/* ************************************************ */
/*  METAGRAPHICS SOFTWARE CORPORATION (c) 1989-1992 */
/*  Enables 256 level greyscale on ATI mach32 boards */
/* ************************************************ */

#include <stdlib.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <conio.h>
#include <dos.h>
#include <ctype.h>
#include "metawndo.h"      /* master MetaWINDOW include file */

/* special stack size declaration if using Turbo or Borland C++ */
#ifdef      TurboC
extern unsigned _stklen = 14336U;  /* stack size 14K */
#endif


/* global variables */
palData  palColors[256];
long     max_colors;

/* function prototypes */
void quit(char*, int );
void draw_palette( void );

void C_WritePalette( int palnum, int start, int end, palData *pdata );
int ATI_Mach32_DAC8( int );

void main( int argc, char *argv[] )
{
   int      i, color;
   rect     scrnR;
   
   /* init the system */
   i = InitGraphics(ATI640x480X);
   if( i != 0 )
      exit(i);
    
   SetDisplay( GrafPg0 ); 
   ScreenRect( &scrnR );
   EraseRect( &scrnR );

   /* set a virtual coordinate system of 1000x1000 */
   SetRect( &scrnR, 0, 0, 1000, 1000 );
   VirtualRect( &scrnR );

   max_colors= QueryColors();

/* draw the palette */
   draw_palette();

   /* program palette for 256 level grey scale */
   for( i = 0; i < 256; i++ ) {
      color = i << 8;               // scale up to 0 thru FFFF
      palColors[i].palRed = color;
      palColors[i].palGreen = color;
      palColors[i].palBlue = color;
   }

   // enable 8 bit dacs
	if( !ATI_Mach32_DAC8( 1 ) )
	   quit("No 8 bit DAC on board!",0);

   /* set the palette */
   C_WritePalette( 0, 0,max_colors, &palColors[0] );

   getch();

   // disable 8 bit dacs
	ATI_Mach32_DAC8( 0 );

   quit("Normal End",0);
}

/* C version of write palette that uses upper 8 bits of paldata */
void C_WritePalette( int palnum, int start, int end, palData *pdata )
{
	
#define DAC_INDEX 0x03C8
#define DAC_DATA  0x03C9

	int i;

	for( i = start; i <= end; i++ ) {

		// even though the index port auto increments,
		// set it each time (interrupts may clober it)

		disable(); // cli
		outportb( DAC_INDEX, i );
		outportb( DAC_DATA, pdata->palRed >> 8 );
		outportb( DAC_DATA, pdata->palGreen >> 8 );
		outportb( DAC_DATA, pdata->palBlue >> 8 );
		enable(); // sti

		pdata++;
	}

}

// enable 8 bit dac on an ATI Mach32 chipset
int ATI_Mach32_DAC8(int on )
{


#define CONFIG_STATUS_1 0x12EE
#define EXT_GE_CONFIG	0x7AEE
#define DAC_MASK			0x02EA
#define ATI68830_DAC 	0x0
#define SIERRA_DAC   	0x200
#define TI_DAC   			0x400
#define BROOKTREE_DAC 	0x600
#define ATT_DAC   		0x800

	int dacType;

	// what kind of DAC on board ?
	dacType = inport( CONFIG_STATUS_1 );
	dacType &= 0x0E00;
	
	switch( dacType ) {

		case ATT_DAC:	// ATT20C491 or Brooktree Bt481/482
			break;

		case TI_DAC:	// TI TLC34075 or ATI ATI34075
			break;

		default:
			// not a 8 bit DAC
			return 0;
	}

   if( on )
   	outport( EXT_GE_CONFIG, 0x401A );
   else
      outport( EXT_GE_CONFIG, 0x1A );

	outportb( DAC_MASK, 0xFF );
	return 1;

}



/*
Draw a screen full of boxes, one for each color combination
*/
void draw_palette()
{
   int color;
   int deltaX, deltaY, sizeX, sizeY;
   rect r;
   char buf[10];

   MoveTo( 0,0 );

   /* size the boxes */
   if( max_colors > 16) {
      deltaX = 40;
      deltaY = 50;
      sizeX = 30;
      sizeY = 40;
   }
   else {
      deltaX = 150;
      deltaY = 200;
      sizeX = 100;
      sizeY = 100;
   }


   SetRect( &r, 0, 0, sizeX, sizeY );

   for( color = 0; color <= max_colors; color++ ) {
      PenColor( color );
      PaintRect( &r );
      PenColor( White );
      FrameRect( &r );

      /* label the color if it will fit on the screen */
      if( max_colors <= 16) {
        MoveTo( r.Xmin + 49, r.Ymax + 35 );
        sprintf( buf, "%d", color );
        DrawString( buf );
      }

      OffsetRect( &r, deltaX, 0 );

      if( r.Xmax > 640 ) {
         r.Xmin = 0; r.Xmax = sizeX;
         OffsetRect( &r, 0, deltaY );
      }

   }

}


/*
** Standardized exit routine. Provides for a safe, orderly shutdown.
** Display a final msg, and returns the passed error code to DOS.
*/
void quit( char *msgptr, int err )
{
   int i;

   StopMouse();
   StopEvent();
   SetDisplay(TextPg0);
   if(err)
      putch(07);
   printf("\n\n%s",msgptr);
   i=QueryError();
   printf("\nQueryError=%d/%d",i >> 7,i & 127);
   if(err)
      i=err;
   StopGraphics();
   exit(i);
}