#pragma once
#include "base.h"
#include "point.h"

// represents the point of view
class Eye
{
public:
    Eye();
    ~Eye() {}
    void ReadConfig(const char* spec, bool ring);
    void Init(const Point& p, double right, double down, double clockwise, double zoom);
    void RotateRight(double x);  // spin right, in radians
    void RotateDown(double x);  // spin down, in radians
    void Clockwise(double x);  // spin clockwise, in radians
	void ShiftRight(int n);  // shift the center right by n pixels
	void ShiftDown(int n);  // shift the center down by n pixels
    void Center(const Point& p) { _m[3] = p; }  // move the viewpoint to the center
    void Move(const Point& p) { _m[4] += p; }  // move the viewpoint to p
	void AdjustZoom(double zoom) { _zoom *= zoom; }
	double GetZoom() { return _zoom; }
    Point Map(const Point& p);  // map a point from the eye's perspective
	Point MapRing(const Point& p);  // map a point from the eye's perspective, as a cross-section of a ring
    int MapX(const Point& p) { return _centerX + (int)(_zoom*(p._x/p._z)); } // x pixel to draw this point at
    int MapY(const Point& p) { return _centerY + (int)(_zoom*(p._y/p._z)); } // y pixel to draw this point at
	double MapRadius(double r, const Point& p) { return p._z > 0.0 ? _zoom * r / p._z : 0.0; }
    void SetWidth(int x) { _maxX = x; _centerX = x/2; }
    void SetHeight(int y) { _maxY = y; _centerY = y/2; }
	int Width() { return _maxX; }
	int Height() { return _maxY; }
	int CenterX() { return _centerX; }
	int CenterY() { return _centerY; }
    
private:
    void Rotate(const double (&d)[3][3]);  // rotate m[][] by d

    int _centerX;  // center x pixel
    int _centerY;  // center y pixel
    int _maxX;     // total width of screen
    int _maxY;     // total height of screen
    double _zoom;  // magnification of image
    Point _m[5];   // [0][1][2] form the matrix of rotation, m[3] is prerotate offset, m[4] is postrotate offset
};