/*
 * vliutils.cpp
 *
 * $Id: vliutils.cpp,v 1.9 2000/01/18 15:18:27 vesper Exp $
 *
 * Module to implement various utilities
 *
 * Copyright, Mitsubishi Electric Information Technology Center 
 * America, Inc., 1999, All rights reserved.
 */

#include "vliutils.h"

VLIMatrix VLIUtCompose(VLIMatrix& inRotation,	// Rotation.
					   double inScale[3],		// X, Y, and Z Scales.
					   double inTranslation[3],	// X, Y, and Z Translations.
					   double inShear[3])		// XY, XZ, and YZ shear.
{
	VLIMatrix shear;
	
	shear[0][1] = inShear[0];
	shear[0][2] = inShear[1];
	shear[1][2] = inShear[2];

 	return (VLIMatrix::Translate (inTranslation[0], inTranslation[1], inTranslation[2]) *
	        inRotation * shear *
	        VLIMatrix::Scale (inScale[0], inScale[1], inScale[2]));	
}

// This is from Graphics Gems II. Adaptation of the Decomposition of
// a matrix by Spencer W. Thomas.
//
void VLIUtDecompose (const VLIMatrix& inMatrix,	// Matrix to decompose
					 VLIMatrix& outRotation,	// Rotation.
					 double outScale[3],		// X, Y, and Z Scales.
					 double outTranslation[3],	// X, Y, and Z Translations.
					 double outShear[3])		// XY, XZ, and YZ shear.
{
    // The translation part of the Matrix
    //
    outTranslation[0] = inMatrix[0][3];
    outTranslation[1] = inMatrix[1][3];
    outTranslation[2] = inMatrix[2][3];

    // Get the scale and shear. Doing it column based as we
    // are column major
    //
    VLIVector3D c0, c1, c2;

    c0.Assign (inMatrix[0][0], inMatrix[1][0], inMatrix[2][0]);
    c1.Assign (inMatrix[0][1], inMatrix[1][1], inMatrix[2][1]);
    c2.Assign (inMatrix[0][2], inMatrix[1][2], inMatrix[2][2]);

    // Compute the X-Scale and normalize first column
    //
    outScale[0] = c0.Length ();
    c0.Normalize ();

    // Compute XY shear and make second column orthogonal to first
    //
    outShear[0] = VLIDot (c0, c1);
    c1 = c1 + (c0 * (-outShear[0]));

    // Compute the Y-Scale and normalize 2nd column
    //
    outScale[1] = c1.Length ();
    c1.Normalize ();
    outShear[0] /= outScale[1];

    // Compute XZ and YZ shears, orthogonalize 3rd column
    //
    outShear[1] = VLIDot (c0, c2);
    c2 = c2 + (c0 * (-outShear[1]));

    outShear[2] = VLIDot (c1, c2);
    c2 = c2 + (c1 * (-outShear[2]));
        
        // Next, get Z scale and normalize 3rd column
    //
    outScale[2] = c2.Length ();
    c2.Normalize ();

    outShear[1] /= outScale[2];
    outShear[2] /= outScale[2];
        
 
        /* At this point, the matrix (in c*) is orthonormal.
         * Check for a coordinate system flip.  If the determinant
         * is -1, then negate the matrix and the scaling factors.
         */
    if (VLIDot (c0, VLICross (c1, c2)) < 0)
    {
        outScale[0] *= -1.0;
        outScale[1] *= -1.0;
        outScale[2] *= -1.0;

        c0 *= -1.0;
        c1 *= -1.0;
        c2 *= -1.0;
    }
        
    // The c0, c1, c2 should be the remaining rotation matrix
    //
    outRotation .Assign (c0[0], c1[0], c2[0], 0.0,
                         c0[1], c1[1], c2[1], 0.0,
                         c0[2], c1[2], c2[2], 0.0,
                         0.0,   0.0,   0.0,   1.0);
}

// TBD: better descriptions needed.
const char *VLIUtGetErrorString(VLIStatus status) {
	unsigned int index;
	static const char *errStrings[] = {
		"kVLIOK - no error.", 
		"kVLIMultiPass - no error, however, multiple renderings will occur.",
		"kVLITimeout - no error, timeout happened before event.",
		"kVLIErrAlloc - some resource required for this operation could not be allocated.",
		"kVLIErrVolumeInvalid - the volume was invalid: format or layout mismatch, or no data available.",
		"kVLIErrMath - divide by zero or similar error.",
		"kVLIErrArgument - bad input, check sizes and formats.",
		"kVLIErrUnimplemented - obsolete error. write a bug report.",
		"kVLIErrTooMany - too many objects (cut planes) being added to a VLIContext.",
		"kVLIErrTooLarge - volume is too large to be mapped or locked.",
		"kVLIErrDuplicate - it is already in the list.",
		"kVLIErrNoHardware - no VGB board was detected.",
		"kVLIErrReadOnly - trying to modify read only volume.",
		"kVLIErrAccess - could not satisfy access request at this time because of current access usage.",
		"kVLIErrAborted - baseplane is not available because the rendering was aborted.",
		"kVLIErrBasePlaneAllocation - no pixel buffers available.",
		"kVLIErrBasePlaneTooLarge - BasePlane is too large for graphics board.",
		"kVLIErrHardware - undetermined hardware error.",
		"kVLIErrInternal - internal error; please write a bug report.",
		"kVLIErrIDRollover - internal IDs have maxed out. Exit all VLI apps and try again.",
		"kVLIErrVersion - application built against a different version of VLI.",
		"kVLIErrMaxAngleDeviation - view angle workaround failed.",
		"not a valid VLI status in VLI 1.0."
	};
	if ((status >= kVLIErrAlloc) && (status <= kVLIErrMaxAngleDeviation))
		index = status + kVLITimeout - kVLIErrAlloc + 1;
	else if ((status >= kVLIOK) && (status <= kVLITimeout))
		index = status;
	else
		index = sizeof(errStrings)/sizeof(const char *) - 1;

	return errStrings[index];
}