Crash when exporting a plasma layer with "Use Texture" unchecked.

[Semjay01]

If a Plasma Standard material contains a Plasma Layer with the "Use Texture" unchecked, the export crashes Max.

Reproduction Steps:

• Create a new scene in 3ds Max
• Create a pageinfo component as usual
• Create a simple object like a box and assign the pageinfo component to it
• In the Materials Editor, create a new Plasma Standard Material
• Assign a Plasma Layer to the new material and choose a bitmap as its texture
• Uncheck the "Use Texture" checkbox
• Assign the material to the box
• Do a Plasma Export.

Expected result:

• The file exports correctly

Actual result

• Max crashes without a helpful error report.

[Semjay01]

The problem seems to be in the code around here:

Plasma/Sources/MaxPlugin/MaxConvert/plLayerConverter.cpp

Lines 295 to 324 in 8c6b364

	// We're using a texture, try and get its info
	plFileName fileName = layer->GetBitmapFileName();
	PBBitmap *pbbm = nullptr;
	BitmapInfo *bi = nullptr;
	if( bitmapPB->GetInt( kBmpUseBitmap ) )
	{
	if( bitmapPB )
	pbbm = bitmapPB->GetBitmap( kBmpBitmap );
	if( pbbm )
	bi = &pbbm->bi;
	}
	// If the texture had bad info, assert and return the empty layer
	if( !fileName.IsValid() )
	{
	if( upperLayer )
	{
	if( fErrorMsg->Set( !( fWarned & kWarnedNoUpperTexture ), "Plasma Export Error", ST::format(sWarnNoUpperTexture, maxNode->GetName()) ).CheckAskOrCancel() )
	fWarned |= kWarnedNoUpperTexture;
	fErrorMsg->Set( false );
	delete plasmaLayer;
	return nullptr;
	}
	else
	{
	return (plLayerInterface *)plasmaLayer;
	}
	}

Because bitmapPB->GetInt( kBmpUseBitmap ) is false, bi remains nullptr, and the attempt to get the width here:

Plasma/Sources/MaxPlugin/MaxConvert/plLayerConverter.cpp

Line 392 in 8c6b364

for( clipID = 0, w = bi->Width(); w > bd.maxDimension; w >>= 1, clipID++ );

causes a null pointer exception.

[Filtik]

I can confirm the problem. It has happened to me often as well.

[Hoikas]

That seems like it would indeed cause an access violation. Out of curiosity, what is the use case for having a Plasma Layer with no associated texture?

[Semjay01]

You wouldn't do this intentionally, of course, but I had inadvertently unchecked the box. Because there was no error message, it took a long time to work out why the export crashed.