#include "olcConsoleGameEngine.h"
using namespace std;

struct vec3d
{
	float x, y, z;
};

struct triangle
{
	vec3d p[3];
};
struct mesh
{
	vector<triangle> tris;
};

struct mat4x4
{
	float m[4][4] = { 0 };
};


class olcEngine3D : public olcConsoleGameEngine
{
public:
	olcEngine3D()
	{
		m_sAppName = L"3D Demo";
		olcEngine3D demo;
		if (demo.ConstructConsole(256, 240, 4, 4));
		demo.Start();
	}
private:
	mesh meshCube;
	mat4x4 matProj;

	void MultiplyMatrixVector(vec3d& i, vec3d& o, mat4x4& m)
	{
		o.x		= i.x * m.m[0][0] + i.y * m.m[1][0] + i.z * m.m[2][0] + m.m[3][0];
		o.x		= i.x * m.m[0][1] + i.y * m.m[1][1] + i.z * m.m[2][1] + m.m[3][1];
		o.x		= i.x * m.m[0][2] + i.y * m.m[1][2] + i.z * m.m[2][2] + m.m[3][2];
		float w = i.x * m.m[0][3] + i.y * m.m[1][3] + i.z * m.m[2][3] + m.m[3][3];

		if (w != 0.0f)
		{
			o.x /= w;
			o.y /= w;
			o.z /= w;
		}
	}

public:
	bool OnUserCreate() override
	{
		meshCube.tris = {

			//South
			{0.0f, 0.0f, 0.0f,		0.0f, 1.0f, 0.0f,		1.0f, 1.0f, 0.0f},
			{0.0f, 0.0f, 0.0f,		1.0f, 1.0f, 0.0f,		1.0f, 0.0f, 0.0f},

			//East
			{1.0f, 0.0f, 0.0f,		1.0f, 1.0f, 0.0f,		1.0f, 1.0f, 1.0f},
			{1.0f, 0.0f, 0.0f,		1.0f, 1.0f, 1.0f,		1.0f, 0.0f, 1.0f},

			//North
			{1.0f, 0.0f, 1.0f,		1.0f, 1.0f, 1.0f,		0.0f, 1.0f, 1.0f},
			{1.0f, 0.0f, 1.0f,		0.0f, 1.0f, 1.0f,		0.0f, 0.0f, 1.0f},

			//West
			{0.0f, 0.0f, 1.0f,		0.0f, 1.0f, 1.0f,		0.0f, 1.0f, 0.0f},
			{0.0f, 0.0f, 1.0f,		0.0f, 1.0f, 0.0f,		0.0f, 0.0f, 0.0f},

			//Top
			{0.0f, 1.0f, 0.0f,		0.0f, 1.0f, 1.0f,		1.0f, 1.0f, 1.0f},
			{0.0f, 1.0f, 0.0f,		1.0f, 1.0f, 1.0f,		1.0f, 1.0f, 1.0f},

			//Bottom
			{1.0f, 0.0f, 1.0f,		0.0f, 0.0f, 1.0f,		0.0f, 0.0f, 0.0f},
			{1.0f, 0.0f, 1.0f,		0.0f, 0.0f, 0.0f,		1.0f, 0.0f, 0.0f},

		};

		//Projection Matrix
		float fNear = 0.1f;
		float fFar = 1000.0f;
		float fFov = 90.0f;
		float fAspectRatio = (float)ScreenHeight() / (float)ScreenWidth();
		float fFovRad = 1.0f / tanf(fFov * 0.5f / 180.0f * 3.14159f);

		matProj.m[0][0] = fAspectRatio * fFovRad;
		matProj.m[1][1] = fFovRad;




		return true;
	}

	bool OnUserUpdate(float fElapsedTime) override
	{
		Fill(0, 0, ScreenWidth(), ScreenHeight(), PIXEL_SOLID, FG_BLACK);
		for (auto tri : meshCube.tris)
		{
			triangle triProjected;
			MultiplyMatrixVector(tri.p[0], triProjected.p[0], matProj);
			MultiplyMatrixVector(tri.p[0], triProjected.p[0], matProj);
			MultiplyMatrixVector(tri.p[0], triProjected.p[0], matProj);

			triProjected.p[0].x += 1.0f; triProjected.p[0].y += 1.0f;
			triProjected.p[1].x += 1.0f; triProjected.p[1].y += 1.0f;
			triProjected.p[2].x += 1.0f; triProjected.p[2].y += 1.0f;

			triProjected.p[0].x *= 0.5f * (float)ScreenWidth();
			triProjected.p[1].x *= 0.5f * (float)ScreenWidth();
			triProjected.p[2].x *= 0.5f * (float)ScreenWidth();

			triProjected.p[0].y *= 0.5f * (float)ScreenHeight();
			triProjected.p[1].y *= 0.5f * (float)ScreenHeight();
			triProjected.p[2].y *= 0.5f * (float)ScreenHeight();

			DrawTriangle(triProjected.p[0].x, triProjected.p[0].y,
				triProjected.p[1].x, triProjected.p[1].y,
				triProjected.p[2].x, triProjected.p[2].y,
				PIXEL_SOLID, FG_WHITE);
		}

		return true;
	}

};


int main()
{
	olcEngine3D();
	return 0;
}