Collision Detection - II

Earlier we talked about Collision Detection, where we detected the collsion between bullet and the enemy. This time we have to detect collision between the enemy and player.

The concepts and techniques are similar as before,

I won't be explaining too much, If you are still confused head back to chapter 7, where I explained in detail about the collision detection.

The conditions

• x + sprEnemy->width >= x1
• x <= x1 + sprPlayer->width
• y + sprEnemy->height >= y1

We check for the range of corners of the enemy, if they satisfy all of the above condition, we can say that they have collided.

Implementation

Update the OnUserUpdate method to contain following snippets,

for(auto &elm : vEnemy){
  if(elm.alive)
  {
   // Same as before..
     if (elm.x + sprEnemy->width >= fPlayerPositionX &&
         elm.x <= fPlayerPositionX + sprPlayer->width &&
         elm.y + sprEnemy->height >= fPlayerPositionY)
        {
          elm.alive = false;
        }
      break;
  }
}

Above code justifies everything we talked earlier, nothing to explain here. We set elm.alive = false to kill the enemy. So now you should see enemies being killed on collision with the player.

All the updated code for OnUserUpdate method can be found here

Next up we will add Scoreboard and implement the concept of life for our Player.