Get rid of random blockgenerator in favor of a linear time one. Changed a sleep in ai to use gfx_sleep

src/ai.c

@@ -1,10 +1,11 @@
 #include "ai.h"
 #include "engine.h"
+#include "gfx.h"
 
 const char moves[] = {'w', 'a', 's', 'd'};
 
 int ai_move(struct gamestate *g)
 {
-    if (g->opts->interactive) usleep(50000);
+    if (g->opts->interactive) gfx_sleep(50);
     return moves[rand() % 4];
 }

src/engine.c

@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <stdlib.h>
 #include <time.h>
 #include "merge.h"
@@ -176,32 +177,28 @@ int gamestate_end_condition(struct gamestate *g)
 void gamestate_new_block(struct gamestate *g)
 {
     /* Exit early if there are no spaces to place a block */
-    if (g->blocks_in_play == g->gridsize) return;
+    if (g->blocks_in_play >= g->gridsize) return;
 
-#ifdef FIX
     int block_number = rand() % (g->gridsize - 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 (!g->grid[x][y]) {
                 if (p == block_number) {
-                g->grid[x][y] = rand() & 1 ? 1 : 2;
+                    g->grid[x][y] = rand() & 3 ? 1 : 2;
                     g->blocks_in_play += 1;
                     return;
                 }
-
+                else {
-            if (!g->grid[x][y]) p++;
+                    ++p;
+                }
+            }
+        }
     }
 
-        if (y == g->opts->grid_height - 1) y = 0;
+    /* This should never be reached; but just in case */
-    }
+    assert(0);
-#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() & 1 ? 1 : 2;
-    g->blocks_in_play += 1;
 }
 
 /* This returns the number of digits in the base10 rep of n. The ceiling is