//------------------------------------------------------------------------------
// File: enemy.c
// Author: George Bain
// Date: May 21, 1997
// Description: Enemy related routines
// Copyright (C) 1997 George Bain, All Rights Reserved
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// I N C L U D E S
//------------------------------------------------------------------------------

#include <libps.h>	   // standard Sony library
#include "enemy.h"
#include "gfx.h"


//------------------------------------------------------------------------------
// Function: DrawEnemy()
// Description: Register enemy sprite into the OT
// Parameters: none
// Returns: void
// Notes: N/A
//------------------------------------------------------------------------------

void DrawEnemy( void )
 {

    int count;

	for( count=0; count<NUM_ENEMIES; count++ ) 
	   {
		 
		  if( red_enemy[count].state == ENEMY_ALIVE )
			  GsSortFastSprite( &red_enemy[count].sprite, 
			                    &world_ordering_table[output_buffer_index], 0 );
		  else
		  if( blue_enemy[count].state == ENEMY_ALIVE )
			  GsSortFastSprite( &blue_enemy[count].sprite, 
			                    &world_ordering_table[output_buffer_index], 0 );	  
	   }// end for

 }// end DrawEnemy




//------------------------------------------------------------------------------
// Function: ControlEnemy()
// Description: Based on a random timer turn state of enemy to ALIVE
//              and give a random direction either left or right, also
//              set the speed of enemy
// Parameters: none
// Returns: none
// Notes: N/A
//------------------------------------------------------------------------------

void ControlEnemy( void )
 {

   int count;

   for( count=0; count<NUM_ENEMIES; count++ )
	  {

	     if( (red_enemy[count].state || blue_enemy[count].state)  == 
			 ENEMY_DEAD && ( rand()%50 == 1 ) )
	       {

	          // select a random direction
	          switch(rand()%2)  
			     {
		         case 0: // move enemy right
			       {
			         red_enemy[count].state = ENEMY_ALIVE;  
			         red_enemy[count].motion_speed = ENEMY_SPEED;
			         red_enemy[count].sprite.x = 0;
			         red_enemy[count].sprite.y = RandLocation();
				   }break;
		         case 1:  // move enemy left
			       {
                     blue_enemy[count].state = ENEMY_ALIVE;  
			         blue_enemy[count].motion_speed = -(ENEMY_SPEED+1);
		             blue_enemy[count].sprite.x = SCREEN_WIDTH;
			         blue_enemy[count].sprite.y = RandLocation();
				   }break;

		         default:break;

		         }// end switch

	       }// end if DEAD

	  }// end for

 }// end ControlEnemy




//------------------------------------------------------------------------------
// Function: MoveEnemyLeft()
// Description: Move the enemy to the left at a set speed, and
//              fire missiles at random
// Parameters: none
// Returns: none
// Notes: N/A
//------------------------------------------------------------------------------

void MoveEnemyLeft( void )
 {

	int count;

		for( count=0; count<NUM_ENEMIES; count++ ) 
		   {

		     if( blue_enemy[count].state == ENEMY_ALIVE ) 
			   {
				 blue_enemy[count].sprite.y += 0; 
				 blue_enemy[count].sprite.x += blue_enemy[count].motion_speed;

				 if( blue_enemy[count].sprite.x <  (-15) )  
					 blue_enemy[count].state = ENEMY_DEAD;

			     if( rand()%35==1 )
				     StartMissiles( blue_enemy[count].sprite.x,
					                blue_enemy[count].sprite.y+9,
			                        -MISSILE_SPEED*2,0,0,255,0,ENEMY_MISSILE );
                   
		       }// end if ALIVE

		   }// end for

 }// end MoveEnemyLeft




//------------------------------------------------------------------------------
// Function: MoveEnemyRight()
// Description: Based on the cosine, if enemy is Alive
//              move the enemy to the right and at the set speed
// Parameters: none
// Returns: none
// Notes: N/A
//------------------------------------------------------------------------------

void MoveEnemyRight( void )
 {

	 int count;

	 for( count=0; count<NUM_ENEMIES; count++ ) 
	    {

		  if( red_enemy[count].state == ENEMY_ALIVE ) 
		    {
			  red_enemy[count].sprite.y += cos_look[red_enemy[count].sprite.x];
			  red_enemy[count].sprite.x += red_enemy[count].motion_speed;

			  if( red_enemy[count].sprite.x > SCREEN_WIDTH + 1)
				  red_enemy[count].state = ENEMY_DEAD;

			  if( rand()%35==1 )
			      StartMissiles( red_enemy[count].sprite.x+21,
					             red_enemy[count].sprite.y+9,
			                     MISSILE_SPEED,0,0,255,0,ENEMY_MISSILE );
								 
		    }// end if ALIVE

		}// end for
	 
 }// end MoveEnemyRight


	
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