From: Alex Lowe <ayin AT 2xtreme DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: small graphics library
Date: Sun, 03 Jan 1999 14:00:31 -0800
Organization: TempleCRC
Lines: 241
Message-ID: <368FE87F.9977698E@2xtreme.net>
References: <368DE8FD DOT E94FFF21 AT 2xtreme DOT net> <3692676b DOT 560489 AT news DOT worldonline DOT nl>
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Thank you, thank you. That is perfect. Thanks a lot...

"sjoerd DOT s DOT bakker AT tip DOT nl" wrote:
> 
> On Sat, 02 Jan 1999 01:38:05 -0800, Alex Lowe <ayin AT 2xtreme DOT net>
> wrote:
> 
> >Hello all,
> >
> >I am searching for a SMALL (ironically in big letters) graphics library.
> >The smaller the better, just a few graphics modes (at least 640x480x16
> >colors) and a putpixel... A Vesa library is nice, if it is SMALL, I
> >don't want to make a VESA library.
> 
> I often needed that myself... I picked up the following VESA-code from
> the Internet about a year ago. It didn't do bank-switching right, so I
> fixed it. It's a *small* demo-program and it has setmode, putpixel,
> rectangle and circle. It only works with VESA-modes 0x101
> (640x480x256), 0x103 (800x600x256), and 0x105 (1024x768x256). When
> running the program just input the hex-values without the leading 0x:
> 101, 103 or 105. I hope this is of some help!
> 
> ------------------------ vesa.c --------------------------
> 
> #include<stdio.h>
> #include<stdlib.h>
> #include<math.h>
> #include<assert.h>
> #include<go32.h>
> #include<dos.h>
> #include<dpmi.h>
> #include<sys/farptr.h>
> 
> #define MODEINFO_SIZE 256
> #define ADDR_TAB_SIZE 256
> #define WRITE_WINDOW 0
> 
> unsigned char modeinfo[MODEINFO_SIZE];
> 
> #define ModeAttributes   (*(unsigned short*)(modeinfo))
> #define WinAAttributes   (*(unsigned char *)(modeinfo+2))
> #define WinBAttributes   (*(unsigned char *)(modeinfo+3))
> #define WinGranularity   (*(unsigned short*)(modeinfo+4))
> #define WinSize          (*(unsigned short*)(modeinfo+6))
> #define WinASegment      (*(unsigned short*)(modeinfo+8))
> #define WinBSegment      (*(unsigned short*)(modeinfo+10))
> #define WinFuncPtr       (*(unsigned long *)(modeinfo+12))
> #define BytesPerScanLine (*(unsigned short*)(modeinfo+16))
> 
> unsigned short mode=0x101;
> 
> unsigned long phys_base;
> unsigned short win_sizegran_prop;
> 
> unsigned short res_tab[8][2] =
>   { { 640,400},  { 640,480}, { 800, 600}, { 800, 600},
>     {1024,768},  {1024,768}, {1280,1024}, {1280,1024}
>   };
> unsigned int addr_tab[ADDR_TAB_SIZE];
> 
> void init_mode(unsigned short mode)
> {
> __dpmi_regs regs;
> 
> regs.x.ax = 0x4F02;
> regs.x.bx = mode;
> __dpmi_int(0x10, &regs);
> }
> 
> unsigned char VBE_getmodeinfo(unsigned short mode, char *modeinfo)
> {
> __dpmi_regs regs;
> 
> assert(MODEINFO_SIZE < _go32_info_block.size_of_transfer_buffer);
> regs.x.ax = 0x4F01;
> regs.x.cx = mode;
> regs.x.di = __tb & 0x0F;
> regs.x.es = (__tb >> 4) & 0xFFFF;
> __dpmi_int(0x10, &regs);
> dosmemget(__tb, MODEINFO_SIZE, modeinfo);
> 
> return regs.h.ah;
> }
> 
> unsigned short curbank = -1;
> 
> void setbank(unsigned short bank, unsigned short rw)
> {
> __dpmi_regs regs;
> unsigned short win_gran = bank * win_sizegran_prop;
> 
> regs.x.ax = 0x4F05;
> regs.x.bx = rw;
> regs.x.dx = win_gran;
> __dpmi_int(0x10, &regs);
> curbank=bank;
> }
> 
> void putpixel(short x, short y, char c)
> {
> int addr = y * BytesPerScanLine + x;
> int bank = addr/addr_tab[1];
> 
> if (bank != curbank)
>     setbank (bank, WRITE_WINDOW);
> _farpokeb(_dos_ds, phys_base + (addr-addr_tab[curbank]), c);
> }
> 
> void line(short x, short y, short x2, short y2, char c)
> {
> int i, steep = 0, sx, sy, dx, dy, e;
> 
> dx = abs(x2 - x);
> sx = ((x2 - x) > 0) ? 1 : -1;
> dy = abs(y2 - y);
> sy = ((y2 - y) > 0) ? 1 : -1;
> 
> if(dy > dx)
>   { steep = 1;
>     x  ^=  y;  y ^=  x;  x ^=  y;
>     dx ^= dy; dy ^= dx; dx ^= dy;
>     sx ^= sy; sy ^= sx; sx ^= sy;
>   }
> 
> e = (dy << 1) - dx;
> for(i = 0;i <= dx; i++)
>   { if (steep)
>         putpixel(y, x, c);
>     else
>         putpixel(x, y, c);
>     while(e >= 0)
>       { y += sy;
>         e -= dx << 1;
>       }
>     x += sx;
>     e += dy << 1;
>   }
> }
> 
> void rectangle(short x1, short y1, short x2, short y2, char c)
> {
> short x, y;
> 
> for (x=x1; x<=x2; x++)
>     putpixel(x, y1, c);
> for (x=x1; x<=x2; x++)
>     putpixel(x, y2, c);
> for (y=y1; y<=y2; y++)
>   { putpixel(x1, y, c);
>     putpixel(x2, y, c);
>   }
> }
> 
> void circle(short xc, short yc, short r, char c)
> {
> int x = 0, y = r, d = (1 - r) << 1;
> 
> while(y >= 0)
>   { putpixel(xc + x, yc + y, c);
>     putpixel(xc + x, yc - y, c);
>     putpixel(xc - x, yc + y, c);
>     putpixel(xc - x, yc - y, c);
>     if(d + y > 0)
>       { y -= 1;
>         d -= (y << 1) - 1;
>       }
>     if(x > d)
>       { x += 1;
>         d += (x << 1) + 1;
>       }
>   }
> return;
> }
> 
> void make_addr_tab()
> {
> int i, base=0, win = WinSize*1024;
> 
> for (i=0; i<ADDR_TAB_SIZE; i++)
>   { addr_tab[i] = base;
>     base+=win;
>   }
> }
> 
> int main(void)
> {
> short x, y;
> double t, yxprop;
> short c;
> int xres, yres;
> 
> printf("Enter the VESA mode you wanna use (ex. 0x101):");
> scanf("%hx",&mode);
> 
> if (mode < 0x100 || mode > 0x107)
>   { fprintf (stderr, "\nMode %hx is not a VBE 1.0 graphics mode\n",
> mode);
>     exit (1);
>   }
> if (VBE_getmodeinfo(mode, modeinfo))
>   { fprintf (stderr, "\nMode %hx not available\n", mode);
>     exit (2);
>   }
> 
> init_mode (mode);
> 
> phys_base = WinASegment*16;
> win_sizegran_prop = WinSize/WinGranularity;
> 
> make_addr_tab();
> 
> xres=res_tab[mode-0x100][0];
> yres=res_tab[mode-0x100][1];
> 
> for (y=0; y < yres; y++)
>   { c = y/(yres/256.0);
>     for (x=0; x < xres; x++)
>        putpixel(x, y, c);
>   }
> 
> yxprop=yres/(double)xres;
> 
> for (c=0; c<xres>>4; c++)
>      rectangle(c, c*yxprop, xres-c, yres-c*yxprop, c/(xres/256.0)+16);
> 
> for(t=0; t<360; t+=.05)
>   { x=sin(t)*(xres>>2);
>     y=cos(t)*(xres>>2);
>     line (xres >> 1, yres >> 1, (xres>>1) + x, (yres>>1) + y, x+16);
>   }
> 
> for(t=0; t<xres>>4; t++)
>    circle(xres>>1, yres>>1, t, t+16);
> 
> getkey();
> 
> init_mode(0x3);
> return 0;
> }
> 
> ------------------------ vesa.c --------------------------