下載源碼和工程
3D圖形引擎的代碼以創建游戲內核中編寫的代碼為基礎進行開發。
使用單一的網格模型雖然可以同時渲染整個層次，但卻意味著那些沒有被看到的部分在通過渲染管道時會被裁剪掉，也就是說這樣做會浪費時間。不要沮喪，因為使用一個單獨的網格模型進行層次的渲染仍然有一些非常好的方法。比如說，在游戲世界中包括了單獨的地牢，每個地牢包含不同的房間，所有的房間通過走廊連接到一起。其實，每個房間和走廊就是一個單獨的網格模型，所要做的就是在游戲的處理過程中加載以及釋放那些代表地牢房間的網格模型。
我們首先定義一些成員變量來存儲數據。
class APP : public APPLICATION
{
private:
GRAPHICS _graphics;
CAMERA _camera;
INPUT _input;
INPUT_DEVICE _keyboard;
INPUT_DEVICE _mouse;
MESH _room_meshes[2];
OBJECT _room_objects[8];
float _x_pos, _z_pos;
}
初始化窗口：
APP()
{
_width = 640;
_height = 480;
_style = WS_BORDER | WS_CAPTION | WS_MINIMIZEBOX | WS_SYSMENU;
strcpy(_class_name, "mesh level class");
strcpy(_caption, "mesh level demo");
}
加載網格模型：
BOOL init()
{
// initialize graphics and set display mode
_graphics.init();
_graphics.set_mode(get_hwnd(), TRUE, TRUE);
_graphics.set_perspective(D3DX_PI / 4, 1.3333f, 1.0f, 10000.0f);
// initialize input and input device
_input.init(get_hwnd(), get_inst());
_keyboard.create(&_input, KEYBOARD);
_mouse.create(&_input, MOUSE, TRUE);
// load the room meshes
_room_meshes[0].load(&_graphics, "..\\Data\\Corridor.x", "..\\Data\\");
_room_meshes[1].load(&_graphics, "..\\Data\\Room.x", "..\\Data\\");
// setup the room objects
_room_objects[0].create(&_graphics, &_room_meshes[1]);
_room_objects[1].create(&_graphics, &_room_meshes[0]);
_room_objects[2].create(&_graphics, &_room_meshes[1]);
_room_objects[3].create(&_graphics, &_room_meshes[0]);
_room_objects[4].create(&_graphics, &_room_meshes[0]);
_room_objects[5].create(&_graphics, &_room_meshes[1]);
_room_objects[6].create(&_graphics, &_room_meshes[0]);
_room_objects[7].create(&_graphics, &_room_meshes[1]);
// place room object in specified position
_room_objects[0].move(-2000.0f, 0.0f, 2000.0f);
_room_objects[1].move( 0.0f, 0.0f, 2000.0f);
_room_objects[2].move( 2000.0f, 0.0f, 2000.0f);
_room_objects[3].move(-2000.0f, 0.0f, 0.0f);
_room_objects[4].move( 2000.0f, 0.0f, 0.0f);
_room_objects[5].move(-2000.0f, 0.0f, -2000.0f);
_room_objects[6].move( 0.0f, 0.0f, -2000.0f);
_room_objects[7].move( 2000.0f, 0.0f, -2000.0f);
// rotate room object into proper orientation
_room_objects[1].rotate(0.0f, 1.57f, 0.0f);
_room_objects[2].rotate(0.0f, 1.57f, 0.0f);
_room_objects[5].rotate(0.0f, -1.57f, 0.0f);
_room_objects[6].rotate(0.0f, -1.57f, 0.0f);
_room_objects[7].rotate(0.0f, 3.14f, 0.0f);
// position view in a room
_x_pos = -2000.0f;
_z_pos = -2000.0f;
return TRUE;
}
這里加載了兩個網格模型corridor.x 和room.x，一個是走廊，一個是房間。
走廊：
房間：
游戲中的每個走廊和房間都使用了一個OBJECT對象，其與網格模型依次相關聯。
我們接著來看看如何渲染這些網格模型。
BOOL frame()
{
static DWORD time_now = timeGetTime();
// calculate elapsed time (plus speed boost)
ulong time_elapsed = (timeGetTime() - time_now) * 2;
time_now = timeGetTime();
// read input device data
_keyboard.read();
_mouse.read();
// process input and update everything, ESC quits program.
if(_keyboard.get_key_state(KEY_ESC))
return FALSE;
float x_move = 0.0f;
float z_move = 0.0f;
// ok, now let me explain next codes.
//
// _camera.get_y_rotation():
// get camera vector in xoz plane.
//
// sin(_camera.get_y_rotation()):
// get x-coordinate of camera vector.
//
// cos(_camera.get_y_rotation()):
// get z-coordinate of camera vector.
// move viewpoint forward
if(_keyboard.get_key_state(KEY_UP))
{
x_move = (float) sin(_camera.get_y_rotation()) * time_elapsed;
z_move = (float) cos(_camera.get_y_rotation()) * time_elapsed;
}
// move viewpoint backward
if(_keyboard.get_key_state(KEY_DOWN))
{
x_move = -(float) sin(_camera.get_y_rotation()) * time_elapsed;
z_move = -(float) cos(_camera.get_y_rotation()) * time_elapsed;
}
// translate camera left-right movement into up-down movement.
//
// _camera.get_y_rotation() - 1.57f:
// rotate camera 90 degree anticlockwise.
//
// sin(_camera.get_y_rotation() - 1.57f):
// get x-coordinate of camera vector after camera rotation.
//
// cos(_camera.get_y_rotation() - 1.57f):
// get z-coordinate of camera vector after camera rotation.
// move viewpoint left
if(_keyboard.get_key_state(KEY_LEFT))
{
x_move = (float) sin(_camera.get_y_rotation() - 1.57f) * time_elapsed;
z_move = (float) cos(_camera.get_y_rotation() - 1.57f) * time_elapsed;
}
// _camera.get_y_rotation() + 1.57f:
// rotate camera 90 degree clockwise.
//
// sin(_camera.get_y_rotation() + 1.57f):
// get x-coordinate of camera vector after camera rotation.
//
// cos(_camera.get_y_rotation() + 1.57f):
// get z-coordinate of camera vector after camera rotation.
// move viewpoint right
if(_keyboard.get_key_state(KEY_RIGHT))
{
x_move = (float) sin(_camera.get_y_rotation() + 1.57f) * time_elapsed;
z_move = (float) cos(_camera.get_y_rotation() + 1.57f) * time_elapsed;
}
// update view coordinates
_x_pos += x_move;
_z_pos += z_move;
// position camera and rotate based on mouse position
_camera.move(_x_pos, 400.0f, _z_pos);
// _mouse.get_y_delta():
// get mouse's relative x movement coordinate.
//
// _mouse.get_x_delta():
// get mouse's relative y movement coordinate.
_camera.rotate_rel(_mouse.get_y_delta() / 200.0f, _mouse.get_x_delta() / 200.0f, 0.0f);
// set camera
_graphics.set_camera(&_camera);
// render everything
_graphics.clear(D3DCOLOR_RGBA(0, 64, 128, 255));
// begin render now
if(_graphics.begin_scene())
{
// render each room
for(short i = 0; i < 8; i++)
_room_objects[i].render();
_graphics.end_scene();
}
_graphics.display();
return TRUE;
}
用上下左右鍵控制相機的位置，用鼠標控制相機的朝向。
截圖：
