///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2004, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

// *       Neither the name of Industrial Light & Magic nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission. 

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

///////////////////////////////////////////////////////////////////////////

//-----------------------------------------------------------------------------

//

//	Environment maps

//

//-----------------------------------------------------------------------------

#include "ImfEnvmap.h"

#include "ImathFun.h"

#include "ImfNamespace.h"

#include <algorithm>

#include <math.h>

using namespace std;

using namespace IMATH_NAMESPACE;

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER

namespace LatLongMap {

V2f	

latLong (const V3f &dir)

{

    float r = sqrt (dir.z * dir.z + dir.x * dir.x);

    float latitude = (r < abs (dir.y))?

			 acos (r / dir.length()) * sign (dir.y):

			 asin (dir.y / dir.length());

    float longitude = (dir.z == 0 && dir.x == 0)? 0: atan2 (dir.x, dir.z);

    return V2f (latitude, longitude);

}

V2f

latLong (const Box2i &dataWindow, const V2f &pixelPosition)

{

    float latitude, longitude;

    if (dataWindow.max.y > dataWindow.min.y)

    {

        latitude = -1 * float(M_PI) *

            ((pixelPosition.y  - dataWindow.min.y) /

            (dataWindow.max.y - dataWindow.min.y) - 0.5f);

    }

    else

    {

	latitude = 0;

    }

    if (dataWindow.max.x > dataWindow.min.x)

    {

	longitude = -2 * float(M_PI) *

		   ((pixelPosition.x  - dataWindow.min.x) /

		    (dataWindow.max.x - dataWindow.min.x) - 0.5f);

    }

    else

    {

	longitude = 0;

    }

    return V2f (latitude, longitude);

}

V2f

pixelPosition (const Box2i &dataWindow, const V2f &latLong)

{

    float x = latLong.y / (-2 * float(M_PI)) + 0.5f;

    float y = latLong.x / (-1 * float(M_PI)) + 0.5f;

    return V2f (x * (dataWindow.max.x - dataWindow.min.x) + dataWindow.min.x,

		y * (dataWindow.max.y - dataWindow.min.y) + dataWindow.min.y);

}

V2f

pixelPosition (const Box2i &dataWindow, const V3f &direction)

{

    return pixelPosition (dataWindow, latLong (direction));

}

V3f

direction (const Box2i &dataWindow, const V2f &pixelPosition)

{

    V2f ll = latLong (dataWindow, pixelPosition);

    return V3f (sin (ll.y) * cos (ll.x),

		sin (ll.x),

		cos (ll.y) * cos (ll.x));

}

} // namespace LatLongMap

namespace CubeMap {

int

sizeOfFace (const Box2i &dataWindow)

{

    return min ((dataWindow.max.x - dataWindow.min.x + 1),

		(dataWindow.max.y - dataWindow.min.y + 1) / 6);

}

Box2i

dataWindowForFace (CubeMapFace face, const Box2i &dataWindow)

{

    int sof = sizeOfFace (dataWindow);

    Box2i dwf;

    dwf.min.x = 0;

    dwf.min.y = int (face) * sof;

    dwf.max.x = dwf.min.x + sof - 1;

    dwf.max.y = dwf.min.y + sof - 1;

    return dwf;

}

V2f

pixelPosition (CubeMapFace face, const Box2i &dataWindow, V2f positionInFace)

{

    Box2i dwf = dataWindowForFace (face, dataWindow);

    V2f pos (0, 0);

    switch (face)

    {

      case CUBEFACE_POS_X:

	pos.x = dwf.min.x + positionInFace.y;

	pos.y = dwf.max.y - positionInFace.x;

	break;

      case CUBEFACE_NEG_X:

	pos.x = dwf.max.x - positionInFace.y;

	pos.y = dwf.max.y - positionInFace.x;

	break;

      case CUBEFACE_POS_Y:

	pos.x = dwf.min.x + positionInFace.x;

	pos.y = dwf.max.y - positionInFace.y;

	break;

      case CUBEFACE_NEG_Y:

	pos.x = dwf.min.x + positionInFace.x;

	pos.y = dwf.min.y + positionInFace.y;

	break;

      case CUBEFACE_POS_Z:

	pos.x = dwf.max.x - positionInFace.x;

	pos.y = dwf.max.y - positionInFace.y;

	break;

      case CUBEFACE_NEG_Z:

	pos.x = dwf.min.x + positionInFace.x;

	pos.y = dwf.max.y - positionInFace.y;

	break;

    }

    return pos;

}

void

faceAndPixelPosition (const V3f &direction,

		      const Box2i &dataWindow,

		      CubeMapFace &face,

		      V2f &pif)

{

    int sof = sizeOfFace (dataWindow);

    float absx = abs (direction.x);

    float absy = abs (direction.y);

    float absz = abs (direction.z);

    if (absx >= absy && absx >= absz)

    {

	if (absx == 0)

	{

	    //

	    // Special case - direction is (0, 0, 0)

	    //

	    face = CUBEFACE_POS_X;

	    pif = V2f (0, 0);

	    return;

	}

	pif.x = (direction.y / absx + 1) / 2 * (sof - 1);

	pif.y = (direction.z / absx + 1) / 2 * (sof - 1);

	if (direction.x > 0)

	    face = CUBEFACE_POS_X;

	else

	    face = CUBEFACE_NEG_X;

    }

    else if (absy >= absz)

    {

	pif.x = (direction.x / absy + 1) / 2 * (sof - 1);

	pif.y = (direction.z / absy + 1) / 2 * (sof - 1);

	if (direction.y > 0)

	    face = CUBEFACE_POS_Y;

	else

	    face = CUBEFACE_NEG_Y;

    }

    else

    {

	pif.x = (direction.x / absz + 1) / 2 * (sof - 1);

	pif.y = (direction.y / absz + 1) / 2 * (sof - 1);

	if (direction.z > 0)

	    face = CUBEFACE_POS_Z;

	else

	    face = CUBEFACE_NEG_Z;

    }

}

V3f

direction (CubeMapFace face, const Box2i &dataWindow, const V2f &positionInFace)

{

    int sof = sizeOfFace (dataWindow);

    V2f pos;

    if (sof > 1)

    {

	pos = V2f (positionInFace.x / (sof - 1) * 2 - 1,

		   positionInFace.y / (sof - 1) * 2 - 1);

    }

    else

    {

	pos = V2f (0, 0);

    }

    V3f dir (1, 0, 0);

    switch (face)

    {

      case CUBEFACE_POS_X:

	dir.x = 1;

	dir.y = pos.x;

	dir.z = pos.y;

	break;

      case CUBEFACE_NEG_X:

	dir.x = -1;

	dir.y = pos.x;

	dir.z = pos.y;

	break;

      case CUBEFACE_POS_Y:

	dir.x = pos.x;

	dir.y = 1;

	dir.z = pos.y;

	break;

      case CUBEFACE_NEG_Y:

	dir.x = pos.x;

	dir.y = -1;

	dir.z = pos.y;

	break;

      case CUBEFACE_POS_Z:

	dir.x = pos.x;

	dir.y = pos.y;

	dir.z = 1;

	break;

      case CUBEFACE_NEG_Z:

	dir.x = pos.x;

	dir.y = pos.y;

	dir.z = -1;

	break;

    }

    return dir;

}

} // namespace CubeMap

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT