game.c

   1 #include <SDL2/SDL.h>
   2
   3 #include <assert.h>
   4 #include <stdbool.h>
   5 #include <math.h>
   6
   7 #include "game.h"
   8
   9 #define SPEED      (0.03 / TICK)
  10 #define ROTATE     (0.03 / TICK)
  11 #define BULL_SPEED (0.4  / TICK)
  12
  13 #define MAX_SPEED  (0.3 / TICK)
  14 #define MAX_ROTATE (0.3 / TICK)
  15
  16 // Цифры взяты с потолка, но вроде неплохо подобраны
  17 #define G      3.673e-4
  18 #define M_STAR 10.0
  19 #define M_SHIP 0.1
  20
  21 Player g_player[MAX_PLAYERS];
  22 Bullet g_bullet[MAX_BULLETS];
  23
  24 static bool svmode;
  25
  26 void g_player_set(unsigned int id, bool live, float x, float y, float r, float vx, float vy, float vr, int shoot) {
  27         assert(id < MAX_PLAYERS);
  28         g_player[id] = (Player) {
  29                 .updated = true,
  30                 .live    = live,
  31                 .x       = x,
  32                 .y       = y,
  33                 .r       = r,
  34                 .vx      = vx,
  35                 .vy      = vy,
  36                 .vr      = vr,
  37         };
  38 }
  39
  40 void g_bullet_set(unsigned int id, unsigned int owner, bool live, float x, float y, float vx, float vy, int tick) {
  41         assert(id < MAX_BULLETS);
  42         assert(owner < MAX_PLAYERS);
  43         g_bullet[id] = (Bullet) {
  44                 .live  = live,
  45                 .owner = owner,
  46                 .x     = x,
  47                 .y     = y,
  48                 .vx    = vx,
  49                 .vy    = vy,
  50                 .tick  = tick,
  51         };
  52 }
  53
  54 static int freebullet() {
  55         for(int i = 0; i < MAX_BULLETS; i++)
  56                 if(!g_bullet[i].live)
  57                         return i;
  58         return -1;
  59 }
  60
  61 static void moveplayer(int id, float speed) {
  62         g_player[id].vx += speed * cos(g_player[id].r * 2 * M_PI);
  63         g_player[id].vy += speed * sin(g_player[id].r * 2 * M_PI);
  64
  65         if(fabs(g_player[id].vx) > MAX_SPEED)
  66                 g_player[id].vx = copysignf(MAX_SPEED, g_player[id].vx);
  67         if(fabs(g_player[id].vy) > MAX_SPEED)
  68                 g_player[id].vy = copysignf(MAX_SPEED, g_player[id].vy);
  69 }
  70
  71 static void roteplayer(int id, float speed) {
  72         g_player[id].vr += speed;
  73         if(fabs(g_player[id].vr) > MAX_ROTATE)
  74                 g_player[id].vr = copysignf(MAX_ROTATE, g_player[id].vr);
  75 }
  76
  77 static void fireplayer(int id) {
  78         int j = freebullet();
  79         if(j < 0)
  80                 return;
  81
  82         if(g_player[id].shoot < PLAYER_SHOOT)
  83                 return;
  84
  85         g_player[id].shoot = 0;
  86
  87         if(svmode) {
  88                 float vx = BULL_SPEED * cos(g_player[id].r * 2 * M_PI);
  89                 float vy = BULL_SPEED * sin(g_player[id].r * 2 * M_PI);
  90                 g_bullet_set(j, id, true, g_player[id].x, g_player[id].y, vx, vy, 0);
  91         }
  92 }
  93
  94 static void checkspacebound(float * a) {
  95         float x = *a;
  96         if(x < -1)
  97                 x = fabs(x);
  98         else if(x > 1)
  99                 x = -x;
 100         *a = x;
 101 }
 102
 103 static float length(float x1, float y1, float x2, float y2) {
 104         return sqrtf(powf(x1 - x2, 2) + powf(y1 - y2, 2));
 105 }
 106
 107 static bool collide(float x1, float y1, float r1, float x2, float y2, float r2) {
 108         return ((length(x1, y1, x2, y2) - r1 - r2) <= 0);
 109 }
 110
 111 static void gravity(float * vx, float * vy, float x, float y) {
 112         *vx += copysign(G * M_STAR * M_SHIP / length(0, 0, x, y), x * -1);
 113         *vy += copysign(G * M_STAR * M_SHIP / length(0, 0, x, y), y * -1);
 114 }
 115
 116 void g_player_does(unsigned int id, DoesBits code) {
 117         assert(id < MAX_PLAYERS);
 118
 119         if(code.up)
 120                 moveplayer(id, SPEED);
 121         if(code.down)
 122                 moveplayer(id, -SPEED);
 123         if(code.left)
 124                 roteplayer(id, -ROTATE);
 125         if(code.right)
 126                 roteplayer(id, ROTATE);
 127         if(code.fire)
 128                 fireplayer(id);
 129 }
 130
 131 void g_update() {
 132         for(int i = 0; i < MAX_PLAYERS; i++) {
 133                 if(g_player[i].live) {
 134                         g_player[i].updated = true;
 135                         g_player[i].x += g_player[i].vx;
 136                         g_player[i].y += g_player[i].vy;
 137                         g_player[i].r += g_player[i].vr;
 138
 139                         gravity(&g_player[i].vx, &g_player[i].vy, g_player[i].x, g_player[i].y);
 140
 141                         checkspacebound(&g_player[i].x);
 142                         checkspacebound(&g_player[i].y);
 143
 144                         ++g_player[i].shoot;
 145                         if(g_player[i].shoot > PLAYER_SHOOT)
 146                                 g_player[i].shoot = PLAYER_SHOOT;
 147
 148                         if(collide(g_player[i].x, g_player[i].y, PLAYER_SIZE, 0, 0, STAR_SIZE))
 149                                 g_player[i].live = false;
 150                 }
 151         }
 152
 153         for(int i = 0; i < MAX_BULLETS; i++) {
 154                 if(g_bullet[i].live) {
 155                         g_bullet[i].updated = true;
 156                         g_bullet[i].tick += 1;
 157                         g_bullet[i].x += g_bullet[i].vx;
 158                         g_bullet[i].y += g_bullet[i].vy;
 159
 160                         checkspacebound(&g_bullet[i].x);
 161                         checkspacebound(&g_bullet[i].y);
 162
 163                         for(int j = 0; j < MAX_PLAYERS; j++)
 164                                 if(g_player[j].live)
 165                                         if(collide(g_bullet[i].x, g_bullet[i].y, 0.0001, g_player[j].x, g_player[j].y, PLAYER_SIZE))
 166                                                 if(j != g_bullet[i].owner)
 167                                                         g_player[j].live = false;
 168
 169                         if(g_bullet[i].tick > BULLET_TIME)
 170                                 g_bullet[i].live = false;
 171                 }
 172         }
 173 }
 174
 175 void g_init(bool server_mode) {
 176         svmode = server_mode;
 177         // TODO memset & co
 178 }