Oops, sorry. As far as I know I haven't used anything C specific.
/***************
MODE 13h
****************/
#include <stdio.h>
#include <dpmi.h> // for dpmi functions
#include <go32.h> // _dos_ds
#include <sys/farptr.h> // far pointer support
#include <sys/movedata.h> //dosmemput
#include <conio.h> // getch()
#include <pc.h> // for outportb
/************
DEFINES
*************/
#define SCREEN_WIDTH 320
#define SCREEN_HEIGHT 200
#define PALETTE_MASK 0x3C6
#define PALETTE_READ 0x3C7
#define PALETTE_WRITE 0x3C8
#define PALETTE_DATA 0x3C9
/*************
TYPEDEFS
**************/
typedef unsigned char byte;
/***************
STRUCTURES
****************/
// An RGB color structure
// Note: MCGA only supports 64 rgb values (0-63).
struct rgb_color
{
byte r,g,b;
};
// A 256 color palette structure
struct palette
{
struct rgb_color index[255];
} pal;
void set_mode(int);
void put_pixel(int, int, byte);
void set_palette_color(byte, struct rgb_color);
struct rgb_color get_palette_color(byte);
void draw_line(int, int, int, int, byte);
void fill_screen(byte*);
void draw_circle(int, int, int, byte);
// PALETTE FUNCTIONS
void vsync(void);
void load_pal(char*);
void apply_pal(void);
/*****************************************
MAIN
******************************************/
int main()
{
set_mode(0x13);
printf("Dit is een string.");
//put_pixel(100,100,2);
draw_line(25,25,66,66,2);
draw_circle(100,100,20,2);
getch();
fill_screen(0);
getch();
set_mode(0x3);
return 0;
}
/******************************************
Set video mode
0x12 = VGA graphics mode 640x480x16
0x13 = MCGA graphics mode 320x200x256
0x3 = text mode
*******************************************/
void set_mode(int mode)
{
__dpmi_regs r;
r.x.ax = mode;
__dpmi_int(0x10, &r);
}
/*****************************************
Put a pixel on the screen
color = palette index
******************************************/
void put_pixel(int x, int y, byte color)
{
_farpokeb(_dos_ds, 0xA0000+y*320+x, color);
}
/*****************************************
Set palette color
index = color index ranging from 0-255
red {
green { rgb value ranging from 0-63
blue {
******************************************/
void set_palette_color( byte index, struct rgb_color rgb)
{
vsync(); // sync with monitor
outportb(PALETTE_WRITE, index);
outportb(PALETTE_DATA, rgb.r);
outportb(PALETTE_DATA, rgb.g);
outportb(PALETTE_DATA, rgb.b);
}
/*****************************
GET PALETTE INDEX COLOR
******************************/
struct rgb_color get_palette_color (byte index)
{
struct rgb_color rgb;
outportb(PALETTE_READ, index);
outportb(PALETTE_DATA, rgb.r);
outportb(PALETTE_DATA, rgb.g);
outportb(PALETTE_DATA, rgb.b);
return rgb;
}
/*************************************
Vsync
Call before set_palette_color
**************************************/
void vsync()
{
/* wait until any previous retrace has ended */
do
{
} while (inportb(0x3DA) & 8);
/* wait until a new retrace has just begun */
do
{
} while (!(inportb(0x3DA) & 8));
}
/*********
LINE
**WILL BE CHANGED**
**********/
void draw_line(int x1,int y1,int x2,int y2, byte color)
{
int x,y,dx,dy,a;
// deltay deltax
dx = x2-x1;
dy = y2-y1;
a = dy/dx;
y = y1;
// decision int
//d = (dy << 2) - dx;
_farsetsel(_dos_ds);
for (x = x1; x < x2; x++) //INcrement x
{
y = (a*x) + y1; // y = ax + b
// draw the pixel
_farnspokeb(0xA0000+y*SCREEN_WIDTH+x, color);
}
}
/************
CIRCLE
(x,y) is the center of the circle
*************/
void draw_circle(int x, int y, int radius, byte color)
{
int d, x1,y1;
// initialize
d = 3 - (2 * radius);
x1 = 0;
y1 = radius;
for(x1=0;x1<=y1;x1++)
{
//draw 8 pixels
put_pixel(x + x1, y + y1, color);
put_pixel(x + x1, y - y1, color);
put_pixel(x - x1, y + y1, color);
put_pixel(x - x1, y - y1, color);
put_pixel(x + y1, y + x1, color);
put_pixel(x + y1, y - x1, color);
put_pixel(x - y1, y + x1, color);
put_pixel(x - y1, y - x1, color);
if(d < 0)
d += (x1 << 2) + 6;
else
{
d += ((x1 - y1) << 2) + 10;
y1--;
}
} //for
}
/**************************
FILL THE SCREEN
with color [index]
**DOESNT WORK YET**
***************************/
void fill_screen(byte* index)
{
/*int x,y;
vsync();
for(x=0;x<320;x++)
{
for(y=0;y<200;y++)
{
put_pixel(x,y,index);
}
}*/
byte screen_buffer[255];
dosmemput(screen_buffer,64000,0xA0000);
//_dosmemputb((int*)index,64000,0xA0000);
}
/*****************
LOAD PALETTE
palette size = 256 * 3 bytes
******************/
void load_pal(char* palfile)
{
byte i; //struct palette pal;
FILE* file = fopen(palfile,"rb");
fseek(file,0,SEEK_SET); // set pointer at start ofthe file
for(i=0;i<=255;i++) // loop through 256 palette entries
{
pal.index[i].r = fgetc(file); // get next 3 bytes and put them in the palette index.
pal.index[i].g = fgetc(file);
pal.index[i].b = fgetc(file);
}
}
/*******************
APPLY PALETTE
********************/
void apply_pal()
{
byte i;
vsync(); // sync with monitor to prevent flickering
for (i=0;i<=255;i++)
{
if(pal.index[i].r > 63) // if >63 dont apply palette color
{
outportb(0x3C8, i); //index
outportb(0x3C9, pal.index[i].r); //red
outportb(0x3C9, pal.index[i].g); //green
outportb(0x3C9, pal.index[i].b); //blue
}
}
}
DJGPP is only compiler that has the REGS union (or struct or whatever) in dos.h, and even then it's a different REGS :\
thought the C standard library was the same or almost the same everywhere (seeing as it is a STANDARD). Oh well.
Yeah, it has to do with protected mode and real mode.