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* rocks.c (bucket): rewrote to work with either division rounding mode (symmetric...
[vor.git] / rocks.c
diff --git a/rocks.c b/rocks.c
index 5653979..428c697 100644 (file)
--- a/rocks.c
+++ b/rocks.c
 #include <stdlib.h>
 #include <string.h>
 
+#include "common.h"
 #include "config.h"
 #include "file.h"
 #include "globals.h"
+#include "mt.h"
 #include "rocks.h"
 #include "shape.h"
 
+SDL_Surface *load_image(char *filename);
+
 struct rock_struct {
+       struct rock_struct *next;
        float x,y,dx,dy;
-       int active;
        SDL_Surface *image;
        struct shape *shape;
        int type_number;
 }; 
 
-struct rock_struct rock[MAXROCKS], *rockptr = rock;
+struct rock_struct rocks[MAXROCKS], *free_rocks;
+
+struct rock_struct **rock_buckets[2];
+int n_buckets;
+// we have two sets of buckets -- this variable tells which we are using.
+int p;
+int bw, bh;
+int grid_size;
 
 SDL_Surface *surf_rock[NROCKS];
 struct shape rock_shapes[NROCKS];
 
 // timers for rock generation.
 float rtimers[4];
-int nrocks;
+
+uint32_t nrocks;
+float nrocks_timer;
+float nrocks_inc_ticks = 2*60*20/(F_ROCKS-I_ROCKS);
 
 // constants for rock generation.
-#define KH 32.0  // 32 s for a speed=1 rock to cross the screen horizontally.
-#define KV 24.0  // 24 s for a speed=1 rock to cross the screen vertically.
+#define KH (32*20)  // 32 s for a speed=1 rock to cross the screen horizontally.
+#define KV (24*20)  // 24 s for a speed=1 rock to cross the screen vertically.
 #define RDX 2.5  // range for rock dx values (+/-)
 #define RDY 2.5  // range for rock dy values (+/-)
 
-float rnd(void);
+static inline struct rock_struct **
+bucket(int x, int y, int p)
+{
+       int b = (x+grid_size)/grid_size + bw*((y+grid_size)/grid_size);
+       return &rock_buckets[p][b];
+}
 
-#define crnd() (2*(rnd()-0.5))
+void
+init_buckets(void)
+{
+       int scr_grid_w = (XSIZE+2*grid_size-1) / grid_size;
+       int scr_grid_h = (YSIZE+2*grid_size-1) / grid_size;
+       bw = 1 + scr_grid_w + 1;
+       bh = 1 + scr_grid_h + 1;
+       n_buckets = bw * bh;
+       
+       rock_buckets[0] = malloc(n_buckets * sizeof(struct rock_struct *));
+       rock_buckets[1] = malloc(n_buckets * sizeof(struct rock_struct *));
+       if(!rock_buckets[0] || !rock_buckets[1]) {
+               fprintf(stderr, "Can't allocate rock buckets.\n");
+               exit(1);
+       }
+       p = 0;
+}
 
+void
+transfer_rock(struct rock_struct *r, struct rock_struct **from, struct rock_struct **to)
+{
+       *from = r->next;
+       r->next = *to;
+       *to = r;
+}
 
-int
-init_rocks(void)
+void
+reset_rocks(void)
 {
        int i;
-       char a[MAX_PATH_LEN];
-       SDL_Surface *temp;
 
-       for(i = 0; i<NROCKS; i++) {
-               snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
-               NULLERROR(temp = IMG_Load(a));
-               NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
-               get_shape(surf_rock[i], &rock_shapes[i]);
+       for(i=0; i<MAXROCKS; i++) rocks[i].image = NULL;
+       rocks[0].next = NULL; free_rocks = &rocks[MAXROCKS-1];
+       for(i = 1; i<MAXROCKS; i++) rocks[i].next = &rocks[i-1];
+       for(i = 0; i<n_buckets; i++) {
+               rock_buckets[0][i] = NULL;
+               rock_buckets[1][i] = NULL;
        }
-       nrocks = 41;
-       return 0;
+
+       nrocks = I_ROCKS;
+       nrocks_timer = 0;
 }
 
-void
-reset_rocks(void)
+#define ROCK_LEN sizeof("sprites/rockXX.png")
+
+int
+init_rocks(void)
 {
        int i;
+       char a[ROCK_LEN];
+       int maxw=0, maxh=0;
 
-       for(i = 0; i<MAXROCKS; i++) rock[i].active = 0;
+       for(i = 0; i<NROCKS; i++) {
+               snprintf(a, ROCK_LEN, "sprites/rock%02d.png", i);
+               NULLERROR(surf_rock[i] = load_image(a));
+               get_shape(surf_rock[i], &rock_shapes[i]);
+               maxw = max(maxw, rock_shapes[i].w);
+               maxh = max(maxh, rock_shapes[i].h);
+       }
+       grid_size = max(maxw, maxh) * 3 / 2;
+       init_buckets();
+       reset_rocks();
+       return 0;
 }
 
 enum { LEFT, RIGHT, TOP, BOTTOM };
 
+
+// compute the number of rocks/tick that should be coming from each side,
+// and the speed ranges of rocks coming from each side
 void
-rock_timer_increments(float *ti)
+rock_sides(float *ti, float *speed_min, float *speed_max)
 {
        float dx0,dx1, dy0,dy1;
        float hfactor, vfactor;
        int i;
 
        for(i=0; i<4; i++) ti[i] = 0;
-       hfactor = nrocks/KH; vfactor = nrocks/KV;
+       for(i=0; i<4; i++) speed_min[i] = 0;
+       for(i=0; i<4; i++) speed_max[i] = 0;
+       hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
 
        dx0 = -RDX - screendx; dx1 = RDX - screendx;
        dy0 = -RDY - screendy; dy1 = RDY - screendy;
 
-       if(dx0 != 0) {
-               if(dx0 < 0) {
-                       if(dx1 < 0) ti[RIGHT] = -(dx0+dx1)/2;
-                       else {
-                               ti[RIGHT] = -dx0/2;
-                               ti[LEFT] = dx1/2;
-                       }
-               } else ti[LEFT] = (dx0+dx1)/2;
+       if(dx0 < 0) {
+               speed_max[RIGHT] = -dx0;
+               if(dx1 < 0) {
+                       // Rocks moving left only. So the RIGHT side of the screen
+                       speed_min[RIGHT] = -dx1;
+                       ti[RIGHT] = -(dx0+dx1)/2;
+               } else {
+                       // Rocks moving left and right
+                       speed_max[LEFT] = dx1;
+                       ti[RIGHT] = -dx0/2;
+                       ti[LEFT] = dx1/2;
+               }
+       } else {
+               // Rocks moving right only. So the LEFT side of the screen
+               speed_min[LEFT] = dx0;
+               speed_max[LEFT] = dx1;
+               ti[LEFT] = (dx0+dx1)/2;
        }
        ti[LEFT] *= hfactor;
        ti[RIGHT] *= hfactor;
 
-       if(dy0 != 0) {
-               if(dy0 < 0) {
-                       if(dy1 < 0) ti[BOTTOM] = -(dy0+dy1)/2;
-                       else {
-                               ti[BOTTOM] = -dy0/2;
-                               ti[TOP] = dy1/2;
-                       }
-               } else ti[TOP] = (dy0+dy1)/2;
+       if(dy0 < 0) {
+               speed_max[BOTTOM] = -dy0;
+               if(dy1 < 0) {
+                       // Rocks moving up only. So the BOTTOM of the screen
+                       speed_min[BOTTOM] = -dy1;
+                       ti[BOTTOM] = -(dy0+dy1)/2;
+               } else {
+                       // Rocks moving up and down
+                       speed_max[TOP] = dy1;
+                       ti[BOTTOM] = -dy0/2;
+                       ti[TOP] = dy1/2;
+               }
+       } else {
+               // Rocks moving down only. so the TOP of the screen
+               speed_min[TOP] = dy0;
+               speed_max[TOP] = dy1;
+               ti[TOP] = (dy0+dy1)/2;
        }
        ti[TOP] *= vfactor;
        ti[BOTTOM] *= vfactor;
 }
 
+float
+weighted_rnd_range(float min, float max) {
+       return sqrt(min * min + frnd() * (max * max - min * min));
+}
+
 void
 new_rocks(void)
 {
-       int i,j;
+       int i;
+       struct rock_struct *r;
        float ti[4];
+       float rmin[4];
+       float rmax[4];
+
+       if(nrocks < F_ROCKS) {
+               nrocks_timer += t_frame;
+               if(nrocks_timer >= nrocks_inc_ticks) {
+                       nrocks_timer -= nrocks_inc_ticks;
+                       nrocks++;
+               }
+       }
+
+       rock_sides(ti, rmin, rmax);
 
-       rock_timer_increments(ti);
+       // increment timers
+       for(i=0; i<4; i++) rtimers[i] += ti[i]*t_frame;
 
+       // generate rocks
        for(i=0; i<4; i++) {
-               rtimers[i] += ti[i]*gamerate/20;
-               if(rtimers[i] >= 1) {
-                       j=0;
-                       while(rockptr->active && j<MAXROCKS) {
-                               if(++rockptr - rock >= MAXROCKS) rockptr = rock;
-                               j++;
-                       }
-                       if(!rockptr->active) {
-                               rtimers[i] -= 1;
-                               rockptr->type_number = random() % NROCKS;
-                               rockptr->image = surf_rock[rockptr->type_number];
-                               rockptr->shape = &rock_shapes[rockptr->type_number];
-                               switch(i) {
-                                       case RIGHT:
-                                               rockptr->x = XSIZE;
-                                               rockptr->y = rnd()*(YSIZE + rockptr->image->h);
-                                               break;
-                                       case LEFT:
-                                               rockptr->x = -rockptr->image->w;
-                                               rockptr->y = rnd()*(YSIZE + rockptr->image->h);
-                                               break;
-                                       case BOTTOM:
-                                               rockptr->x = rnd()*(XSIZE + rockptr->image->w);
-                                               rockptr->y = YSIZE;
-                                               break;
-                                       case TOP:
-                                               rockptr->x = rnd()*(XSIZE + rockptr->image->w);
-                                               rockptr->y = -rockptr->image->h;
-                                               break;
-                               }
-
-                               rockptr->dx = RDX*crnd();
-                               rockptr->dy = RDY*crnd();
-
-                               rockptr->active = 1;
+               while(rtimers[i] >= 1) {
+                       rtimers[i] -= 1;
+                       if(!free_rocks) return;  // sorry, we ran out of rocks!
+                       r = free_rocks;
+                       r->type_number = urnd() % NROCKS;
+                       r->image = surf_rock[r->type_number];
+                       r->shape = &rock_shapes[r->type_number];
+                       switch(i) {
+                               case RIGHT:
+                                       r->x = XSIZE;
+                                       r->y = frnd()*(YSIZE + r->image->h);
+
+                                       r->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
+                                       r->dy = RDY*crnd();
+                                       break;
+                               case LEFT:
+                                       r->x = -r->image->w;
+                                       r->y = frnd()*(YSIZE + r->image->h);
+
+                                       r->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
+                                       r->dy = RDY*crnd();
+                                       break;
+                               case BOTTOM:
+                                       r->x = frnd()*(XSIZE + r->image->w);
+                                       r->y = YSIZE;
+
+                                       r->dx = RDX*crnd();
+                                       r->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
+                                       break;
+                               case TOP:
+                                       r->x = frnd()*(XSIZE + r->image->w);
+                                       r->y = -r->image->h;
+
+                                       r->dx = RDX*crnd();
+                                       r->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
+                                       break;
                        }
+                       transfer_rock(r, &free_rocks, bucket(r->x, r->y, p));
                }
        }
 }
@@ -154,83 +255,131 @@ new_rocks(void)
 void
 move_rocks(void)
 {
-       int i;
+       int b;
+       struct rock_struct **head;
+       struct rock_struct *r;
 
        // Move all the rocks
-       for(i = 0; i < MAXROCKS; i++) {
-               if(rock[i].active) {
+       for(b=0; b<n_buckets; b++) {
+               head=&rock_buckets[p][b]; r=*head;
+               while(*head) {
+                       r=*head;
+
                        // move
-                       rock[i].x += (rock[i].dx-screendx)*gamerate;
-                       rock[i].y += (rock[i].dy-screendy)*gamerate;
-                       // clip
-                       if(rock[i].x < -rock[i].image->w || rock[i].x >= XSIZE
-                                       || rock[i].y < -rock[i].image->h || rock[i].y >= YSIZE) {
-                               rock[i].active = 0;
-                       }
+                       r->x += (r->dx - screendx)*t_frame;
+                       r->y += (r->dy - screendy)*t_frame;
+
+                       // clip it, or sort it into the other bucket set
+                       // (either way we move it out of this list).
+                       if(r->x + r->image->w < 0 || r->x >= XSIZE
+                                       || r->y + r->image->h < 0 || r->y >= YSIZE) {
+                               transfer_rock(r, head, &free_rocks);
+                               r->image = NULL;
+                       } else transfer_rock(r, head, bucket(r->x, r->y, 1-p));
                }
        }
+       p = 1-p;  // switch current set of buckets.
 }
 
 void
 draw_rocks(void)
 {
        int i;
-       SDL_Rect src, dest;
+       SDL_Rect dest;
 
-       src.x = 0; src.y = 0;
-
-       for(i = 0; i<MAXROCKS; i++) {
-               if(rock[i].active) {
-                       src.w = rock[i].image->w;
-                       src.h = rock[i].image->h;
-
-                       dest.w = src.w;
-                       dest.h = src.h;
-                       dest.x = (int) rock[i].x;
-                       dest.y = (int) rock[i].y;
-
-                       SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
+       for(i=0; i<MAXROCKS; i++) {
+               if(!rocks[i].image) continue;
+               dest.x = rocks[i].x; dest.y = rocks[i].y;
+               SDL_BlitSurface(rocks[i].image,NULL,surf_screen,&dest);
+       }
+}
 
-               }
+int
+hit_in_bucket(struct rock_struct *r, float x, float y, struct shape *shape)
+{
+       for(; r; r=r->next) {
+               if(collide(x - r->x, y - r->y, r->shape, shape)) return 1;
        }
+       return 0;
 }
 
 int
 hit_rocks(float x, float y, struct shape *shape)
 {
-       int i;
+       int ix, iy;
+       int l, r, t, b;
+       struct rock_struct **bucket;
+
+       ix = x + grid_size; iy = y + grid_size;
+       l = ix / grid_size; r = (ix+shape->w)/grid_size;
+       t = iy / grid_size; b = (iy+shape->h)/grid_size;
+       bucket = &rock_buckets[p][l + t*bw];
+
+       if(hit_in_bucket(*bucket, x, y, shape)) return true;
+       if(l && hit_in_bucket(*(bucket-1), x, y, shape)) return true;
+       if(r && hit_in_bucket(*(bucket-bw), x, y, shape)) return true;
+       if(l && r && hit_in_bucket(*(bucket-(1+bw)), x, y, shape)) return true;
+
+       if(r > l) {
+               if(hit_in_bucket(*(bucket+1), x, y, shape)) return true;
+               if(hit_in_bucket(*(bucket+1-bw), x, y, shape)) return true;
+       }
+       if(t > b) {
+               if(hit_in_bucket(*(bucket+bw), x, y, shape)) return true;
+               if(hit_in_bucket(*(bucket+bw-1), x, y, shape)) return true;
+       }
+       if(r > l && t > b && hit_in_bucket(*(bucket+bw+1), x, y, shape)) return true;
+       return false;
+}
 
-       for(i=0; i<MAXROCKS; i++) {
-               if(rock[i].active) {
-                       if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape)) 
-                               return 1;
-               }
+int
+pixel_hit_in_bucket(struct rock_struct *r, float x, float y)
+{
+       for(; r; r=r->next) {
+               if(x < r->x || y < r->y) continue;
+               if(pixel_collide(x - r->x, y - r->y, r->shape)) return 1;
        }
        return 0;
 }
 
+int
+pixel_hit_rocks(float x, float y)
+{
+       struct rock_struct **b = bucket(x, y, p);
+       if(pixel_hit_in_bucket(*b, x, y)) return 1;
+       if(pixel_hit_in_bucket(*(b-1), x, y)) return 1;
+       if(pixel_hit_in_bucket(*(b-bw), x, y)) return 1;
+       if(pixel_hit_in_bucket(*(b-bw-1), x, y)) return 1;
+       return 0;
+}
+
 void
 blast_rocks(float x, float y, float radius, int onlyslow)
 {
-       int i;
+       int b;
+       struct rock_struct *r;
        float dx, dy, n;
 
-       for(i = 0; i<MAXROCKS; i++ ) {
-               if(rock[i].x <= 0) continue;
+       if(onlyslow) return;
 
-               // This makes it so your explosion from dying magically doesn't leave
-               // any rocks that aren't moving much on the x axis. If onlyslow is set,
-               // only rocks that are barely moving will be pushed.
-               if(onlyslow && (rock[i].dx-screendx < -4 || rock[i].dx-screendx > 3)) continue;
+       for(b=0; b<n_buckets; b++) {
+               for(r=rock_buckets[p][b]; r; r=r->next) {
+                       if(r->x <= 0) continue;
 
-               dx = rock[i].x - x;
-               dy = rock[i].y - y;
+                       // This makes it so your explosion from dying magically doesn't leave
+                       // any rocks that aren't moving much on the x axis. If onlyslow is set,
+                       // only rocks that are barely moving will be pushed.
+                       if(onlyslow && (r->dx - screendx < -4 || r->dx - screendx > 3)) continue;
 
-               n = sqrt(dx*dx + dy*dy);
-               if(n < radius) {
-                       n *= 20;
-                       rock[i].dx += 54.0*(dx+30)/n;
-                       rock[i].dy += 54.0*dy/n;
+                       dx = r->x - x;
+                       dy = r->y - y;
+
+                       n = sqrt(dx*dx + dy*dy);
+                       if(n < radius) {
+                               n *= 15;
+                               r->dx += 54.0*dx/n;
+                               r->dy += 54.0*dy/n;
+                       }
                }
        }
 }