raiders3d.cpp

书的配套源码

ties[index].xv = -4+rand()%8;
ties[index].yv = -4+rand()%8;
ties[index].zv = -4-rand()%64;

// turn the tie fighter on
ties[index].state = 1;
} // end Init_Tie

/////////////////////////////////////////////////////////

void Process_Ties(void)
{
// process the tie fighters and do AI (what there is of it!)
int index; // looping var

// move each tie fighter toward the viewpoint
for (index=0; index<NUM_TIES; index++)
    {
    // is this one dead?
    if (ties[index].state==0)
       continue;

    // move the next star
    ties[index].z+=ties[index].zv;
    ties[index].x+=ties[index].xv;
    ties[index].y+=ties[index].yv;

    // test for past near clipping plane
    if (ties[index].z <= NEAR_Z)
       {
       // reset this tie
       Init_Tie(index);

       // another got away
       misses++;

       } // reset tie

    } // end for index

}  // Process_Ties

//////////////////////////////////////////////////////////

void Draw_Ties(void)
{
// draw the tie fighters in 3D wireframe with perspective

int index; // looping var

// used to compute the bounding box of tie fighter
// for collision detection
int bmin_x, bmin_y, bmax_x, bmax_y; 

// draw each tie fighter
for (index=0; index < NUM_TIES; index++)
    {
    // draw the next tie fighter

    // is this one dead?
    if (ties[index].state==0)
       continue;

    // reset the bounding box to impossible values
    bmin_x =  100000;
    bmax_x = -100000;
    bmin_y =  100000;
    bmax_y = -100000;

    // based on z-distance shade tie fighter
    // normalize the distance from 0 to max_z then
    // scale it to 255, so the closer the brighter
    USHORT rgb_tie_color = RGB16Bit(0,(255-255*(ties[index].z/(4*FAR_Z))),0);

    // each tie fighter is made of a number of edges
    for (int edge=0; edge < NUM_TIE_EDGES; edge++)
    {
    POINT3D p1_per, p2_per; // used to hold perspective endpoints
      
    // step 1: perspective transform each end point
    // note the translation of each point to the position of the tie fighter
    // that is the model is relative to the position of each tie fighter -- IMPORTANT
    p1_per.x = 
            VIEW_DISTANCE*(ties[index].x+tie_vlist[tie_shape[edge].v1].x)/
            (tie_vlist[tie_shape[edge].v1].z+ties[index].z);
        
    p1_per.y = VIEW_DISTANCE*(ties[index].y+tie_vlist[tie_shape[edge].v1].y)/
               (tie_vlist[tie_shape[edge].v1].z+ties[index].z);

    p2_per.x = VIEW_DISTANCE*(ties[index].x+tie_vlist[tie_shape[edge].v2].x)/
               (tie_vlist[tie_shape[edge].v2].z+ties[index].z);
        
    p2_per.y = VIEW_DISTANCE*(ties[index].y+tie_vlist[tie_shape[edge].v2].y)/
               (tie_vlist[tie_shape[edge].v2].z+ties[index].z);

    // step 2: compute screen coords
    int p1_screen_x = WINDOW_WIDTH/2  + p1_per.x;
    int p1_screen_y = WINDOW_HEIGHT/2 - p1_per.y;
    int p2_screen_x = WINDOW_WIDTH/2  + p2_per.x;
    int p2_screen_y = WINDOW_HEIGHT/2 - p2_per.y;

    // step 3: draw the edge
    Draw_Clip_Line16(p1_screen_x, p1_screen_y, p2_screen_x, p2_screen_y,
                     rgb_tie_color,back_buffer, back_lpitch);

    // update bounding box with next edge
    int min_x = min(p1_screen_x, p2_screen_x);
    int max_x = max(p1_screen_x, p2_screen_x);

    int min_y = min(p1_screen_y, p2_screen_y);
    int max_y = max(p1_screen_y, p2_screen_y);

    bmin_x = min(bmin_x, min_x);
    bmin_y = min(bmin_y, min_y);

    bmax_x = max(bmax_x, max_x);
    bmax_y = max(bmax_y, max_y);
        
    } // end for edge

    // test if this guy has been hit by lasers???
    if (cannon_state==1)
       {
       // simple test of screen coords of bounding box contain laser target
       if (target_x_screen > bmin_x && target_x_screen < bmax_x &&
           target_y_screen > bmin_y && target_y_screen < bmax_y)
         {
         // this tie is dead meat!
         Start_Explosion(index);

         // start sound
         DSound_Play(explosion_id );

         // increase score
         score+=ties[index].z;

         // add one more hit
         hits++;

         // finally reset this tie figher
         Init_Tie(index);
         
         } // end if

       } // end if

    } // end for index

} // end Draw_Ties

//////////////////////////////////////////////////////////

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 your game go here!

int        index;       // looping var

// start the timing clock
Start_Clock();

// clear the drawing surface 
DDraw_Fill_Surface(lpddsback, 0);

// read keyboard and other devices here
DInput_Read_Keyboard();

// game logic here...

if (game_state==GAME_RUNNING)
{
// move players crosshair
if (keyboard_state[DIK_RIGHT])
   {
   // move cross hair to right
   cross_x+=CROSS_VEL;

   // test for wraparound
   if (cross_x > WINDOW_WIDTH/2)
      cross_x = -WINDOW_WIDTH/2;   

   } // end if
if (keyboard_state[DIK_LEFT])
   {
   // move cross hair to left
   cross_x-=CROSS_VEL;

   // test for wraparound
   if (cross_x < -WINDOW_WIDTH/2)
      cross_x = WINDOW_WIDTH/2;   
   } // end if
if (keyboard_state[DIK_DOWN])
   {
   // move cross hair up
   cross_y-=CROSS_VEL;

   // test for wraparound
   if (cross_y < -WINDOW_HEIGHT/2)
      cross_y = WINDOW_HEIGHT/2;   
   } // end if
if (keyboard_state[DIK_UP])
   {
   // move cross hair up
   cross_y+=CROSS_VEL;

   // test for wraparound
   if (cross_y > WINDOW_HEIGHT/2)
      cross_y = -WINDOW_HEIGHT/2;   
   } // end if

// speed of ship controls
if (keyboard_state[DIK_A])
   player_z_vel++;
else
if (keyboard_state[DIK_S])
   player_z_vel--;

// test if player is firing laser cannon
if (keyboard_state[DIK_SPACE] && cannon_state==0)
   {
   // fire the cannon
   cannon_state = 1;
   cannon_count = 0;

   // save last position of targeter
   target_x_screen = cross_x_screen;
   target_y_screen = cross_y_screen;

   // make sound
   DSound_Play(laser_id);

   } // end if   

} // end if game running

// process cannon, simple FSM ready->firing->cool

// firing phase
if (cannon_state == 1)
   if (++cannon_count > 15)
      cannon_state = 2;

// cool down phase
if (cannon_state == 2)
   if (++cannon_count > 20)
      cannon_state = 0;

// move the starfield
Move_Starfield();

// move and perform ai for ties
Process_Ties();

// Process the explosions
Process_Explosions();

// lock the back buffer and obtain pointer and width
DDraw_Lock_Back_Surface();

// draw the starfield
Draw_Starfield();

// draw the tie fighters
Draw_Ties();

// draw the explosions
Draw_Explosions();

// draw the crosshairs 

// first compute screen coords of crosshair
// note inversion of y-axis
cross_x_screen = WINDOW_WIDTH/2  + cross_x;
cross_y_screen = WINDOW_HEIGHT/2 - cross_y;

// draw the crosshair in screen coords
Draw_Clip_Line16(cross_x_screen-16,cross_y_screen,
                 cross_x_screen+16,cross_y_screen,
                 rgb_red,back_buffer,back_lpitch);

Draw_Clip_Line16(cross_x_screen,cross_y_screen-16,
                 cross_x_screen,cross_y_screen+16,
                 rgb_red,back_buffer,back_lpitch);

Draw_Clip_Line16(cross_x_screen-16,cross_y_screen-4,
                 cross_x_screen-16,cross_y_screen+4,
                 rgb_red,back_buffer,back_lpitch);

Draw_Clip_Line16(cross_x_screen+16,cross_y_screen-4,
                 cross_x_screen+16,cross_y_screen+4,
                 rgb_red,back_buffer,back_lpitch);

// draw the laser beams
if (cannon_state == 1)
   {
   if ((rand()%2 == 1))
      { 
      // right beam
      Draw_Clip_Line16(WINDOW_WIDTH-1, WINDOW_HEIGHT-1,
             -4+rand()%8+target_x_screen,-4+rand()%8+target_y_screen,
             RGB16Bit(0,0,rand()),back_buffer,back_lpitch);
      } // end if    
   else
      {
      // left beam
      Draw_Clip_Line16(0, WINDOW_HEIGHT-1,
             -4+rand()%8+target_x_screen,-4+rand()%8+target_y_screen,
             RGB16Bit(0,0,rand()),back_buffer,back_lpitch);
      } // end if

   } // end if

// done rendering, unlock back buffer surface
DDraw_Unlock_Back_Surface();

// draw the informtion
sprintf(buffer, "Score %d     Kills %d      Escaped %d", score, hits, misses);
Draw_Text_GDI(buffer, 0,0,RGB(0,255,0), lpddsback);

if (game_state==GAME_OVER)
    Draw_Text_GDI("G A M E  O V E R", WINDOW_WIDTH/2-8*10,WINDOW_HEIGHT/2,RGB(255,255,255), lpddsback);

// check if the music has finished, if so restart
if (DMusic_Status_MIDI(main_track_id)==MIDI_STOPPED)
    DMusic_Play(main_track_id);

// flip the surfaces
DDraw_Flip();

// sync to 30ish fps
Wait_Clock(30);

// check for game state switch
if (misses > 4*NUM_TIES)
   game_state = GAME_OVER;

// 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

//////////////////////////////////////////////////////////