camera.cpp

Direct 9.0 游戏编程 包括PDF书籍和源代码

//////////////////////////////////////////////////////////////////////////////////////////////////
// 
// File: camera.cpp
// 
// Author: Frank Luna (C) All Rights Reserved
//
// System: AMD Athlon 1800+ XP, 512 DDR, Geforce 3, Windows XP, MSVC++ 7.0 
//
// Desc: Defines a camera's position and orientation.
//         
//////////////////////////////////////////////////////////////////////////////////////////////////

#include "camera.h"

Camera::Camera()
{
	_cameraType = AIRCRAFT;

	_pos   = D3DXVECTOR3(0.0f, 0.0f, 0.0f);
	_right = D3DXVECTOR3(1.0f, 0.0f, 0.0f);
	_up    = D3DXVECTOR3(0.0f, 1.0f, 0.0f);
	_look  = D3DXVECTOR3(0.0f, 0.0f, 1.0f);
}

Camera::Camera(CameraType cameraType)
{
	_cameraType = cameraType;

	_pos   = D3DXVECTOR3(0.0f, 0.0f, 0.0f);
	_right = D3DXVECTOR3(1.0f, 0.0f, 0.0f);
	_up    = D3DXVECTOR3(0.0f, 1.0f, 0.0f);
	_look  = D3DXVECTOR3(0.0f, 0.0f, 1.0f);
}

Camera::~Camera()
{

}

void Camera::getPosition(D3DXVECTOR3* pos)
{
	*pos = _pos;
}

void Camera::setPosition(D3DXVECTOR3* pos)
{
	_pos = *pos;
}

void Camera::getRight(D3DXVECTOR3* right)
{
	*right = _right;
}

void Camera::getUp(D3DXVECTOR3* up)
{
	*up = _up;
}

void Camera::getLook(D3DXVECTOR3* look)
{
	*look = _look;
}

void Camera::walk(float units)
{
	// move only on xz plane for land object
	if( _cameraType == LANDOBJECT )
		_pos += D3DXVECTOR3(_look.x, 0.0f, _look.z) * units;

	if( _cameraType == AIRCRAFT )
		_pos += _look * units;
}

void Camera::strafe(float units)
{
	// move only on xz plane for land object
	if( _cameraType == LANDOBJECT )
		_pos += D3DXVECTOR3(_right.x, 0.0f, _right.z) * units;

	if( _cameraType == AIRCRAFT )
		_pos += _right * units;
}

void Camera::fly(float units)
{
	if( _cameraType == AIRCRAFT )
		_pos += _up * units;
}

void Camera::pitch(float angle)
{
	D3DXMATRIX T;
	D3DXMatrixRotationAxis(&T, &_right,	angle);

	// rotate _up and _look around _right vector
	D3DXVec3TransformCoord(&_up,&_up, &T);
	D3DXVec3TransformCoord(&_look,&_look, &T);
}

void Camera::yaw(float angle)
{
	D3DXMATRIX T;

	// rotate around world y (0, 1, 0) always for land object
	if( _cameraType == LANDOBJECT )
		D3DXMatrixRotationY(&T, angle);

	// rotate around own up vector for aircraft
	if( _cameraType == AIRCRAFT )
		D3DXMatrixRotationAxis(&T, &_up, angle);

	// rotate _right and _look around _up or y-axis
	D3DXVec3TransformCoord(&_right,&_right, &T);
	D3DXVec3TransformCoord(&_look,&_look, &T);
}

void Camera::roll(float angle)
{
	// only roll for aircraft type
	if( _cameraType == AIRCRAFT )
	{
		D3DXMATRIX T;
		D3DXMatrixRotationAxis(&T, &_look,	angle);

		// rotate _up and _right around _look vector
		D3DXVec3TransformCoord(&_right,&_right, &T);
		D3DXVec3TransformCoord(&_up,&_up, &T);
	}
}

void Camera::getViewMatrix(D3DXMATRIX* V)
{
	// Keep camera's axes orthogonal to eachother
	D3DXVec3Normalize(&_look, &_look);

	D3DXVec3Cross(&_up, &_look, &_right);
	D3DXVec3Normalize(&_up, &_up);

	D3DXVec3Cross(&_right, &_up, &_look);
	D3DXVec3Normalize(&_right, &_right);

	// Build the view matrix:
	float x = -D3DXVec3Dot(&_right, &_pos);
	float y = -D3DXVec3Dot(&_up, &_pos);
	float z = -D3DXVec3Dot(&_look, &_pos);

	(*V)(0,0) = _right.x; (*V)(0, 1) = _up.x; (*V)(0, 2) = _look.x; (*V)(0, 3) = 0.0f;
	(*V)(1,0) = _right.y; (*V)(1, 1) = _up.y; (*V)(1, 2) = _look.y; (*V)(1, 3) = 0.0f;
	(*V)(2,0) = _right.z; (*V)(2, 1) = _up.z; (*V)(2, 2) = _look.z; (*V)(2, 3) = 0.0f;
	(*V)(3,0) = x;        (*V)(3, 1) = y;     (*V)(3, 2) = z;       (*V)(3, 3) = 1.0f;
}

void Camera::setCameraType(CameraType cameraType)
{
	_cameraType = cameraType;
}