/*
// Copyright (C) 1997-2008 Autodesk, Inc., and/or its licensors.
// All rights reserved.
//
// The coded instructions, statements, computer programs, and/or related
// material (collectively the "Data") in these files contain unpublished
// information proprietary to Autodesk, Inc. ("Autodesk") and/or its licensors,
// which is protected by U.S. and Canadian federal copyright law and by
// international treaties.
//
// The Data is provided for use exclusively by You. You have the right to use,
// modify, and incorporate this Data into other products for purposes authorized
// by the Autodesk software license agreement, without fee.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND. AUTODESK
// DOES NOT MAKE AND HEREBY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTIES
// INCLUDING, BUT NOT LIMITED TO, THE WARRANTIES OF NON-INFRINGEMENT,
// MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, OR ARISING FROM A COURSE
// OF DEALING, USAGE, OR TRADE PRACTICE. IN NO EVENT WILL AUTODESK AND/OR ITS
// LICENSORS BE LIABLE FOR ANY LOST REVENUES, DATA, OR PROFITS, OR SPECIAL,
// DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES, EVEN IF AUTODESK AND/OR ITS
// LICENSORS HAS BEEN ADVISED OF THE POSSIBILITY OR PROBABILITY OF SUCH DAMAGES.
*/

	===========================
	  mental ray for Maya 10.0

	     example to access
	particle data in mental ray
	===========================


This document provides a complete example that
accesses particle user data and prints some values.
This information is provided as is and is not
guarenteed to work across versions of Maya. The
structure of the particle user data block is
subject to change.


--- particleinfo.mi ---

declare shader
        "particleinfo" (
                geometry        "particleData"
                )
        version 1
end declare

--- particleinfo.c ---

#include <shader.h>
#include "particle.h"     /* provides particle user data layout,
                             see InternParticleData.txt */

typedef struct {
        miTag   particleData;
} Parms;

DLLEXPORT int particleinfo_version(void) { return 1; }

DLLEXPORT miBoolean particleinfo(
        miColor         *result,
        miState         *state,
        Parms           *parms)
{
        miTag userTag = (miTag) *mi_eval_tag(&parms->particleData);
        miUserdata *userPtr = mi_db_access(userTag);
        if (userPtr) {
                int i, count = 0;

                ParticleSystem *ps = (ParticleSystem*)(userPtr->parameters);

                /* check that we use Maya data with right endian */
                if (ps->magic != 0x4D617961) {
                        mi_db_unpin(userTag);
                        return miFALSE;
                        }

                /* access fields */
                
                count = PS_COUNT(ps);
                
                mi_info("particle count: %d", count);
                
                for (i=0; i < count; i++) { 
                        miScalar radius   = (miScalar)  PS_RADIUS(ps, i);
                        miVector position = (miVector) *PS_POSITION(ps, i);
                        miScalar age      = (miScalar)  PS_AGE(ps, i);
                        
                        mi_info("radius %f, position %f %f %f, age %f",
                                radius,
                                position.x, position.y, position.z,
                                age);
                        }
                
                mi_db_unpin(userTag);
                }
        
        return miTRUE;
}

---


To use this example, a common particle scene should be exported
to an .mi file, and manipulated as follows:


Search for the particle user block and remember its name, like

---

data "particleShape1:ptdata"
        7216 [
        '4d617961020000010000000100000001000001270000001b0000000100000142'
	...

---

Add a call to the example shader at the end of the .mi file,
supplying the actual name of the particle data, like

---
...
render ":MayaTranslatedWorld" "persp" "miDefaultOptions"

call "particleinfo" ("particleSystem" "particleShape1:ptdata")

---


Render.