topic Re: How to pass a MaxScript bitmap to C++ using function-publishing in 3ds Max Programming Forum

How to pass a MaxScript bitmap to C++ using function-publishing

Anonymous — Mon, 26 Nov 2018 20:56:51 GMT

Greetings,

I have a question regarding how to pass a MaxScript bitmap to C++ using function-publishing?

I use the following definition for my function-published interface

void SetImage(PBBitmap &bmap);
PBBitmap& GetImage();

PROP_FNS(IFP_OpenVINO::em_getBmap, GetImage, IFP_OpenVINO::em_setBmap, SetImage, TYPE_BITMAP_BV)

And on the MaxScript side I use

myBitmap = openBitmap <some-path to an image>

fp.Image = myBitmap

showproperties myBitmap

My expectation is that on the C++ side my GetImage has received by-value a MXS Bitmap object that I can work with. This is not working as I am getting trash. Might anyone be so kind as to pointing me to working samples or how-tos that demonstrate proper usage of function-publishing and bitmaps?

Re: How to pass a MaxScript bitmap to C++ using function-publishing

istan — Mon, 26 Nov 2018 22:14:13 GMT

not sure, but have you also tried "by reference" instead of "by value"?

Re: How to pass a MaxScript bitmap to C++ using function-publishing

Anonymous — Tue, 27 Nov 2018 18:19:59 GMT

Greetings Istan -

I have approached the problem both ways - taking the Bitmap objects from Maxscript to C++ both by-value and by-reference. In both cases I get clean builds - so no insight from the compiler - and Maxscript seems perfectly happy in passing the Bitmap object to the C++ layer. However, when I set a breakpoint in my C++ getter I am still getting trash.

I have reviewed the HowTo.sln and specifically the FunctionPublishing project for guidance and that is where I am coming from. What I really would like is a bit of code-sample - either from the samples or from elsewhere - that demonstrate either thru FnPub or through traditional paramblock2 how to pass a Bitmap from MXS to C++ layer.

Let me know if you have additional questions ... RudyC

Re: How to pass a MaxScript bitmap to C++ using function-publishing

klvnk — Thu, 06 Dec 2018 23:48:15 GMT

MXS will pass it as a MAXBitMap value not a Bitmap so you could try it as a TYPE_VALUE not TYPE_BITMAP

then do something like...

void SetImage(Value* val)
{
    if(val->tag == class_tag(MAXBitMap)) //maxscript.h/value.h
    {
         MAXBitMap* maxbitmap = (MAXBitMap*)val;
         Bitmap* bm = maxbitmap->bm;
         if(bm)......

Re: How to pass a MaxScript bitmap to C++ using function-publishing

klvnk — Thu, 06 Dec 2018 23:55:28 GMT

you could also try is like this

void SetImage(Bitmap *bmap);
Bitmap* GetImage();

PROP_FNS(IFP_OpenVINO::em_getBmap, GetImage, IFP_OpenVINO::em_setBmap, SetImage, TYPE_BITMAP)

Re: How to pass a MaxScript bitmap to C++ using function-publishing

klvnk — Fri, 07 Dec 2018 17:50:07 GMT

the value version works as expected

the other method partially...

though it should be

void SetImage(PBBitmap *bmap);
PBBitmap * GetImage();

PROP_FNS(IFP_OpenVINO::em_getBmap, GetImage, IFP_OpenVINO::em_setBmap, SetImage, TYPE_BITMAP)

unfortunately only the bitmapinfo ptr of the PBBitmap is valid the Bitmap is a null pointer and you can only pass "saved"/loaded bitmaps which is odd though it could be bug in the version i use

Re: How to pass a MaxScript bitmap to C++ using function-publishing

Anonymous — Fri, 07 Dec 2018 17:53:53 GMT

Thanks klvnk -

I tried your approach and can see the situation in Max 2019 ... the PBBitmap has data and the ptr to Bitmap is null. It indeed might be a bug.

RudyC

Re: How to pass a MaxScript bitmap to C++ using function-publishing

klvnk — Fri, 07 Dec 2018 18:07:11 GMT

the value version works ok though, you could get it to throw typical max script errors so from the mxs side theres no difference.