epfl-archive/cs440-acg/ext/openexr/OpenEXR/exrenvmap/resizeImage.cpp

///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2007, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
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//-----------------------------------------------------------------------------
//
//	resizeLatLong(), resizeCube() -- functions that resample
//	an environment map and convert it to latitude-longitude or
//	cube-face format.
//
//-----------------------------------------------------------------------------

#include <resizeImage.h>

#include "Iex.h"
#include <string.h>

#include "namespaceAlias.h"
using namespace IMF;
using namespace std;
using namespace IMATH;


void
resizeLatLong (const EnvmapImage &image1,
	       EnvmapImage &image2,
	       const Box2i &image2DataWindow,
	       float filterRadius,
	       int numSamples)
{
    int w = image2DataWindow.max.x - image2DataWindow.min.x + 1;
    int h = image2DataWindow.max.y - image2DataWindow.min.y + 1;
    float radius = 0.5f * 2 * M_PI * filterRadius / w;

    image2.resize (ENVMAP_LATLONG, image2DataWindow);
    image2.clear ();

    Array2D<Rgba> &pixels = image2.pixels();

    for (int y = 0; y < h; ++y)
    {
	for (int x = 0; x < w; ++x)
	{
	    V3f dir = LatLongMap::direction (image2DataWindow, V2f (x, y));
	    pixels[y][x] = image1.filteredLookup (dir, radius, numSamples);
	}
    }
}


void
resizeCube (const EnvmapImage &image1,
	    EnvmapImage &image2,
	    const Box2i &image2DataWindow,
	    float filterRadius,
	    int numSamples)
{
    if (image1.type() == ENVMAP_CUBE && image1.dataWindow() == image2DataWindow)
    {
        //
        // Special case - the input image is a cube-face environment
        // map with the same size as the output image.  We can copy
        // the input image without resampling.
        // 

        image2.resize (ENVMAP_CUBE, image2DataWindow);

        int w = image2DataWindow.max.x - image2DataWindow.min.x + 1;
        int h = image2DataWindow.max.y - image2DataWindow.min.y + 1;

        memcpy (&(image2.pixels()[0][0]),
                &(image1.pixels()[0][0]),
                sizeof (Rgba) * w * h);

        return;
    }

    //
    // Resampe the input image
    //

    int sof = CubeMap::sizeOfFace (image2DataWindow);
    float radius = 1.5f * filterRadius / sof;

    image2.resize (ENVMAP_CUBE, image2DataWindow);
    image2.clear ();

    Array2D<Rgba> &pixels = image2.pixels();

    for (int f = CUBEFACE_POS_X; f <= CUBEFACE_NEG_Z; ++f)
    {
	CubeMapFace face = CubeMapFace (f);

	for (int y = 0; y < sof; ++y)
	{
	    for (int x = 0; x < sof; ++x)
	    {
		V2f posInFace (x, y);

		V3f dir =
		    CubeMap::direction (face, image2DataWindow, posInFace);

		V2f pos =
		    CubeMap::pixelPosition (face, image2DataWindow, posInFace);
		
		pixels[int (pos.y + 0.5f)][int (pos.x + 0.5f)] =
		    image1.filteredLookup (dir, radius, numSamples);
	    }
	}
    }
}