//sketch_3D_Z_Channel みぞ形鋼
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(1, 1,1);
  
  Z_Channel(100,50,5,7.5,100);//Channel みぞ形鋼
}

void Z_Channel(float H,float B,float T1,float T2,float L)//Channel みぞ形鋼
{
  int Pn=9;//ポイント数
  float x1=B/2;
  float x2=B/2-T1;
  float y1=H/2;
  float y2=H/2-T2;
  
  float X[]={-x1,-x1,x1,x1,-x2,-x2,x1,x1,-x1};
  float Y[]={-y1,y1,y1,y2,y2,-y2,-y2,-y1,-y1};
  
  pushMatrix();
  Z_Side(Pn,X,Y,L);//側面
  translate(0,0,-L/2);
  Z_Polyon(Pn,X,Y);//多角形
  translate(0,0,L);
  Z_Polyon(Pn,X,Y);//多角形
  popMatrix();
}

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(int Pn,float X[],float Y[])//多角形
{
  int i;
  beginShape();
  for (i = 0; i < Pn; ++i)
  {
    vertex(X[i],Y[i]);
  }
  endShape(CLOSE);
}