RE: CClusterPropertyBuilder make XSI go boom!

[Marc-André Belzile <mbelzile(at)Softimage.COM>]

Odd, I'll check that one. 

 

thanks

 

-mab

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From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf Of Matt Lind
Sent: April-13-08 3:31 PM
To: xsi(at)Softimage.COM
Subject: CClusterPropertyBuilder make XSI go boom!

I've been saddled with a technical question from our realtime shader dev:

Using the C++ API, how do you make and assign a vertex color property to a specific cluster on a polygon mesh?

Using the CClusterPropertyBuilder causes XSI to crash (6.01, 6.5) using either method shown in the docs (ie: with no arguments, or with 2 arguments).  I jumped into the problem myself to verify, and sure enough it's true.  So, I tried the technique I normally use in scripting which is to create a cluster, then use Cluster.AddProperty() to create the vertex color property on the cluster.  Works fine, but the problem is the C++ SDK docs state only ClusterProperties created using the CClusterPropertyBuilder can have their values changed and set using the ClusterProperty.SetValues() method.  Sooo, what good is that?
[mab] ClusterProperty.SetValues uses a cache created by the builder to map geometry elements to cluster indices. This cache is not available for non-builder cluster properties which makes ClusterProperty.SetValues unusable. 


----------------start code example (C++)------------------------
//===============================================================================================
// ML_VertexColorCreate v1.0 (c)2008 Matt Lind
//
// Simple demonstration of how to create a vertex color property on a selected polygon mesh object.
//===============================================================================================
#include <xsi_application.h>
#include <xsi_context.h>
#include <xsi_pluginregistrar.h>
#include <xsi_status.h>
#include <xsi_argument.h>
#include <xsi_command.h>

#include <xsi_selection.h>
#include <xsi_model.h>
#include <xsi_x3dobject.h>
#include <xsi_siobject.h>
#include <xsi_primitive.h>
#include <xsi_geometry.h>
#include <xsi_cluster.h>
#include <xsi_clusterproperty.h>
#include <xsi_clusterpropertybuilder.h>
#include <xsi_vertexcolor.h>
#include <xsi_polygonmesh.h>

using namespace XSI;


//===========================================================================
// XSILoadPlugin()
//
//===========================================================================
XSIPLUGINCALLBACK CStatus XSILoadPlugin( PluginRegistrar& oPluginRegistrar )
{
    oPluginRegistrar.PutAuthor( L"Matt Lind" );
    oPluginRegistrar.PutName(   L"ML_VertexColorCreate" );
    oPluginRegistrar.PutEmail(  L"" );
    oPluginRegistrar.PutURL(    L"" );
    oPluginRegistrar.PutVersion( 1, 0 );

    oPluginRegistrar.RegisterCommand( L"ML_VertexColorCreate", L"ML_VertexColorCreate" );

    return( CStatus::OK );
}

//===========================================================================
// XSIUnloadPlugin()
//
//===========================================================================
XSIPLUGINCALLBACK CStatus XSIUnloadPlugin( const PluginRegistrar& in_reg )
{
    CString strPluginName = in_reg.GetName();
    Application().LogMessage( strPluginName + L" has been unloaded.", siVerboseMsg );
    return( CStatus::OK );
}

//===========================================================================
// Init()
//
//===========================================================================
XSIPLUGINCALLBACK CStatus ML_VertexColorCreate_Init( CRef& in_ctxt )
{
    Context oContext( in_ctxt );

    Command oCommand = oContext.GetSource();
    oCommand.PutDescription( L"" );
    oCommand.EnableReturnValue( true );

    ArgumentArray oArguments = oCommand.GetArguments();
    oArguments.AddWithHandler( L"oSelection", L"Collection" );

    return( CStatus::OK );
}

//===========================================================================
// Execute()
//
//===========================================================================
XSIPLUGINCALLBACK CStatus ML_VertexColorCreate_Execute( CRef& in_ctxt )
{
    Context oContext( in_ctxt );
    //CValueArray oArguments  = oContext.GetAttribute( L"Arguments" );
    //CValue oSelection       = oArguments[0];

    // Get hook to the XSI Application
    Application oApplication;

    // Check selection
    Selection oSelection( oApplication.GetSelection() );
    LONG Count = oSelection.GetCount();
    if ( Count <= 0 ) {
        oApplication.LogMessage( L"Nothing selected", siErrorMsg );
        return( CStatus::Fail );
    }
 
    // Get 1st element in selection
    SIObject oElement( oSelection[0] );
    X3DObject oObject;

    if ( oElement.IsA( siX3DObjectID ) ) {
        // We only care about X3DObjects with geometry
        oObject = oElement;
    }

    // Get object's geometry primitive at frame zero.
    PolygonMesh oGeometry( oObject.GetActivePrimitive().GetGeometry() );

    //---------------------------------------------
    // Vertex Color via AddProperty()
    //---------------------------------------------
    // Add a cluster to the geometry
    Cluster oCluster;
    CLongArray indices;  // define empty index array to let XSI know we want an 'always complete' cluster,

    oGeometry.AddCluster( siSampledPointCluster, L"VertexData", indices, oCluster );

    // Add a vertex color property to the cluster (Notice the space in 1st argument)
    ClusterProperty oPrimaryVertexColor;
    oCluster.AddProperty( L"Vertex Color", false, L"PrimaryColor", oPrimaryVertexColor );

    //-------------------------------------------
    // Vertex Color via AddVertexColor()
    //-------------------------------------------
    // This call reuses the cluster created in the previous steps
    // If cluster didn't exist, AddVertexColor() would create the cluster automatically with a name like "UV_Cluster_AUTO" or similar.
    ClusterProperty oSecondaryVertexColor = oGeometry.AddVertexColor( L"SecondaryColor" );

    //-------------------------------------------
    // Vertex Color via ClusterPropertyBuilder()
    //-------------------------------------------

    CClusterPropertyBuilder oClusterPropertyBuilder = oGeometry.GetClusterPropertyBuilder();

    // *** both of these 2 invocations of ClusterPropertyBuilder.AddVertexColor() will cause XSI to crash: ***

    // Option 1
    // ClusterProperty oTertiaryVertexColor = oClusterPropertyBuilder.AddVertexColor();

    // Option 2
    // CString VertexColorName = L"TertiaryColor";
    // CString ClusterName     = L"VertexData";
    // ClusterProperty oTertiaryVertexColor = oClusterPropertyBuilder.AddVertexColor( VertexColorName, ClusterName );

    // Return a value by setting this attribute:
    oContext.PutAttribute( L"ReturnValue", true );

    return( CStatus::OK );
}

---------------end code example--------------------------

 

 

 

------------------------------
Matt Lind
Animator / Technical Director
SOFTIMAGE certified instructor:
    SOFTIMAGE|3D
    SOFTIMAGE|XSI
Matt.Lind(at)Mantom(dot)net