hwRefractReflectShader_NV20/MNormalMapConverter.cpp

//-
// ==========================================================================
// Copyright (C) 1995 - 2006 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// material (collectively the "Data") in these files contain unpublished 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 copyright notices in the Software and this entire statement, 
// including the above license grant, this restriction and the 
// following disclaimer, must be included in all copies of the 
// Software, in whole or in part, and all derivative works of 
// the Software, unless such copies or derivative works are solely 
// in the form of machine-executable object code generated by a 
// source language processor.
//
// 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.
//
// ==========================================================================
//+


// DESCRIPTION: 
//  Some utilities to do file format conversions and others ...
//

#include <maya/MStatus.h>
#include <math.h>
#include "MNormalMapConverter.h"


// Convert the heightfield texture to its corresponding normal map texture
//
bool MNormalMapConverter::convertToNormalMap(
        unsigned char* inImagePtr,
        unsigned int width,
        unsigned int height,
        OutFormatType outputPixelFormat,
        float bumpScale,
        unsigned char* outImagePtr )
{
    bool    isOK = true;
    
    // Firewall: The input image should not be a NULL pointer,
    //
    if( NULL == inImagePtr )    return false;
    
    // No output file specified: convert in place
    //
    if( NULL == outImagePtr )
    {
        convertToNormalMap_InPlace( inImagePtr, width, height, outputPixelFormat, bumpScale );
    }
    else
    {
        if( outputPixelFormat == RGBA ) {
            //
            // Not implemented yet
            //
            // similar to the convertToNormalMap_InPlace but we store
            // the resulting texture in the outImagePtr and not
            // in the inImagePtr texture
            //
        }
        else if( outputPixelFormat == HILO ) {
            // Not implemented yet
        }
        else {
            isOK = false;
        }
    }

    return isOK;
}


// The heightfield texture inImage will be replaced from grey levels in RGBA
// to the normal map values as specified by the pixel format
//
bool MNormalMapConverter::convertToNormalMap_InPlace(
        unsigned char* inImagePtr,
        unsigned int width,
        unsigned int height,
        OutFormatType outputPixelFormat,
        float bumpScale )
{
    bool    isOK = true;

    if( outputPixelFormat == RGBA ) {

        bumpScale /= 255.0f;    // will be used on unsignedChar

        unsigned int widthMinus1  =  width - 1;
        unsigned int heightMinus1 = height - 1;
        unsigned int offset = (4 * width);  // = sizeof(rgba) * width

        // ==================
        // Process the texels
        // ==================

        // Get the current pointer to the starting texel at (0,0)
        //
        unsigned char* imagePtr = inImagePtr;

        // For each rows (except the last one)
        //
        unsigned int m, n;
        for( m=0; m<heightMinus1; m++ )
        {
            // Process the texel in each column of this row
            //
            for( n=0; n<widthMinus1; n++ )
            {
                float deltaU = bumpScale * (float)(imagePtr[0] - imagePtr[4]);
                float deltaV = bumpScale * (float)(imagePtr[0] - imagePtr[offset]);
                
                // Normalize (deltaU, deltaV, 1.)
                float sqlen = deltaU*deltaU + deltaV*deltaV + 1.0f;
                float rclen = 1.0f / sqrtf( sqlen );
                
                float nx = deltaU * rclen;
                float ny = deltaV * rclen;
                float nz = rclen;
                
                // Store the vector in red, green, blue
                *(imagePtr++) = (unsigned char) ((nx + 1.0f) * 127.5f); 
                *(imagePtr++) = (unsigned char) ((ny + 1.0f) * 127.5f); 
                *(imagePtr++) = (unsigned char) ((nz + 1.0f) * 127.5f); 
                
                // reset the alpha
                *(imagePtr++) = 255;
            }
            
            // At the end of the row, just copy the last value. One
            // could implement wraping instead.
            *(imagePtr++) = imagePtr[-4];
            *(imagePtr++) = imagePtr[-4];
            *(imagePtr++) = imagePtr[-4];
            *(imagePtr++) = 255;
        }

        // Fill in the last row (copy from the (last-1) row)
        // memcpy is the faster loop when memory is aligned.
        memcpy(imagePtr, imagePtr-offset, width*4);
    }
    else if( outputPixelFormat == HILO ) {
        // Not implemented yet
    }
    else {
        isOK = false;
    }

    return isOK;
}


bool MNormalMapConverter::convertToHeightMap(
    unsigned char* inImagePtr,
    unsigned int width,
    unsigned int height,
    OutFormatType outputPixelFormat,
    float heightScale,
    unsigned char* outImagePtr)
{
    // Not implemented yet
    //
    return false;
}