src/tesuto.c

   1 #include "src/tesuto.h"
   2
   3 global_game_variables_t gvar;
   4
   5 static unsigned char palette[768];
   6
   7 int main(int argc,char **argv) {
   8         struct vrl1_vgax_header *vrl_header;
   9         vrl1_vgax_offset_t *vrl_lineoffs;
  10         unsigned char *buffer;
  11         unsigned int bufsz;
  12         int fd;
  13
  14         if (argc < 3) {
  15                 fprintf(stderr,"drawvrl <VRL file> <palette file>\n");
  16                 return 1;
  17         }
  18
  19         fd = open(argv[1],O_RDONLY|O_BINARY);
  20         if (fd < 0) {
  21                 fprintf(stderr,"Unable to open '%s'\n",argv[1]);
  22                 return 1;
  23         }
  24         {
  25                 unsigned long sz = lseek(fd,0,SEEK_END);
  26                 if (sz < sizeof(*vrl_header)) return 1;
  27                 if (sz >= 65535UL) return 1;
  28
  29                 bufsz = (unsigned int)sz;
  30                 buffer = malloc(bufsz);
  31                 if (buffer == NULL) return 1;
  32
  33                 lseek(fd,0,SEEK_SET);
  34                 if ((unsigned int)read(fd,buffer,bufsz) < bufsz) return 1;
  35
  36                 vrl_header = (struct vrl1_vgax_header*)buffer;
  37                 if (memcmp(vrl_header->vrl_sig,"VRL1",4) || memcmp(vrl_header->fmt_sig,"VGAX",4)) return 1;
  38                 if (vrl_header->width == 0 || vrl_header->height == 0) return 1;
  39         }
  40         close(fd);
  41
  42         probe_dos();
  43         if (!probe_vga()) {
  44                 printf("VGA probe failed\n");
  45                 return 1;
  46         }
  47         int10_setmode(19);
  48         update_state_from_vga();
  49         //vga_enable_256color_modex(); // VGA mode X
  50         VGAmodeX(1, &gvar);
  51
  52         /* load color palette */
  53         fd = open(argv[2],O_RDONLY|O_BINARY);
  54         if (fd >= 0) {
  55                 unsigned int i;
  56
  57                 read(fd,palette,768);
  58                 close(fd);
  59
  60                 vga_palette_lseek(0);
  61                 for (i=0;i < 256;i++) vga_palette_write(palette[(i*3)+0]>>2,palette[(i*3)+1]>>2,palette[(i*3)+2]>>2);
  62         }
  63
  64         /* preprocess the sprite to generate line offsets */
  65         vrl_lineoffs = vrl1_vgax_genlineoffsets(vrl_header,buffer+sizeof(*vrl_header),bufsz-sizeof(*vrl_header));
  66         if (vrl_lineoffs == NULL) return 1;
  67
  68         {
  69                 unsigned int i,j,o;
  70
  71                 /* fill screen with a distinctive pattern */
  72                 for (i=0;i < 320;i++) {
  73                         o = i >> 2;
  74                         vga_write_sequencer(0x02/*map mask*/,1 << (i&3));
  75                         for (j=0;j < 240;j++,o += vga_state.vga_stride)
  76                                 vga_state.vga_graphics_ram[o] = (i^j)&15; // VRL samples put all colors in first 15!
  77                 }
  78         }
  79         while (getch() != 13);
  80
  81         /* make distinctive pattern offscreen, render sprite, copy onscreen */
  82         {
  83                 const unsigned int offscreen_ofs = 0x8000; /* middle of VGA RAM */
  84                 unsigned int i,j,o,o2,x,y,rx,ry,w,h;
  85                 unsigned int overdraw = 1;      // how many pixels to "overdraw" so that moving sprites with edge pixels don't leave streaks.
  86                                                 // if the sprite's edge pixels are clear anyway, you can set this to 0.
  87                 VGA_RAM_PTR omemptr;
  88                 int xdir=1,ydir=1;
  89
  90                 /* starting coords. note: this technique is limited to x coordinates of multiple of 4 */
  91                 x = 0;
  92                 y = 0;
  93
  94                 /* do it */
  95                 omemptr = vga_state.vga_graphics_ram; // save original mem ptr
  96                 while (1) {
  97                         /* stop animating if the user hits ENTER */
  98                         if (kbhit()) {
  99                                 if (getch() == 13) break;
 100                         }
 101
 102                         /* render box bounds. y does not need modification, but x and width must be multiple of 4 */
 103                         if (x >= overdraw) rx = (x - overdraw) & (~3);
 104                         else rx = 0;
 105                         if (y >= overdraw) ry = (y - overdraw);
 106                         else ry = 0;
 107                         h = vrl_header->height + overdraw + y - ry;
 108                         w = (x + vrl_header->width + (overdraw*2) + 3 - rx) & (~3);
 109                         if ((rx+w) > 320) w = 320-rx;
 110
 111                         /* replace VGA stride with our own and mem ptr. then sprite rendering at this stage is just (0,0) */
 112                         vga_state.vga_draw_stride = w >> 2;
 113                         vga_state.vga_graphics_ram = omemptr + offscreen_ofs;
 114
 115                         /* first draw pattern corresponding to that part of the screen. this COULD be optimized, obviously, but it's designed for study.
 116                          * also note we don't have to use the same stride as the display! */
 117                         for (i=rx;i < (rx+w);i++) {
 118                                 o = (i-rx) >> 2;
 119                                 vga_write_sequencer(0x02/*map mask*/,1 << (i&3));
 120                                 for (j=ry;j < (ry+h);j++,o += vga_state.vga_draw_stride)
 121                                         vga_state.vga_graphics_ram[o] = (i^j)&15; // VRL samples put all colors in first 15!
 122                         }
 123
 124                         /* then the sprite. note modding ram ptr means we just draw to (x&3,0) */
 125                         draw_vrl1_vgax_modex(x-rx,y-ry,vrl_header,vrl_lineoffs,buffer+sizeof(*vrl_header),bufsz-sizeof(*vrl_header));
 126
 127                         /* restore ptr */
 128                         vga_state.vga_graphics_ram = omemptr;
 129
 130                         /* block copy to visible RAM from offscreen */
 131                         // TODO: Maybe it would be better for VGA state to have "display stride" vs "draw stride" to avoid saving/restoring like this?
 132                         vga_setup_wm1_block_copy();
 133                         o = offscreen_ofs; // source offscreen
 134                         o2 = (ry * vga_state.vga_stride) + (rx >> 2); // dest visible (original stride)
 135                         for (i=0;i < h;i++,o += vga_state.vga_draw_stride,o2 += vga_state.vga_stride) vga_wm1_mem_block_copy(o2,o,w >> 2);
 136                         /* must restore Write Mode 0/Read Mode 0 for this code to continue drawing normally */
 137                         vga_restore_rm0wm0();
 138
 139                         /* restore stride */
 140                         vga_state.vga_draw_stride = vga_state.vga_stride;
 141
 142                         /* step */
 143                         x += xdir;
 144                         y += ydir;
 145                         if (x >= (319 - vrl_header->width) || x >= 319 || x == 0)
 146                                 xdir = -xdir;
 147                         if (y >= (239 - vrl_header->height) || y >= 239 || y == 0)
 148                                 ydir = -ydir;
 149                 }
 150         }
 151
 152         /* make distinctive pattern offscreen, render sprite, copy onscreen.
 153          * this time, we render the distinctive pattern to another offscreen location and just copy.
 154          * note this version is much faster too! */
 155         {
 156                 const unsigned int offscreen_ofs = 0x8000; /* middle of VGA RAM */
 157                 const unsigned int pattern_ofs = 0xC000;
 158                 unsigned int i,j,o,o2,x,y,rx,ry,w,h;
 159                 unsigned int overdraw = 1;      // how many pixels to "overdraw" so that moving sprites with edge pixels don't leave streaks.
 160                                                 // if the sprite's edge pixels are clear anyway, you can set this to 0.
 161                 VGA_RAM_PTR omemptr;
 162                 int xdir=1,ydir=1;
 163
 164                 /* fill pattern offset with a distinctive pattern */
 165                 for (i=0;i < 320;i++) {
 166                         o = (i >> 2) + pattern_ofs;
 167                         vga_write_sequencer(0x02/*map mask*/,1 << (i&3));
 168                         for (j=0;j < 240;j++,o += vga_state.vga_stride)
 169                                 vga_state.vga_graphics_ram[o] = (i^j)&15; // VRL samples put all colors in first 15!
 170                 }
 171
 172                 /* starting coords. note: this technique is limited to x coordinates of multiple of 4 */
 173                 x = 0;
 174                 y = 0;
 175
 176                 /* do it */
 177                 omemptr = vga_state.vga_graphics_ram; // save original mem ptr
 178                 while (1) {
 179                         /* stop animating if the user hits ENTER */
 180                         if (kbhit()) {
 181                                 if (getch() == 13) break;
 182                         }
 183
 184                         /* render box bounds. y does not need modification, but x and width must be multiple of 4 */
 185                         if (x >= overdraw) rx = (x - overdraw) & (~3);
 186                         else rx = 0;
 187                         if (y >= overdraw) ry = (y - overdraw);
 188                         else ry = 0;
 189                         h = vrl_header->height + overdraw + y - ry;
 190                         w = (x + vrl_header->width + (overdraw*2) + 3 - rx) & (~3);
 191                         if ((rx+w) > 320) w = 320-rx;
 192
 193                         /* block copy pattern to where we will draw the sprite */
 194                         vga_setup_wm1_block_copy();
 195                         o2 = offscreen_ofs;
 196                         o = pattern_ofs + (ry * vga_state.vga_stride) + (rx >> 2); // source offscreen
 197                         for (i=0;i < vrl_header->height;i++,o += vga_state.vga_stride,o2 += (w >> 2)) vga_wm1_mem_block_copy(o2,o,w >> 2);
 198                         /* must restore Write Mode 0/Read Mode 0 for this code to continue drawing normally */
 199                         vga_restore_rm0wm0();
 200
 201                         /* replace VGA stride with our own and mem ptr. then sprite rendering at this stage is just (0,0) */
 202                         vga_state.vga_draw_stride = w >> 2;
 203                         vga_state.vga_graphics_ram = omemptr + offscreen_ofs;
 204
 205                         /* then the sprite. note modding ram ptr means we just draw to (x&3,0) */
 206                         draw_vrl1_vgax_modex(x-rx,y-ry,vrl_header,vrl_lineoffs,buffer+sizeof(*vrl_header),bufsz-sizeof(*vrl_header));
 207
 208                         /* restore ptr */
 209                         vga_state.vga_graphics_ram = omemptr;
 210
 211                         /* block copy to visible RAM from offscreen */
 212                         // TODO: Maybe it would be better for VGA state to have "display stride" vs "draw stride" to avoid saving/restoring like this?
 213                         vga_setup_wm1_block_copy();
 214                         o = offscreen_ofs; // source offscreen
 215                         o2 = (ry * vga_state.vga_stride) + (rx >> 2); // dest visible (original stride)
 216                         for (i=0;i < vrl_header->height;i++,o += vga_state.vga_draw_stride,o2 += vga_state.vga_stride) vga_wm1_mem_block_copy(o2,o,w >> 2);
 217                         /* must restore Write Mode 0/Read Mode 0 for this code to continue drawing normally */
 218                         vga_restore_rm0wm0();
 219
 220                         /* restore stride */
 221                         vga_state.vga_draw_stride = vga_state.vga_stride;
 222
 223                         /* step */
 224                         x += xdir;
 225                         y += ydir;
 226                         if (x >= (319 - vrl_header->width) || x >= 319 || x == 0)
 227                                 xdir = -xdir;
 228                         if (y >= (239 - vrl_header->height) || y >= 239 || y == 0)
 229                                 ydir = -ydir;
 230                 }
 231         }
 232
 233         int10_setmode(3);
 234         //VGAmodeX(0, &gvar);
 235         free(vrl_lineoffs);
 236         buffer = NULL;
 237         free(buffer);
 238         bufsz = 0;
 239         return 0;
 240 }