chiark - git - mdw - newkind/blob - trade.c

   1 /*
   2  * Elite - The New Kind.
   3  *
   4  * Reverse engineered from the BBC disk version of Elite.
   5  * Additional material by C.J.Pinder.
   6  *
   7  * The original Elite code is (C) I.Bell & D.Braben 1984.
   8  * This version re-engineered in C by C.J.Pinder 1999-2001.
   9  *
  10  * email: <christian@newkind.co.uk>
  11  *
  12  *
  13  */
  14
  15 /*
  16  * trade.c
  17  */
  18
  19 #include <stdlib.h>
  20
  21 #include "config.h"
  22 #include "gfx.h"
  23 #include "elite.h"
  24 #include "trade.h"
  25 #include "docked.h"
  26 #include "planet.h"
  27 #include "space.h"
  28 #include "sound.h"
  29 #include "random.h"
  30 #include "main.h"
  31 #include "swat.h"
  32
  33 #define SLAVES          3
  34 #define NARCOTICS       6
  35 #define FIREARMS        10
  36
  37 /*
  38  * The following holds the Elite Planet Stock Market.
  39  */
  40
  41 #define TONNES          0
  42 #define KILOGRAMS       1
  43 #define GRAMS           2
  44
  45 struct stock_item stock_market[NO_OF_STOCK_ITEMS]=
  46 {
  47         {"Food",                 0, 0,  19, -2,   6, 0x01, TONNES},
  48         {"Textiles",     0, 0,  20, -1,  10, 0x03, TONNES},
  49         {"Radioactives", 0, 0,  65, -3,   2, 0x07, TONNES},
  50         {"Slaves",               0, 0,  40, -5, 226, 0x1F, TONNES},
  51         {"Liquor/Wines", 0, 0,  83, -5, 251, 0x0F, TONNES},
  52         {"Luxuries",     0, 0, 196,  8,  54, 0x03, TONNES},
  53         {"Narcotics",    0, 0, 235, 29,   8, 0x78, TONNES},
  54         {"Computers",    0, 0, 154, 14,  56, 0x03, TONNES},
  55         {"Machinery",    0, 0, 117,  6,  40, 0x07, TONNES},
  56         {"Alloys",               0, 0,  78,  1,  17, 0x1F, TONNES},
  57         {"Firearms",     0, 0, 124, 13,  29, 0x07, TONNES},
  58         {"Furs",                 0, 0, 176, -9, 220, 0x3F, TONNES},
  59         {"Minerals",     0, 0,  32, -1,  53, 0x03, TONNES},
  60         {"Gold",                 0, 0,  97, -1,  66, 0x07, KILOGRAMS},
  61         {"Platinum",     0, 0, 171, -2,  55, 0x1F, KILOGRAMS},
  62         {"Gem-Stones",   0, 0,  45, -1, 250, 0x0F, GRAMS},
  63         {"Alien Items",  0, 0,  53, 15, 192, 0x07, TONNES},
  64 };
  65
  66
  67
  68
  69 /*
  70  * Generate the Elite stock market.
  71  * The prices and quantities are affected by the planet's economy.
  72  * There is also a slight amount of randomness added in.
  73  * The random value is changed each time we hyperspace.
  74  */
  75
  76
  77 void generate_stock_market (void)
  78 {
  79         int quant;
  80         int price;
  81         int i;
  82
  83         for (i = 0; i < NO_OF_STOCK_ITEMS; i++)
  84         {
  85                 price  = stock_market[i].base_price;                                                            /* Start with the base price    */
  86                 price += cmdr.market_rnd & stock_market[i].mask;                                        /* Add in a random amount               */
  87                 price += current_planet_data.economy * stock_market[i].eco_adjust;      /* Adjust for planet economy    */
  88                 price &= 255;                                                                                                           /* Only need bottom 8 bits              */
  89
  90                 quant  = stock_market[i].base_quantity;                                                         /* Start with the base quantity */
  91                 quant += cmdr.market_rnd & stock_market[i].mask;                                        /* Add in a random amount               */
  92                 quant -= current_planet_data.economy * stock_market[i].eco_adjust;      /* Adjust for planet economy    */
  93                 quant &= 255;                                                                                                           /* Only need bottom 8 bits              */
  94
  95                 if (quant > 127)        /* In an 8-bit environment '>127' would be negative */
  96                         quant = 0;              /* So we set it to a minimum of zero. */
  97
  98                 quant &= 63;            /* Quantities range from 0..63 */
  99
 100                 stock_market[i].current_price = price * 4;
 101                 stock_market[i].current_quantity = quant;
 102         }
 103
 104
 105         /* Alien Items are never available for purchase... */
 106
 107         stock_market[ALIEN_ITEMS_IDX].current_quantity = 0;
 108 }
 109
 110
 111
 112 void set_stock_quantities(int *quant)
 113 {
 114         int i;
 115
 116         for (i = 0; i < NO_OF_STOCK_ITEMS; i++)
 117                 stock_market[i].current_quantity = quant[i];
 118
 119         stock_market[ALIEN_ITEMS_IDX].current_quantity = 0;
 120 }
 121
 122
 123 int carrying_contraband (void)
 124 {
 125         return (cmdr.current_cargo[SLAVES] + cmdr.current_cargo[NARCOTICS]) * 2 +
 126                         cmdr.current_cargo[FIREARMS];
 127 }
 128
 129
 130 int total_cargo (void)
 131 {
 132         int i;
 133         int cargo_held;
 134
 135         cargo_held = 0;
 136         for (i = 0; i < 17; i++)
 137         {
 138                 if ((cmdr.current_cargo[i] > 0) &&
 139                         (stock_market[i].units == TONNES))
 140                 {
 141                         cargo_held += cmdr.current_cargo[i];
 142                 }
 143         }
 144
 145         return cargo_held;
 146 }
 147
 148
 149 void scoop_item (int un)
 150 {
 151         int type;
 152         int trade;
 153
 154         if (universe[un].flags & FLG_DEAD)
 155                 return;
 156
 157         type = universe[un].type;
 158
 159         if (type == SHIP_MISSILE)
 160                 return;
 161
 162         if ((cmdr.fuel_scoop == 0) || (universe[un].location.y >= 0) ||
 163                 (total_cargo() == cmdr.cargo_capacity))
 164         {
 165                 universe[un].flags |= FLG_TARGET;
 166                 explode_object (un);
 167                 damage_ship (128 + (universe[un].energy / 2), universe[un].location.z > 0);
 168                 return;
 169         }
 170
 171         if (type == SHIP_CARGO)
 172         {
 173                 trade = rand255() & 7;
 174                 cmdr.current_cargo[trade]++;
 175                 info_message (stock_market[trade].name);
 176                 remove_ship (un);
 177                 return;
 178         }
 179
 180         if (ship_list[type]->scoop_type != 0)
 181         {
 182                 trade = ship_list[type]->scoop_type + 1;
 183                 cmdr.current_cargo[trade]++;
 184                 info_message (stock_market[trade].name);
 185                 remove_ship (un);
 186                 return;
 187         }
 188
 189         explode_object (un);
 190         damage_ship (universe[un].energy / 2, universe[un].location.z > 0);
 191 }
 192