sorrow@oak.circa.ufl.edu (06/23/91)
I am attempting to write a 3d graphics program. I mean REAL three d here. I have a homebrewed set of goggles (X-specs for the Amiga) that I modified to work with the IBM serial port. They flip everytime I set DTR or RTS high and low. I need to be able to flip them the same time the monitor swaps...is this possible? I know the Amiga somehow does this (although I think it relies on the interlacing). During the retrace I also have to swap video pages...is this possible? In other words, an image on page 0 will have a picture that is slightly offset from the image on page 1. Swapping pages at the same time that the glasses swap shutters would produce a 3d effect...I know this works since I've done in character mode, where speed isn't as larage a concern. Any info in C would be appreciated. Brian /* Brian Hook -- Specialist in X to ANSI.SYS porting software ----------------------------------------------------------------- "Seamus, that's my dog...I saw her today at the reception...sorry, sixTEEN inches....better save the women and children first...but this one goes to 11! ..anymore of that plutonium nyborg?....there can be only ONE!....like a finger pointing to the moon....ease the seat back...one day closer to death */
frank@cavebbs.gen.nz (Frank van der Hulst) (06/24/91)
In article <0094A875.86885A20@MAPLE.CIRCA.UFL.EDU> sorrow@oak.circa.ufl.edu writes: >I am attempting to write a 3d graphics program. I mean REAL three >d here. I have a homebrewed set of goggles (X-specs for the Amiga) that >I modified to work with the IBM serial port. They flip everytime >I set DTR or RTS high and low. I need to be able to flip them the >same time the monitor swaps...is this possible? I know the Amiga >somehow does this (although I think it relies on the interlacing). Snap! I have 3d specs (Sega 3d glasses) working exactly the same. Here's C code that should do everything you want, assuming you have a VGA card. /* VGA 320 * 400 * 256 * 2 frames routines. Written by: F van der Hulst, 20/2/91 These routines display pixels in 320*400 mode by modifying the VGA registers, as outlined in Programmer's Journal V7.1 (Jan/Feb '89) article, pages 18-30, by Michael Abrash. The advantage of 320 * 400, is that it gives two separate video pages, which can be displayed on the screen independently. These can contain two views of a scene, taken from slightly different viewpoints. These are displayed alternately on the screen, in sync with a pair of "chopper glasses", to give a 3D effect. */ #include <conio.h> typedef unsigned char DacPalette[256][3]; /* Setvgapalette sets the entire 256 color palette */ /* PalBuf contains RGB values for all 256 colors */ /* R,G,B values range from 0 to 63 */ /* Taken from SVGA256.H, by Jordan Hargraphix Software */ void setvgapalette(DacPalette *PalBuf) { struct REGPACK reg; reg.r_ax = 0x1012; reg.r_bx = 0; reg.r_cx = 256; reg.r_es = FP_SEG(PalBuf); reg.r_dx = FP_OFF(PalBuf); intr(0x10,®); } unsigned int act_page = 0; /* Current page being written to */ #define VGA_SEGMENT 0xa000 #define SC_INDEX 0x3c4 #define GC_INDEX 0x3ce #define CRTC_INDEX 0x3d4 #define DISPIO 0x3DA #define MAP_MASK 2 #define MEMORY_MODE 4 #define GRAPHICS_MODE 5 #define MISCELLANEOUS 6 #define VRT_bit 8 #define MAX_SCAN_LINE 9 #define START_ADDRESS_HIGH 0x0c #define UNDERLINE 0x14 #define MODE_CONTROL 0x17 void writepixel(int x, int y, unsigned char colour) { long addr; addr = ((x >> 2) + 320/4 * y + act_page); addr = ((addr & 0xffff0000l) << 4) + (addr & 0xffffL) + ((long) VGA_SEGMENT << 16); outport(SC_INDEX, (0x100 << (x & 3)) | MAP_MASK); *(char far*)addr = colour; } void set320x400mode(void) { struct REGPACK regs; unsigned char x; regs.r_ax = 0x13; /* Set 320*200*256 graphics mode via BIOS */ intr(0x10, ®s); /* Change CPU addressing of video memory to linear (not odd/even, chain, or chain 4), to allow access to all 256K of display memory. Each byte will now control one pixel, with 4 adjacent pixels at any given address, one pixel per plane. */ outportb(SC_INDEX, MEMORY_MODE); x = inportb(SC_INDEX+1); x &= 0xf7; /* Turn off chain 4 */ x |= 4; /* Turn off odd/even */ outportb(SC_INDEX+1, x); outportb(GC_INDEX, GRAPHICS_MODE); x = inportb(GC_INDEX+1); x &= 0xef; /* Turn off odd/even */ outportb(GC_INDEX+1, x); outportb(GC_INDEX, MISCELLANEOUS); x = inportb(GC_INDEX+1); x &= 0xfd; /* Turn off chain */ outportb(GC_INDEX+1, x); /* Now clear the whole screen, since the mode 13h set only clears 64K. Do this before switching CRTC out of mode 13h, so that we don't see grabage on the screen. */ outport(SC_INDEX, 0x0f00 | MAP_MASK); /* Write to 4 planes at once */ setmem(MK_FP(VGA_SEGMENT, 0), 0xffff, 0); /* Change mode to 320*400 by not scanning each line twice. */ outportb(CRTC_INDEX, MAX_SCAN_LINE); x = inportb(CRTC_INDEX+1); x &= 0xe0; /* Set maximum scan line to 0 */ outportb(CRTC_INDEX+1, x); /* Change CRTC scanning from doubleword to byte mode, allowing the CRTC to scan more than 64K */ outportb(CRTC_INDEX, UNDERLINE); x = inportb(CRTC_INDEX+1); x &= 0xbf; /* Turn off doubleword */ outportb(CRTC_INDEX+1, x); outportb(CRTC_INDEX, MODE_CONTROL); x = inportb(CRTC_INDEX+1); x |= 0x40; /* Turn on the byte mode bit, so memory is linear */ outportb(CRTC_INDEX+1, x); } void end320x400mode(void) { struct REGPACK regs; regs.r_ax = 3; /* Return to text mode */ intr(0x10, ®s); } /* Set visible page */ void setvispage(int page) { outport(CRTC_INDEX, (page << 15) | START_ADDRESS_HIGH); } /* Set active page (page being written to */ void setactpage(int page) { act_page = page ? 0x8000 : 0; } void WaitForVerticalRetrace(void) { static char chopper = 1; while (inportb(DISPIO) & VRT_bit) /* wait */ ; while ((inportb(DISPIO) & VRT_bit) == 0) /* wait */ ; if ((chopper++ & 1)== 0) outportb(0x3fc, 1); else outportb(0x3fc, 3); } void main(int argc, char *argv[]) { set320x400mode(); /* Now fill the rgb_palette structure in memory with colour info */ setvgapalette(&rgb_palette); setactpage(0); /* Now call writepixel to put stuff on page 0 */ setactpage(1); /* Now call writepixel to put stuff on page 1 */ while (!kbhit()) { WaitForVerticalRetrace(); setvispage(0); WaitForVerticalRetrace(); setvispage(1); } getch(); end320x400mode(); } -- Take a walk on the wild side, and I don't mean the Milford Track. Kayaking: The art of appearing to want to go where your boat is taking you.