So rotate it around 0,0,0
Then scale it if needed
Then translate it to xyz, then it looks like it rotated around itself. Though the center of the vertices/the center of the spaceships model must be around 0,0,0, in terms of vertices.
well I tried rotating then translating but it does not move up or down.
well I am only doing what tatuk was suggesting
Not exactly. I meant something like this:
void DrawShip(float x, float y, float z, float rotation) { // rotation in degrees
glPushMatrix();
float radr = 0.017453292519943295 * rotatation; // convert rotation from degrees to radians
float temp = x;
x = x * cosf( radr ) - y * sinf( radr );
y = temp * sinf( radr ) + y * cosf( radr );
// First translate to the wanted position
glTranslatef(x, y, z);
// Then render the shape of the object, you have already translated and rotated it to the right place
glBegin(GL_LINE_LOOP);
glVertex3f(0.0f,-0.25f,0.0f);
glVertex3f(-0.25f,-0.5f,0.0f);
glVertex3f(-0.5f,-0.5f,0.0f);
glVertex3f(-0.0f,0.5f,0.0f);
glVertex3f(0.5f,-0.5f,0.0f);
glVertex3f(0.25f,-0.5f,0.0f);
glVertex3f(0.0f,-0.25f,0.0f);
glEnd();
glPopMatrix();
well I tried the above code but it does not rotate, here is my code,
void DrawShip(GLfloat x,GLfloat y,GLfloat z,GLfloat rotation,GLfloat color)
{
glPushMatrix();
float radr = 0.017453292519943295 * rotation; // convert rotation from degrees to radians
float temp = x;
x = x * cosf( radr ) - y * sinf( radr );
y = temp * sinf( radr ) + y * cosf( radr );
// First translate to the wanted position
glTranslatef(x, y, z);
glColor3f(color,0.0f,0.0f);
// Then render the shape of the object, you have already translated and rotated it to the right place
glBegin(GL_LINE_LOOP);
glVertex3f(0.0f,-0.25f,0.0f);
glVertex3f(-0.25f,-0.5f,0.0f);
glVertex3f(-0.5f,-0.5f,0.0f);
glVertex3f(-0.0f,0.5f,0.0f);
glVertex3f(0.5f,-0.5f,0.0f);
glVertex3f(0.25f,-0.5f,0.0f);
glVertex3f(0.0f,-0.25f,0.0f);
glEnd();
glPopMatrix();
}
well what *does* happen? something's *got* to happen because you're changing the x,y,z position (by a rotation matrix) ... are you even supplying new `rotation` values? it has to gradually increase from 0->360
That is because he did it in the wrong order.well I tried sponji code but it still does not rotate around a its central axis after I move it up or down.
void DrawShip(float x, float y, float z, float rotation) {
glPushMatrix();
// First rotate.
glRotatef(rotation, 0.0f, 0.0f, 1.0f);
// THEN translate.
glTranslatef(x, y, z);
// Then render the shape of the object, you have already translated and rotated it to the right place
glBegin(GL_LINE_LOOP);
glVertex3f(0.0f,-0.25f,0.0f);
glVertex3f(-0.25f,-0.5f,0.0f);
glVertex3f(-0.5f,-0.5f,0.0f);
glVertex3f(-0.0f,0.5f,0.0f);
glVertex3f(0.5f,-0.5f,0.0f);
glVertex3f(0.25f,-0.5f,0.0f);
glVertex3f(0.0f,-0.25f,0.0f);
glEnd();
glPopMatrix();
}well spiro I did what you said and it moves up and down, but it still rotates around the center of the screen, but does not rotate around the center of the shape. sorry spiro but I am trying. I commend you, you are a very bright person.
Show your code.
I get the feeling you mixed what I posted with the math you have been trying to use.
The solution is my post, the whole post, and nothing but the post, so help me Todd.
L. Spiro
That is because he did it in the wrong order.well I tried sponji code but it still does not rotate around a its central axis after I move it up or down.
What, in wrong order? I don't understand, when would he even want to use the order you suggested? First translate, then rotate.
But still, I bet the problem is somewhere else. I think he isn't moving the object correctly, and that should be done outside the render function.
stop using trigonometry manually
He needs to. He wants to rotate AROUND a point. Not at the centerpoint which glRotatef() would do. 
