6 load_sprite(Sprite *sprite, char *filename)
8 struct base_sprite *spr = &sprite->sprite;
9 spr->image = load_image(filename);
10 if(!spr->image) return;
12 spr->shape = malloc(sizeof(struct shape));
14 fprintf(stderr, "load_sprite(): can't allocate shape structure.\n");
17 get_shape(spr->image, spr->shape);
22 get_shape(SDL_Surface *img, struct shape *s)
26 uint32_t bits = 0, bit, *p;
28 if(img->format->BytesPerPixel != 2) {
29 fprintf(stderr, "get_shape(): not a 16-bit image!\n");
34 s->w = img->w; s->h = img->h;
35 s->mw = ((img->w+31)>>5);
36 s->mask = malloc(4*s->mw*s->h);
38 fprintf(stderr, "get_shape(): can't allocate bitmask.\n");
44 transp = img->format->colorkey;
46 for(y=0; y<img->h; y++) {
48 for(x=0; x<img->w; x++) {
49 if(!bit) { bits = 0; bit = 0x80000000; }
50 if(*px++ != transp) { bits |= bit; s->area++; }
52 if(!bit || x == img->w - 1) { *(p++) = bits; }
54 px = (uint16_t *) ((uint8_t *) px + img->pitch - 2*img->w);
56 SDL_UnlockSurface(img);
60 line_collide(int xov, struct shape *r, uint32_t *rbits, struct shape *s, uint32_t *sbits)
62 int lshift, n, i, ret = 0;
69 st = r; r = s; s = st;
70 bt = rbits; rbits = sbits; sbits = bt;
75 lshift = (r->w - xov) & 31;
76 rbits += (r->w - xov) >> 5;
78 for(i=0; i<n-1; i++) {
79 lbits = *rbits++ << lshift;
80 lbits |= *rbits >> (32 - lshift);
81 if(lbits & *sbits++) ret = 1;
83 lbits = *rbits << lshift;
84 if(lbits & *sbits) ret = 1;
90 mask_collide(int xov, int yov, struct shape *r, struct shape *s)
93 uint32_t *rbits, *sbits;
96 ry = r->h - yov; sy = 0;
97 rbits = r->mask + (r->h - yov) * r->mw;
100 ry = 0; sy = s->h + yov;
102 sbits = s->mask + (s->h + yov) * s->mw;
105 for(y=0; y<abs(yov); y++) {
106 if(line_collide(xov, r, rbits, s, sbits)) return 1;
107 rbits += r->mw; sbits += s->mw;
114 collide(Sprite *r, Sprite *s)
116 struct shape *rs = r->sprite.shape;
117 struct shape *ss = s->sprite.shape;
118 int dx = s->sprite.x - r->sprite.x;
119 int dy = s->sprite.y - r->sprite.y;
122 if(dx >= 0) xov = max(min(rs->w - dx, ss->w), 0);
123 else xov = -max(min(ss->w + dx, rs->w), 0);
125 if(dy >= 0) yov = max(min(rs->h - dy, ss->h), 0);
126 else yov = -max(min(ss->h + dy, rs->h), 0);
128 if(xov == 0 || yov == 0) return false;
129 else return mask_collide(xov, yov, rs, ss);
133 pixel_collide(unsigned int xoff, unsigned int yoff, struct shape *r)
137 if(xoff >= r->w || yoff >= r->h) return 0;
139 pmask = 0x80000000 >> (xoff&0x1f);
140 return r->mask[(yoff*r->mw) + (xoff>>5)] & pmask;