git.mutantstargoat.com Git - retrocrawl/blob - src/sprite.c

   1 #include <string.h>
   2 #include "sprite.h"
   3 #include "hwregs.h"
   4 #include "copper.h"
   5
   6 #define MAX_SPRITES     32
   7
   8 static int scount;
   9 static struct sprite *spr[MAX_SPRITES];
  10 static struct sprite *hwspr[4]; /* 4 channels because we support only attached sprites */
  11
  12 static uint16_t nullspr[] = {
  13         0x2000, 0x2100,
  14         0x0000, 0x0000,
  15         0x0000, 0x0000
  16 };
  17 static uint32_t nullspr_addr = (intptr_t)nullspr;
  18
  19 static uint32_t *coplist;
  20
  21
  22 void begin_sprites(void)
  23 {
  24         scount = 0;
  25         memset(hwspr, 0, sizeof hwspr);
  26
  27         coplist = copperlist_end;
  28 }
  29
  30 void end_sprites(void)
  31 {
  32         int i, j, reg;
  33
  34         copperlist_end = coplist;
  35
  36         /* initially point all sprites to the null sprite */
  37         reg = REGN_SPR0PTH;
  38         for(i=0; i<8; i++) {
  39                 add_copper(COPPER_MOVE(reg, nullspr_addr >> 16));
  40                 add_copper(COPPER_MOVE(reg + 2, nullspr_addr));
  41                 reg += 4;
  42         }
  43
  44         /* sort sprites by increasing start position */
  45         for(i=0; i<scount; i++) {
  46                 for(j=i+1; j<scount; j++) {
  47                         if(spr[j]->y < spr[i]->y) {
  48                                 struct sprite *tmp = spr[i];
  49                                 spr[i] = spr[j];
  50                                 spr[j] = tmp;
  51                         }
  52                 }
  53         }
  54
  55         /* set sprite positions and populate copperlist to draw
  56          * hardware sprites
  57          */
  58         for(i=0; i<scount; i++) {
  59                 struct sprite *s = spr[i];
  60                 uint16_t sx = 0x80 + s->x;
  61                 uint16_t sy = 0x2c + s->y;
  62                 uint16_t vstop = sy + s->height;
  63                 uint32_t addr;
  64                 int reuse = 0;
  65
  66                 int chan[4];
  67                 int nchan_found = 0;
  68                 for(j=0; j<4; j++) {
  69                         if(!hwspr[j] || hwspr[j]->y + hwspr[j]->height < s->y) {
  70                                 if(hwspr[j]) {
  71                                         reuse = 1;
  72                                 }
  73                                 chan[nchan_found++] = j;
  74                                 hwspr[j] = s;
  75                                 if(nchan_found >= s->hwslices) {
  76                                         break;
  77                                 }
  78                         }
  79                 }
  80                 if(nchan_found < s->hwslices) continue;
  81
  82                 if(reuse) {
  83                         add_copper(COPPER_VWAIT(sy));
  84                 }
  85
  86                 for(j=0; j<s->hwslices; j++) {
  87                         int idx = chan[j] * 2;
  88                         reg = REGN_SPR0PTH + idx * 4;
  89
  90                         s->hwspr[idx][0] = s->hwspr[idx + 1][0] = (sx >> 1) | (sy << 8);
  91                         s->hwspr[idx][1] = s->hwspr[idx + 1][1] = (vstop << 8) |
  92                                 ((vstop >> 7) & 2) | (sx & 1) | 0x80;
  93
  94                         addr = (intptr_t)s->hwspr[idx];
  95                         add_copper(COPPER_MOVE(reg, addr >> 16));
  96                         add_copper(COPPER_MOVE(reg + 2, addr));
  97                         reg += 4;
  98                         addr = (intptr_t)s->hwspr[idx + 1];
  99                         add_copper(COPPER_MOVE(reg, addr >> 16));
 100                         add_copper(COPPER_MOVE(reg + 2, addr));
 101
 102                         sx += 16;
 103                 }
 104         }
 105
 106         *copperlist_end = COPPER_END;
 107         copperlist_end = coplist;
 108 }
 109
 110 void draw_sprite(struct sprite *s, int x, int y)
 111 {
 112         if(s->img) {
 113                 /* blitter sprite */
 114         } else {
 115                 /* hw sprites */
 116                 spr[scount++] = s;
 117                 s->x = x - s->origx;
 118                 s->y = y - s->origy;
 119         }
 120 }