Shawn619

Just wondering how the components for eyeX, eyeY, eyeZ are derived

 

I'll give you an idea on how I would approach this assignment and answer your question at the same time.

For rotation, you say that your rotation method is working, instead of using the traditional glrotate, so i'll leave the rotation alone.

For translation, the first 3 components of gluLookAt are the position of your eye in world space, which you seem to have calculated correctly, assuming your rotation are correct.

The next 3 components are where your eye will be looking. So, in your scenario of an earth orbiting around a sun, assuming your sun in centered at the origin, these 3 components would be (0,0,0), which would have your eye looking towards the origin(at the sun). 

 

http://www.opengl.org/sdk/docs/man2/xhtml/gluLookAt.xml

 

Also, shouldn't

gluLookAt(eyeZ * cos(theta) * sin(phi), eyeZ * sin(theta), eyeZ * cos(theta) * cos(phi), 0, 0, 0, 0, 1, 0);

 

be

gluLookAt(eyeX * cos(theta) * sin(phi), eyeY * sin(theta), eyeZ * cos(theta) * cos(phi), 0, 0, 0, 0, 1, 0);

I translate my object(soccer ball) -20z pixels away from the camera, keep the camera and rotating sphere(blue sphere=light, so you know where the light is) at origin, and rotate the light(represented by the sphere) around the origin to simulate moving light.

 

I think this short video(00:14) should clear things up:

*note: blue sphere=light, soccer ball=object, grey plane=flat ground

 

Why is my object acting as if it is at the origin, where the light is rotating around, but in reality it is -20z further away from the origin?

 

main function:

void drawScene() {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
 
 
 
    //lighting+sphere
    rot+=1.0f;
    glPushMatrix();
 
    //glTranslatef(0.0f, 0.0f, -20.0f);
    glRotatef(rot,0.0f,1.0f,0.0);
    glTranslatef(0.0f, 0.0f, 10.0f);
 
    initSceneLighting();//set position light[0] {0,0,0,1}
    drawSceneSphereLight();//blue sphere
    glPopMatrix();
 
    //soccer ball(object)
    glPushMatrix();
    glTranslatef(0.0f, 0.0f, -20.0f);
 
    glColor3f(1.0f,0.0f,0.0f);
    glCallList(soccerBall);
    glPopMatrix();
 
 
    //floor
    glPushMatrix();
 
    glColor3f(0.5f,0.5f,0.4f);
    drawSceneFloor();//grey ground
 
    glPopMatrix();
　
 
    glutSwapBuffers();
}

(Edited by mod. Not appropriate for Game Design forum. For Help Wanted posts, try the Classifieds.)