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View Full Version : Rotate a sphrere and cube, but one vanish when rotating.



Azteker
07-02-2015, 11:52 PM
Here is the display code. I just don't understand why the sphere disappear when rotating the viewing angle.

void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glPushMatrix();

GLfloat eyeX = 5 * cos(degToRad(theta));
GLfloat eyeY = 5 * sin(degToRad(theta));
GLfloat eyeZ = rho;
gluLookAt(eyeX, eyeY, eyeZ, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0);


glPushMatrix();
{
glColor3f(0.0, 0.0, 0.9);
glTranslatef(-1.5, 1.5, 0.0);
glutSolidCube(1.0f);
}
glPopMatrix();

glPushMatrix();
{
glColor3f(0.9, 0.0, 0.9);
glutSolidSphere(1/std::sqrt(2), 20, 20);
}
glPopMatrix();

glutSwapBuffers();
}