287 lines
8.4 KiB
C
287 lines
8.4 KiB
C
#include <stdlib.h>
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#include <time.h>
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#include "engine.h"
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/* Utilize block counter to improve some of the functions so they can run
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* quicker */
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/* This function will move all blocks in the given game the given direction.
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* The callback function is called after each single move. It can be used to
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* animate the movement of the board. */
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static void gravitate(struct gfx_state *s, struct gamestate *g, int d, void (*callback)(struct gfx_state *s, struct gamestate *g))
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{
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#define swap_if_space(xoff, yoff)\
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do {\
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if (g->grid[x][y] == 0 && g->grid[x+xoff][y+yoff] != 0) {\
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g->grid[x][y] = g->grid[x+xoff][y+yoff];\
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g->grid[x+xoff][y+yoff] = 0;\
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done = 0;\
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g->moved = 1;\
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}\
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} while (0)
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int x, y;
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int done = 0;
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if (d == dir_left) {
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while (!done) {
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done = 1;
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for (x = 0; x < g->opts->grid_width - 1; ++x) {
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for (y = 0; y < g->opts->grid_height; ++y) {
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swap_if_space(1, 0);
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}
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}
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if (callback)
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callback(s, g);
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}
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}
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else if (d == dir_right) {
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while (!done) {
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done = 1;
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for (x = g->opts->grid_width - 1; x > 0; --x) {
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for (y = 0; y < g->opts->grid_height; ++y) {
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swap_if_space(-1, 0);
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}
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}
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if (callback)
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callback(s, g);
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}
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}
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else if (d == dir_down) {
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while (!done) {
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done = 1;
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for (y = g->opts->grid_height - 1; y > 0; --y) {
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for (x = 0; x < g->opts->grid_width; ++x) {
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swap_if_space(0, -1);
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}
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}
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if (callback)
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callback(s, g);
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}
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}
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else if (d == dir_up) {
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while (!done) {
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done = 1;
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for (y = 0; y < g->opts->grid_height - 1; ++y) {
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for (x = 0; x < g->opts->grid_width; ++x) {
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swap_if_space(0, 1);
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}
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}
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if (callback)
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callback(s, g);
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}
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}
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else {
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fatal("Invalid direction passed to gravitate()");
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/* Not reached */
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}
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#undef swap_if_space
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}
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/* The merge function will combine adjacent blocks with the same value for
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* the given direction. Note, left and right merges will merge in a different
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* order, so they are not identical in all cases.
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*
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* Consider 2 2 2 0
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*
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* Right merging: 4 0 2 0
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* Left merging: 2 0 4 0
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*/
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static void merge(struct gfx_state *s, struct gamestate *g, int d, void (*callback)(struct gfx_state *s, struct gamestate *g))
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{
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#define merge_if_equal(xoff, yoff)\
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do {\
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if (g->grid[x][y] && (g->grid[x][y] == g->grid[x+xoff][y+yoff])) {\
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g->grid[x][y] += g->grid[x+xoff][y+yoff];\
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g->grid[x+xoff][y+yoff] = 0;\
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g->blocks_in_play -= 1;\
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g->score_last += g->grid[x][y];\
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g->score += g->grid[x][y];\
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g->moved = 1;\
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}\
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} while (0)
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int x, y;
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g->score_last = 0;
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if (d == dir_left) {
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for (x = 0; x < g->opts->grid_width - 1; ++x) {
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for (y = 0; y < g->opts->grid_height; ++y) {
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merge_if_equal(1, 0);
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}
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}
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}
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else if (d == dir_right) {
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for (x = g->opts->grid_width - 1; x > 0; --x) {
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for (y = 0; y < g->opts->grid_height; ++y) {
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merge_if_equal(-1, 0);
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}
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}
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}
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else if (d == dir_down) {
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for (y = g->opts->grid_height - 1; y > 0; --y) {
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for (x = 0; x < g->opts->grid_width; ++x) {
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merge_if_equal(0, -1);
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}
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}
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}
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else if (d == dir_up) {
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for (y = 0; y < g->opts->grid_height - 1; ++y) {
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for (x = 0; x < g->opts->grid_width; ++x) {
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merge_if_equal(0, 1);
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}
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}
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}
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else {
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fatal("Invalid direction passed to merge()");
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/* Not reached */
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}
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if (callback)
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callback(s, g);
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#undef merge_if_equal
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}
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/* Scan the current board and determine if an end outcome has been reached.
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* -1 indicates a lose condition, 1 indicates a win condition, 0 indicates
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* end has not yet been reached. */
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int gamestate_end_condition(struct gamestate *g)
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{
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int ret = -1;
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//size_t blocks_counted = 0;
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for (int x = 0; x < g->opts->grid_width; ++x) {
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for (int y = 0; y < g->opts->grid_height; ++y) {
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if (g->grid[x][y] >= g->opts->goal)
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return 1;
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if (!g->grid[x][y] || ((x + 1 < g->opts->grid_width) &&
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(g->grid[x][y] == g->grid[x+1][y]))
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|| ((y + 1 < g->opts->grid_height) &&
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(g->grid[x][y] == g->grid[x][y+1])))
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ret = 0;
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}
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}
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return ret;
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}
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/* Place a random block into the current grid */
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void gamestate_new_block(struct gamestate *g)
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{
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/* pick random square, if it is full, then move forward until we find
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* an empty square. This is biased */
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static int seeded = 0;
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if (!seeded) {
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seeded = 1;
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srand(time(NULL));
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}
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/* Fix up this random number generator */
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/* Method:
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* - Find a non-biased index between 0 and blocks_play, n
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* - Find the nth 0 element in the array
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* - insert a random value there
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*/
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/* Error here */
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#ifdef SKIP
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size_t block_position = (size_t)rand() % (
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g->opts->grid_width * g->opts->grid_height - g->blocks_in_play);
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size_t i, ps;
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for (i = 0, ps = 0; ps < block_position; ++i) {
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if (!g->grid[i / g->opts->grid_width][i % g->opts->grid_height]) ps++;
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}
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g->grid[i / g->opts->grid_width][i % g->opts->grid_height]
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= (rand() & 3) ? g->opts->spawn_value : g->opts->spawn_value * 2;
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#endif
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/* Use rudimentary for now */
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int x, y;
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while (g->grid[x = rand() % g->opts->grid_width][y = rand() % g->opts->grid_height]);
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g->grid[x][y] = (rand() & 3) ? g->opts->spawn_value : g->opts->spawn_value * 2;
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g->blocks_in_play += 1;
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}
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/* This returns the number of digits in the base10 rep of n. The ceiling is
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* taken so this will be one greater than required */
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static int digits_ceiling(unsigned int n)
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{
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int l = 0;
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while (n) n /= 10, ++l;
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return l + 1;
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}
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/* Return NULL if we couldn't allocate space for the gamestate. The opt
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* argument can be passed directly via gameoptions_default i.e
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* *o = gamestate_init(gameoptions_default) is valid, as the delete function
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* will find the pointer to the gameoptions and delete the data accordingly. */
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struct gamestate* gamestate_init(struct gameoptions *opt)
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{
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if (!opt) return NULL;
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struct gamestate *g = malloc(sizeof(struct gamestate));
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if (!g) goto gamestate_alloc_fail;
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g->gridsize = opt->grid_width * opt->grid_height;
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g->grid_data_ptr = calloc(g->gridsize, sizeof(long));
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if (!g->grid_data_ptr) goto grid_data_alloc_fail;
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g->grid = malloc(opt->grid_height * sizeof(long*));
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if (!g->grid) goto grid_alloc_fail;
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/* Switch to two allocation version */
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long **iterator = g->grid;
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for (int i = 0; i < g->gridsize; i += opt->grid_width)
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*iterator++ = &g->grid_data_ptr[i];
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g->moved = 0;
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g->score = 0;
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g->score_high = 0;
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g->score_last = 0;
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g->print_width = digits_ceiling(opt->goal);
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g->blocks_in_play = 0;
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g->opts = opt;
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/* Initial 3 random blocks */
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gamestate_new_block(g);
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gamestate_new_block(g);
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gamestate_new_block(g);
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return g;
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grid_alloc_fail:
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free(g->grid_data_ptr);
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grid_data_alloc_fail:
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free(g);
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gamestate_alloc_fail:
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return NULL;
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}
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/* A tick is a gravitate, merge then gravitate all in the same direction.
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* the moved variable is set to 0 initially and if the gravitate of merge
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* functions modify it, we can determine which action to take. */
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int gamestate_tick(struct gfx_state *s, struct gamestate *g, int d, void (*callback)(struct gfx_state*, struct gamestate*))
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{
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/* Reset move. Altered by gravitate and merge if we do move */
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g->moved = 0;
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gravitate(s, g, d, callback);
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merge(s, g, d, callback);
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gravitate(s, g, d, callback);
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return g->moved;
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}
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/* Free all data associated with the gamestate */
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void gamestate_clear(struct gamestate *g)
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{
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gameoptions_destroy(g->opts);
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free(g->grid_data_ptr); /* Free grid data */
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free(g->grid); /* Free pointers to data slots */
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free(g);
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}
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