/*
** File   : Prog2.c
** Author : D Smethurst
** Description: second demo program for the SprLib library.
**              Note that the second sprite is jerky I've done
**              this to show off the update loop and how it works.
** Version: v1.0 (SprLib v0.2)
*/

/*
** System headers
*/
#include <stdio.h>
#include <libps.h>

/*
** Include my headers
*/
#include "sprite.h"
#include "pad.h"
#include "screen.h"
#include "tims.h"

/*
** Local defines
*/
#define OTABLE_LENGTH (2)
#define MAX_PACKETS   (2048*24)

/*
** Ordering tables
*/
static GsOT       OTHeader[2];
static GsOT_TAG   OTArray[2][1<<OTABLE_LENGTH];

/*
** Work area
*/
PACKET   pktMem[2][MAX_PACKETS];

/*
** Globals
*/
lpspritelist head=NULL;
u_long drawTime;
u_long rpad = PADstart;
short FntOut;

/*
** Forward declerations
*/
void InitScreen();
void Update();
void UpdateSpr( void *s );

void main()
{
   /* Buffer we are using */
   u_long currBuff;

   /* Temp sprite */
   lpSprite tmpSpr;

   /* Initialise screen */
   InitScreen();

   /* Start joypad stuff */
   InitialiseJoyPad();

   /* Create a sprite and add it's screen position */
   tmpSpr = SprCreate( PLAYER01 );
   tmpSpr->spr.x = SCREEN_W/2;
   tmpSpr->spr.y = SCREEN_H/2;
   tmpSpr->x = tmpSpr->spr.x;
   tmpSpr->y = tmpSpr->spr.y;
   tmpSpr->dx = 3;
   tmpSpr->dy = 3;

   /* Attach an update handle that runs every 2 frames */
   SprAttachCallBack( tmpSpr, UpdateSpr, 2 );

   /* Add sprite to the list */
   head = SprLstAdd( tmpSpr, head );

   /* Create a second sprite and add it's screen position */
   tmpSpr = SprCreate( PLAYER01 );
   tmpSpr->spr.x = SCREEN_W/4;
   tmpSpr->spr.y = SCREEN_H/2;
   tmpSpr->x = tmpSpr->spr.x;
   tmpSpr->y = tmpSpr->spr.y;
   tmpSpr->dx = 5;   /* Made this one sightly faster */
   tmpSpr->dy = 5;

   /* Attach an update handle to work every 4 frames */
   SprAttachCallBack( tmpSpr, UpdateSpr, 4 );

   /* Add sprite to the list */
   head = SprLstAdd( tmpSpr, head );

   while( !(rpad & PADselect && rpad & PADstart) )
   {
      /* Read joypad */
      rpad = ReadJoyPad();

      /* Update */
      Update();

      /* Get current buffer */
      currBuff = GsGetActiveBuff();

      /* Set the work base */
      GsSetWorkBase( (PACKET *)pktMem[currBuff] );

      /* Clear the OT */
      GsClearOt( 0, 0, &OTHeader[currBuff] );

      /* Draw the sprite list (see sprlst.c) */
      SprLstDraw( head, OTHeader[currBuff] );

      /* Sync to end of frame */
      DrawSync( 0 );
      drawTime = VSync( 0 );

      /* Swap buffers */
      GsSwapDispBuff();

      /* Add a clear to the front of the OT */
      GsSortClear( 0, 0, 0, &OTHeader[currBuff] );

      /* Draw the OT */
      GsDrawOt( &OTHeader[currBuff] );

      /* Output some text */
      FntPrint( FntOut, "Screen Draw Time: %d", drawTime );
      FntFlush( FntOut );
   }
   ResetGraph( 3 );
}

/*
** This function is attached to each sprite I've created to
** update it's position on the screen.
*/
void UpdateSpr(void * s)
{
   /* Cast the void * to a sprite
   ** Note: this should be done as it is a sprite
   ** structure which is passed through (see sprlst.c )
   */
   lpSprite spr = (lpSprite)s;

   /*
   ** Update x position
   */
   spr->x += spr->dx;
   if( spr->x+spr->w > SCREEN_W )
   {
      spr->x = SCREEN_W-spr->w;
      spr->dx = -spr->dx;
   }

   if( spr->x < 0 )
   {
      spr->x = 0;
      spr->dx = -spr->dx;
   }

   /*
   ** Update y position
   */
   spr->y += spr->dy;
   if( spr->y+spr->h > SCREEN_H )
   {
      spr->y = SCREEN_H - spr->h;
      spr->dy = -spr->dy;
   }

   if( spr->y < 0 ) 
   {
      spr->y = 0;
      spr->dy = -spr->dy;
   }

}

/*
** InitScreen - Screen initialisation stuff
*/
void InitScreen()
{
   /* VideMode - Can be changed in screen.h */
   SetVideoMode( VID_MODE );

   /* Setup graphics subsystem */
   GsInitGraph( SCREEN_W, SCREEN_H, 0, 0, 0 );

   /* Set the default display buffer */
   GsDefDispBuff( 0, 0, 0, SCREEN_H );

   /* Load font and set area to print out */
   FntLoad( 960, 256 );
   FntOut = FntOpen( 0, 0, SCREEN_W, 50, 0, 256 );

   /* Setup the OT information */
   OTHeader[0].length = OTABLE_LENGTH;
   OTHeader[1].length = OTABLE_LENGTH;
   OTHeader[0].org = OTArray[0];
   OTHeader[1].org = OTArray[1];

   /* Initialise the OT's */
   GsClearOt( 0, 0, &OTHeader[0] );
   GsClearOt( 0, 0, &OTHeader[1] );

}

/* Global track of rotation */
long rot=0;

/*
** Update function called once every loop.
*/
void Update()
{
   SprLstUpdate( head );   
}