ofx3DUtils camera to look around

beginners
#1

Hello,

I’ve been using the camera fuctionality of ofx3DUtils to ‘look around’ my 3d space like a first person view. The problem I have is with looking up and down.
I use:

  
camera.rotate(ofxVec3f(-1.0f,0.0f,0.0f) , myVariable);

To look ‘up and down’. This works just fine if I face forward (facing the negative side of the Z-axis) but when I turn around (facing the positive side of the Z-axis) the way the camera behaves changes; and now when I look up the screen goes down and vice-versa.

This change happens quite gradually and midway of turning, facing either side of the X-axis, it’s not possible to look up/down at all.

I find it quite difficult to get good camera movement and was hoping to find a nice library to help me with this (that’s how I did it in Processing). If anybody has any idea what I might be doing wrong, or if anybody has a better way of dealing with the camera I would love to hear it!
Thanks.

#2

Could you maybe post a more complete code sample? Then I could test it out and see what the problem is exactly.

#3 
  
  
//--------------------------------------------------------------  
void testApp::setup(){  
    camera.position(ofGetWidth()/2, ofGetHeight()/2, 1000);  
}  
  
//--------------------------------------------------------------  
void testApp::draw(){  
    camera.place();  
    if(mrp==true){  
        camera.moveLocal(0.0f,0.0f,20.0f);  
    }  
  
    ofTranslate(400,400,0);  
    glBegin(GL_TRIANGLES);  
        glColor3f(0.2f,0.0f,0.8f);  
        glVertex3f(0.0f,50.0f,0.0f);  
        glVertex3f(-50.0f,-50.0f,50.0f);  
        glVertex3f(50.0f,-50.0f,50.0f);  
        glColor3f(0.6f,1.0f,0.9f);  
        glVertex3f(0.0f,50.0f,0.0f);  
        glVertex3f(50.0f,-50.0f,50.0f);  
        glVertex3f(50.f,-50.0f,-50.0f);  
        glColor3f(0.0f,0.2f,0.5f);  
        glVertex3f(0.0f,50.0f,0.0f);  
        glVertex3f(50.0f,-50.0f,-50.0f);  
        glVertex3f(-50.0f,-50.0f,-50.0f);  
        glColor3f(1.0f,0.5f,0.5f);  
        glVertex3f(0.0f,50.0f,0.0f);  
        glVertex3f(-50.0f,-50.0f,-50.0f);  
        glVertex3f(-50.0f,-50.0f,50.0f);  
    glEnd();  
}  
//--------------------------------------------------------------  
void testApp::keyPressed(int key){  
    keys[key] = true;  
  
    if(key == OF_KEY_UP){  
        camera.moveGlobal(0.0f,12.0f,0.0f);  
    }  
    if(key == OF_KEY_DOWN){  
        camera.moveGlobal(0.0f,-12.0f,0.0f);  
    }  
    if(key == OF_KEY_LEFT){  
        camera.moveLocal(-12.0f,0.0f,0.0f);  
    }  
    if(key == OF_KEY_RIGHT){  
        camera.moveLocal(12.0f,0.0f,0.0f);  
    }  
}  
  
//--------------------------------------------------------------  
void testApp::keyReleased(int key){  
    keys[key] = false;  
}  
  
//--------------------------------------------------------------  
void testApp::mouseDragged(int x, int y, int button){  
    if(pmousex==NULL){  
        pmousex=x;  
        pmousey=y;  
    }  
    camera.rotate(ofxVec3f(0.0f,-1.0f,0.0f) , (x-pmousex)*0.2f);  
    camera.rotate(ofxVec3f(-1.0f,0.0f,0.0f) , (y-pmousey)*0.2f);  
    pmousex=x;  
    pmousey=y;  
}  
//--------------------------------------------------------------  
void testApp::mousePressed(int x, int y, int button){  
    if(button==2){  
        mrp=true;  
    }  
}  
//--------------------------------------------------------------  
void testApp::mouseReleased(int x, int y, int button){  
    pmousex=NULL;  
    if(button==2){  
        mrp=false;  
    }  
}

This piece of code is from my testApp.cpp and shows the way I use the camera. I deleted most of the other code to keep it as short as possible. I use the left mouse button to look around and the right mouse button to go forward in the direction you are looking.
Thanks

#4

What exactly are the variables pmousex and pmousex?
They look like pointer variables, especially since you set them to NULL at some stage, but maybe they’re not.

#5

Hmm yes sorry if I wasn’t to clear about some things. pmousex and pmousey hold the previous mouse x and y coordinates. In order to reset them once a mouse button is released I make them NULL. If the button is pressed again I check if they are NULL and if they are, give them the current x and y coordinates.
I geuss the resetting of the coordinates could also be in the mousePressed function. I’m not even sure why I used NULL here because actually I never do!