//-
// ==========================================================================
// 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: 
//   Demonstrates how to create your own custom image plane based on
//   Maya's internal image plane classes. This allows API users to
//   override the default Maya image plane behavior. This class works
//   like typical API nodes in that it can have a compute method and
//   can contain static attributes added by the API user.  This
//   example class overrides the default image plane behavior and
//   allows users to add transparency to an image plane using the
//   transparency attribute on the node. Note, this code also 
//   illustrates how to use MImage to control the floating point
//   depth buffer.  When useDepthMap is set to true, depth is added
//   is added to the image such that half of the iamge is at the near 
//   clip plane and the remaining half is at the far clip plane. 
//
//   Note, once the image plane node has been created it you must
//   attached it to the camera shape that is displaying the node.
//   Image planes are attached to cameras via the imagePlane message
//   attribute on the camera shape.  To attach this example image
//   plane you should connect the image plane's message attribute to
//   the cameraShapes imagePlane attribute.  Note, the imagePlane
//   attribute is a multi attribute and can hold references to
//   multiple image planes.
//
//   This example works only with renderers that use node evaluation
//   as a part of the rendering process, e.g. Maya Software. It does 
//   not work with renderes that rely on a scene translation mechanism,
//   e.g. mental ray.
// 
//   For example, 
//     string $imageP = `createNode customImagePlane`
//	   connectAttr -f ($imageP + ".message") "perspShape.imagePlane[0]"
//    

#include <maya/MPxImagePlane.h>
#include <maya/MFnPlugin.h>
#include <maya/MImage.h>
#include <maya/MString.h>
#include <maya/MFnNumericAttribute.h> 
#include <maya/MFnNumericData.h> 
#include <maya/MDataHandle.h> 
#include <maya/MPlug.h> 

class customImagePlane : public MPxImagePlane
{
public:
						customImagePlane();
	virtual MStatus		loadImageMap( const MString &fileName, int frame, MImage &image );

	virtual bool		getInternalValueInContext( 
		const MPlug&, MDataHandle&,  MDGContext&);

    virtual bool		setInternalValueInContext( 
		const MPlug&, const MDataHandle&, MDGContext&);

	static  void*		creator();
	static  MStatus		initialize();

	static	MTypeId		id;				// The IFF type id
	static  MObject		aTransparency; 

private: 
	double				fTransparency; 
};

MObject customImagePlane::aTransparency; 

customImagePlane::customImagePlane() : 
	fTransparency( 0.0 )
{
}

bool		
customImagePlane::getInternalValueInContext( 
	const MPlug &plug, MDataHandle &handle,  MDGContext& context )
{
	if ( plug == aTransparency ) { 
		handle.set( fTransparency ); 
		return true; 
	}
		
	return MPxImagePlane::getInternalValueInContext( plug, handle, context ); 
}

bool		
customImagePlane::setInternalValueInContext( 
	const MPlug &plug, const MDataHandle &handle, MDGContext &context)
{
	if ( plug == aTransparency ) { 
		fTransparency = handle.asDouble();
		setImageDirty();
		return true; 
	}
	
	return MPxImagePlane::setInternalValueInContext( plug, handle, context );
}

MStatus	
customImagePlane::loadImageMap( 
	const MString &fileName, int frame, MImage &image )
{
	image.readFromFile(fileName);
	
	unsigned int width, height;
	image.getSize(width, height);
	unsigned int size = width * height; 
	
	unsigned char *pixels = image.pixels(); 
	unsigned int i; 
	for ( i = 0; i < size; i ++, pixels += 4 ) { 
		pixels[3] = (unsigned char)(pixels[3] * (1.0 - fTransparency));
	}

	MPlug depthMap( thisMObject(), useDepthMap ); 
	bool value; 
	depthMap.getValue( value ); 
	
	if ( value ) {
		float *buffer = new float[width*height];
		unsigned int c, j; 
		for ( c = i = 0; i < height; i ++ ) { 
			for ( j = 0; j < width; j ++, c++ ) { 
				if ( i > height/2 ) { 
					buffer[c] = -1.0f;
				} else { 
					buffer[c] = 0.0f;
				}
			}
		}
		image.setDepthMap( buffer, width, height ); 
		delete [] buffer;
	}

	return MStatus::kSuccess;
}

MTypeId customImagePlane::id( 0x1A19 );

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

MStatus
customImagePlane::initialize()
{
	MFnNumericAttribute nAttr; 
	
	aTransparency = nAttr.create( "transparency", "tp", 
								  MFnNumericData::kDouble, 0 );
	nAttr.setStorable(true); 
	nAttr.setInternal(true); 
	nAttr.setMin(0.0); 
	nAttr.setMax(1.0); 
	nAttr.setDefault(0.0);
	nAttr.setKeyable(true); 

	addAttribute( aTransparency ); 
	
	return MStatus::kSuccess;
}

// These methods load and unload the plugin, registerNode registers the
// new node type with maya
//
MStatus initializePlugin( MObject obj )
{ 
	MStatus   status;
	MFnPlugin plugin( obj, PLUGIN_COMPANY, "7.0", "Any");

	status = plugin.registerNode( "customImagePlane", customImagePlane::id, 
								  customImagePlane::creator,
								  customImagePlane::initialize, 
								  MPxNode::kImagePlaneNode );
	if (!status) {
		status.perror("registerNode");
		return( status );
	}

	return( status );
}

MStatus uninitializePlugin( MObject obj)
{
	MStatus   status;
	MFnPlugin plugin( obj );

	status = plugin.deregisterNode( customImagePlane::id );
	if (!status) {
		status.perror("deregisterNode");
		return( status );
	}

	return( status );
}