#include "common.h"
#include "SampleGenerator.h"
#include "Halton.h"

using namespace std;

//SampleGenerator::SampleGenerator() {}

SampleGenerator::SampleGenerator(int numSamples, float radius):
mNumSamples(numSamples), mRadius(radius)
{}


PoissonDiscSampleGenerator::PoissonDiscSampleGenerator(int numSamples, float radius):
SampleGenerator(numSamples, radius)
{}


void PoissonDiscSampleGenerator::Generate(Sample2 *samples) const
{
	static HaltonSequence halton;
	float r[2];

	// generates poisson distribution on disc
	float minDist = 2.0f / sqrt((float)mNumSamples);

	//cout << "minDist before= " << minDist << endl;

	for (int i = 0; i < mNumSamples; ++ i)
	{
		int tries = 0, totalTries = 0;

		// repeat until valid sample was found
		while (1)
		{
			++ tries;
			++ totalTries;

			halton.GetNext(2, r);

			const float rx = r[0] * 2.0f - 1.0f;
			const float ry = r[1] * 2.0f - 1.0f;

			// check if in disk, else exit early
			if (rx * rx + ry * ry > 1)
				continue;

			bool sampleValid = true;

			// check poisson property
			for (int j = 0; ((j < i) && sampleValid); ++ j)
			{
				const float dist = 
					sqrt((samples[j].x - rx) * (samples[j].x - rx) +
					     (samples[j].y - ry) * (samples[j].y - ry));
			
				if (dist < minDist)
					sampleValid = false;
			}

			if (sampleValid)
			{
				samples[i].x = rx;
				samples[i].y = ry;
				break;
			}

			if (tries > 2000)
			{
				minDist *= 0.9f;
				tries = 0;
			}
		}
		
		//cout << "sample: " << samples[i].x << " " << i << " " << samples[i].y << " r: " << sqrt(samples[i].x * samples[i].x  + samples[i].y * samples[i].y) << " tries: " << totalTries << endl;
	}

	//cout << "minDist after= " << minDist << endl;
}