70 lines
2.3 KiB
C++
70 lines
2.3 KiB
C++
#include<cstdio>
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#include<iostream>
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#include<cmath>
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#include<cstring>
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using namespace std;
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const double Pi=acos(-1.0);
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const double EP=1e-10;
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struct Point{
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double x,y;
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};
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double x_mult(Point sp, Point ep, Point op){
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return (sp.x-op.x)*(ep.y-op.y)-(sp.y-op.y)*(ep.x-op.x);
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}
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double cross(Point a,Point b,Point c){
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return (a.x-c.x)*(b.x-c.x)+(a.y-c.y)*(b.y-c.y);
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}
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double dist(Point a,Point b){
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return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
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}
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double cal_area(Point a,Point b,Point c,double r){
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double A,B,C,x,y,tS;
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A=dist(b,c);
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B=dist(a,c);
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C=dist(b,a);
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if(A<r&&B<r)
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return x_mult(a,b,c)/2;
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else if(A<r&&B>=r){
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x=(cross(a,c,b)+sqrt(r*r*C*C-x_mult(a,c,b)*x_mult(a,c,b)))/C;
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tS=x_mult(a,b,c)/2;
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return asin(tS*(1-x/C)*2/r/B*(1-EP))*r*r/2+tS*x/C;
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}
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else if(A>=r&&B<r){
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y=(cross(b,c,a)+sqrt(r*r*C*C-x_mult(b,c,a)*x_mult(b,c,a)))/C;
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tS=x_mult(a,b,c)/2;
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return asin(tS*(1-y/C)*2/r/A*(1-EP))*r*r/2+tS*y/C;
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}
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else if(fabs(x_mult(a,b,c))>=r*C||cross(b,c,a)<=0||cross(a,c,b)<=0){
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if(cross(a,b,c)<0)
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if(x_mult(a,b,c)<0)
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return (-acos(-1.0)-asin(x_mult(a,b,c)/A/B*(1-EP)))*r*r/2;
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else return (acos(-1.0)-asin(x_mult(a,b,c)/A/B*(1-EP)))*r*r/2;
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else return asin(x_mult(a,b,c)/A/B*(1-EP))*r*r/2;
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}
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else{
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x=(cross(a,c,b)+sqrt(r*r*C*C-x_mult(a,c,b)*x_mult(a,c,b)))/C;
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y=(cross(b,c,a)+sqrt(r*r*C*C-x_mult(b,c,a)*x_mult(b,c,a)))/C;
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tS=x_mult(a,b,c)/2;
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return (asin(tS*(1-x/C)*2/r/B*(1-EP))+asin(tS*(1-y/C)*2/r/A*(1-EP)))*r*r/2+tS*((y+x)/C-1);
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}
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}
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int main(){
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Point p[105],cir;
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double r,area, x0, y0, v, angle, t, g;
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int i, n;
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while(scanf("%lf%lf%lf%lf%lf%lf%lf", &x0, &y0, &v, &angle, &t, &g, &r)!=EOF){
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if(fabs(x0)+fabs(y0)+fabs(v)+fabs(angle)+fabs(t)+fabs(g)+
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fabs(r)<0.0000001)break;
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scanf("%d", &n);
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for(i=0; i<n; i++)
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scanf("%lf%lf", &p[i].x, &p[i].y);
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area=0;cir.x=x0+v*cos(angle/180.0*Pi)*t;
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cir.y=y0+v*sin(angle/180.0*Pi)*t-0.5*g*t*t;
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for(i=0;i<n;i++){
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area+=cal_area(p[i], p[(i+1)%n], cir, r);
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}
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printf("%.2f\n",fabs(area));
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}
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return 0;
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}
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