convertBumpCmd.cpp

//-
// ==========================================================================
// Copyright 1995,2006,2008 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk
// license agreement provided at the time of installation or download,
// or which otherwise accompanies this software in either electronic
// or hard copy form.
// ==========================================================================
//+

//
// ---------------------------------------------------------------------------
//
// Description:
// ------------
//              This plug-in command can be used to convert a bump file texture
// from the a grey-scale height field format (used by Maya) to a normal map
// format that is typically used for real-time, hardware-based rendering.
//
//              This code also demonstrates how to use the MImage class to load,
// manipulate and save image files on disk. 
// (Note that the MImage class is new as of Maya 4.0.1, but that the saving
// and filtering capability was only introduced in Maya4.5)
//
//
// Usage:
// ------
//              To test this plug-in, first compile and load it using the plug-in 
// manager, then type the following in the script editor:
//
// convertBump "C:/bump.tga" "C:/bump_norm.tga" "tga" 1.0
//
//              This would convert the input texture (c:/bump.tga) into
// an output normal map (c:/bump_norm.tga) using the default
// bumpScale ratio. The bumpScale parameter can be used to increase or
// decrease the bumpiness of the resulting normal map.
//
//              See the documentation of MImage::saveToFile() for a complete
// list of the available file formats supported.
//

#include <maya/MPxCommand.h>
#include <maya/MStatus.h>
#include <maya/MArgList.h>
#include <maya/MFnPlugin.h>
#include <maya/MObject.h>
#include <maya/MGlobal.h>
#include <maya/MString.h>
#include <maya/MPoint.h>
#include <maya/MImage.h>

#include <maya/MIOStream.h>

#define IFFCHECKERR(stat, call) \
if (!stat) { \
        MString string = reader.errorString(); \
    string += " in method "; \
        string += #call; \
    displayError (string); \
        return MS::kFailure; \
}

class convertBump : public MPxCommand
{
public:
                convertBump();
    virtual     ~convertBump();

    MStatus     doIt ( const MArgList& args );
    bool        isUndoable() const;

    static      void* creator();
};

convertBump::convertBump()
{
}

convertBump::~convertBump() {}

void* convertBump::creator()
{
    return new convertBump;
}

bool convertBump::isUndoable() const
{
    return false;
}

MString itoa (int n)
{
        char buffer [256];
        sprintf (buffer, "%d", n);
        return MString (buffer);
}

MStatus convertBump::doIt( const MArgList& args )
{
        // Verify that the required conversion exists before doing anything else.
        if (!MImage::filterExists(MImage::kHeightFieldBumpFormat, MImage::kNormalMapBumpFormat))
        {
                displayError ("Fatal Error! The required filter (kHeightFieldBumpFormat -> kNormalMapBumpFormat) isn't supported!");
                return MS::kFailure;
        }

        if (args.length () < 2 || args.length () > 4) 
        {
                displayError ("Syntax: convertBump inputFile outputFile [outputFormat [bumpScale]]");
                displayError ("(eg: convertBump \"C:/bump.tga\" \"C:/bump_norm.tga\" \"tga\" 1.0)");
                return MS::kFailure;
        }

        double bumpScale = 1.0;

        MString inputFilename, outputFilename;
        MString outputFormat = "iff";

        args.get(0, inputFilename);
        args.get(1, outputFilename);

        if (args.length() > 2)
                args.get(2, outputFormat);

        // Get the desired bumpscale, if it is provided as an argument.
        if (args.length() == 4)
        {
                MString lastArg;
                args.get (3, bumpScale);
        }


        MImage image;
        MStatus stat = image.readFromFile(inputFilename);
        if (!stat)
        {
                displayError ("Unable to open input file \"" + inputFilename + "\".");
                return MS::kFailure;
        }

        // Get the dimension of the texture.
        unsigned int width, height;
        stat = image.getSize(width, height);
        if (!stat)
        {
                displayError ("Unable to get size.");
                return MS::kFailure;
        }

        // Attempt to convert from height field to normal map.
        stat = image.filter(MImage::kHeightFieldBumpFormat, MImage::kNormalMapBumpFormat, bumpScale);
        if (!stat)
        {
                displayError ("Unable to apply the filter from height field to normal map bump format.");
                return MS::kFailure;
        }

        // Save back to disk.
        stat = image.writeToFile(outputFilename, outputFormat);
        if (!stat)
        {
                displayError ("Unable to write to output file \"" + outputFilename + "\" using output format " + outputFormat + 
                        ". (read-only? disk full? invalid path?)");
                return MS::kFailure;
        }

    return MS::kSuccess;
}

MStatus initializePlugin( MObject obj )
{
        MStatus status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "4.0.1", "Any");
    status = plugin.registerCommand( "convertBump", convertBump::creator );

        if (!status)
                status.perror("registerCommand");

    return status;
}

MStatus uninitializePlugin( MObject obj )
{
        MStatus status;
    MFnPlugin plugin( obj );
    status = plugin.deregisterCommand( "convertBump" );

        if (!status)
                status.perror("deregisterCommand");

    return status;
}