From:	VANGEL AT VMREDIPN DOT IPN DOT MX
Message-Id:	<199707120129.VAA10007@delorie.com>
Date:	Fri, 11 Jul 97 20:22:06 EST
To:	djgpp AT delorie DOT com
Subject:	About RGB in VGA

Hi!!

In the Turbo C and Turbo C++, there are two functions for start the graphics
mode in 640 X 480 with RGB (0-255 colors) :

--> void far setrgbpalete(int colornum, int red, int green, int blue)

This function defines colors for IBM-8514 graphics card ..

--> void far setrgbcolor(int colornum, int red, int green, int blue)

And this function set palettes entries for VGA and IBM-8514 cards ........

I have the Graphics Card IBM-8514  ( VGA ) and I try to Start the Graphics
Mode for 320 X 240 in RGB with follow code ...  :

----------------------------------------------------------------------

/*** HARDWARE.C *******************************************\
 *  (MSDOS, i386+, VGA, DJGPPv1 or v2)                    *
 *    HW_open_screen         opening output surface;      *
\**********************************************************/

#include <pc.h>
#if DJGPP == 2
#include <sys/nearptr.h>                    /* v2  __djgpp stuff */
#endif

unsigned char *G_vram;                      /* points video ram */
unsigned char *HW_colourmap;                /* where drwaings go to */

/**********************************************************\
 *  Opening output surface and setting the palette.       *
 *  RETURNS: always 1.                                    *
\**********************************************************/

int HW_open_screen(char *display_name,
                   char *screen_name,
                   struct HW_colour palette256ู,
                   unsigned char *colourmap
                  )
{
 int i;
 unsigned char r,g,b;

#if DJGPP == 1
 G_vram=(unsigned char*)0xd0000000;
#endif
#if DJGPP == 2
 G_vram=(unsigned char*)0xa0000+__djgpp_conventional_base;
#endif

 HW_colourmap=colourmap;                    /* for later blits */

 asm("movb  $0x13,%%al":::"%al");           /* %al mode number */
 asm("xorb  %%ah,%%ah":::"%ah");            /* function #0 */
 asm("int   $0x10");

 for(i=0;i<256;i++)
 {
  r=(unsigned char)paletteiู.hw_r;
  g=(unsigned char)paletteiู.hw_g;
  b=(unsigned char)paletteiู.hw_b;

  asm("movb  %0,%%dh":: "g" (r):"%dh");     /* Red */
  asm("movb  %0,%%ch":: "g" (g):"%ch");     /* Green */
  asm("movb  %0,%%cl":: "g" (b):"%cl");     /* Blue */
  asm("movw  %0,%%ebx":: "g" (i):"%ebx");   /* Colour to set */
  asm("movw  $0x1010,%%ax":::"%ax");        /* function 0x10 subfun 0x10 */
  asm("int   $0x10");
 }
 return(1);
}

/**********************************************************\
 *  Colormap onto the screen.                             *
\**********************************************************/

void HW_blit(void)
{
#if DJGPP == 2
 __djgpp_nearptr_enable();
#endif
 HW_copy_int((int*)HW_colourmap,(int*)G_vram,HW_COLOURMAP_SIZE_INT);
#if DJGPP == 2
 __djgpp_nearptr_disable();
#endif
}



/**** HARDWARE.H  (Header file) ****************************/
#ifndef _HARDWARE_H_
#define _HARDWARE_H_

\**********************************************************/
 *  (MSDOS, i386+, VGA, DJGPP)                            *
\**********************************************************/

#define HW_copy_int(src,dst,lng)  asm("movl  %0,%%esi \n"             \
                                      "movl  %1,%%edi \n"             \
                                      "movl  %2,%%ecx \n"             \
                                      "cld \n"                        \
                                      "rep \n"                        \
                                      "movsl (%%esi),(%%edi) \n"      \
                                      ::"g" (src),"g" (dst),"g" (lng) \
                                      :"esi","edi","ecx"              \
                                     )

#define HW_SCREEN_X_SIZE         320
#define HW_SCREEN_Y_SIZE         200        /* number of pixels total */

#define HW_COLOURMAP_SIZE_CHAR 64000        /* bytes in the colourmap */
#define HW_COLOURMAP_SIZE_INT  16000        /* ints in the colourmap */

struct HW_colour                            /* describes colour */
{
 int hw_r;
 int hw_g;
 int hw_b;                                  /* intensity components */
};

int HW_open_screen(char *display_name,
                   char *screen_name,
                   struct HW_colour palette256ู,
                   unsigned char *colourmap
                  );
void HW_blit(void);

#endif

-----------------------------------------------------------------------


 The last code it's very good for start Graphics Mode 320 X 200 (RBG) ...
(By the way, Sergei Savchenko --> savs AT cs DOT mcgill DOT ca ( www.cs.mcgill.ca/~savs
... wrote it .......)

 But I want to write the code for start Graphics in Mode 640 X 480 (RGB)
how the function of Turbo C and Turbo C++ ....

Could anybody tell me how I can to start Mode 640 X 480 and RBG ...?

Which is the code about it ..?

Thanks in advance ....


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