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ashstampede

OpenGL OpenGL Vector Based Camera Class Troubles

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I have been attempting to put together a camera class for a couple of weeks and trying various ways, but never any luck figuring it out. I would Like some help getting what I have done till now to work please. I have set up a camera class in opengl that uses 4 vectors to represent the camera axis and the it position in the "world". Position Forward Right Up I am trying to get my camera to have three modes, FPS style camera, Manual(free-fly) camera and a Agent or 3rd person camera. I havent attempted the 3rd person on as i havnt got any of the "standard" ones to work as yet. My fps camera works to a point actully until the point where you rotate 180 degrees. I rotate on the Y based on the World's Z axis so (0,0,-1), this is where the camera starts and is its facing. When i rotate the Forward vector, i then get the cross product of Forward and Up to recalculate Right. The camera works as it should until the camera facing is (0,0,1). forward movement is so
Position -= Forward*(GameSpeed*movementSpeed);
the call to camera rotateY is
Forward = defaultDirection.RotateY(angleY);
Right = Forward.CrossProduct(Up);
and rotation on the Y formula is
   static Vector3D rota;
   //calculate a new look direction using the default start location of the
   //camera
   //this prevents overtime rounding down of values by the compiler as well as  
   //giving us the orgin axis
   float sinAngle, cosAngle;
   SinCos( angle, &sinAngle, &cosAngle );
   rota.x = x;
   rota.y = y * cosAngle  + z *sinAngle;
   rota.z = -y *sinAngle + z*cosAngle;

   return rota;
when it is time to display the scene the calls to gl are
glRotatef(glCam->GetAngleX(),1.0f,0.0f,0.0f);
glRotatef(glCam->GetAngleY(),0.0f,1.0f,0.0f);
glTranslatef(glCam->GetX(),glCam->GetY(),glCam->GetZ());
Now I am fully lost on my Manual camera as movment on the right vector doesnt work. where
Position += Right*(GameSpeed*movementSpeed);
works for the FPS camera, on manual it effectivly loops back and forth between a very small point so effectivly standing still. for the Manual camera this is how i look down and right,(up and left are just negative values to these functions)
void GLCamera::LookUp(float GameSpeed)
 {
  if(invertCam !=true)
    angleX -= GameSpeed*rotationSpeed;
  else
    angleX += GameSpeed*rotationSpeed;
	
    //need to rotate on the local right vector, which doesnt change
    //this gives a new look direction
   //Forward = Forward.RotateLocalX(angleX,Right,Up);
	Forward = defaultDirection.RotateX(angleX);
	Up = Forward.CrossProduct(Right);
	Up.Normalize();
}
void GLCamera::TurnRight(float GameSpeed)
 {
	angleY += GameSpeed*rotationSpeed;
	
	//Forward = defaultDirection.RotateLocalY(angleY,Up,Right);
	 Forward = defaultDirection.RotateY(angleY);
	 Forward.Normalize();
	 Right = Forward.CrossProduct(Up);
}
I was not getting anywhere with my attempts at local rotation and found rotating from the axis works if i rotate on the X as well where in a FPS camera it is just the Y rotation that the Translation vectors need to change. here are my rotation codes in full
/****Move camera around*****/
//-Rotation-//
//using the given x,y,z use the Rotation function called to will rotate on the give axis to rotate along 
Vector3D Vector3D::RotateX(float angle)
{
	static Vector3D rota;
    //calculate a new look direction using the default start location of the camera
	//this prevents overtime rounding down of values by the compiler as well as giving us the orgin axis
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	rota.x = x;
	rota.y = y * cosAngle  + z *sinAngle;
	rota.z = -y *sinAngle + z*cosAngle;

	return rota;
	
}
//Rotate around the local X axis, the local Z axis calls this function
Vector3D Vector3D::RotateLocalX(float angle,Vector3D const &X,Vector3D &Y)
{
	
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	static Vector3D v1 = *this;

	//v1 = (v1 * cosAngle) + (Y * sinAngle);
	//v1.Normalize();
	////create the new Up
	//Y = v1.CrossProduct(X) *-1;

	//original code attempt
	//create the new Forward which is this object
	v1 = (Y * -sinAngle) + (v1 * cosAngle);
	v1.Normalize();
	
	//create the new Up
	Y = v1.CrossProduct(X);
	Y.Normalize();
	
	return v1;
}

Vector3D Vector3D::RotateY(float angle)
{
	static Vector3D rota;
    //rotate are current direction facing about the Y axis
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	rota.x = x* cosAngle - z *sinAngle ;
	rota.y = y;
	rota.z = x *sinAngle + z*cosAngle;
	//assign the new rotation of the vector to the given vector
	return rota;

}

//rotate around the local Y axis, the local Z axis calls this function
Vector3D Vector3D::RotateLocalY(float angle,Vector3D const &Y,Vector3D &X)
{
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	static Vector3D v1 = *this;
	//v1 =  (v1 * cosAngle) - (X * sinAngle) ;
	//v1.Normalize();

	////calculate the new X
	//X = v1.CrossProduct(Y);

	//original code attempt
	v1 = (X * sinAngle) + (v1 * cosAngle);
	v1.Normalize();

	//calculate the new X
	X = Y.CrossProduct(v1);
	X.Normalize();

	return v1;
}


Vector3D Vector3D::RotateZ(float angle)
{
	static Vector3D rota;
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	rota.x = x* cosAngle + y *sinAngle ;
	rota.y = -x *sinAngle + y*cosAngle;
	rota.z = z;
	return rota;
}


//Rotate on the local Z axis, the local right axis calls the function
Vector3D Vector3D::RotateLocalZ(float angle,Vector3D const &Z, Vector3D &Y)
{
	float sinAngle, cosAngle;
	SinCos( angle, &sinAngle, &cosAngle );
	static Vector3D v1 = *this;
	
	//v1 = (v1 *cosAngle) + (Y * sinAngle);
	//v1.Normalize();
	////create the new Up
	//Y = Z.CrossProduct(v1)*-1;
	
	//original code attempt
	v1 = (v1 *cosAngle) + (Y * sinAngle);
	v1.Normalize();
	//create the new Up
	Y = Z.CrossProduct(v1);
	Y.Normalize();

	return v1;
}
so to iterate the errors and troubles I am having. In FPS mode since I rotate the cameras default look Z axis around the world Y axis. This works until I am looking at the positive Z direction. I dont know how to test I have reached this point and Forward.z never gets to 1 or greater to invert my default look. With the manual camera same problem with the Z, but a new problem arise in that I cant move sideways(i.e. strafe). What am i doing wrong please help, and if any more info from me is needed let me know.

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Please put the code inside [ "source" ] tags... without the ", of course.

I decided to drop my vector based camera and went for a matrix-based instead. It saved me a lot of headaches.. =)

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maybe this helps:


const float piover180 = 0.0174532925f;

this is what my forward movement looks like(as stolen out of a NeHe-tutorial):

cam_x += (float)sin(-lookleftright*piover180) * 0.05f;
cam_y += (float)cos(lookleftright*piover180) * 0.05f;

if not please explain(didnt get it):
can you move the camera around normally with your mouse?
or does a problem only occur if you try to walk left right up or down?
or do you only get a problem walking around if you face a certain angle?

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Working code for FPS/6DOF OpenGL-style object/camera.

(No support for 3rd-person, I'm afraid, but you should be able to add that fairly easily.)

Note that I'm not suggesting that you simply use the code as is (although you're welcome to if you wish); rather, I'm just offering it as a reference in the hopes that it might help you identify where your own code is going off the rails.

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Quote:


if not please explain(didnt get it):
can you move the camera around normally with your mouse?
or does a problem only occur if you try to walk left right up or down?
or do you only get a problem walking around if you face a certain angle?


well my rotation is done with the mouse and it does rotate correctly , so yeah the problems happen with the translation, so when i am walking around when i face the opposite direction its starts to go wrong, as in I look down the camera 0,0,-1 z axis. when i look down the 0,0,1 everything messes up

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