// Various functions for PSX programs
// Coded by Scott Evans 24/5/97
// Last modified 24/5/97

#ifndef _USEFUL_H
#define _USEFUL_H

#include <libps.h>
#include <stdlib.h>
#include <mytypes.h>
#include <mypad.h>

// Size of various PSX structures

#define GsOT_TAGsize 	(sizeof(GsOT_TAG))
#define GsOTsize		(sizeof(GsOT))
#define GsPktSize		24

// Switch between ordering tables and packet buffers for double buffering

#define _SetOTpktBuff(newOT,oldOT,newPkt,oldPkt,offset)	\
	(newOT==oldOT ? (newOT=oldOT+1,newPkt=oldPkt+offset) : (newOT=oldOT,newPkt=oldPkt))
				 
// Set up packet buffer
// Parameters : size of buffer in number of packets
// Returns    : pointer to packet buffer

PACKET *InitPktBuff(_long npkts)
{
	return((PACKET *)malloc((GsPktSize*npkts)<<1));
}

// Free memory used by packet buffer
// Parameters : pointer to packet buffer

void KillPktBuff(PACKET *p)
{
	free(p);
}

// Set up ordering table 
// Parameters : length of ordering table
// Returns    : pointer to ordering table

GsOT *InitOT(_byte OTlength)
{
	GsOT_TAG *tags=(GsOT_TAG *)malloc(((1<<OTlength)*GsOT_TAGsize)<<1);
	GsOT *ot=(GsOT *)malloc(GsOTsize<<1);
	
	if(ot && tags)
	{
		ot->length=OTlength,(ot+1)->length=OTlength;
		ot->org=tags,(ot+1)->org=tags+(1<<OTlength);
		return(ot);
	}
	
	return((GsOT *)NULL);
}

// Free memory used by ordering table
// Parameters : pointer to ordering table

void KillOT(GsOT *ot)
{
	free(ot->org);
	free(ot);
}

// Initialise graphics sytems
// Parameters : video mode, screen resolution, interlace on/off offset GTE/GPU, dither on/off, buffer mode

void InitGraphics(_long mode,int xres,int yres,int flags,int dither,int vram)
{
	SetVideoMode(mode);
	GsInitGraph(xres,yres,flags,dither,vram);
	GsDefDispBuff(0,0,0,yres);
}

// Initialize controller buffers

#define _InitControllers	GetPadBuf(&pad1,&pad2);

#endif