//sketch_3D_Arc_Straight
void setup()
{
  size(400, 400, P3D);
}

void draw()
{
  background(255, 255, 255);
  lights();
  ortho(-width/2, width/2, -height/2, height/2); // Same as ortho()
  translate(width / 2, height / 2);
  rotateY(map(mouseX, 0, width, -PI/1, PI/1));
  rotateX(map(mouseY, 0, height, PI/1, -PI/1));
  //noStroke();
  strokeWeight(0.5);
    
  fill(255, 255, 255);
  scale(2,2,2);
  //void Z_Parasol(int Sn,float R,float A)//パラソル面
  //Z_Parasol(4,72.5,60);//パラソル面
  Z_Arc_Straight(40,20,70,20);
}

void Z_Arc_Straight(float R1,float R2,float L,float H)
{
  int Pn1=6;//R2ポイント数
  int Pn2=6;//R1ポイント数
  int Pn=4*Pn1+2+2*Pn2+3;//R2ポイント数
  float[] X=new float[Pn];
  float[] Y=new float[Pn];
  float L0=R1*L/(R1-R2);
  float A=acos(R1/L0);
  int i;
  float Ai1;
  for(i=0;i<=Pn1;i++)
  {
    Ai1=i*A/Pn1;
    X[i]=R2*cos(Ai1)+L;
    Y[i]=R2*sin(Ai1);
  }
  float Ai2;
  float dA2=(PI-2*A)/Pn2;
  for(i=0;i<=Pn2;i++)
  {
    Ai2=A+i*dA2;
    X[Pn1+i+1]=R1*cos(Ai2);
    Y[Pn1+i+1]=R1*sin(Ai2);
  }
  for(i=0;i<=2*Pn1;i++)
  {
    Ai1=PI-A+i*A/Pn1;
    X[Pn1+Pn2+2+i]=R2*cos(Ai1)-L;
    Y[Pn1+Pn2+2+i]=R2*sin(Ai1);
  }
  for(i=0;i<=Pn2;i++)
  {
    Ai2=PI+A+i*dA2;
    X[3*Pn1+Pn2+i+3]=R1*cos(Ai2);
    Y[3*Pn1+Pn2+i+3]=R1*sin(Ai2);
  }
  for(i=0;i<=Pn1;i++)
  {
    Ai1=2*PI-A+i*A/Pn1;
    X[3*Pn1+2*Pn2+i+4]=R2*cos(Ai1)+L;
    Y[3*Pn1+2*Pn2+i+4]=R2*sin(Ai1);
  }
  Z_Side(Pn,X,Y,H);//側面
  Z_Polyon_PZS(Pn,X,Y,H/2);
  Z_Polyon_PZS(Pn,X,Y,-H/2);
  
}

void Z_Side(int Pn,float X[],float Y[],float L)//側面
  {
    int i;
    beginShape(QUAD_STRIP);
    for (i = 0; i < Pn; ++i)
    {
      vertex(X[i],Y[i], -L/2);
      vertex(X[i],Y[i], L/2);
    }
    endShape(CLOSE);
  }
  
void Z_Polyon_PZS(int Pn,float X[],float Y[],float Z)//多角形Z指定タイプ
{
  int i;
  beginShape();
  for (i = 0; i < Pn; i++)
  {
    vertex(X[i],Y[i],Z);
  }
  endShape(CLOSE);
}