//
// env_map.cc
//
// Environmental mapping for sky
//
// Copyright (C) J. Belson	2003.5.3
//


#include <cassert>
#include <cmath>

#include "env_map.h"


/**
 * Constructor
 */
env_map::env_map(int env_map_size)
	: size(env_map_size)
{
	// Allocate space for each of the cube faces
	for (int i=0; i<6; i++) {
		maps[i] = new uint32[size*size];
		clear_map(i);
	}
}


/**
 * Destructor
 */
env_map::~env_map()
{
	for (int i=0; i<6; i++) {
		delete [] maps[i];
	}
}


/**
 * Clear map
 */
void env_map::clear_map(int map_num)
{
	static const uint32 col[] = {
		0x000000ff, 0x0000ff00, 0x00ff0000,
		0x00ffff00, 0x00ff00ff, 0x0000ffff
	};

	static const int CHECK = 40;

	for (int j=0; j<size*size; j++) {
		int y = (j/size);
		int x = j/CHECK;
		bool b = (x%2);
		if ((y/CHECK)%2) b = !b;
		maps[map_num][j] = b ? col[map_num] : 0x0;
	}
}


/**
 * Return pointer to specified map
 */
uint32* env_map::get_map(int map_num) const
{
	assert(map_num>=0 && map_num<=6);

	return maps[map_num];
}


/**
 * Return colour from reflection map
 * @param x x coordinate
 * @param y y coordinate
 * @param map_num Which map to use
 */
fcolour env_map::read_map(int x, int y, int map_num) const
{
	assert(map_num>=0 && map_num<=6);
	assert(x>0 && x<size);
	assert(y>0 && y<size);

	uint32 rgb = (maps[map_num])[(y*size) + x];

	return fcolour(rgb);
}


/**
 * Return the colour in specified direction
 */
fcolour env_map::get_colour(const vector3d& view) const
{
	// Figure out which map we're looking at
	int		map_num;
	float	u, v;

if (view.j < 0) {
	printf("Downwards vector!!");
}

	float abs_i = std::abs(view.i);
	float abs_j = std::abs(view.j);
	float abs_k = std::abs(view.k);

	if (abs_i > abs_j) {
		if (abs_i > abs_k) {
			map_num = (view.i > 0) ? RIGHT : LEFT;
			u = view.k;
			v = -view.j;
		} else {
			map_num = (view.k > 0) ? BACK : FORWARD;
			u = view.i;
			v = -view.j;
		}
	} else {
		if (abs_j > abs_k) {
			map_num = (view.j > 0) ? UP : DOWN;
			u = view.i;
			v = view.k;
		} else {
			map_num = (view.k > 0) ? BACK : FORWARD;
			u = view.i;
			v = -view.j;
		}
	}

	// Transform from [-1,1] to [0,1]
	u /= 2.0;
	v /= 2.0;
	u += 0.5;
	v += 0.5;

	return read_map(u*size, v*size, map_num);
}