游戏

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Visual C++

demoII14_3.cpp：源码内容
							// DEMOII14_2.CPP - shadow demo with scaling of the shadow and projection 
// on the ground plane based on actual lightsource position
// READ THIS!
// To compile make sure to include DDRAW.LIB, DSOUND.LIB,
// DINPUT.LIB, DINPUT8.LIB, WINMM.LIB in the project link list, and of course 
// the C++ source modules T3DLIB1-12.CPP and the headers T3DLIB1-12.H
// be in the working directory of the compiler
// INCLUDES ///////////////////////////////////////////////
#define DEBUG_ON
#define INITGUID       // make sure al the COM interfaces are available
                       // instead of this you can include the .LIB file
                       // DXGUID.LIB
#define WIN32_LEAN_AND_MEAN  
#include <windows.h>   // include important windows stuff
#include <windowsx.h> 
#include <mmsystem.h>
#include <iostream.h> // include important C/C++ stuff
#include <conio.h> 
#include <stdlib.h> 
#include <malloc.h> 
#include <memory.h> 
#include <string.h>   
#include <stdarg.h>
#include <stdio.h>    
#include <math.h>
#include <io.h>
#include <fcntl.h>
#include <ddraw.h>  // directX includes 
#include <dsound.h> 
#include <dmksctrl.h>
#include <dmusici.h>
#include <dmusicc.h>
#include <dmusicf.h>
#include <dinput.h> 
#include "T3DLIB1.h" // game library includes
#include "T3DLIB2.h"
#include "T3DLIB3.h"
#include "T3DLIB4.h"
#include "T3DLIB5.h"
#include "T3DLIB6.h"
#include "T3DLIB7.h"
#include "T3DLIB8.h"
#include "T3DLIB9.h"
#include "T3DLIB10.h"
#include "T3DLIB11.h"
#include "T3DLIB12.h"
                                 
// DEFINES ////////////////////////////////////////////////
// defines for windows interface
#define WINDOW_CLASS_NAME "WIN3DCLASS"  // class name
#define WINDOW_TITLE      "T3D Graphics Console Ver 2.0"
#define WINDOW_WIDTH      800  // size of window
#define WINDOW_HEIGHT     600
#define WINDOW_BPP        16    // bitdepth of window (8,16,24 etc.)
                                // note: if windowed and not
                                // fullscreen then bitdepth must
                                // be same as system bitdepth
                                // also if 8-bit the a pallete
                                // is created and attached
   
#define WINDOWED_APP      0 // 0 not windowed, 1 windowed
// create some constants for ease of access
#define AMBIENT_LIGHT_INDEX   0 // ambient light index
#define INFINITE_LIGHT_INDEX  1 // infinite light index
#define POINT_LIGHT_INDEX     2 // point light index
#define POINT_LIGHT2_INDEX    3 // point light index
// terrain defines
#define TERRAIN_WIDTH         4000
#define TERRAIN_HEIGHT        4000
#define TERRAIN_SCALE         700
#define MAX_SPEED             20
#define PITCH_RETURN_RATE (.33) // how fast the pitch straightens out
#define PITCH_CHANGE_RATE (.02) // the rate that pitch changes relative to height
#define CAM_HEIGHT_SCALER (.3)  // percentage cam height changes relative to height
#define VELOCITY_SCALER (.025)  // rate velocity changes with height
#define CAM_DECEL       (.25)   // deceleration/friction
#define NUM_OBJECTS          3 // number of objects per class
#define NUM_LIGHT_OBJECTS    5 // number of light models
// PROTOTYPES /////////////////////////////////////////////
// game console
int Game_Init(void *parms=NULL);
int Game_Shutdown(void *parms=NULL);
int Game_Main(void *parms=NULL);
// GLOBALS ////////////////////////////////////////////////
HWND main_window_handle           = NULL; // save the window handle
HINSTANCE main_instance           = NULL; // save the instance
char buffer[2048];                        // used to print text
// initialize camera position and direction
POINT4D  cam_pos    = {0,500,-400,1};
POINT4D  cam_target = {0,0,0,1};
VECTOR4D cam_dir    = {0,0,0,1};
// all your initialization code goes here...
VECTOR4D vscale={1.0,1.0,1.0,1}, 
         vpos = {0,0,150,1}, 
         vrot = {0,0,0,1};
CAM4DV1         cam;            // the single camera
OBJECT4DV2      obj_terrain;    // the terrain object
OBJECT4DV2_PTR  obj_work;
OBJECT4DV2      obj_array[NUM_OBJECTS]; 
OBJECT4DV2_PTR  obj_light;
OBJECT4DV2      obj_light_array[NUM_LIGHT_OBJECTS];
OBJECT4DV2      shadow_obj; 
// filenames of objects to load
char *object_filenames[NUM_OBJECTS] = {
                                        "earth01.cob",
                                        "sphere_gouraud_textured_02.cob",  
                                        "fire_constant_cube01.cob",
                                      };
int curr_object  = 0;
#define INDEX_RED_LIGHT_INDEX       0
#define INDEX_GREEN_LIGHT_INDEX     1
#define INDEX_BLUE_LIGHT_INDEX      2
#define INDEX_YELLOW_LIGHT_INDEX    3
#define INDEX_WHITE_LIGHT_INDEX     4
// filenames of objects to load
char *object_light_filenames[NUM_LIGHT_OBJECTS] = {
                                            "cube_constant_red_01.cob",
                                            "cube_constant_green_01.cob",  
                                            "cube_constant_blue_01.cob",
                                            "cube_constant_yellow_01.cob",
                                            "cube_constant_white_01.cob",
                                            };
int curr_light_object  = 0;
RENDERLIST4DV2  rend_list;      // the render list
RGBAV1          white,          // general colors 
                gray, 
                black, 
                red, 
                green, 
                blue,
                yellow,
                orange; 
ZBUFFERV1 zbuffer;   // our little z buffer!
RENDERCONTEXTV1  rc; // the rendering context;
// physical model defines play with these to change the feel of the vehicle
float gravity       = -.40;    // general gravity
float vel_y         = 0;       // the y velocity of camera/jeep
float cam_speed     = 0;       // speed of the camera/jeep
float sea_level     = 50;      // sea level of the simulation
float gclearance    = 125;      // clearance from the camera to the ground
float neutral_pitch = 10;   // the neutral pitch of the camera
// sounds
int wind_sound_id = -1;
// game imagery assets
BOB cockpit;               // the cockpit image
// FUNCTIONS //////////////////////////////////////////////
LRESULT CALLBACK WindowProc(HWND hwnd, 
						    UINT msg, 
                            WPARAM wparam, 
                            LPARAM lparam)
{
// this is the main message handler of the system
PAINTSTRUCT	ps;		   // used in WM_PAINT
HDC			hdc;	   // handle to a device context
// what is the message 
switch(msg)
	{	
	case WM_CREATE: 
        {
		// do initialization stuff here
		return(0);
		} break;
    case WM_PAINT:
         {
         // start painting
         hdc = BeginPaint(hwnd,&ps);
         // end painting
         EndPaint(hwnd,&ps);
         return(0);
        } break;
	case WM_DESTROY: 
		{
		// kill the application			
		PostQuitMessage(0);
		return(0);
		} break;
	default:break;
    } // end switch
// process any messages that we didn't take care of 
return (DefWindowProc(hwnd, msg, wparam, lparam));
} // end WinProc
// WINMAIN ////////////////////////////////////////////////
int WINAPI WinMain(	HINSTANCE hinstance,
					HINSTANCE hprevinstance,
					LPSTR lpcmdline,
					int ncmdshow)
{
// this is the winmain function
WNDCLASS winclass;	// this will hold the class we create
HWND	 hwnd;		// generic window handle
MSG		 msg;		// generic message
HDC      hdc;       // generic dc
PAINTSTRUCT ps;     // generic paintstruct
// first fill in the window class stucture
winclass.style			= CS_DBLCLKS | CS_OWNDC | 
                          CS_HREDRAW | CS_VREDRAW;
winclass.lpfnWndProc	= WindowProc;
winclass.cbClsExtra		= 0;
winclass.cbWndExtra		= 0;
winclass.hInstance		= hinstance;
winclass.hIcon			= LoadIcon(NULL, IDI_APPLICATION);
winclass.hCursor		= LoadCursor(NULL, IDC_ARROW);
winclass.hbrBackground	= (HBRUSH)GetStockObject(BLACK_BRUSH);
winclass.lpszMenuName	= NULL; 
winclass.lpszClassName	= WINDOW_CLASS_NAME;
// register the window class
if (!RegisterClass(&winclass))
	return(0);
// create the window, note the test to see if WINDOWED_APP is
// true to select the appropriate window flags
if (!(hwnd = CreateWindow(WINDOW_CLASS_NAME, // class
						  WINDOW_TITLE,	 // title
						  (WINDOWED_APP ? (WS_OVERLAPPED | WS_SYSMENU | WS_CAPTION) : (WS_POPUP | WS_VISIBLE)),
					 	  0,0,	   // x,y
						  WINDOW_WIDTH,  // width
                          WINDOW_HEIGHT, // height
						  NULL,	   // handle to parent 
						  NULL,	   // handle to menu
						  hinstance,// instance
						  NULL)))	// creation parms
return(0);
// save the window handle and instance in a global
main_window_handle = hwnd;
main_instance      = hinstance;
// resize the window so that client is really width x height
if (WINDOWED_APP)
{
// now resize the window, so the client area is the actual size requested
// since there may be borders and controls if this is going to be a windowed app
// if the app is not windowed then it won't matter
RECT window_rect = {0,0,WINDOW_WIDTH-1,WINDOW_HEIGHT-1};
// make the call to adjust window_rect
AdjustWindowRectEx(&window_rect,
     GetWindowStyle(main_window_handle),
     GetMenu(main_window_handle) != NULL,  
     GetWindowExStyle(main_window_handle));
// save the global client offsets, they are needed in DDraw_Flip()
window_client_x0 = -window_rect.left;
window_client_y0 = -window_rect.top;
// now resize the window with a call to MoveWindow()
MoveWindow(main_window_handle,
           0,                                    // x position
           0,                                    // y position
           window_rect.right - window_rect.left, // width
           window_rect.bottom - window_rect.top, // height
           FALSE);
// show the window, so there's no garbage on first render
ShowWindow(main_window_handle, SW_SHOW);
} // end if windowed
// perform all game console specific initialization
Game_Init();
// disable CTRL-ALT_DEL, ALT_TAB, comment this line out 
// if it causes your system to crash
SystemParametersInfo(SPI_SCREENSAVERRUNNING, TRUE, NULL, 0);
// enter main event loop
while(1)
	{
	if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
		{ 
		// test if this is a quit
        if (msg.message == WM_QUIT)
           break;
	
		// translate any accelerator keys
		TranslateMessage(&msg);
		// send the message to the window proc
		DispatchMessage(&msg);
		} // end if
    
    // main game processing goes here
    Game_Main();
	} // end while
// shutdown game and release all resources
Game_Shutdown();
// enable CTRL-ALT_DEL, ALT_TAB, comment this line out 
// if it causes your system to crash
SystemParametersInfo(SPI_SCREENSAVERRUNNING, FALSE, NULL, 0);
// return to Windows like this
return(msg.wParam);
} // end WinMain
// T3D II GAME PROGRAMMING CONSOLE FUNCTIONS ////////////////
int Game_Init(void *parms)
{
// this function is where you do all the initialization 
// for your game
int index; // looping var
// start up DirectDraw (replace the parms as you desire)
DDraw_Init2(WINDOW_WIDTH, WINDOW_HEIGHT, WINDOW_BPP, WINDOWED_APP,0);
// initialize directinput
DInput_Init();
// acquire the keyboard 
DInput_Init_Keyboard();
// add calls to acquire other directinput devices here...
// initialize directsound and directmusic
DSound_Init();
DMusic_Init();
// hide the mouse
if (!WINDOWED_APP)
    ShowCursor(FALSE);
// seed random number generator
srand(Start_Clock()); 
Open_Error_File("ERROR.TXT");
// initialize math engine
Build_Sin_Cos_Tables();
// initialize the camera with 90 FOV, normalized coordinates
Init_CAM4DV1(&cam,            // the camera object
             CAM_MODEL_EULER, // the euler model
             &cam_pos,        // initial camera position
             &cam_dir,        // initial camera angles
             &cam_target,     // no target
             10.0,            // near and far clipping planes
             12000.0,
             90.0,            // field of view in degrees
             WINDOW_WIDTH,    // size of final screen viewport
             WINDOW_HEIGHT);
VECTOR4D terrain_pos = {0,0,0,0}; 
Generate_Terrain_OBJECT4DV2(&obj_terrain,            // pointer to object
                            TERRAIN_WIDTH,           // width in world coords on x-axis
                            TERRAIN_HEIGHT,          // height (length) in world coords on z-axis
                            TERRAIN_SCALE,           // vertical scale of terrain
                            "height_grass_40_40_01.bmp",  // filename of height bitmap encoded in 256 colors
                            "stone256_256_01.bmp", // "grass256_256_01.bmp", //"checker2562562.bmp",   // filename of texture map
                             RGB16Bit(255,255,255),  // color of terrain if no texture        
                             &terrain_pos,           // initial position
                             NULL,                   // initial rotations
                             POLY4DV2_ATTR_RGB16  
                             //| POLY4DV2_ATTR_SHADE_MODE_FLAT 
                             | POLY4DV2_ATTR_SHADE_MODE_GOURAUD
                             | POLY4DV2_ATTR_SHADE_MODE_TEXTURE);
// set a scaling vector
VECTOR4D_INITXYZ(&vscale, 40, 40, 40);  
// load all the objects in
for (int index_obj=0; index_obj < NUM_OBJECTS; index_obj++)
    {
    Load_OBJECT4DV2_COB2(&obj_array[index_obj], object_filenames[index_obj],  
                        &vscale, &vpos, &vrot, VERTEX_FLAGS_INVERT_WINDING_ORDER 
                                               | VERTEX_FLAGS_TRANSFORM_LOCAL 
                                               | VERTEX_FLAGS_TRANSFORM_LOCAL_WORLD
                                               ,0 );
    // angle for circular rotation
    obj_array[index_obj].ivar1 = 0;
    // set initial position
    obj_array[index_obj].world_pos.x = 0;
    obj_array[index_obj].world_pos.y = 200;
    obj_array[index_obj].world_pos.z = 0;
    
    } // end for index_obj
// set current object
curr_object = 0;
obj_work    = &obj_array[curr_object];
// set a scaling vector
VECTOR4D_INITXYZ(&vscale, 20, 20, 20); 
// load all the light objects in
for (index_obj=0; index_obj < NUM_LIGHT_OBJECTS; index_obj++)
    {
    Load_OBJECT4DV2_COB2(&obj_light_array[index_obj], object_light_filenames[index_obj],  
                        &vscale, &vpos, &vrot, VERTEX_FLAGS_INVERT_WINDING_ORDER 
                                               | VERTEX_FLAGS_TRANSFORM_LOCAL 
                                               | VERTEX_FLAGS_TRANSFORM_LOCAL_WORLD
                                              ,0 );
    } // end for index
   
// set current object
curr_light_object = 0;
obj_light    = &obj_light_array[curr_light_object];
// load the shadow object in
VECTOR4D_INITXYZ(&vscale, 1, 1, 1); 
Load_OBJECT4DV2_COB2(&shadow_obj,"shadow_poly_01.cob",  
                    &vscale, &vpos, &vrot, VERTEX_FLAGS_INVERT_WINDING_ORDER | VERTEX_FLAGS_SWAP_YZ 
                                          | VERTEX_FLAGS_TRANSFORM_LOCAL 
                                          | VERTEX_FLAGS_TRANSFORM_LOCAL_WORLD
                                          ,0 );
// set up lights
Reset_Lights_LIGHTV2(lights2, MAX_LIGHTS);
// create some working colors
white.rgba = _RGBA32BIT(255,255,255,0);
gray.rgba  = _RGBA32BIT(100,100,100,0);
black.rgba = _RGBA32BIT(0,0,0,0);
red.rgba   = _RGBA32BIT(255,0,0,0);
green.rgba = _RGBA32BIT(0,255,0,0);
blue.rgba  = _RGBA32BIT(0,0,255,0);
orange.rgba = _RGBA32BIT(255,128,0,0);
yellow.rgba  = _RGBA32BIT(255,255,0,0);
// ambient light
Init_Light_LIGHTV2(lights2,
                   AMBIENT_LIGHT_INDEX,   
                   LIGHTV2_STATE_ON,      // turn the light on
                   LIGHTV2_ATTR_AMBIENT,  // ambient light type
                   gray, black, black,    // color for ambient term only
                   NULL, NULL,            // no need for pos or dir
                   0,0,0,                 // no need for attenuation
                   0,0,0);                // spotlight info NA
VECTOR4D dlight_dir = {-1,1,-1,1};
// directional light
Init_Light_LIGHTV2(lights2,
                   INFINITE_LIGHT_INDEX,  
                   LIGHTV2_STATE_ON,      // turn the light on
                   LIGHTV2_ATTR_INFINITE, // infinite light type
                   black, gray, black,    // color for diffuse term only
                   NULL, &dlight_dir,     // need direction only
                   0,0,0,                 // no need for attenuation
                   0,0,0);                // spotlight info NA
VECTOR4D plight_pos = {0,500,0,1};
// point light
Init_Light_LIGHTV2(lights2,
                   POINT_LIGHT_INDEX,
                   LIGHTV2_STATE_ON,      // turn the light on
                   LIGHTV2_ATTR_POINT,    // pointlight type
                   black, green, black,   // color for diffuse term only
                   &plight_pos, NULL,     // need pos only
                   0,.001,0,              // linear attenuation only
                   0,0,1);                // spotlight info NA
// point light
Init_Light_LIGHTV2(lights2,
                   POINT_LIGHT2_INDEX,
                   LIGHTV2_STATE_ON,     // turn the light on
                   LIGHTV2_ATTR_POINT,   // pointlight type
                   black, red, black,  // color for diffuse term only
                   &plight_pos, NULL,    // need pos only
                   0,.002,0,             // linear attenuation only
                   0,0,1);               // spotlight info NA
VECTOR4D slight2_pos = {0,200,0,1};
VECTOR4D slight2_dir = {-1,1,-1,1};
// create lookup for lighting engine
RGB_16_8_IndexedRGB_Table_Builder(DD_PIXEL_FORMAT565,  // format we want to build table for
                                  palette,             // source palette
                                  rgblookup);          // lookup table
// create the z buffer
Create_Zbuffer(&zbuffer,
               WINDOW_WIDTH,
               WINDOW_HEIGHT,
               ZBUFFER_ATTR_32BIT);
 
// build alpha lookup table
RGB_Alpha_Table_Builder(NUM_ALPHA_LEVELS, rgb_alpha_table);
// load background sounds
wind_sound_id = DSound_Load_WAV("STATIONTHROB.WAV");
// start the sounds
DSound_Play(wind_sound_id, DSBPLAY_LOOPING);
DSound_Set_Volume(wind_sound_id, 100);
#if 1
// load in the cockpit image
Create_BOB(&cockpit, 0,0,800,600,2, BOB_ATTR_VISIBLE | BOB_ATTR_SINGLE_FRAME, DDSCAPS_SYSTEMMEMORY, 0, 16); 
Load_Bitmap_File(&bitmap16bit, "lego02.BMP");
Load_Frame_BOB16(&cockpit, &bitmap16bit,0,0,0,BITMAP_EXTRACT_MODE_ABS);
Unload_Bitmap_File(&bitmap16bit);
Load_Bitmap_File(&bitmap16bit, "lego02b.BMP");
Load_Frame_BOB16(&cockpit, &bitmap16bit,1,0,0,BITMAP_EXTRACT_MODE_ABS);
Unload_Bitmap_File(&bitmap16bit);
#endif
// set single precission
//_control87( _PC_24, MCW_PC );
// return success
return(1);
} // end Game_Init
///////////////////////////////////////////////////////////
int Game_Shutdown(void *parms)
{
// this function is where you shutdown your game and
// release all resources that you allocated
// shut everything down
// release all your resources created for the game here....
// now directsound
DSound_Stop_All_Sounds();
DSound_Delete_All_Sounds();
DSound_Shutdown();
// directmusic
DMusic_Delete_All_MIDI();
DMusic_Shutdown();
// shut down directinput
DInput_Release_Keyboard();
// shutdown directinput
DInput_Shutdown();
// shutdown directdraw last
DDraw_Shutdown();
Close_Error_File();
// return success
return(1);
} // end Game_Shutdown
//////////////////////////////////////////////////////////
int Game_Main(void *parms)
{
// this is the workhorse of your game it will be called
// continuously in real-time this is like main() in C
// all the calls for you game go here!
static MATRIX4X4 mrot;   // general rotation matrix
static float plight_ang = 0, 
             slight_ang = 0; // angles for light motion
// use these to rotate objects
static float x_ang = 0, y_ang = 0, z_ang = 0;
// state variables for different rendering modes and help
static int wireframe_mode   = 1;
static int backface_mode    = 1;
static int lighting_mode    = 1;
static int help_mode        = 1;
static int zsort_mode       = 1;
static int x_clip_mode      = 1;
static int y_clip_mode      = 1;
static int z_clip_mode      = 1;
static float hl = 300, // artificial light height
             ks = 1.25; // generic scaling factor to make things look good
char work_string[256]; // temp string
int index; // looping var
// start the timing clock
Start_Clock();
// clear the drawing surface 
DDraw_Fill_Surface(lpddsback, 0);
// draw the sky
Draw_Rectangle(0,0, WINDOW_WIDTH-1, WINDOW_HEIGHT-1, RGB16Bit(50,50,200), lpddsback);
// draw the ground
//Draw_Rectangle(0,WINDOW_HEIGHT*.38, WINDOW_WIDTH, WINDOW_HEIGHT, RGB16Bit(25,50,110), lpddsback);
// read keyboard and other devices here
DInput_Read_Keyboard();
// game logic here...
// reset the render list
Reset_RENDERLIST4DV2(&rend_list);
// modes and lights
// wireframe mode
if (keyboard_state[DIK_W]) 
   {
   // toggle wireframe mode
   if (++wireframe_mode > 1)
       wireframe_mode=0;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// backface removal
if (keyboard_state[DIK_B])
   {
   // toggle backface removal
   backface_mode = -backface_mode;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// lighting
if (keyboard_state[DIK_L])
   {
   // toggle lighting engine completely
   lighting_mode = -lighting_mode;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// toggle ambient light
if (keyboard_state[DIK_A])
   {
   // toggle ambient light
   if (lights2[AMBIENT_LIGHT_INDEX].state == LIGHTV2_STATE_ON)
      lights2[AMBIENT_LIGHT_INDEX].state = LIGHTV2_STATE_OFF;
   else
      lights2[AMBIENT_LIGHT_INDEX].state = LIGHTV2_STATE_ON;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// toggle infinite light
if (keyboard_state[DIK_I])
   {
   // toggle ambient light
   if (lights2[INFINITE_LIGHT_INDEX].state == LIGHTV2_STATE_ON)
      lights2[INFINITE_LIGHT_INDEX].state = LIGHTV2_STATE_OFF;
   else
      lights2[INFINITE_LIGHT_INDEX].state = LIGHTV2_STATE_ON;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// toggle point light
if (keyboard_state[DIK_P])
   {
   // toggle point light
   if (lights2[POINT_LIGHT_INDEX].state == LIGHTV2_STATE_ON)
      lights2[POINT_LIGHT_INDEX].state = LIGHTV2_STATE_OFF;
   else
      lights2[POINT_LIGHT_INDEX].state = LIGHTV2_STATE_ON;
   // toggle point light
   if (lights2[POINT_LIGHT2_INDEX].state == LIGHTV2_STATE_ON)
      lights2[POINT_LIGHT2_INDEX].state = LIGHTV2_STATE_OFF;
   else
      lights2[POINT_LIGHT2_INDEX].state = LIGHTV2_STATE_ON;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// help menu
if (keyboard_state[DIK_H])
   {
   // toggle help menu 
   help_mode = -help_mode;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// z-sorting
if (keyboard_state[DIK_Z])
   {
   // toggle z sorting
   zsort_mode = -zsort_mode;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// move to next object
if (keyboard_state[DIK_O])
   {
   VECTOR4D old_pos;
   old_pos = obj_work->world_pos;
   if (++curr_object >= NUM_OBJECTS)
      curr_object = 0;
   // update pointer
   obj_work = &obj_array[curr_object];
   obj_work->world_pos = old_pos;
   Wait_Clock(100); // wait, so keyboard doesn't bounce
   } // end if
// forward/backward
if (keyboard_state[DIK_UP])
   {
   // move forward
   if ( (cam_speed+=1) > MAX_SPEED) cam_speed = MAX_SPEED;
   } // end if
else
if (keyboard_state[DIK_DOWN])
   {
   // move backward
   if ((cam_speed-=1) < -MAX_SPEED) cam_speed = -MAX_SPEED;
   } // end if
// rotate around y axis or yaw
if (keyboard_state[DIK_RIGHT])
   {
   cam.dir.y+=5;
   } // end if
if (keyboard_state[DIK_LEFT])
   {
   cam.dir.y-=5;
   } // end if
// change height of point light source 1
if (keyboard_state[DIK_1])
   {
   lights2[POINT_LIGHT_INDEX].pos.y-=10;
   } // end if
if (keyboard_state[DIK_2])
   {
   lights2[POINT_LIGHT_INDEX].pos.y+=10;
   } // end if
// change height of point light source 2
if (keyboard_state[DIK_3])
   {
   lights2[POINT_LIGHT2_INDEX].pos.y-=10;
   } // end if
if (keyboard_state[DIK_4])
   {
   lights2[POINT_LIGHT2_INDEX].pos.y+=10;
   } // end if
// motion section /////////////////////////////////////////////////////////
// terrain following, simply find the current cell we are over and then
// index into the vertex list and find the 4 vertices that make up the 
// quad cell we are hovering over and then average the values, and based
// on the current height and the height of the terrain push the player upward
// the terrain generates and stores some results to help with terrain following
//ivar1 = columns;
//ivar2 = rows;
//fvar1 = col_vstep;
//fvar2 = row_vstep;
int cell_x = (cam.pos.x  + TERRAIN_WIDTH/2) / obj_terrain.fvar1;
int cell_y = (cam.pos.z  + TERRAIN_HEIGHT/2) / obj_terrain.fvar1;
static float terrain_height, delta;
// test if we are on terrain
if ( (cell_x >=0) && (cell_x < obj_terrain.ivar1) && (cell_y >=0) && (cell_y < obj_terrain.ivar2) )
   {
   // compute vertex indices into vertex list of the current quad
   int v0 = cell_x + cell_y*obj_terrain.ivar2;
   int v1 = v0 + 1;
   int v2 = v1 + obj_terrain.ivar2;
   int v3 = v0 + obj_terrain.ivar2;   
   // now simply index into table 
   terrain_height = 0.25 * (obj_terrain.vlist_trans[v0].y + obj_terrain.vlist_trans[v1].y +
                            obj_terrain.vlist_trans[v2].y + obj_terrain.vlist_trans[v3].y);
   // compute height difference
   delta = terrain_height - (cam.pos.y - gclearance);
   // test for penetration
   if (delta > 0)
      {
      // apply force immediately to camera (this will give it a springy feel)
      vel_y+=(delta * (VELOCITY_SCALER));
      // test for pentration, if so move up immediately so we don't penetrate geometry
      cam.pos.y+=(delta*CAM_HEIGHT_SCALER);
      // now this is more of a hack than the physics model :) let move the front
      // up and down a bit based on the forward velocity and the gradient of the 
      // hill
      cam.dir.x -= (delta*PITCH_CHANGE_RATE);
 
      } // end if
   } // end if
// decelerate camera
if (cam_speed > (CAM_DECEL) ) cam_speed-=CAM_DECEL;
else
if (cam_speed < (-CAM_DECEL) ) cam_speed+=CAM_DECEL;
else
   cam_speed = 0;
// force camera to seek a stable orientation
if (cam.dir.x > (neutral_pitch+PITCH_RETURN_RATE)) cam.dir.x -= (PITCH_RETURN_RATE);
else
if (cam.dir.x < (neutral_pitch-PITCH_RETURN_RATE)) cam.dir.x += (PITCH_RETURN_RATE);
 else 
   cam.dir.x = neutral_pitch;
// apply gravity
vel_y+=gravity;
// test for absolute sea level and push upward..
if (cam.pos.y < sea_level)
   { 
   vel_y = 0; 
   cam.pos.y = sea_level;
   } // end if
// move camera
cam.pos.x += cam_speed*Fast_Sin(cam.dir.y);
cam.pos.z += cam_speed*Fast_Cos(cam.dir.y);
cam.pos.y += vel_y;
// move point light source in ellipse around game world
lights2[POINT_LIGHT_INDEX].pos.x = 500*Fast_Cos(plight_ang);
//lights2[POINT_LIGHT_INDEX].pos.y = 200;
lights2[POINT_LIGHT_INDEX].pos.z = 500*Fast_Sin(plight_ang);
// move point light source in ellipse around game world
lights2[POINT_LIGHT2_INDEX].pos.x = 200*Fast_Cos(-2*plight_ang);
//lights2[POINT_LIGHT2_INDEX].pos.y = 400;
lights2[POINT_LIGHT2_INDEX].pos.z = 200*Fast_Sin(-2*plight_ang);
if ((plight_ang+=1) > 360)
    plight_ang = 0;
// generate camera matrix
Build_CAM4DV1_Matrix_Euler(&cam, CAM_ROT_SEQ_ZYX);
//////////////////////////////////////////////////////////////////////////
// the terrain
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(&obj_terrain);
// generate rotation matrix around y axis
//Build_XYZ_Rotation_MATRIX4X4(x_ang, y_ang, z_ang, &mrot);
MAT_IDENTITY_4X4(&mrot); 
// rotate the local coords of the object
Transform_OBJECT4DV2(&obj_terrain, &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(&obj_terrain, TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, &obj_terrain,0);
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
// shaded object
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(obj_work);
// set position of object 
// update rotation angle of object
obj_work->ivar1+=1.0;
if (obj_work->ivar1 >= 360)
    obj_work->ivar1 = 0;
obj_work->world_pos.x = 150*Fast_Cos(obj_work->ivar1);
obj_work->world_pos.y = 200+75*Fast_Sin(obj_work->ivar1);
obj_work->world_pos.z = 150*Fast_Sin(obj_work->ivar1);
// generate rotation matrix around y axis
Build_XYZ_Rotation_MATRIX4X4(x_ang, y_ang, z_ang, &mrot);
// rotate the local coords of the object
Transform_OBJECT4DV2(obj_work, &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(obj_work, TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, obj_work,0);
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
// draw all the light objects to represent the position of light sources
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(&obj_light_array[INDEX_GREEN_LIGHT_INDEX]);
// set position of object to light
obj_light_array[INDEX_GREEN_LIGHT_INDEX].world_pos = lights2[POINT_LIGHT_INDEX].pos;
// create identity matrix
MAT_IDENTITY_4X4(&mrot);
// transform the local coords of the object
Transform_OBJECT4DV2(&obj_light_array[INDEX_GREEN_LIGHT_INDEX], &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(&obj_light_array[INDEX_GREEN_LIGHT_INDEX], TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, &obj_light_array[INDEX_GREEN_LIGHT_INDEX],0);
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(&obj_light_array[INDEX_RED_LIGHT_INDEX]);
// set position of object to light
obj_light_array[INDEX_RED_LIGHT_INDEX].world_pos = lights2[POINT_LIGHT2_INDEX].pos;
// create identity matrix
MAT_IDENTITY_4X4(&mrot);
// transform the local coords of the object
Transform_OBJECT4DV2(&obj_light_array[INDEX_RED_LIGHT_INDEX], &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(&obj_light_array[INDEX_RED_LIGHT_INDEX], TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, &obj_light_array[INDEX_RED_LIGHT_INDEX],0);
////////////////////////////////////////////////////////////////////////////////////
// reset number of polys rendered
debug_polys_rendered_per_frame = 0;
debug_polys_lit_per_frame = 0;
// perform first rendering pass
// remove backfaces
if (backface_mode==1)
   Remove_Backfaces_RENDERLIST4DV2(&rend_list, &cam);
// apply world to camera transform
World_To_Camera_RENDERLIST4DV2(&rend_list, &cam);
// clip the polygons themselves now
Clip_Polys_RENDERLIST4DV2(&rend_list, &cam, CLIP_POLY_X_PLANE | CLIP_POLY_Y_PLANE | CLIP_POLY_Z_PLANE );
// light scene all at once 
if (lighting_mode==1)
   {
   Transform_LIGHTSV2(lights2, 4, &cam.mcam, TRANSFORM_LOCAL_TO_TRANS);
   Light_RENDERLIST4DV2_World2_16(&rend_list, &cam, lights2, 4);
   } // end if
// sort the polygon list (hurry up!)
if (zsort_mode == 1)
   Sort_RENDERLIST4DV2(&rend_list,  SORT_POLYLIST_AVGZ);
// apply camera to perspective transformation
Camera_To_Perspective_RENDERLIST4DV2(&rend_list, &cam);
// apply screen transform
Perspective_To_Screen_RENDERLIST4DV2(&rend_list, &cam);
// lock the back buffer
DDraw_Lock_Back_Surface();
// reset number of polys rendered
debug_polys_rendered_per_frame = 0;
// render the object
if (wireframe_mode  == 0)
   Draw_RENDERLIST4DV2_Wire16(&rend_list, back_buffer, back_lpitch);
else
if (wireframe_mode  == 1)
   {
   // perspective mode affine texturing
      // set up rendering context
      rc.attr =    RENDER_ATTR_ZBUFFER  
              // | RENDER_ATTR_ALPHA  
              // | RENDER_ATTR_MIPMAP  
              // | RENDER_ATTR_BILERP
                 | RENDER_ATTR_TEXTURE_PERSPECTIVE_AFFINE;
   // initialize zbuffer to 0 fixed point
   Clear_Zbuffer(&zbuffer, (16000 << FIXP16_SHIFT));
   // set up remainder of rendering context
   rc.video_buffer   = back_buffer;
   rc.lpitch         = back_lpitch;
   rc.mip_dist       = 0;
   rc.zbuffer        = (UCHAR *)zbuffer.zbuffer;
   rc.zpitch         = WINDOW_WIDTH*4;
   rc.rend_list      = &rend_list;
   rc.texture_dist   = 0;
   rc.alpha_override = -1;
   // render scene
   Draw_RENDERLIST4DV2_RENDERCONTEXTV1_16_2(&rc);
   } // end if
// now make second rendering pass and draw shadow
// reset the render list
Reset_RENDERLIST4DV2(&rend_list);
// reset shadow image for car, if in shadow change to 0
cockpit.curr_frame = 0;
int v0, v1, v2, v3; // used to track vertices
VECTOR4D pl,  // position of the light
         po,  // position of the occluder object
         vlo, // vector from light to object
         ps;  // position of the shadow
float    rs,  // radius of shadow 
         t;   // parameter t
//////////////////////////////////////////////////////////////////////////
// shadow object
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(&shadow_obj);
// compute terrain cell shadow is over
cell_x = (obj_work->world_pos.x  + TERRAIN_WIDTH/2) / obj_terrain.fvar1;
cell_y = (obj_work->world_pos.z  + TERRAIN_HEIGHT/2) / obj_terrain.fvar1;
// compute vertex indices into vertex list of the current quad
v0 = cell_x + cell_y*obj_terrain.ivar2;
v1 = v0 + 1;
v2 = v1 + obj_terrain.ivar2;
v3 = v0 + obj_terrain.ivar2;   
// now simply index into table 
terrain_height = MAX(    MAX(obj_terrain.vlist_trans[v0].y, obj_terrain.vlist_trans[v1].y), 
                         MAX(obj_terrain.vlist_trans[v2].y, obj_terrain.vlist_trans[v3].y) );
// update position
//shadow_obj.world_pos   = obj_work->world_pos;
shadow_obj.world_pos.y = terrain_height+25;
// using point light source 1 as the projector, compute target projection
// position, use local variables to make the math easier to understand
// assign light position from point light
pl = lights2[POINT_LIGHT_INDEX].pos;
// assign object position
po = obj_work->world_pos;
// create vector from lightsource to object
VECTOR4D_Build(&pl, &po, &vlo);
// now, comes the fun part, solve for t when y=0 of the projector line
// technically, we are placing the shadow slightly higher in the math above,
// so if you like, you can change the solution of t to take that into consideration
// but this is cleaner for now
t = -pl.y / vlo.y;
// now compute x,z of projected shadow position (scale t by .5 to keep the shadow close)
shadow_obj.world_pos.x = pl.x + t*vlo.x;
shadow_obj.world_pos.z = pl.z + t*vlo.z;
// now compute the size of the shadow radius based on the calculations shown in the book
// the size of the projected shadow, assuming a sphere as the occluder with a point lightsource
// height hl above the ground plane, a spherical object with radius ro, and height above
// the groundplane ho, the radius of the shadow is rs:
//
//    rs = ro * (hl)/(hl - ho)
// set height to altitude of light
hl = lights2[POINT_LIGHT_INDEX].pos.y;
// use the average radius of the object to base calcs on, better than nothing
rs = ks * ( obj_work->avg_radius[0] * (hl/ (hl - obj_work->world_pos.y)) );
// generate scaling matrix bases on shadow scale
MAT_IDENTITY_4X4(&mrot);
// set scaling values to scale in X-Z plane
mrot.M00 = rs;
mrot.M11 = 1.0;
mrot.M22 = rs;
// scale the local coords of the object
Transform_OBJECT4DV2(&shadow_obj, &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(&shadow_obj, TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, &shadow_obj,0);
//////////////////////////////////////////////////////////////////////////
// test if camera is in shadow
VECTOR4D vd;
VECTOR4D_Build(&cam.pos, &shadow_obj.world_pos, &vd);
float d = VECTOR4D_Length_Fast(&vd);
// test if distance is within 1.5 times the radius of the shadow, the 1.5 makes it
// a little more noticeable
if (d < 1.5*rs)
   cockpit.curr_frame = 1; // cockpit with lower brightness
//////////////////////////////////////////////////////////////////////////
// shadow object
// reset the object (this only matters for backface and object removal)
Reset_OBJECT4DV2(&shadow_obj);
// compute terrain cell shadow is over
cell_x = (obj_work->world_pos.x  + TERRAIN_WIDTH/2) / obj_terrain.fvar1;
cell_y = (obj_work->world_pos.z  + TERRAIN_HEIGHT/2) / obj_terrain.fvar1;
// compute vertex indices into vertex list of the current quad
v0 = cell_x + cell_y*obj_terrain.ivar2;
v1 = v0 + 1;
v2 = v1 + obj_terrain.ivar2;
v3 = v0 + obj_terrain.ivar2;   
// now simply index into table 
terrain_height = MAX(    MAX(obj_terrain.vlist_trans[v0].y, obj_terrain.vlist_trans[v1].y), 
                         MAX(obj_terrain.vlist_trans[v2].y, obj_terrain.vlist_trans[v3].y) );
// update position
//shadow_obj.world_pos   = obj_work->world_pos;
shadow_obj.world_pos.y = terrain_height+25;
// using point light source 1 as the projector, compute target projection
// position, use local variables to make the math easier to understand
// assign light position from point light
pl = lights2[POINT_LIGHT2_INDEX].pos;
// assign object position
po = obj_work->world_pos;
// create vector from lightsource to object
VECTOR4D_Build(&pl, &po, &vlo);
// now, comes the fun part, solve for t when y=0 of the projector line
// technically, we are placing the shadow slightly higher in the math above,
// so if you like, you can change the solution of t to take that into consideration
// but this is cleaner for now
t = -pl.y / vlo.y;
// now compute x,z of projected shadow position (scale t by .5 to keep the shadow close)
shadow_obj.world_pos.x = pl.x + t*vlo.x;
shadow_obj.world_pos.z = pl.z + t*vlo.z;
// now compute the size of the shadow radius based on the calculations shown in the book
// the size of the projected shadow, assuming a sphere as the occluder with a point lightsource
// height hl above the ground plane, a spherical object with radius ro, and height above
// the groundplane ho, the radius of the shadow is rs:
//
//    rs = ro * (hl)/(hl - ho)
// set height to altitude of light
hl = lights2[POINT_LIGHT2_INDEX].pos.y;
// use the average radius of the object to base calcs on, better than nothing
rs = ks * ( obj_work->avg_radius[0] * (hl/ (hl - obj_work->world_pos.y)) );
// generate scaling matrix bases on shadow scale
MAT_IDENTITY_4X4(&mrot);
// set scaling values to scale in X-Z plane
mrot.M00 = rs;
mrot.M11 = 1.0;
mrot.M22 = rs;
// scale the local coords of the object
Transform_OBJECT4DV2(&shadow_obj, &mrot, TRANSFORM_LOCAL_TO_TRANS,1);
// perform world transform
Model_To_World_OBJECT4DV2(&shadow_obj, TRANSFORM_TRANS_ONLY);
// insert the object into render list
Insert_OBJECT4DV2_RENDERLIST4DV2(&rend_list, &shadow_obj,0);
//////////////////////////////////////////////////////////////////////////
// test if camera is in shadow
VECTOR4D_Build(&cam.pos, &shadow_obj.world_pos, &vd);
d = VECTOR4D_Length_Fast(&vd);
// test if distance is within 1.5 times the radius of the shadow, the 1.5 makes it
// a little more noticeable
if (d < 1.5*rs)
   cockpit.curr_frame = 1; // cockpit with lower brightness
// remove backfaces
if (backface_mode==1)
   Remove_Backfaces_RENDERLIST4DV2(&rend_list, &cam);
// apply world to camera transform
World_To_Camera_RENDERLIST4DV2(&rend_list, &cam);
// clip the polygons themselves now
Clip_Polys_RENDERLIST4DV2(&rend_list, &cam, CLIP_POLY_X_PLANE | CLIP_POLY_Y_PLANE | CLIP_POLY_Z_PLANE );
// light scene all at once 
if (lighting_mode==1)
   {
   Transform_LIGHTSV2(lights2, 4, &cam.mcam, TRANSFORM_LOCAL_TO_TRANS);
   Light_RENDERLIST4DV2_World2_16(&rend_list, &cam, lights2, 4);
   } // end if
// sort the polygon list (hurry up!)
if (zsort_mode == 1)
   Sort_RENDERLIST4DV2(&rend_list,  SORT_POLYLIST_AVGZ);
// apply camera to perspective transformation
Camera_To_Perspective_RENDERLIST4DV2(&rend_list, &cam);
// apply screen transform
Perspective_To_Screen_RENDERLIST4DV2(&rend_list, &cam);
// render the object
if (wireframe_mode  == 0)
   Draw_RENDERLIST4DV2_Wire16(&rend_list, back_buffer, back_lpitch);
else
if (wireframe_mode  == 1)
   {
   // perspective mode affine texturing
      // set up rendering context
      rc.attr =    RENDER_ATTR_ZBUFFER  
                 | RENDER_ATTR_ALPHA  
              // | RENDER_ATTR_MIPMAP  
              // | RENDER_ATTR_BILERP
                 | RENDER_ATTR_TEXTURE_PERSPECTIVE_AFFINE;
   // initialize zbuffer to 0 fixed point
   //Clear_Zbuffer(&zbuffer, (16000 << FIXP16_SHIFT));
   // set up remainder of rendering context
   rc.video_buffer   = back_buffer;
   rc.lpitch         = back_lpitch;
   rc.mip_dist       = 0;
   rc.zbuffer        = (UCHAR *)zbuffer.zbuffer;
   rc.zpitch         = WINDOW_WIDTH*4;
   rc.rend_list      = &rend_list;
   rc.texture_dist   = 0;
   rc.alpha_override = -1;
   // render scene
   Draw_RENDERLIST4DV2_RENDERCONTEXTV1_16_3(&rc);
   } // end if
// unlock the back buffer
DDraw_Unlock_Back_Surface();
// draw cockpit
Draw_BOB16(&cockpit, lpddsback);
sprintf(work_string,"Lighting [%s]: Ambient=%d, Infinite=%d, Point=%d, BckFceRM [%s], Green Light y=%f, Red Light y=%f", 
                                                                                 ((lighting_mode == 1) ? "ON" : "OFF"),
                                                                                 lights2[AMBIENT_LIGHT_INDEX].state,
                                                                                 lights2[INFINITE_LIGHT_INDEX].state, 
                                                                                 lights2[POINT_LIGHT_INDEX].state,
                                                                                 ((backface_mode == 1) ? "ON" : "OFF"), 
                                                                                 lights2[POINT_LIGHT_INDEX].pos.y, lights2[POINT_LIGHT2_INDEX].pos.y);
Draw_Text_GDI(work_string, 0, WINDOW_HEIGHT-34, RGB(0,255,0), lpddsback);
// draw instructions
Draw_Text_GDI("Press ESC to exit. Press <H> for Help.", 0, 0, RGB(0,255,0), lpddsback);
// should we display help
int text_y = 16; 
if (help_mode==1)
    {
    // draw help menu
    Draw_Text_GDI("<A>..............Toggle ambient light source.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<I>..............Toggle infinite light source.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<P>..............Toggle point light source.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<W>..............Toggle wire frame/solid mode.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<B>..............Toggle backface removal.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<O>..............Select different objects.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<1>,<2>..........Change height of green point light.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<3>,<4>..........Change height of red point light.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<H>..............Toggle Help.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    Draw_Text_GDI("<ESC>............Exit demo.", 0, text_y+=12, RGB(255,255,255), lpddsback);
    } // end help
sprintf(work_string,"Polys Rendered: %d, Polys lit: %d", debug_polys_rendered_per_frame, debug_polys_lit_per_frame);
Draw_Text_GDI(work_string, 0, WINDOW_HEIGHT-34-16-16, RGB(0,255,0), lpddsback);
sprintf(work_string,"CAM [%5.2f, %5.2f, %5.2f], CELL [%d, %d]",  cam.pos.x, cam.pos.y, cam.pos.z, cell_x, cell_y);
Draw_Text_GDI(work_string, 0, WINDOW_HEIGHT-34-16-16-16, RGB(0,255,0), lpddsback);
// flip the surfaces
DDraw_Flip2();
// sync to 30ish fps
Wait_Clock(30);
// check of user is trying to exit
if (KEY_DOWN(VK_ESCAPE) || keyboard_state[DIK_ESCAPE])
    {
    PostMessage(main_window_handle, WM_DESTROY,0,0);
    } // end if
// return success
return(1);
 
} // end Game_Main
//////////////////////////////////////////////////////////

						