/*

 * scene.cc: screen sample generation and image reconstruction

 *

 * This file is part of Pyrit Ray Tracer.

 *

 * Copyright 2008  Radek Brich

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include <math.h>

#include "common.h"

#include "scene.h"

void DefaultSampler::init()

{

	phase = 0;

}

int DefaultSampler::initSampleSet()

{

	static const int gridsamples[] = {1,5,9,16};

	const int samples = gridsamples[oversample];

	if ( phase == 0 )

	{

		phase++;

		sx = -1;

		return w*h*samples;

	}

	else if ( phase == 1 && oversample )

	{

		phase = -1;

		Float *buf;

		for (buf = buffer; buf != buffer + w*h*3; buf++)

			*buf = *buf * (1.0/samples);

		return 0;

	}

	else

	{

		phase = -1;

		return 0;

	}

}

Sample* DefaultSampler::nextSample()

{

	DefaultSample *s = new DefaultSample;

	/* grid oversampling */

	static const int gridsamples[] = {1,5,9,16};

	static const Float osa5x[] = {0.0, -0.4, +0.4, +0.4, -0.4};

	static const Float osa5y[] = {0.0, -0.4, -0.4, +0.4, +0.4};

	static const Float osa9x[] = {-0.34,  0.00, +0.34,

		-0.34,  0.00, +0.34, -0.34,  0.00, +0.34};

	static const Float osa9y[] = {-0.34, -0.34, -0.34,

			0.00,  0.00,  0.00, +0.34, +0.34, +0.34};

	static const Float osa16x[] = {-0.375, -0.125, +0.125, +0.375,

		-0.375, -0.125, +0.125, +0.375, -0.375, -0.125, +0.125, +0.375,

		-0.375, -0.125, +0.125, +0.375};

	static const Float osa16y[] = {-0.375, -0.375, -0.375, -0.375,

		-0.125, -0.125, -0.125, -0.125, +0.125, +0.125, +0.125, +0.125,

		+0.375, +0.375, +0.375, +0.375};

	static const Float *osaSx[] = {NULL, osa5x, osa9x, osa16x};

	static const Float *osaSy[] = {NULL, osa5y, osa9y, osa16y};

	const int samples = gridsamples[oversample];

	const Float *osax = osaSx[oversample];

	const Float *osay = osaSy[oversample];

	if (sx < 0)

	{

		// first sample

		s->x = -(Float)w/h/2.0;

		s->y = -0.5;

		sx = 0;

		sy = 0;

		osa_samp = 0;

	}

	else

	{

		osa_samp++;

		if (oversample && oversample <= 3 && osa_samp < samples)

		{

			s->x = osax[osa_samp]/h + (Float)sx/h - (Float)w/h/2.0;

			s->y = osay[osa_samp]/h + (Float)sy/h - 0.5;

		}

		else

		{

			sx++;

			if (sx >= w)

			{

				sx = 0;

				sy++;

			}

			if (sy >= h)

			{

				delete s;

				return NULL;

			}

			s->x = (Float)sx/h - (Float)w/h/2.0;

			s->y = (Float)sy/h - 0.5;

			osa_samp = 0;

		}

	}

	if (osa_samp == 0 && oversample && oversample <= 3)

	{

		s->x += osax[0]/h;

		s->y += osay[0]/h;

		Float *buf = buffer + 3*(sy*w + sx);

		*(buf++) = 0;

		*(buf++) = 0;

		*(buf++) = 0;

	}

	s->sx = sx;

	s->sy = sy;

	s->osa_samp = osa_samp;

	return s;

}

void DefaultSampler::saveSample(Sample *samp, Colour &col)

{

	DefaultSample *sp = static_cast<DefaultSample*>(samp);

	Float *buf = buffer + 3*(sp->sy*w + sp->sx);

	if (oversample)

	{

		*(buf+0) += col.r;

		*(buf+1) += col.g;

		*(buf+2) += col.b;

	}

	else

	{

		*(buf++) = col.r;

		*(buf++) = col.g;

		*(buf++) = col.b;

	}

}