Added easy extension of custom merge results. Example fib merge rules added. Code altered to make use of this new style

Makefile

@@ -1,4 +1,4 @@
-CC	    ?= clang
+CC	    := clang
 CFLAGS  += -g -Wall -Wextra
 LFLAGS  +=
 DEFINES := -DVT100 $(shell pkg-config --cflags sdl2)

src/engine.c

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <time.h>
+#include "merge.h"
 #include "engine.h"
 #include "highscore.h"
 
@@ -95,12 +96,12 @@ static void merge(struct gfx_state *s, struct gamestate *g, int d, void (*callba
 
 #define merge_if_equal(xoff, yoff)\
     do {\
-        if (g->grid[x][y] && (g->grid[x][y] == g->grid[x+xoff][y+yoff])) {\
-            g->grid[x][y] += g->grid[x+xoff][y+yoff];\
+        if (g->grid[x][y] && (merge_possible(g->grid[x][y], g->grid[x+xoff][y+yoff]))) {\
+            g->grid[x][y] = merge_result(g->grid[x][y], g->grid[x+xoff][y+yoff]);\
             g->grid[x+xoff][y+yoff] = 0;\
             g->blocks_in_play -= 1;\
-            g->score_last += g->grid[x][y];\
-            g->score += g->grid[x][y];\
+            g->score_last += merge_value(g->grid[x][y]);\
+            g->score += merge_value(g->grid[x][y]);\
             g->moved = 1;\
         }\
     } while (0)
@@ -158,12 +159,12 @@ int gamestate_end_condition(struct gamestate *g)
 
     for (x = 0; x < g->opts->grid_width; ++x) {
         for (y = 0; y < g->opts->grid_height; ++y) {
-            if (g->grid[x][y] >= g->opts->goal)
+            if (g->grid[x][y] == merge_goal())
                 return 1;
             if (!g->grid[x][y] || ((x + 1 < g->opts->grid_width) &&
-                        (g->grid[x][y] == g->grid[x+1][y]))
+                        merge_possible(g->grid[x][y], g->grid[x+1][y]))
                     || ((y + 1 < g->opts->grid_height) &&
-                        (g->grid[x][y] == g->grid[x][y+1])))
+                        merge_possible(g->grid[x][y], g->grid[x][y+1])))
                 ret = 0;
         }
     }
@@ -174,43 +175,30 @@ int gamestate_end_condition(struct gamestate *g)
 /* Place a random block into the current grid */
 void gamestate_new_block(struct gamestate *g)
 {
-    /* pick random square, if it is full, then move forward until we find
-     * an empty square. This is biased */
-
-    static int seeded = 0;
-    if (!seeded) {
-        seeded = 1;
-        srand(time(NULL));
-    }
-
     /* Exit early if there are no spaces to place a block */
     if (g->blocks_in_play == g->gridsize) return;
 
-    /* Fix up this random number generator */
-    /* Method:
-     *  -   Find a non-biased index between 0 and blocks_play, n
-     *  -   Find the nth 0 element in the array
-     *  -   insert a random value there
-     */
+#ifdef FIX
+    int block_number = rand() % (g->gridsize - g->blocks_in_play);
 
-    /* Error here */
-#ifdef SKIP
-    size_t block_position = (size_t)rand() % (
-            g->opts->grid_width * g->opts->grid_height - g->blocks_in_play);
+    int x, y, p = 0;
+    for (y = 0; y < g->opts->grid_height; ++y) {
+        for (x = 0; x < g->opts->grid_width; ++x) {
+            if (p == block_number) {
+                g->grid[x][y] = rand() & 1 ? 1 : 2;
+                g->blocks_in_play += 1;
+                return;
+            }
 
-    size_t i, ps;
-    for (i = 0, ps = 0; ps < block_position; ++i) {
-        if (!g->grid[i / g->opts->grid_width][i % g->opts->grid_height]) ps++;
+            if (!g->grid[x][y]) p++;
+        }
     }
-
-    g->grid[i / g->opts->grid_width][i % g->opts->grid_height]
-         = (rand() & 3) ? g->opts->spawn_value : g->opts->spawn_value * 2;
 #endif
 
     /* Use rudimentary for now */
     int x, y;
     while (g->grid[x = rand() % g->opts->grid_width][y = rand() % g->opts->grid_height]);
-    g->grid[x][y] = (rand() & 3) ? g->opts->spawn_value : g->opts->spawn_value * 2;
+    g->grid[x][y] = rand() & 1 ? 1 : 2;
     g->blocks_in_play += 1;
 }
 
@@ -231,19 +219,21 @@ struct gamestate* gamestate_init(struct gameoptions *opt)
 {
     if (!opt) return NULL;
 
+    srand(time(NULL));
+
     struct gamestate *g = malloc(sizeof(struct gamestate));
     if (!g) goto gamestate_alloc_fail;
     g->gridsize = opt->grid_width * opt->grid_height;
 
-    g->grid_data_ptr = calloc(g->gridsize, sizeof(long));
+    g->grid_data_ptr = calloc(g->gridsize, sizeof(int));
     if (!g->grid_data_ptr) goto grid_data_alloc_fail;
 
-    g->grid = malloc(opt->grid_height * sizeof(long*));
+    g->grid = malloc(opt->grid_height * sizeof(int*));
     if (!g->grid) goto grid_alloc_fail;
 
     /* Switch to two allocation version */
     int i;
-    long **iterator = g->grid;
+    int **iterator = g->grid;
     for (i = 0; i < g->gridsize; i += opt->grid_width)
         *iterator++ = &g->grid_data_ptr[i];
 
@@ -251,7 +241,7 @@ struct gamestate* gamestate_init(struct gameoptions *opt)
     g->score = 0;
     g->score_high = 0;
     g->score_last = 0;
-    g->print_width = digits_ceiling(opt->goal);
+    g->print_width = digits_ceiling(merge_value(merge_goal()));
     g->blocks_in_play = 0;
     g->opts = opt;
 

src/engine.h

@@ -13,8 +13,8 @@
 
 struct gamestate {
     /* Game state */
-    long *grid_data_ptr;
-    long **grid;
+    int *grid_data_ptr;
+    int **grid;
     int gridsize;
     int moved;
     long score;

src/gfx.h

@@ -3,13 +3,6 @@
 
 #include "engine.h"
 
-/* These can be defined by an implemenation if special codes are used
- * to represent some keys. e.g. KEY_LEFT in ncurses */
-#define GFX_RIGHT_EXTRA
-#define GFX_LEFT_EXTRA
-#define GFX_DOWN_EXTRA
-#define GFX_UP_EXTRA
-
 struct gfx_state;
 
 /* Initialization of a graphics context */

src/gfx_curses.c

@@ -3,11 +3,6 @@
 #include <unistd.h>
 #include "gfx.h"
 
-#define GFX_EXTRA_UP    case KEY_UP:
-#define GFX_EXTRA_DOWN  case KEY_DOWN:
-#define GFX_EXTRA_RIGHT case KEY_RIGHT:
-#define GFX_EXTRA_LEFT  case KEY_LEFT:
-
 #define NUMBER_OF_COLORS 7
 
 #define iterate(n, expression)\
@@ -38,28 +33,18 @@ struct gfx_state* gfx_init(struct gamestate *g)
     if (g->opts->enable_color && has_colors()) {
         start_color();
 
-        int x = 0;
-        init_pair(x++, 1, 0);
-        init_pair(x++, 2, 0);
-        init_pair(x++, 3, 0);
-        init_pair(x++, 4, 0);
-        init_pair(x++, 5, 0);
-        init_pair(x++, 6, 0);
-        init_pair(x++, 7, 0);
-        char dummy[x == NUMBER_OF_COLORS ? 1 : -1];
+        init_pair(0, 1, 0);
+        init_pair(1, 2, 0);
+        init_pair(2, 3, 0);
+        init_pair(3, 4, 0);
+        init_pair(4, 5, 0);
+        init_pair(5, 6, 0);
+        init_pair(6, 7, 0);
     }
 
     return s;
 }
 
-static int int_log2(int n)
-{
-    int k = 0;
-    while (n)
-        ++k, n /= 2;
-    return k;
-}
-
 void gfx_draw(struct gfx_state *s, struct gamestate *g)
 {
     if (g->score_last)
@@ -79,9 +64,9 @@ void gfx_draw(struct gfx_state *s, struct gamestate *g)
 
         for (x = 0; x < g->opts->grid_width; ++x) {
             if (g->grid[x][y]) {
-                wattron(s->window, COLOR_PAIR(int_log2(g->grid[x][y]) % NUMBER_OF_COLORS));
-                mvwprintw(s->window, ypos, xpos, "%*d", g->print_width, g->grid[x][y]);
-                wattroff(s->window, COLOR_PAIR(int_log2(g->grid[x][y]) % NUMBER_OF_COLORS));
+                wattron(s->window, COLOR_PAIR(g->grid[x][y] % NUMBER_OF_COLORS));
+                mvwprintw(s->window, ypos, xpos, "%*ld", g->print_width, merge_value(g->grid[x][y]));
+                wattroff(s->window, COLOR_PAIR(g->grid[x][y] % NUMBER_OF_COLORS));
                 mvwprintw(s->window, ypos, xpos + g->print_width, " |");
             }
             else {

src/gfx_sdl.c

@@ -102,7 +102,7 @@ void gfx_draw(struct gfx_state *s, struct gamestate *g)
 
         for (x = 0; x < g->opts->grid_width; ++x) {
             if (g->grid[x][y]) {
-                snprintf(string_buffer, buffer_length, "%*ld |", g->print_width, g->grid[x][y]);
+                snprintf(string_buffer, buffer_length, "%*ld |", g->print_width, merge_value(g->grid[x][y]));
                 strncpy(line_buffer + line_index, string_buffer, buffer_length - line_index);
                 line_index += strlen(string_buffer);
             }

src/gfx_terminal.c

@@ -45,7 +45,7 @@ void gfx_draw(struct gfx_state *s, struct gamestate *g)
 
         for (x = 0; x < g->opts->grid_width; ++x) {
             if (g->grid[x][y])
-                printf("%*zd |", g->print_width, g->grid[x][y]);
+                printf("%*zd |", g->print_width, merge_value(g->grid[x][y]));
             else
                 printf("%*s |", g->print_width, "");
         }

src/highscore.c

@@ -64,6 +64,8 @@ void highscore_load(struct gamestate *g)
 
 void highscore_save(struct gamestate *g)
 {
+    /* Someone could make their own merge rules for highscores and this could be meaningless,
+     * howeverhighscores are in plaintext, so that isn't that much of a concern */
     if (g->score < g->score_high || g->opts->grid_width != 4 || g->opts->grid_height != 4)
         return;
 

src/merge.c

@@ -0,0 +1,30 @@
+#include "assert.h"
+#include "merge.h"
+
+#define MERGE_GOAL 11
+
+:a
+const long merge_values[] = {
+    0, 2, 4, 8, 16, 32, 64, 128, 256, 512,
+    1024, 2048
+};
+
+inline long merge_value(const int v1)
+{
+    return v1 <= MERGE_GOAL ? merge_values[v1] : -1;
+}
+
+inline long merge_goal(void)
+{
+    return MERGE_GOAL;
+}
+
+inline int merge_possible(const int v1, const int v2)
+{
+    return v1 == v2;
+}
+
+inline int merge_result(const int v1, const int v2)
+{
+    return merge_possible(v1, v2) ? v1 + 1 : -1;
+}

src/merge.h

@@ -0,0 +1,21 @@
+#ifndef MERGE_H
+#define MERGE_H
+
+/* When defining a new set of rules, remember that the grid values (and the
+ * therefore the arguments v1, v2) are index values and should be treated as
+ * such */
+
+/* This should return the value of a given index. 0 should default to 0 (empty) */
+long merge_value(const int v1);
+
+/* This should return the goal value */
+long merge_goal(void);
+
+/* Return if a merge is possible between two indices */
+int merge_possible(const int v1, const int v2);
+
+/* The result of a merge of two values. If the two parameters are not mergeable,
+ * then a -1 error code is the suggested return value */
+int merge_result(const int v1, const int v2);
+
+#endif

src/merge_fib.c.nomk

@@ -0,0 +1,30 @@
+#include "assert.h"
+#include "merge.h"
+
+#define MERGE_GOAL 17
+
+const long merge_values[] = {
+    0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144,
+    233, 377, 610, 987, 1597, 2584
+};
+
+inline long merge_value(const int v1)
+{
+    return v1 <= MERGE_GOAL ? merge_values[v1] : -1;
+}
+
+inline long merge_goal(void)
+{
+    return MERGE_GOAL;
+}
+
+inline int merge_possible(const int v1, const int v2)
+{
+    return v1 == v2 - 1 || v2 == v1 - 1;
+}
+
+inline int merge_result(const int v1, const int v2)
+{
+    int max = v1 > v2 ? v1 : v2;
+    return merge_possible(v1, v2) ? max + 1 : -1;
+}

src/options.c

@@ -5,7 +5,7 @@
 
 void print_usage(void)
 {
-    printf("usage: 2048 [-cCaArh] [-s SIZE] [-b RATE] [-g GOAL]\n");
+    printf("usage: 2048 [-cCaArh] [-s SIZE] [-b RATE]\n");
 }
 
 
@@ -17,7 +17,6 @@ struct gameoptions* gameoptions_default(void)
 
     opt->grid_height = DEFAULT_GRID_HEIGHT;
     opt->grid_width = DEFAULT_GRID_WIDTH;
-    opt->goal = DEFAULT_GOAL;
     opt->spawn_value = DEFAULT_SPAWN_VALUE;
     opt->spawn_rate = DEFAULT_SPAWN_RATE;
     opt->enable_color = DEFAULT_COLOR_TOGGLE;
@@ -34,7 +33,7 @@ void gameoptions_destroy(struct gameoptions *opt)
 struct gameoptions* parse_options(struct gameoptions *opt, int argc, char **argv)
 {
     int c;
-    while ((c = getopt(argc, argv, "aArcChg:s:b:")) != -1) {
+    while ((c = getopt(argc, argv, "aArcCh:s:b:")) != -1) {
         switch (c) {
         case 'a':
             opt->animate = 1;
@@ -48,9 +47,6 @@ struct gameoptions* parse_options(struct gameoptions *opt, int argc, char **argv
         case 'C':
             opt->enable_color = 0;
             break;
-        case 'g':
-            opt->goal = strtol(optarg, NULL, 10);
-            break;
         case 's':;
             /* Stick with square for now */
             int optint = strtol(optarg, NULL, 10);

src/options.h

@@ -7,7 +7,6 @@
 #define CONSTRAINT_GRID_MAX 20
 #define DEFAULT_GRID_HEIGHT 4
 #define DEFAULT_GRID_WIDTH 4
-#define DEFAULT_GOAL 2048
 #define DEFAULT_SPAWN_VALUE 2
 #define DEFAULT_SPAWN_RATE 1
 #define DEFAULT_COLOR_TOGGLE 0
@@ -16,7 +15,6 @@
 struct gameoptions {
     int grid_height;
     int grid_width;
-    long goal;
     long spawn_value;
     int spawn_rate;
     int enable_color;