#pragma once

#include "dvr_triangle.h"
#include "math/dvc_vector4.h"

class Canvas
{
public:
	struct Pixel
	{
		davinci::fVector3 color;
		float alpha;
		uint32_t mask;
		int32_t fragementID;
	};
	typedef std::vector<Pixel> PixelArray;

	struct Fragement
	{
		int32_t id;
		davinci::fVector3 color;
		uint32_t mask;
		int32_t next;
	};
	typedef std::vector<Fragement> FragementArray;

public:
	int32_t width() const { return m_width; }
	int32_t height() const { return m_height; }
	const Pixel& pixel(int32_t x, int32_t y) const
	{
		return m_pixels[y * m_width + x];
	}

	void reset(int32_t width, int32_t height);
	void update(davinci::AntiAliasingTech aaTech, const TriangleArray& riangleArray, const Triangle* pActionTriangle = nullptr);

private:
	void _insertTriangle(const Triangle& triangle);
	void _update_without_AA();

	template<int32_t kSampleSize>
	void _update_with_AA()
	{
		for (size_t i = 0; i < m_pixels.size(); i++)
		{
			Pixel& pixel = m_pixels[i];
			if (pixel.fragementID < 0) continue;

			FragementArray pixelFragements;
			int32_t fragementID = pixel.fragementID;
			while (fragementID >= 0 && fragementID < m_fragementArray.size())
			{
				const Fragement& fragement = m_fragementArray[fragementID];
				pixelFragements.insert(pixelFragements.begin(), fragement);
				fragementID = fragement.next;
			}

			if (pixelFragements.size() == 0) continue;
			else if (pixelFragements.size() == 1)
			{
				const Fragement& fragement = pixelFragements[0];
				pixel.mask = fragement.mask;
				pixel.color = fragement.color;
				pixel.alpha = davinci::MathUtil::popcount((uint16_t)(fragement.mask)) / (float32_t)kSampleSize;
			}
			else
			{
				std::array<int32_t, kSampleSize> samples;
				samples.fill(-1);
				for (size_t j = 0; j < pixelFragements.size(); j++)
				{
					const Fragement& fragement = pixelFragements[j];
					for (int32_t k = 0; k < kSampleSize; k++)
					{
						if ((fragement.mask & (1 << k)) != 0)
						{
							samples[k] = fragement.id;
						}
					}
				}

				pixel.mask = 0;
				int32_t bitCounts = 0;
				for (int32_t k = 0; k < kSampleSize; k++)
				{
					int32_t fragementID = samples[k];
					if (fragementID < 0 || fragementID>m_fragementArray.size()) continue;

					const Fragement& fragement = m_fragementArray[fragementID];
					pixel.mask |= (1 << k);
					pixel.color += fragement.color;
					bitCounts++;
				}
				if (bitCounts > 1) {
					pixel.color /= (float32_t)bitCounts;
				}
				pixel.alpha = bitCounts / (float32_t)kSampleSize;
			}
		}
	}

private:
	int32_t		m_width;
	int32_t		m_height;
	PixelArray	m_pixels; // final pixels in the canvas
	FragementArray m_fragementArray;
};