///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2004, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
// 
// All rights reserved.
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// modification, are permitted provided that the following conditions are
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///////////////////////////////////////////////////////////////////////////


//-----------------------------------------------------------------------------
//
//	function makeLatLongMap() -- makes latitude-longitude environment maps
//
//-----------------------------------------------------------------------------

#include <makeLatLongMap.h>

#include <ImfRgbaFile.h>
#include <ImfTiledRgbaFile.h>
#include <ImfStandardAttributes.h>
#include <EnvmapImage.h>
#include <Iex.h>
#include <iostream>
#include <algorithm>


using namespace std;
using namespace Imf;
using namespace Imath;


void
makeLatLongMap (const char inFileName[],
	        const char outFileName[],
	        int tileWidth,
	        int tileHeight,
	        LevelMode levelMode,
	        LevelRoundingMode roundingMode,
		Compression compression,
	        int mapWidth,
	        float padTop,
	        float padBottom,
	        float filterRadius,
	        int numSamples,
	        bool verbose)
{
    if (levelMode == RIPMAP_LEVELS)
    {
	throw Iex::NoImplExc ("Cannot generate ripmap "
			      "latitude-longitude environments.");
    }

    //
    // Read the input image, and if necessary,
    // pad the image at the top and bottom.
    //

    EnvmapImage image1;
    Header header;
    RgbaChannels channels;

    {
	RgbaInputFile in (inFileName);

	if (verbose)
	    cout << "reading file " << inFileName << endl;

	header = in.header();
	channels = in.channels();

	Envmap type = ENVMAP_LATLONG;

	if (hasEnvmap (in.header()))
	    type = envmap (in.header());

	const Box2i &dw = in.dataWindow();
	int w = dw.max.x - dw.min.x + 1;
	int h = dw.max.y - dw.min.y + 1;

	int pt = 0;
	int pb = 0;

	if (type == ENVMAP_LATLONG)
	{
	    pt = int (padTop * h + 0.5f);
	    pb = int (padBottom * h + 0.5f);
	}

	Box2i paddedDw (V2i (dw.min.x, dw.min.y - pt),
		        V2i (dw.max.x, dw.max.y + pb));
	
	image1.resize (type, paddedDw);
	Array2D<Rgba> &pixels = image1.pixels();

	in.setFrameBuffer (&pixels[-paddedDw.min.y][-paddedDw.min.x], 1, w);
	in.readPixels (dw.min.y, dw.max.y);

	for (int y = 0; y < pt; ++y)
	    for (int x = 0; x < w; ++x)
		pixels[y][x] = pixels[pt][x];

	for (int y = h + pt; y < h + pt + pb; ++y)
	{
	    for (int x = 0; x < w; ++x)
		pixels[y][x] = pixels[h + pt - 1][x];
	}
    }

    //
    // Open the file that will contain the latitude-longitude map,
    // and write the header.
    //

    int mapHeight = mapWidth / 2;

    header.dataWindow() = Box2i (V2i (0, 0), V2i (mapWidth - 1, mapHeight - 1));
    header.displayWindow() = header.dataWindow();
    header.compression() = compression;

    addEnvmap (header, ENVMAP_LATLONG);

    TiledRgbaOutputFile out (outFileName,
			     header,
			     channels,
			     tileWidth, tileHeight,
			     levelMode,
			     roundingMode);
    if (verbose)
	cout << "writing file " << outFileName << endl;

    //
    // Generate the pixels for the various levels of the latitude-longitude
    // map, and store them in the file.  The pixels for the highest-resolution
    // level are generated by resampling the original input image; for each of
    // the other levels, the pixels are generated by resampling the previous
    // level.
    //

    EnvmapImage image2;
    EnvmapImage *iptr1 = &image1;
    EnvmapImage *iptr2 = &image2;
    
    for (int level = 0; level < out.numLevels(); ++level)
    {
	if (verbose)
	    cout << "level " << level << endl;

	Box2i dw = out.dataWindowForLevel (level);
	int w = dw.max.x - dw.min.x + 1;
	int h = dw.max.y - dw.min.y + 1;
	float radius = 0.5f * 2 * M_PI * filterRadius / w;

	iptr2->resize (ENVMAP_LATLONG, dw);
	iptr2->clear ();

	Array2D<Rgba> &pixels = iptr2->pixels();

	for (int y = 0; y < h; ++y)
	{
	    for (int x = 0; x < w; ++x)
	    {
		V3f dir = LatLongMap::direction (dw, V2f (x, y));
		pixels[y][x] = iptr1->filteredLookup (dir, radius, numSamples);
	    }
	}

	out.setFrameBuffer (&pixels[0][0], 1, dw.max.x + 1);

	for (int tileY = 0; tileY < out.numYTiles (level); ++tileY)
	    for (int tileX = 0; tileX < out.numXTiles (level); ++tileX)
		out.writeTile (tileX, tileY, level);

	swap (iptr1, iptr2);
    }

    if (verbose)
	cout << "done." << endl;
}