# OpenGL NEED HELP: Spherical Camera Class :: Spherical Coordinates

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I am working an a spherical camera class for OpenGL. I have the calculations but i think i am still doing it wrong. All i want to do is have a camera somwhere in 3d space always looking at point 0,0,0, that rotates about a sphere. here is what i have. SphericalCamera.h
#ifndef SPHERICALCAMERA_H
#define SPHERICALCAMERA_H

#include "windows.h"
#include <math.h>
#include "GL/gl.h"
#include "GL/glu.h"
#include "SDL.h"

#define pi 3.14159265358979f

struct Vector3f{
float x;
float y;
float z;
};

class SphericalCamera  {
public:
SphericalCamera(float eyeX, float eyeY, float eyeZ);
~SphericalCamera();

void UpdateView(void);
void RotateY(float degrees);
void RotateZ(float degrees);

protected:

void CartesianToSpherical(void);				//Convert from Cartesian To Spherical.
void SphericalToCartesian(void);				//Convert from Spherical To Cartesian.

void CalcRadius(void);	//				These functions may be needed to calculate things we yet do not know.
void CalcTheta(void);	//				...
void CalcPhi(void);		//				...

float theta;			//				0 to pi (radians) (180 degrees)
float phi;				//				rotation in x/y plane
float radius;			//				Radius or distance from point of origin

Vector3f eye;    		//				The current position in 3d space of the eye
//				using Cartesian coordinates

Vector3f center;		//				The center of the scene, or what we are looking at
Vector3f upVector;		//				Current Up Vector

Vector3f eyeOrigin;		//				Camera's eye Point of origin
Vector3f centerOrigin;	//				Center of scene point of origin
Vector3f upOrigin;		//				The original Up Vector
};

#endif


SphericalCamera.cpp
#include "SphericalCamera.h"

SphericalCamera::SphericalCamera(float eyeX, float eyeY, float eyeZ)
{
SphericalCamera::centerOrigin.x = 0.0f;
SphericalCamera::centerOrigin.y = 0.0f;
SphericalCamera::centerOrigin.z = 0.0f;
SphericalCamera::center = centerOrigin;

SphericalCamera::eyeOrigin.x = eyeX;
SphericalCamera::eyeOrigin.y = eyeY;
SphericalCamera::eyeOrigin.z = eyeZ;
SphericalCamera::eye = eyeOrigin;

SphericalCamera::upOrigin.x = 0.0f;
SphericalCamera::upOrigin.y = 1.0f;
SphericalCamera::upOrigin.z = 0.0f;
SphericalCamera::upVector = upOrigin;

SphericalCamera::CartesianToSpherical();
}

SphericalCamera::~SphericalCamera(void)  {
}

void SphericalCamera::CartesianToSpherical(void)  {
CalcTheta();
CalcPhi();
eye.y = theta;
eye.z = phi;
}

void SphericalCamera::SphericalToCartesian(void)  {
eye.x = radius * sin(theta) * cos(phi);
eye.y = radius * sin(theta) * sin(phi);
eye.z = radius * cos(theta);

}

radius = sqrt((pow(eye.x,2) + pow(eye.y,2) + pow(eye.z,2)) );
}

void SphericalCamera::CalcTheta(void)  {
theta = acos(eye.x / radius);
}

void SphericalCamera::CalcPhi(void)  {
phi = acos( eye.x /(radius * sin(theta) ) );
}

float SphericalCamera::RadtoDeg(float x)  {
return x * 180.0f / pi;
}

float SphericalCamera::DegToRad(float x)  {
return x * pi / 180.0f;
}

void SphericalCamera::RotateY(float degrees)  {
theta += degrees;
}

void SphericalCamera::RotateZ(float degrees)  {
phi += degrees;
}

void SphericalCamera::UpdateView(void)  {

SphericalCamera::SphericalToCartesian();
center.x = centerOrigin.x - eye.x;
center.y = centerOrigin.y - eye.y;
center.z = centerOrigin.z - eye.z;
float length;

length = sqrt(pow(center.x, 2) + pow(center.y, 2) + pow(center.z, 2));

center.x /= length;
center.y /= length;
center.z /= length;

gluLookAt(eye.x, eye.y, eye.z, center.x, center.y, center.z, upVector.x, upVector.y, upVector.z);
}


Now the problem lies in the converison i think, if i feed it 0,0,10 (x,y,z) after all the convertions i dont even get numbers back that are close to 0,0,10 i get like -2.5044781e-006, 1.0000000,-4.3711388e-008 after a convertion from spherical to cartesian. Can someone hlp me figure out where my convertions are going wrong? thanks guys i've been hung up on this for a long time now.

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How do you handle how to look?

What I did was use the mouse coords as my Theta and Phi and reversed the values of y and z. Although you prolly don't need to in OpenGL because when I did my spherical system, I made it in pure sofware. From triangle fillers to matrix math.
Here's a brief explanation

The camera in action

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All done. Got my questions answered, if you too had questions on this, jump over to the math forum and there is a great explination of what went wrong.

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All done. Got my questions answered, if you too had questions on this, jump over to the math forum and there is a great explination of what went wrong.

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I am not a professional programmer, just a hobbyist, so it may well be that i got something principally wrong :-)
And thanks for any hints and so ...

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