//------------------------------------------------------------------------------
// File: rocket.c
// Author: George Bain
// Date: May 24, 1997
// Description: Enemy rocket 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 "rocket.h"
#include "gfx.h"


//------------------------------------------------------------------------------
// Function: DrawRockets()
// Description: Register rocket sprites into the OT
// Parameters: none
// Returns: void
// Notes: N/A
//------------------------------------------------------------------------------

void DrawRockets( void )
 {
    
    int count;

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

       if( rockets[count].state == ROCKET_ALIVE ) 
	       GsSortFastSprite( &rockets[count].sprite, 
		                     &world_ordering_table[output_buffer_index], 0 );
		   		   
	   }// end for
       
 }// end DrawRockets




//------------------------------------------------------------------------------
// Function: MoveRockets()
// Description: Move the rocket and perform collision check
// Parameters: none
// Returns: void
// Notes: N/A
//------------------------------------------------------------------------------

void MoveRockets( void )
  {

	 int count,                   // loop vars
		 rocket_x, rocket_y;      // location of missile

	 // loop thru all rockets
	 for( count=0; count<NUM_ROCKETS; count++ ) 
	    {

		  if( rockets[count].state == ROCKET_ALIVE ) 
		    {

			  // move rocket
			  rocket_x = ( rockets[count].sprite.x += -(ROCKET_SPEED) );

			  if( player.sprite.y + 5 <= rockets[count].sprite.y )
					rocket_y = rockets[count].sprite.y-=(ROCKET_SPEED);

			  if( player.sprite.y + 5 >= rockets[count].sprite.y )
					rocket_y = rockets[count].sprite.y+=(ROCKET_SPEED);

			  // test if rocket hit edge of screen
			  if( (rocket_x >= SCREEN_WIDTH) || (rocket_x <=3) ||
					(rocket_y > SCREEN_HEIGHT) ||  (rocket_y <=3) )
					rockets[count].state = ROCKET_DEAD;  // kill it

		 }// end if rocket ALIVE

	 }// end count

 }// end MoveRockets




//------------------------------------------------------------------------------
// Function: StartRockets()
// Description: StartRockets
// Parameters: x: x location to launch rocket
//             y: y location to launch rocket
// Returns: void
// Notes: N/A
//------------------------------------------------------------------------------

void StartRockets( int x, int y )
 {

	int count;

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

		 // find a rocket that is not being used
		 if( rockets[count].state == ROCKET_DEAD )
		  {

			// set up the fields
			rockets[count].state = ROCKET_ALIVE;
			rockets[count].sprite.x     = x;
			rockets[count].sprite.y     = y;
			break;  // jump out of loop

		  }// end if found a good one

	   }// end for

 }// end StartRockets





//------------------------------------------------------------------------------
// Function: RocketPlayerCollision()
// Description: Check if enemy rocket hits player, if true
//               destroy the rocket and display explosion animation
// Parameters: none
// Returns: void
// Notes: N/A
//------------------------------------------------------------------------------

void RocketPlayerCollision( void )
 {

	int count; 
				
	object_ptr current;   // current rocket 
    
	// check all rockets
	for( count=0; count<NUM_ROCKETS; count++ )
	   {
         // check if rocket is ALIVE
		 if( rockets[count].state == ROCKET_ALIVE )
		   {
                    
		     // extract current rocket
			 current = (object_ptr)&rockets[count];

			 // test for collision
			 if( SpriteCollision( (object_ptr)&player, 
							      (object_ptr)&rockets[count] ) )
			   {

			     // kill the rocket
			     current->state = ROCKET_DEAD;
			  
				 // start an explosion
				 StartExplosions( player.sprite.x+10, 
								  player.sprite.y+10, 
								  EXPLOSION_SPEED );

				 // decrease players health
				 game_info.player_energy-=5;
                 				
			   }// end collision

		   }// end if ROCKET_ALIVE

	   }// end for NUM_ROCKETS

 }// end PlayerRocketCollision



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