simpleImageFile/simpleImageFile.cpp

//-
// ==========================================================================
// Copyright 2015 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: 
//  Simple Image File plugin. This plugin registers a new image
//  file format against file extension ".moo". Loading any ".moo"
//  image file will produce a procedurally generated colour 
//  spectrum including values outside 0 to 1.
//

#include <maya/MPxImageFile.h>
#include <maya/MImageFileInfo.h>
#include <maya/MImage.h>
#include <maya/MFnPlugin.h>
#include <maya/MStringArray.h>
#include <maya/MIOStream.h>
#include <maya/MGL.h>

MString kImagePluginName( "SimpleImageFile");

class SimpleImageFile : public MPxImageFile
{
public:
                    SimpleImageFile();
            ~SimpleImageFile() override;
    static void*    creator();
    MStatus open( MString pathname, MImageFileInfo* info) override;
    MStatus load( MImage& image, unsigned int idx) override;
    MStatus glLoad( const MImageFileInfo& info, unsigned int imageNumber) override;

private:
    void            populateTestImage( float* pixels, unsigned int w, unsigned int h);
};

//
// DESCRIPTION:
SimpleImageFile::SimpleImageFile()
{
}

//
// DESCRIPTION:
SimpleImageFile::~SimpleImageFile()
{
}

//
// DESCRIPTION:
void * SimpleImageFile::creator()
{
    return new SimpleImageFile();
}

//
// DESCRIPTION:
// Configure the image characteristics. A real image file
// format plugin would extract these values from the image
// file header. 
//
MStatus SimpleImageFile::open( MString pathname, MImageFileInfo* info)
{
    if( info)
    {
        info->width( 512);
        info->height( 512);
        info->channels( 3);
        info->pixelType( MImage::kFloat);

        // Only necessary if your format defines a native
        // hardware texture loader
        info->hardwareType( MImageFileInfo::kHwTexture2D);
    }
    return MS::kSuccess;
}


//
// DESCRIPTION:
// Internal helper method to populate our procedural test image
//
void SimpleImageFile::populateTestImage( float* pixels, unsigned int w, unsigned int h)
{
    #define RAINBOW_SCALE 4.0f
    unsigned int x, y;
    for( y = 0; y < h; y++)
    {
        float g = RAINBOW_SCALE * y / (float)h;
        for( x = 0; x < w; x++)
        {
            float r = RAINBOW_SCALE * x / (float)w;
            *pixels++ = r;
            *pixels++ = g;
            *pixels++ = RAINBOW_SCALE * 1.5f - r - g;
        }
    }
}


//
// DESCRIPTION:
// Load the contents of this image file into an MImage. A real
// file format plugin would extract the pixel data from the image
// file here.
//
MStatus SimpleImageFile::load( MImage& image, unsigned int)
{
    unsigned int w = 512;
    unsigned int h = 512;

    // Create a floating point image and fill it with
    // a pretty rainbow test image.
    //
    image.create( w, h, 3, MImage::kFloat);
    populateTestImage( image.floatPixels(), w, h);
    return MS::kSuccess;
}


//
// DESCRIPTION:
// Load the contents of this image file into an OpenGL texture. A 
// real file format plugin would extract the pixel data from the 
// image file here.
//
MStatus SimpleImageFile::glLoad( const MImageFileInfo& info, unsigned int)
{
    // Create a floating point image
    unsigned int w = info.width();
    unsigned int h = info.height();
    float* pixels = new float[ w * h * 3];
    populateTestImage( pixels, w, h);
    
    // Now load it into OpenGL as a floating point image
    ::glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_FLOAT, pixels);

    delete[] pixels;
    return MS::kSuccess;
}


// DESCRIPTION:
MStatus initializePlugin( MObject obj )
{
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "8.0", "Any" );
    MStringArray extensions;
    extensions.append( "moo");
    CHECK_MSTATUS( plugin.registerImageFile(
                    kImagePluginName,
                    SimpleImageFile::creator, 
                    extensions));
    
    return MS::kSuccess;
}

// DESCRIPTION:
MStatus uninitializePlugin( MObject obj )
{
    MFnPlugin plugin( obj );
    CHECK_MSTATUS( plugin.deregisterImageFile( kImagePluginName ) );

    return MS::kSuccess;
}