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 Player g_player[MAX_PLAYERS];
  17 Bullet g_bullet[MAX_BULLETS];
  18
  19 static bool svmode;
  20
  21 void g_player_set(unsigned int id, bool live, float x, float y, float r, float vx, float vy, float vr, int shoot) {
  22         assert(id < MAX_PLAYERS);
  23         g_player[id] = (Player) {
  24                 .updated = true,
  25                 .live    = live,
  26                 .x       = x,
  27                 .y       = y,
  28                 .r       = r,
  29                 .vx      = vx,
  30                 .vy      = vy,
  31                 .vr      = vr,
  32         };
  33 }
  34
  35 void g_bullet_set(unsigned int id, unsigned int owner, bool live, float x, float y, float vx, float vy, int tick) {
  36         assert(id < MAX_BULLETS);
  37         assert(owner < MAX_PLAYERS);
  38         g_bullet[id] = (Bullet) {
  39                 .live  = live,
  40                 .owner = owner,
  41                 .x     = x,
  42                 .y     = y,
  43                 .vx    = vx,
  44                 .vy    = vy,
  45                 .tick  = tick,
  46         };
  47 }
  48
  49 static int freebullet() {
  50         for(int i = 0; i < MAX_BULLETS; i++)
  51                 if(!g_bullet[i].live)
  52                         return i;
  53         return -1;
  54 }
  55
  56 static void moveplayer(int id, float speed) {
  57         g_player[id].vx += speed * cos(g_player[id].r * 2 * M_PI);
  58         g_player[id].vy += speed * sin(g_player[id].r * 2 * M_PI);
  59
  60         if(fabs(g_player[id].vx) > MAX_SPEED)
  61                 g_player[id].vx = copysignf(MAX_SPEED, g_player[id].vx);
  62         if(fabs(g_player[id].vy) > MAX_SPEED)
  63                 g_player[id].vy = copysignf(MAX_SPEED, g_player[id].vy);
  64 }
  65
  66 static void roteplayer(int id, float speed) {
  67         g_player[id].vr += speed;
  68         if(fabs(g_player[id].vr) > MAX_ROTATE)
  69                 g_player[id].vr = copysignf(MAX_ROTATE, g_player[id].vr);
  70 }
  71
  72 static void fireplayer(int id) {
  73         int j = freebullet();
  74         if(j < 0)
  75                 return;
  76
  77         if(g_player[id].shoot < PLAYER_SHOOT)
  78                 return;
  79
  80         g_player[id].shoot = 0;
  81
  82         if(svmode) {
  83                 float vx = BULL_SPEED * cos(g_player[id].r * 2 * M_PI);
  84                 float vy = BULL_SPEED * sin(g_player[id].r * 2 * M_PI);
  85                 g_bullet_set(j, id, true, g_player[id].x, g_player[id].y, vx, vy, 0);
  86         }
  87 }
  88
  89 static void checkspacebound(float * a) {
  90         float x = *a;
  91         if(x < -1)
  92                 x = fabs(x);
  93         else if(x > 1)
  94                 x = -x;
  95         *a = x;
  96 }
  97
  98 static bool collide(float x1, float y1, float r1, float x2, float y2, float r2) {
  99         float l = sqrtf(powf(x1 - x2, 2) + powf(y1 - y2, 2));
 100         return ((l - r1 - r2) <= 0);
 101 }
 102
 103 void g_player_does(unsigned int id, DoesBits code) {
 104         assert(id < MAX_PLAYERS);
 105
 106         if(code.up)
 107                 moveplayer(id, SPEED);
 108         if(code.down)
 109                 moveplayer(id, -SPEED);
 110         if(code.left)
 111                 roteplayer(id, -ROTATE);
 112         if(code.right)
 113                 roteplayer(id, ROTATE);
 114         if(code.fire)
 115                 fireplayer(id);
 116 }
 117
 118 void g_update() {
 119         for(int i = 0; i < MAX_PLAYERS; i++) {
 120                 if(g_player[i].live) {
 121                         g_player[i].updated = true;
 122                         g_player[i].x += g_player[i].vx;
 123                         g_player[i].y += g_player[i].vy;
 124                         g_player[i].r += g_player[i].vr;
 125                         checkspacebound(&g_player[i].x);
 126                         checkspacebound(&g_player[i].y);
 127
 128                         ++g_player[i].shoot;
 129                         if(g_player[i].shoot > PLAYER_SHOOT)
 130                                 g_player[i].shoot = PLAYER_SHOOT;
 131                 }
 132         }
 133
 134         for(int i = 0; i < MAX_BULLETS; i++) {
 135                 if(g_bullet[i].live) {
 136                         g_bullet[i].updated = true;
 137                         g_bullet[i].tick += 1;
 138                         g_bullet[i].x += g_bullet[i].vx;
 139                         g_bullet[i].y += g_bullet[i].vy;
 140
 141                         checkspacebound(&g_bullet[i].x);
 142                         checkspacebound(&g_bullet[i].y);
 143
 144                         for(int j = 0; j < MAX_PLAYERS; j++)
 145                                 if(g_player[j].live)
 146                                         if(collide(g_bullet[i].x, g_bullet[i].y, 0.0001, g_player[j].x, g_player[j].y, PLAYER_SIZE))
 147                                                 if(j != g_bullet[i].owner)
 148                                                         g_player[j].live = false;
 149
 150                         if(g_bullet[i].tick > BULLET_TIME)
 151                                 g_bullet[i].live = false;
 152                 }
 153         }
 154 }
 155
 156 void g_init(bool server_mode) {
 157         svmode = server_mode;
 158         // TODO memset & co
 159 }