+#include <math.h>
#include <stdlib.h>
+#include <string.h>
+#include "config.h"
#include "common.h"
+#include "globals.h"
#include "sprite.h"
+#include "rocks.h"
-void
-load_sprite(Sprite *s, char *filename)
-{
- s->image = load_image(filename);
- if(s->image) get_shape(s);
-}
+SDL_Surface *load_image(char *filename);
+void load_ship(void);
-void
+// 2 sets of sprites, sorted by position
+static Sprite **sprites[2] = { NULL, NULL };
+
+// which set are we using?
+static int set = 0;
+
+// size of squares into which sprites are sorted.
+static int grid_size = 0;
+
+// screen size in grid squares.
+static int gw = 0, gh = 0;
+
+// lists of free sprites, by type.
+Sprite *free_sprites[N_TYPES];
+
+
+static void
get_shape(Sprite *s)
{
int x, y;
uint16_t *px, transp;
uint32_t bits = 0, bit, *p;
+ s->area = 0;
if(s->image->format->BytesPerPixel != 2) {
fprintf(stderr, "get_shape(): not a 16-bit image!\n");
exit(1);
}
s->w = s->image->w; s->h = s->image->h;
- s->mask_w = ((s->image->w+31)>>5);
- s->mask = malloc(4*s->mask_w*s->h);
+ grid_size = max(grid_size, max(s->w, s->h));
+ s->mask_w = ((s->w+31)>>5);
+ s->mask = malloc(s->mask_w*s->h*sizeof(uint32_t));
if(!s->mask) {
fprintf(stderr, "get_shape(): can't allocate bitmask.\n");
exit(1);
bit = 0;
for(x=0; x<s->image->w; x++) {
if(!bit) { bits = 0; bit = 0x80000000; }
- if(*px++ != transp) { bits |= bit; }
+ if(*px++ != transp) { bits |= bit; s->area++; }
bit >>= 1;
if(!bit || x == s->image->w - 1) { *(p++) = bits; }
}
SDL_UnlockSurface(s->image);
}
+
+void
+load_sprite(Sprite *s, char *filename)
+{
+ s->image = load_image(filename);
+ if(s->image) get_shape(s);
+}
+
+
+static void
+load_sprites(void)
+{
+ load_ship();
+ load_rocks();
+}
+
+
+void
+init_sprites(void)
+{
+ load_sprites();
+
+ grid_size = grid_size * 3 / 2;
+ gw = (XSIZE-1 + 2*grid_size) / grid_size;
+ gh = (YSIZE-1 + 2*grid_size) / grid_size;
+
+ sprites[0] = malloc(2 * gw * gh * sizeof(Sprite *));
+ sprites[1] = (void *)sprites[0] + gw * gh * sizeof(Sprite *);
+ if(!sprites[0]) {
+ fprintf(stderr, "init_sprites(): can't allocate grid squares.\n");
+ exit(1);
+ }
+ memset(sprites[0], 0, 2 * gw * gh * sizeof(Sprite *));
+ set = 0;
+}
+
+static inline Sprite **
+square(int x, int y, int set)
+{
+ int b = (x+grid_size)/grid_size + gw*((y+grid_size)/grid_size);
+ return &sprites[set][b];
+}
+
+void
+add_sprite(Sprite *s)
+{
+ insert_sprite(square(s->x, s->y, set), s);
+}
+
+void
+move_sprite(Sprite *s)
+{
+ // move it.
+ s->x += (s->dx - screendx)*t_frame;
+ s->y += (s->dy - screendy)*t_frame;
+}
+
+void
+sort_sprite(Sprite *s)
+{
+ // clip it, or sort it into the other set of sprites.
+ if(s->x + s->w < 0 || s->x >= XSIZE
+ || s->y + s->h < 0 || s->y >= YSIZE) {
+ insert_sprite(&free_sprites[s->type], s);
+ s->type = NONE;
+ } else insert_sprite(square(s->x, s->y, 1-set), s);
+}
+
+void
+move_sprites(void)
+{
+ int sq;
+ Sprite **head;
+
+ // Move all the sprites (position and set)
+ for(sq=0; sq<gw*gh; sq++) {
+ head=&sprites[set][sq];
+ while(*head) {
+ Sprite *s = remove_sprite(head);
+ move_sprite(s); sort_sprite(s);
+ }
+ }
+ set = 1-set; // switch to other set of sprites.
+}
+
+
static int
line_collide(int xov, unsigned bit, uint32_t *amask, uint32_t *bmask)
{
xov = max(min(a->w - dx, b->w), 0);
if(dy >= 0) yov = max(min(a->h - dy, b->h), 0);
- else yov = -max(min(a->h - -dy, b->h), 0);
+ else yov = -max(min(b->h - -dy, a->h), 0);
if(xov == 0 || yov == 0) return false;
else return mask_collide(xov, yov, a, b);
}
+Sprite *
+hit_in_square(Sprite *r, Sprite *s)
+{
+ for(; r; r=r->next)
+ if(collide(r, s)) break;
+ return r;
+}
+
+Sprite *
+collides(Sprite *s)
+{
+ int l, r, t, b;
+ Sprite **sq;
+ Sprite *c;
+
+ l = (s->x + grid_size) / grid_size;
+ r = (s->x + s->w + grid_size) / grid_size;
+ t = (s->y + grid_size) / grid_size;
+ b = (s->y + s->h + grid_size) / grid_size;
+ sq = &sprites[set][l + t*gw];
+
+ if((c = hit_in_square(*sq, s))) return c;
+ if(l > 0 && (c = hit_in_square(*(sq-1), s))) return c;
+ if(t > 0 && (c = hit_in_square(*(sq-gw), s))) return c;
+ if(l > 0 && t > 0 && (c = hit_in_square(*(sq-1-gw), s))) return c;
+
+ if(r > l) {
+ if((c = hit_in_square(*(sq+1), s))) return c;
+ if(t > 0 && hit_in_square(*(sq+1-gw), s)) return c;
+ }
+ if(b > t) {
+ if((c = hit_in_square(*(sq+gw), s))) return c;
+ if(l > 0 && (c = hit_in_square(*(sq-1+gw), s))) return c;
+ }
+ if(r > l && b > t && (c = hit_in_square(*(sq+1+gw), s))) return c;
+ return NULL;
+}
+
int
pixel_collide(Sprite *s, int x, int y)
{
pmask = 0x80000000 >> (x&0x1f);
return s->mask[(y*s->mask_w) + (x>>5)] & pmask;
}
+
+int
+pixel_hit_in_square(Sprite *r, float x, float y)
+{
+ for(; r; r=r->next) {
+ if(pixel_collide(r, x, y)) return 1;
+ }
+ return 0;
+}
+
+int
+pixel_collides(float x, float y)
+{
+ int l, t;
+ Sprite **sq;
+
+ l = (x + grid_size) / grid_size; t = (y + grid_size) / grid_size;
+ sq = &sprites[set][l + t*gw];
+ if(pixel_hit_in_square(*sq, x, y)) return true;
+ if(l > 0 && pixel_hit_in_square(*(sq-1), x, y)) return true;
+ if(t > 0 && pixel_hit_in_square(*(sq-gw), x, y)) return true;
+ if(l > 0 && t > 0 && pixel_hit_in_square(*(sq-1-gw), x, y)) return true;
+ return false;
+}
+
+
+float
+sprite_mass(Sprite *s)
+{
+ if(s->type == SHIP_SPRITE) return s->area;
+ else if(s->type == ROCK_SPRITE) return 3*s->area;
+ else return 0;
+}
+
+void
+bounce(Sprite *a, Sprite *b)
+{
+ float x, y, n;
+ float va, vb;
+ float ma, mb, mr;
+
+ // (x, y) is unit vector pointing from A's center to B's center.
+ x = (b->x + b->w / 2) - (a->x + a->w / 2);
+ y = (b->y + b->h / 2) - (a->y + a->h / 2);
+ n = sqrt(x*x + y*y); x /= n; y /= n;
+
+ // velocities along (x, y), or 0 if already moving away.
+ va = max(x*a->dx + y*a->dy, 0);
+ vb = min(x*b->dx + y*b->dy, 0);
+
+ // mass ratio
+ ma = sprite_mass(a); mb = sprite_mass(b);
+ if(ma && mb) mr = mb/ma; else mr = 1;
+
+ a->dx += x*(mb*vb - ma*va)/ma; a->dy += y*(mb*vb - ma*va)/ma;
+ b->dx += x*(ma*va - mb*vb)/mb; b->dy += y*(ma*va - mb*vb)/mb;
+}
Got questions, comments, patches, etc.? Contact Jason Woofenden