#include "camera.h"

const double PI = 3.14159265358979;

Camera::Camera()
{
	eye = Point3D(0, 0, 5);
	n = Vector3D(0, 0, 1);
	u = Vector3D(1, 0, 0);
	v = Vector3D(0, 1, 0);
	viewAngle = 60;
	aspect = 4.0/3.0;
	nearDist = 0.1;
	farDist = 100.0;
	speed = 1.0;		// units per second
	return;
}

Camera::Camera(Point3D e, Point3D look, Vector3D up)
{
	eye = e;
	n.set(eye.x - look.x, eye.y - look.y, eye.z - look.z);
	n = n.normalize();
	u = up.cross(n);
	u = u.normalize();
	v = n.cross(u);
	viewAngle = 60.0;
	aspect = 4.0/3.0;
	nearDist = 0.1;
	farDist = 100.0;
	speed = 1.0;		// units per second
	return;
}

void Camera::set(Point3D e, Point3D look, Vector3D up)
{
	eye = e;
	n.set(eye.x - look.x, eye.y - look.y, eye.z - look.z);
	n = n.normalize();
	u = up.cross(n);
	u = u.normalize();
	v = n.cross(u);
	setModelViewMatrix();
	return;
}

void Camera::roll(float angle)
{
	float c = cos(PI/180.0*angle);
	float s = sin(PI/180.0*angle);
	Vector3D t = u;
	u.set(c*t.x - s*v.x, c*t.y - s*v.y, c*t.z - s*v.z);
	v.set(s*t.x + c*v.x, s*t.y + c*v.y, s*t.z + c*v.z);
	setModelViewMatrix();
	return;
}

void Camera::pitch(float angle)
{
	float c = cos(PI/180.0*angle);
	float s = sin(PI/180.0*angle);
	Vector3D t = v;
	v.set(c*t.x - s*n.x, c*t.y - s*n.y, c*t.z - s*n.z);
	n.set(s*t.x + c*n.x, s*t.y + c*n.y, s*t.z + c*n.z);
	setModelViewMatrix();
	return;
}

void Camera::yaw(float angle)
{
	float c = cos(PI/180.0*angle);
	float s = sin(PI/180.0*angle);
	Vector3D t = n;
	n.set(c*t.x - s*u.x, c*t.y - s*u.y, c*t.z - s*u.z);
	u.set(s*t.x + c*u.x, s*t.y + c*u.y, s*t.z + c*u.z);
	setModelViewMatrix();
	return;
}

void Camera::forward(float dt)
{
	eye.x -= n.x*dt;
	eye.y -= n.y*dt;
	eye.z -= n.z*dt;
	setModelViewMatrix();
	return;
}

void Camera::setShape(float va, float ar, float nd, float fd)
{
	viewAngle = va;
	aspect = ar;
	nearDist = nd;
	farDist = fd;
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(viewAngle, aspect, nearDist, farDist);
	return;
}

void Camera::setModelViewMatrix()
{
	float m[16];
	Vector3D eyeV(eye.x, eye.y, eye.z);
	m[0] = u.x; m[4] = u.y; m[ 8] = u.z; m[12] = -eyeV.dot(u);
	m[1] = v.x; m[5] = v.y; m[ 9] = v.z; m[13] = -eyeV.dot(v);
	m[2] = n.x; m[6] = n.y; m[10] = n.z; m[14] = -eyeV.dot(n);
	m[3] = 0.0; m[7] = 0.0; m[11] = 0.0; m[15] = 1.0;
	glMatrixMode(GL_MODELVIEW);
	glLoadMatrixf(m);
	return;
}