Autoshooter on this game

no-reply@allegro.cc (AleX-G Squadron) — Sun, 02 Sep 2012 02:19:58 +0000

I am trying to add an autoshooter to this game i was building from scratch but it seems unclear this concept to me. (It is based on mike geig shooter)
I have already opened a thread about the autoshooter, but i don't get the logic and how do i apply to codes like the game i am trying to build?
Also, pls add comments in each line you have added and explain step by step.
Anyone pls help!
Here is all the game's code so far:
source.cpp

#SelectExpand
   1#include 
   2#include 
   3#include 
   4#include 
   5#include 
   6#include "objects.h"
   7
   8// Buttons
   9enum BUTON{A,S,D,W,SPACE};
  10bool buton[5] = {false,false,false,false,false};
  11
  12// Globals
  13const int FPS = 80, width = 800, height = 600;
  14const int NUM_BULLETS = 5;
  15
  16// Protorypes
  17void InitShip(SpaceShip &ship);
  18void DrawShip(SpaceShip &ship);
  19void MoveShipUp(SpaceShip &ship);
  20void MoveShipDown(SpaceShip &ship);
  21void MoveShipLeft(SpaceShip &ship);
  22void MoveShipRight(SpaceShip &ship);
  23
  24void InitBullet(Bullet bullet[], int size);
  25void DrawBullet(Bullet bullet[], int size);
  26void FireBullet(Bullet bullet[], int size, SpaceShip &ship);
  27void UpdateBullet(Bullet bullet[], int size);
  28
  29int main()
  30{
  31  // Initialization
  32  al_init();
  33  al_init_primitives_addon();
  34  al_init_image_addon();
  35  al_init_font_addon();
  36  al_init_ttf_addon();
  37
  38  // Installations
  39  al_install_keyboard();
  40  al_install_mouse();
  41
  42  // Variables
  43  SpaceShip ship;
  44  Bullet bullets[5];
  45  int fireCooldown = 0;
  46
  47  int x = width / 2;
  48  int y = height / 2;
  49
  50  bool quit = false;
  51  bool draw = true;
  52
  53  // ALLEGRO variables
  54  ALLEGRO_DISPLAY *window = al_create_display(width, height);
  55  ALLEGRO_BITMAP *icon = al_load_bitmap("image/1.png");
  56  ALLEGRO_FONT *font16 = al_load_ttf_font("fonts/1.ttf", 80, ALLEGRO_ALIGN_CENTRE);
  57  ALLEGRO_TIMER *timer = NULL;
  58  ALLEGRO_EVENT_QUEUE *event = NULL;
  59
  60  event = al_create_event_queue();
  61  timer = al_create_timer(1.0 / FPS);
  62  
  63  // Events
  64  al_register_event_source(event, al_get_keyboard_event_source());
  65  al_register_event_source(event, al_get_mouse_event_source());
  66  al_register_event_source(event, al_get_display_event_source(window));
  67  al_register_event_source(event, al_get_timer_event_source(timer));
  68
  69  // Window title, icon and mouse hide
  70  al_set_window_title(window, "Game programming");
  71  al_set_display_icon(window, icon);
  72  al_hide_mouse_cursor(window);
  73  
  74  // Player initializations
  75  InitShip(ship);
  76  InitBullet(bullets, NUM_BULLETS);
  77
  78  // Start timer
  79  al_start_timer(timer);
  80
  81
  82  // The drawing
  83  while(!quit)
  84  {
  85    // Call of the event
  86    ALLEGRO_EVENT e;
  87    al_wait_for_event(event, &e);
  88
  89    // Drawing
  90    if(e.type == ALLEGRO_EVENT_TIMER)
  91    {
  92      draw = true;
  93      
  94    if(buton[A])
  95      MoveShipLeft(ship);
  96    if(buton[D])
  97      MoveShipRight(ship);
  98    if(buton[S])
  99      MoveShipDown(ship);
 100    if(buton[W])
 101      MoveShipUp(ship);
 102
 103      UpdateBullet(bullets, NUM_BULLETS);
 104    }
 105
 106    // Key down or up
 107    switch(e.type)
 108    {
 109      case ALLEGRO_EVENT_KEY_DOWN:
 110        switch(e.keyboard.keycode)
 111        {
 112        case ALLEGRO_KEY_A:
 113          buton[A] = true;
 114          break;
 115
 116        case ALLEGRO_KEY_S:
 117          buton[S] = true;
 118          break;
 119
 120        case ALLEGRO_KEY_D:
 121          buton[D] = true;
 122          break;
 123
 124        case ALLEGRO_KEY_W:
 125          buton[W] = true;
 126          break;
 127
 128        case ALLEGRO_KEY_SPACE:
 129          buton[SPACE] = true;
 130          FireBullet(bullets, NUM_BULLETS, ship);
 131          break;
 132
 133        case ALLEGRO_KEY_ESCAPE:
 134          quit = true;
 135          break;
 136        }
 137    }
 138
 139    switch(e.type)
 140    {
 141      case ALLEGRO_EVENT_KEY_UP:
 142        switch(e.keyboard.keycode)
 143        {
 144        case ALLEGRO_KEY_A:
 145          buton[A] = false;
 146          break;
 147
 148        case ALLEGRO_KEY_S:
 149          buton[S] = false;
 150          break;
 151
 152        case ALLEGRO_KEY_D:
 153          buton[D] = false;
 154          break;
 155
 156        case ALLEGRO_KEY_W:
 157          buton[W] = false;
 158          break;
 159
 160        case ALLEGRO_KEY_SPACE:
 161          buton[SPACE] = false;
 162          break;
 163        }
 164    }
 165
 166
 167    // Close display when X is pressed
 168    if(e.type == ALLEGRO_EVENT_DISPLAY_CLOSE)
 169    {
 170      quit = true;
 171    }
 172
 173    // Mouse movement
 174    else if(e.type == ALLEGRO_EVENT_MOUSE_AXES)
 175    {
 176      ship.y = e.mouse.y;
 177    }
 178
 179    else if(e.mouse.button & 1)
 180    {
 181      FireBullet(bullets, NUM_BULLETS, ship);
 182    }
 183
 184    if(draw && al_event_queue_is_empty(event))
 185    {
 186      draw = false;
 187      DrawShip(ship);
 188      DrawBullet(bullets, NUM_BULLETS);
 189
 190      al_flip_display();
 191      al_clear_to_color(al_map_rgb(0,0,0));
 192    }
 193
 194  }
 195
 196  // Destroy
 197  al_destroy_event_queue(event);
 198  al_destroy_bitmap(icon);
 199  al_destroy_display(window);
 200}
 201
 202void InitShip(SpaceShip &ship)
 203{
 204  ship.x = 20;
 205  ship.y = height / 2;
 206  ship.ID = PLAYER;
 207  ship.lives = 3;
 208  ship.speed = 7;
 209  ship.boundx = 6;
 210  ship.boundy = 7;
 211  ship.score = 0;
 212}
 213
 214void DrawShip(SpaceShip &ship)
 215{
 216  al_draw_filled_rectangle(ship.x - 10, ship.y-15, ship.x + 35, ship.y, al_map_rgb(255,128,0)); 
 217  al_draw_filled_rectangle(ship.x + 35, ship.y-15, ship.x + 130, ship.y, al_map_rgb(255,255,255)); 
 218}
 219
 220void MoveShipUp(SpaceShip &ship)
 221{
 222  ship.y -= ship.speed;
 223  if(ship.y < 15)
 224    ship.y = 15;
 225}
 226
 227void MoveShipDown(SpaceShip &ship)
 228{
 229  ship.y += ship.speed;
 230  if(ship.y > height)
 231    ship.y = height;
 232}
 233
 234void MoveShipLeft(SpaceShip &ship)
 235{
 236  ship.x -= ship.speed;
 237  if(ship.x < 10)
 238    ship.x = 10;
 239}
 240
 241void MoveShipRight(SpaceShip &ship)
 242{
 243  ship.x += ship.speed;
 244  if(ship.x > 100)
 245    ship.x = 100;
 246}
 247
 248void InitBullet(Bullet bullet[], int size)
 249{
 250  for(int i = 0; i < size; i++)
 251  {
 252    bullet[i].ID = BULLET;
 253    bullet[i].speed = 10;
 254    bullet[i].live = false;
 255  }
 256}
 257
 258void DrawBullet(Bullet bullet[], int size)
 259{
 260  for(int i = 0; i < size; i++)
 261  {
 262    if(bullet[i].live)
 263      al_draw_filled_circle(bullet[i].x, bullet[i].y, 5, al_map_rgb(128,128,128));
 264  }
 265}
 266
 267void FireBullet(Bullet bullet[], int size, SpaceShip &ship)
 268{
 269  for(int i = 0; i < size; i++)
 270  {
 271    if(!bullet[i].live)
 272    {
 273      bullet[i].x = ship.x + 120;
 274      bullet[i].y = ship.y - 7;
 275      bullet[i].live = true;
 276      break;
 277    }
 278  }
 279}
 280
 281void UpdateBullet(Bullet bullet[], int size)
 282{
 283  for(int i = 0; i < size; i++)
 284  {
 285    if(bullet[i].live)
 286    {
 287      bullet[i].x += bullet[i].speed;
 288      if(bullet[i].x > width)
 289      {
 290        bullet[i].live = false;
 291      break;
 292      }
 293    }
 294  }
 295}

objects.h

#SelectExpand
  1// Objects IDs
  2enum ID{PLAYER, BULLET, ENEMY};
  3
  4// The player
  5struct SpaceShip
  6{
  7  int ID;
  8  int x;
  9  int y;
 10  int lives;
 11  int speed;
 12  int boundx;
 13  int boundy;
 14  int score;
 15};
 16
 17struct Bullet
 18{
 19  int ID;
 20  int x;
 21  int y;
 22  bool live;
 23  int speed;
 24};

no-reply@allegro.cc (l j) — Sun, 02 Sep 2012 04:04:49 +0000

#SelectExpand
   1#include 
   2#include 
   3#include 
   4#include 
   5#include 
   6#include "objects.h"
   7
   8// Buttons
   9enum BUTON{A,S,D,W,SPACE};
  10bool buton[5] = {false,false,false,false,false};
  11
  12// Globals
  13const int FPS = 80, width = 800, height = 600;
  14const int NUM_BULLETS = 5;
  15
  16// Protorypes
  17void InitShip(SpaceShip &ship);
  18void DrawShip(SpaceShip &ship);
  19void MoveShipUp(SpaceShip &ship);
  20void MoveShipDown(SpaceShip &ship);
  21void MoveShipLeft(SpaceShip &ship);
  22void MoveShipRight(SpaceShip &ship);
  23
  24void InitBullet(Bullet bullet[], int size);
  25void DrawBullet(Bullet bullet[], int size);
  26void FireBullet(Bullet bullet[], int size, SpaceShip &ship);
  27void UpdateBullet(Bullet bullet[], int size);
  28
  29int main()
  30{
  31  // Initialization
  32  al_init();
  33  al_init_primitives_addon();
  34  al_init_image_addon();
  35  al_init_font_addon();
  36  al_init_ttf_addon();
  37
  38  // Installations
  39  al_install_keyboard();
  40  al_install_mouse();
  41
  42  // Variables
  43  SpaceShip ship;
  44  Bullet bullets[5];
  45  // I don't think you are actually using this variable
  46  int fireCooldown = 0;
  47
  48  int x = width / 2;
  49  int y = height / 2;
  50
  51  bool quit = false;
  52  bool draw = true;
  53
  54  // ALLEGRO variables
  55  ALLEGRO_DISPLAY *window = al_create_display(width, height);
  56  ALLEGRO_BITMAP *icon = al_load_bitmap("image/1.png");
  57  ALLEGRO_FONT *font16 = al_load_ttf_font("fonts/1.ttf", 80, ALLEGRO_ALIGN_CENTRE);
  58  ALLEGRO_TIMER *timer = NULL;
  59  ALLEGRO_EVENT_QUEUE *event = NULL;
  60
  61  event = al_create_event_queue();
  62  timer = al_create_timer(1.0 / FPS);
  63  
  64  // Events
  65  al_register_event_source(event, al_get_keyboard_event_source());
  66  al_register_event_source(event, al_get_mouse_event_source());
  67  al_register_event_source(event, al_get_display_event_source(window));
  68  al_register_event_source(event, al_get_timer_event_source(timer));
  69
  70  // Window title, icon and mouse hide
  71  al_set_window_title(window, "Game programming");
  72  al_set_display_icon(window, icon);
  73  al_hide_mouse_cursor(window);
  74  
  75  // Player initializations
  76  InitShip(ship);
  77  InitBullet(bullets, NUM_BULLETS);
  78
  79  // Start timer
  80  al_start_timer(timer);
  81
  82
  83  // The drawing
  84  while(!quit)
  85  {
  86    // Call of the event
  87    ALLEGRO_EVENT e;
  88    al_wait_for_event(event, &e);
  89
  90    // Drawing
  91    if(e.type == ALLEGRO_EVENT_TIMER)
  92    {
  93      draw = true;
  94      
  95    if(buton[A])
  96      MoveShipLeft(ship);
  97    if(buton[D])
  98      MoveShipRight(ship);
  99    if(buton[S])
 100      MoveShipDown(ship);
 101    if(buton[W])
 102      MoveShipUp(ship);
 103    // Why didn't you apply the same logic to firing your bullets?
 104    if(buton[SPACE])
 105    {
 106       // also it's button, you got it right in the comments though.
 107       // Or is this a different language?
 108       if(fireCooldown == 0)
 109       {
 110          // We'll decrement this variable later
 111          // This block will only get executed if fireCooldown equals 0
 112          fireCooldown = 10;
 113          // Now that we've assigned 10 to fireCooldown we can be sure the next bullet is not going to be fired for a couple of frames
 114          FireBullet(bullets, NUM_BULLETS, ship);
 115       }
 116    }
 117    
 118    // Let's get the ship ready for the next shot
 119    if(fireCooldown > 0)
 120       fireCooldown--;
 121     
 122
 123      UpdateBullet(bullets, NUM_BULLETS);
 124    }
 125
 126    // Key down or up
 127    switch(e.type)
 128    {
 129      case ALLEGRO_EVENT_KEY_DOWN:
 130        switch(e.keyboard.keycode)
 131        {
 132        case ALLEGRO_KEY_A:
 133          buton[A] = true;
 134          break;
 135
 136        case ALLEGRO_KEY_S:
 137          buton[S] = true;
 138          break;
 139
 140        case ALLEGRO_KEY_D:
 141          buton[D] = true;
 142          break;
 143
 144        case ALLEGRO_KEY_W:
 145          buton[W] = true;
 146          break;
 147
 148        case ALLEGRO_KEY_SPACE:
 149          buton[SPACE] = true;
 150          // Now you are going to fire a bullet each time you press your spacebar, so let's move this out of here
 151          //FireBullet(bullets, NUM_BULLETS, ship);
 152
 153          break;
 154
 155        case ALLEGRO_KEY_ESCAPE:
 156          quit = true;
 157          break;
 158        }
 159    }
 160
 161    switch(e.type)
 162    {
 163      case ALLEGRO_EVENT_KEY_UP:
 164        switch(e.keyboard.keycode)
 165        {
 166        case ALLEGRO_KEY_A:
 167          buton[A] = false;
 168          break;
 169
 170        case ALLEGRO_KEY_S:
 171          buton[S] = false;
 172          break;
 173
 174        case ALLEGRO_KEY_D:
 175          buton[D] = false;
 176          break;
 177
 178        case ALLEGRO_KEY_W:
 179          buton[W] = false;
 180          break;
 181
 182        case ALLEGRO_KEY_SPACE:
 183          buton[SPACE] = false;
 184          break;
 185        }
 186    }
 187
 188
 189    // Close display when X is pressed
 190    if(e.type == ALLEGRO_EVENT_DISPLAY_CLOSE)
 191    {
 192      quit = true;
 193    }
 194
 195    // Mouse movement
 196    else if(e.type == ALLEGRO_EVENT_MOUSE_AXES)
 197    {
 198      ship.y = e.mouse.y;
 199    }
 200    
 201    // Bad idea, an ALLEGRO_EVENT is an union
 202    // Meaning that multiple different members can take the same place in memory
 203    // Other events might 'overwrite' e.mouse.button, causing it to falsely evaluate to true and this is more likely than you might think as it caused the firing to seem irregular with this not being commented
 204    /*else if(e.mouse.button & 1)
 205    {
 206      FireBullet(bullets, NUM_BULLETS, ship);
 207    }*/
 208    if(e.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN)
 209    {
 210       if(e.mouse.button & 1)
 211       {
 212          buton[SPACE] = true; // Ugly hack but it works
 213       }
 214    }
 215    else if(e.type == ALLEGRO_EVENT_MOUSE_BUTTON_UP)
 216    {
 217       if(e.mouse.button & 1)
 218       {
 219          buton[SPACE] = false;
 220       }
 221    }
 222
 223    if(draw && al_event_queue_is_empty(event))
 224    {
 225      draw = false;
 226      DrawShip(ship);
 227      DrawBullet(bullets, NUM_BULLETS);
 228
 229      al_flip_display();
 230      al_clear_to_color(al_map_rgb(0,0,0));
 231    }
 232
 233  }
 234
 235  // Destroy
 236  al_destroy_event_queue(event);
 237  al_destroy_bitmap(icon);
 238  al_destroy_display(window);
 239}
 240
 241void InitShip(SpaceShip &ship)
 242{
 243  ship.x = 20;
 244  ship.y = height / 2;
 245  ship.ID = PLAYER;
 246  ship.lives = 3;
 247  ship.speed = 7;
 248  ship.boundx = 6;
 249  ship.boundy = 7;
 250  ship.score = 0;
 251}
 252
 253void DrawShip(SpaceShip &ship)
 254{
 255  al_draw_filled_rectangle(ship.x - 10, ship.y-15, ship.x + 35, ship.y, al_map_rgb(255,128,0)); 
 256  al_draw_filled_rectangle(ship.x + 35, ship.y-15, ship.x + 130, ship.y, al_map_rgb(255,255,255)); 
 257}
 258
 259void MoveShipUp(SpaceShip &ship)
 260{
 261  ship.y -= ship.speed;
 262  if(ship.y < 15)
 263    ship.y = 15;
 264}
 265
 266void MoveShipDown(SpaceShip &ship)
 267{
 268  ship.y += ship.speed;
 269  if(ship.y > height)
 270    ship.y = height;
 271}
 272
 273void MoveShipLeft(SpaceShip &ship)
 274{
 275  ship.x -= ship.speed;
 276  if(ship.x < 10)
 277    ship.x = 10;
 278}
 279
 280void MoveShipRight(SpaceShip &ship)
 281{
 282  ship.x += ship.speed;
 283  if(ship.x > 100)
 284    ship.x = 100;
 285}
 286
 287void InitBullet(Bullet bullet[], int size)
 288{
 289  for(int i = 0; i < size; i++)
 290  {
 291    bullet[i].ID = BULLET;
 292    bullet[i].speed = 10;
 293    bullet[i].live = false;
 294  }
 295}
 296
 297void DrawBullet(Bullet bullet[], int size)
 298{
 299  for(int i = 0; i < size; i++)
 300  {
 301    if(bullet[i].live)
 302      al_draw_filled_circle(bullet[i].x, bullet[i].y, 5, al_map_rgb(128,128,128));
 303  }
 304}
 305
 306void FireBullet(Bullet bullet[], int size, SpaceShip &ship)
 307{
 308  for(int i = 0; i < size; i++)
 309  {
 310    if(!bullet[i].live)
 311    {
 312      bullet[i].x = ship.x + 120;
 313      bullet[i].y = ship.y - 7;
 314      bullet[i].live = true;
 315      break;
 316    }
 317  }
 318}
 319
 320void UpdateBullet(Bullet bullet[], int size)
 321{
 322  for(int i = 0; i < size; i++)
 323  {
 324    if(bullet[i].live)
 325    {
 326      bullet[i].x += bullet[i].speed;
 327      if(bullet[i].x > width)
 328      {
 329        bullet[i].live = false;
 330      break;
 331      }
 332    }
 333  }
 334}

Well most of your code worked, I just don't understand why you decided to handle your shooting so different in comparison to the movement of the ship.

no-reply@allegro.cc (AleX-G Squadron) — Sun, 02 Sep 2012 14:16:50 +0000

So you mean this is the code block which makes the autoshooting?

#SelectExpand
  // Why didn't you apply the same logic to firing your bullets?
  if(buton[SPACE])
  {
     // also it's button, you got it right in the comments though.
     // Or is this a different language?
     if(fireCooldown == 0)
     {
        // We'll decrement this variable later
        // This block will only get executed if fireCooldown equals 0
        fireCooldown = 10;
        // Now that we've assigned 10 to fireCooldown we can be sure the next bullet is not going to be fired for a couple of frames
        FireBullet(bullets, NUM_BULLETS, ship);
     }
  }
 15

  // Let's get the ship ready for the next shot
  if(fireCooldown > 0)
     fireCooldown--;

And than i can apply int firecooldown to all games i will create?

Also, i didnt understand why did you put firecooldown = 10. What is the logic?
It decrements 10 loops and than shoots a bullet?

no-reply@allegro.cc (J-Gamer) — Sun, 02 Sep 2012 14:32:50 +0000

That code fires every 10 ticks. You can increase it to lower the rate of fire, or decrease it to make it fire faster.

no-reply@allegro.cc (AleX-G Squadron) — Sun, 02 Sep 2012 14:37:27 +0000

Just did that
It works perfect, i don't get one last thing.
The same block of code is used to make the autoshooting?

no-reply@allegro.cc (l j) — Sun, 02 Sep 2012 16:43:20 +0000

Yes, every time you fire a bullet the counter will get increased. As long as this counter is not zero the next bullet won't be fired.
Every frame(timer event) this counter gets decreased so it can become 0 again.

no-reply@allegro.cc (AleX-G Squadron) — Sun, 02 Sep 2012 16:47:21 +0000

Ok, thank you very much!