richard

typedef float real;class Matrix;class Vector {public:	enum {length=4};	Vector();	Vector(real x,real y,real z);	Vector(const Vector& rhs);	real x() const { return data[0];}	real y() const { return data[1];}	real z() const { return data[2];}	real& x() { return data[0];}	real& y() { return data[1];}	real& z() { return data[2];}	Vector mul(const Vector &rhs);	Vector mul(const Matrix& rhs);	Vector mul(const real scale);	real dot(const Vector &rhs);	Vector cross(const Vector& rhs);	real mag();	Vector unit();	real get(int i) const { return data[i];}private:	real data[length];};class Matrix {	public:		enum {length=4};		Matrix mul(const Matrix& rhs);		Matrix();		Matrix(const Matrix& rhs);		real get(int i,int j) const { return data[i][j];}		void set(int i,int j,real val)  { data[i][j]=val;}	private:		real data[length][length];};#include <cmath>#include <cstring>Matrix::Matrix() {	for(int i=0;i<length;++i)		for(int j=0;j<length;++j)			data[i][j]=i==j ? 1:0;}Matrix::Matrix(const Matrix&rhs) {	memcpy(data,rhs.data,sizeof(data));}Matrix Matrix::mul(const Matrix &rhs) {		Matrix ret;		for (int i = 0; i < length; ++i) {			for (int j = 0; j < length; ++j) {				real cell = 0;				for (int r = 0; r < length; ++r) {					cell += this->get(i, r) * rhs.get(r, j);				}				ret.set(i, j, cell);			}		}		return ret;	}Vector Vector::mul(const Matrix& mat) {		 int m = 1;		int n = length;		int p = n;		Vector ret;			for (int j = 0; j < p; ++j) {				int cell = 0;				for (int r = 0; r < n; ++r) {					cell += this->get(r) * mat.get(r, j);				}				ret.data[j]= cell;			}		return ret;	}Vector::Vector() {	for(int i=0;i<length-1;++i)		data[i]=0;	data[length-1]=1;}Vector::Vector(real x,real y,real z) {	data[0]=x;	data[1]=y;	data[2]=z;	data[3]=1;}Vector Vector::mul(real scale) {	Vector v;	for(int i=0;i<length;++i) {		v.data[i] = this->data[i] * scale;	}	return v;}Vector Vector::cross(const Vector& rhs) {	return Vector(y()*rhs.z() - rhs.y()*z() , z()*rhs.x()-rhs.z()*x(), x()*rhs.y()-rhs.x()*y());}Vector::Vector(const Vector &rhs) {	for(int i=0;i<length;++i)		data[i]=rhs.data[i];}real Vector::mag() {	real tot=0;	for(int i=0;i<length;++i)		tot+= data[i]*data[i];	return sqrt(tot);}Vector Vector::unit() {	real l=this->mag();	real s=1/l;	return this->mul(s);}real Vector::dot(const Vector& rhs) {	float d=0;	for(int i=0;i<length;++i)		d += data[i]*rhs.data[i];	return d;}Matrix frustrum(real l,real r,real b,real t,real n,real f) {	Matrix m;	m.set(0,0, (2.0f*n)/(r-l));	m.set(0,2, (r+l)/(r-l));	m.set(1,1, (2.0f*n)/(t-b));	m.set(1,2, (t+b)/(t-b));	m.set(2,2,(-(f+n))/(f-n));	m.set(2,3,(-(2.0f*f*n))/(f-n));	m.set(3,2,-1);	return m;}#include <cstdio>void printMat(const Matrix& m) {	int l=m.length;	for(int i=0;i<l;++i) {		printf("[");		for(int j=0;j<l;++j) {			printf(" %5.02f ",m.get(i,j));		}		printf("]\n");	}}void printVec(const Vector& v) {	for(int i=0;i<v.length;++i) {		printf("[%5.02f]\n",v.get(i));	}}void printVec2(const Vector&v) {	for(int i=0;i<v.length-1;++i) {		printf("[%5.02f]\n",v.get(i)/v.get(v.length-1));	}}int main(void) {			 // simple projection test	Vector X(1,0,0);	Vector Y(0,1,0);	Vector G(5,1,191);	printf("X.Y = %.2f\n",X.dot(Y));	printf("X.G = %.2f\n",X.dot(G));	printf("Y.G = %.2f\n",Y.dot(G));	real view_height=4;	Matrix f = frustrum(.5f, -.5f, -1.f , 1.f , 1.f, 90.f);	printMat(f);	printVec(G);	Vector s=G.mul(f);	printVec2(s);return 0;}