I’m making a program to draw a trajectory, was using as a basis the tangent, but when I put 90 degrees, the tangent is very large, so I thought of putting an if (angle == 90) did not use the tangent.

the design is right, but after choosing it 90 degrees it stops to draw.

for example

1-30 degrees - draws

2-45 degrees ---- draws

3 draws -90 degrees —

4-60 degrees — not drawing

5 — 80 degrees — not drawing

*

*

anyone know what is happening? making routine design is presented below:

thank

void Draw() {

glColor3f(1.0, 1.0, 1.0);

glBegin(GL_LINES);

convert(graus);

if (ant){

x=xx;

y=yy;

}

double rad = (graus*3.1415926)/180;
GLfloat varx= s*abc;

GLfloat vary= f

*abc*tan(rad);

if (graus==90 || graus == 270) {varx = 0;

vary = f*abc;

}

glVertex3f(x, y, 0.0);

glVertex3f(x+varx, y+vary, 0.0);

if(_kbhit())

{

xx= x+s*abc;
yy= y+f*abc*tan(rad);

```
cout<< "Digite o angulo: ";
cin>>graus;
rad = (graus*3.1415926)/180;
convert(graus);
ant =1;
abc = 0.0;
}
```

glEnd();

glFlush();

abc += var;

glutPostRedisplay();

}