HI,
Im re-writing the camera class for my game engine since the one im currently using is from somebody else and i cant GPL it with the rest of the engine.
The camera is misbehaving! It seems to work fine, but as i move it forward and backwards, the orientation vector is being de-formed,causing teh camera to take a parabolic path. If I normalize it, I get strange behaviour.
The camera class will call glulookat with the three vectors position, (position + orientation) and the up vector which as yet im not modifying.
the orientation vector is rotated in teh x and y using euler matrices. Gimbal lock is not a problem since im using incremental rotation, i think thats what its called anyway.
Can anybody see what i've done wrong?
My vector and matrix classes and the function gv_x_gm() which multiplies a vector and a matrix have passed every test ive thrown at them, but if anybody thinks thats the problem i will include those as well.
camera_control.h:
/*
* camera_control.h
* game_engine
*
* Created by gavin on 10/04/2007.
* Copyright 2007 __MyCompanyName__. All rights reserved.
*
*/
class camera_control;
#ifndef class_camera_control_h
#define class_camera_control_h 1
#include "SDL_GL_include.h"
#include "g_maths.h"
class camera_control
{
private:
void normalize();
float xr,yr;
g_vector orientation;
g_vector up;
public:
g_vector position;
g_vector target;
void set_position(float x, float y, float z);
void set_target(float x, float y, float z);
void set_up(float x, float y, float z);
void rotate(float x, float y);
void move_forward(float d);
camera_control();
~camera_control();
void look_at_scene();
};
#endif
camera_control.cpp:
/*
* camera_control.cpp
* game_engine
*
* Created by gavin on 10/04/2007.
* Copyright 2007 __MyCompanyName__. All rights reserved.
*
*/
#include "camera_control.h"
camera_control::camera_control()
{
xr = 0;
yr = 0;
position.set_vector(0,10,0);
target.set_vector(0,0,1);
up.set_vector(0,1,0);
normalize();
};
void camera_control::normalize()
{
orientation = position - target;
orientation.normalize();
};
camera_control::~camera_control()
{
};
void camera_control::look_at_scene()
{
normalize();
g_matrix xrot(4,4);
g_matrix yrot(4,4);
yrot.y_rot(xr*pirad);
xrot.x_rot(yr*pirad);
g_matrix rotation(4,4);
rotation = matrix_multiply(xrot,yrot);
orientation = gv_x_gm(orientation,rotation);
float px,py,pz,tx,ty,tz,ux,uy,uz;
position.get_vector(px,py,pz);
orientation.get_vector(tx,ty,tz);
up.get_vector(ux,uy,uz);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(px,py,pz,px+tx,py+ty,pz+tz,ux,uy,uz);
};
void camera_control::rotate(float x, float y)
{
xr -= x;
yr -= y;
};
void camera_control::move_forward(float d)
{
position = position + orientation*d;
};
