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[vor.git] / rocks.c
1 #include <SDL_image.h>
2 #include <math.h>
3 #include <stdlib.h>
4 #include <string.h>
5
6 #include "common.h"
7 #include "vorconfig.h"
8 #include "file.h"
9 #include "globals.h"
10 #include "mt.h"
11 #include "rocks.h"
12 #include "sprite.h"
13
14 static struct rock rocks[MAXROCKS];
15 static struct rock prototypes[NROCKS];
16
17 // timers for rock generation.
18 static float rtimers[4];
19
20 uint32_t nrocks = NORMAL_I_ROCKS;
21 uint32_t initial_rocks = NORMAL_I_ROCKS;
22 uint32_t final_rocks = NORMAL_F_ROCKS;
23 float nrocks_timer = 0;
24 float nrocks_inc_ticks = 2*60*20/(NORMAL_F_ROCKS-NORMAL_I_ROCKS);
25
26 // constants for rock generation.
27 #define KH (32*20)  // 32 s for a speed=1 rock to cross the screen horizontally.
28 #define KV (24*20)  // 24 s for a speed=1 rock to cross the screen vertically.
29 #define RDX 2.5  // range for rock dx values (+/-)
30 #define RDY 2.5  // range for rock dy values (+/-)
31
32 void
33 reset_rocks(void)
34 {
35         nrocks = initial_rocks;
36         nrocks_inc_ticks = 2*60*20/(final_rocks-initial_rocks);
37         nrocks_timer = 0;
38 }
39
40 #define ROCK_LEN sizeof("rockXX.png")
41
42 void
43 load_rocks(void)
44 {
45         int i;
46         char a[ROCK_LEN];
47
48         for(i=0; i<NROCKS; i++) {
49                 snprintf(a, ROCK_LEN, "rock%02d.png", i);
50                 load_sprite(SPRITE(&prototypes[i]), a);
51                 prototypes[i].sprite_type = ROCK;
52                 prototypes[i].flags = MOVE|DRAW|COLLIDE;
53         }
54
55         memset(rocks, 0, MAXROCKS*sizeof(struct rock));
56
57         for(i=1; i<MAXROCKS; i++) rocks[i].next = &rocks[i-1];
58         free_sprites[ROCK] = SPRITE(&rocks[MAXROCKS-1]);
59
60         reset_rocks();
61 }
62
63 enum { LEFT, RIGHT, TOP, BOTTOM };
64
65
66 // compute the number of rocks/tick that should be coming from each side,
67 // and the speed ranges of rocks coming from each side
68 void
69 rock_sides(float *ti, float *speed_min, float *speed_max)
70 {
71         float dx0,dx1, dy0,dy1;
72         float hfactor, vfactor;
73         int i;
74
75         for(i=0; i<4; i++) ti[i] = 0;
76         for(i=0; i<4; i++) speed_min[i] = 0;
77         for(i=0; i<4; i++) speed_max[i] = 0;
78         hfactor = (float)nrocks/KH; vfactor = (float)nrocks/KV;
79
80         dx0 = -RDX - screendx; dx1 = RDX - screendx;
81         dy0 = -RDY - screendy; dy1 = RDY - screendy;
82
83         if(dx0 < 0) {
84                 speed_max[RIGHT] = -dx0;
85                 if(dx1 < 0) {
86                         // Rocks moving left only. So the RIGHT side of the screen
87                         speed_min[RIGHT] = -dx1;
88                         ti[RIGHT] = -(dx0+dx1)/2;
89                 } else {
90                         // Rocks moving left and right
91                         speed_max[LEFT] = dx1;
92                         ti[RIGHT] = -dx0/2;
93                         ti[LEFT] = dx1/2;
94                 }
95         } else {
96                 // Rocks moving right only. So the LEFT side of the screen
97                 speed_min[LEFT] = dx0;
98                 speed_max[LEFT] = dx1;
99                 ti[LEFT] = (dx0+dx1)/2;
100         }
101         ti[LEFT] *= hfactor;
102         ti[RIGHT] *= hfactor;
103
104         if(dy0 < 0) {
105                 speed_max[BOTTOM] = -dy0;
106                 if(dy1 < 0) {
107                         // Rocks moving up only. So the BOTTOM of the screen
108                         speed_min[BOTTOM] = -dy1;
109                         ti[BOTTOM] = -(dy0+dy1)/2;
110                 } else {
111                         // Rocks moving up and down
112                         speed_max[TOP] = dy1;
113                         ti[BOTTOM] = -dy0/2;
114                         ti[TOP] = dy1/2;
115                 }
116         } else {
117                 // Rocks moving down only. so the TOP of the screen
118                 speed_min[TOP] = dy0;
119                 speed_max[TOP] = dy1;
120                 ti[TOP] = (dy0+dy1)/2;
121         }
122         ti[TOP] *= vfactor;
123         ti[BOTTOM] *= vfactor;
124 }
125
126 float
127 weighted_rnd_range(float min, float max) {
128         return sqrt(min * min + frnd() * (max * max - min * min));
129 }
130
131 void
132 new_rocks(void)
133 {
134         int i, type;
135         struct rock *r;
136         float ti[4];
137         float rmin[4];
138         float rmax[4];
139
140         if(nrocks < final_rocks) {
141                 nrocks_timer += t_frame;
142                 if(nrocks_timer >= nrocks_inc_ticks) {
143                         nrocks_timer -= nrocks_inc_ticks;
144                         nrocks++;
145                 }
146         }
147
148         rock_sides(ti, rmin, rmax);
149
150         // increment timers
151         for(i=0; i<4; i++) rtimers[i] += ti[i]*t_frame;
152
153         // generate rocks
154         for(i=0; i<4; i++) {
155                 while(rtimers[i] >= 1) {
156                         rtimers[i] -= 1;
157                         if(!free_sprites[ROCK]) return;  // sorry, we ran out of rocks!
158                         r = (struct rock *) remove_sprite(&free_sprites[ROCK]);
159                         type = urnd() % NROCKS;
160                         *r = prototypes[type];
161                         r->type = type;
162                         r->life = r->area * 300;
163                         switch(i) {
164                                 case RIGHT:
165                                         r->x = XSIZE;
166                                         r->y = frnd()*(YSIZE + r->image->h);
167
168                                         r->dx = -weighted_rnd_range(rmin[i], rmax[i]) + screendx;
169                                         r->dy = RDY*crnd();
170                                         break;
171                                 case LEFT:
172                                         r->x = -r->image->w;
173                                         r->y = frnd()*(YSIZE + r->image->h);
174
175                                         r->dx = weighted_rnd_range(rmin[i], rmax[i]) + screendx;
176                                         r->dy = RDY*crnd();
177                                         break;
178                                 case BOTTOM:
179                                         r->x = (frnd()*(XSIZE + r->image->w)) - r->image->w;
180                                         r->y = YSIZE;
181
182                                         r->dx = RDX*crnd();
183                                         r->dy = -weighted_rnd_range(rmin[i], rmax[i]) + screendy;
184                                         break;
185                                 case TOP:
186                                         r->x = (frnd() * (XSIZE + r->image->w)) - r->image->w;
187                                         r->y = -r->image->h;
188
189                                         r->dx = RDX*crnd();
190                                         r->dy = weighted_rnd_range(rmin[i], rmax[i]) + screendy;
191                                         break;
192                         }
193                         add_sprite(SPRITE(r));
194                 }
195         }
196 }
197
198
199 void
200 draw_rocks(void)
201 {
202         int i;
203         for(i=0; i<MAXROCKS; i++) draw_sprite(SPRITE(&rocks[i]));
204 }