -1, or, for readability, the macro "INT_ID_UNDEFINED"
>
> Some fields are for internal use only, these field names will start off with an underscore. I'll go through a field here for the Shape node.
>
> >From generated code.c:
>
> const int OFFSETS_Shape[] = {
> ...
> (int) FIELDNAMES_appearance,
> - this is the shape "Appearance" field...
>
> (int) offsetof (struct X3D_Shape, appearance),
> - offset in the structure of this field; offset is in bytes;
>
> (int) FIELDTYPE_SFNode,
> - this is the type of the node; other types might be FIELDTYPE_SFInt32, etc.
>
> (int) KW_inputOutput,
> - for routing, can we send and/or receive events to this node???
>
> (int) (SPEC_VRML | SPEC_X3D30 | SPEC_X3D31 | SPEC_X3D32 | SPEC_X3D33),
> - if we are interested in checking, we can see if this field exists in a specific level of X3D.
> ....
>
>
>
>> That's what the makeFIELDDEFret() appears to be doing.
>>
>> /* now go through and get the name, type, keyword */
>> np = NODE_OFFSETS[boxptr->_nodeType];
>> while (*np != -1) {
>> if (strcmp (FIELDNAMES[*np],"_") != 0) {
>> sprintf (myline,"%s %c %s ",stringFieldType(np[0]), (char) mapFieldTypeToEAItype(np[2]),
>> stringKeywordType(np[3]));
>> strcat (buf, myline);
>> }
>> np += 5;
>> }
>>
>
> Absolutely correct method of accessing. Note that the strcmp in the above while loop gets rid of the internal-only fields, as mentioned briefly above.
>
> If you change the "sprintf(myLine," to a "printf(", you'll get the fields of the node printed out, much like you'll see in the VRML/X3D spec.
OK, a crude patch to replace boxptr = X3D_NODE(myptr); with boxptr =
getEAINodeFromTable(myptr,-1); in makeFIELDDEFret
produces: (line breaks inserted for clarity)
........
56
13
transparency d inputOutput
specularColor c inputOutput
shininess d inputOutput
diffuseColor c inputOutput
ambientIntensity d inputOutput
_scol P inputOutput
_dcol P inputOutput
_ecol P inputOutput
emissiveColor c inputOutput
metadata h inputOutput
_amb P inputOutput
__oldmetadata h inputOutput
_shin d inputOutput
I suspect this needs a bit of a cleanup to deliver what (in theory)
the SAI wants, according to the Java code in the other mail thread,
but I will look at this in more detail.
I think Java wants 7 transparency specularColor shininess diffuseColor
ambientIntensity emissiveColor metadata
(Unsure about metadata)
Dave
|