Index: apps/plugins/maze.c
===================================================================
--- apps/plugins/maze.c	(revision 0)
+++ apps/plugins/maze.c	(revision 0)
@@ -0,0 +1,378 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id: helloworld.c 8349 2006-01-15 18:20:18Z amiconn $
+ *
+ * Copyright (C) 2007 Matthias Wientapper
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+
+/* This is the implementation of a maze generation algorithm.
+ * The generated mazes are "perfect", i.e. there is one and only 
+ * one path from any point in the maze to any other point.
+ *
+ *
+ * The implemented algorithm is called "Depth-First search", the
+ * solving is done by a dead-end filler routine.
+ *
+ */ 
+
+#include "plugin.h"
+#include "pluginlib_actions.h"
+
+PLUGIN_HEADER
+
+#define MAZE_NEW   PLA_RIGHT
+#define MAZE_QUIT  PLA_QUIT
+#define MAZE_SOLVE PLA_FIRE
+
+
+/* propertie bits of the cell */
+#define WALL_N    0x00000001
+#define WALL_E    0x00000002
+#define WALL_S    0x00000004
+#define WALL_W    0x00000008
+#define WALL_ALL  0x0000000F
+
+#define BORDER_N  0x00000010
+#define BORDER_E  0x00000020
+#define BORDER_S  0x00000040
+#define BORDER_W  0x00000080
+
+static struct plugin_api* rb;
+const struct button_mapping *plugin_contexts[]
+= {generic_directions, generic_actions};
+
+#if ( LCD_WIDTH == 112 )
+#define MAZE_WIDTH  16
+#define MAZE_HEIGHT 12
+#else
+#define MAZE_WIDTH  32
+#define MAZE_HEIGHT 24
+#endif
+
+unsigned char maze[MAZE_WIDTH][MAZE_HEIGHT];
+int  stack[MAZE_WIDTH*MAZE_HEIGHT];
+
+char buf[30];
+
+
+void init_maze(void){
+  int x, y;
+
+  rb->memset(maze, 0, sizeof(maze));
+
+
+  for(y=0; y<MAZE_HEIGHT; y++){
+    for(x=0; x<MAZE_WIDTH; x++){
+
+      /* all walls are up */
+      maze[x][y] |= WALL_ALL;
+
+      /* setup borders */
+      if(x == 0) 
+        maze[x][y]|= BORDER_W;
+      if(y == 0)
+        maze[x][y]|= BORDER_N;
+      if(x == MAZE_WIDTH-1)
+        maze[x][y]|= BORDER_E;
+      if(y == MAZE_HEIGHT-1)
+        maze[x][y]|= BORDER_S;
+    }
+  }
+}
+      
+void show_maze(void){
+  int x, y;
+  int wx, wy;
+  unsigned char cell;
+
+  wx = (int) LCD_WIDTH / MAZE_WIDTH;
+  wy = (int) LCD_HEIGHT / MAZE_HEIGHT;
+
+  rb->lcd_clear_display();
+
+  for(y=0; y<MAZE_HEIGHT; y++){
+    rb->yield();
+    for(x=0; x<MAZE_WIDTH; x++){
+
+      cell = maze[x][y];
+
+      /* draw walls */
+
+#if LCD_DEPTH >= 16
+      rb->lcd_set_foreground( LCD_RGBPACK( 125, 125, 125));
+#elif LCD_DEPTH == 2
+      rb->lcd_set_foreground(2);
+#endif
+      if(cell & WALL_N)
+        rb->lcd_drawline(x*wx, y*wy, x*wx+wx, y*wy);
+      if(cell & WALL_E)
+        rb->lcd_drawline(x*wx+wx, y*wy, x*wx+wx, y*wy+wy);
+      if(cell & WALL_S)
+        rb->lcd_drawline(x*wx, y*wy+wy, x*wx+wx, y*wy+wy);
+      if(cell & WALL_W)
+        rb->lcd_drawline(x*wx, y*wy, x*wx, y*wy+wy);
+
+      /* draw borders */
+#if LCD_DEPTH >= 16
+      rb->lcd_set_foreground( LCD_RGBPACK( 0, 0, 0));
+#elif LCD_DEPTH == 2
+      rb->lcd_set_foreground(0);
+#endif
+      if(cell & BORDER_N)
+        rb->lcd_drawline(x*wx, y*wy, x*wx+wx, y*wy);
+      if(cell & BORDER_E)
+        rb->lcd_drawline(x*wx+wx, y*wy, x*wx+wx, y*wy+wy);
+      if(cell & BORDER_S)
+        rb->lcd_drawline(x*wx, y*wy+wy, x*wx+wx, y*wy+wy);
+      if(cell & BORDER_W)
+        rb->lcd_drawline(x*wx, y*wy, x*wx, y*wy+wy);
+    }
+  }
+
+  /* mark start and end */
+  rb->lcd_drawline(0, 0, wx, wy);
+  rb->lcd_drawline(0, wy, wx, 0);
+  rb->lcd_drawline((MAZE_WIDTH-1)*wx,(MAZE_HEIGHT-1)*wy, 
+                   (MAZE_WIDTH-1)*wx+wx, (MAZE_HEIGHT-1)*wy+wy);
+  rb->lcd_drawline((MAZE_WIDTH-1)*wx,(MAZE_HEIGHT-1)*wy+wy, 
+                   (MAZE_WIDTH-1)*wx+wx, (MAZE_HEIGHT-1)*wy);
+
+  rb->lcd_update();
+}
+
+
+int random_neighbour_cell_with_walls(int *px, int *py, int *pnx, int *pny){
+
+  int ncount = 0;
+  int neighbours[4];
+  int found_cell;
+
+
+  /* look for neighbour cells with walls */
+
+  /* north */
+  if(!(maze[*px][*py] & BORDER_N)){
+    if((maze[*px][*py-1] & WALL_ALL) == WALL_ALL){
+      /* save found cell coordinates */
+      neighbours[ncount]=(*px<<8)|((*py)-1);
+      ncount++;
+    }
+  }
+
+  /* west */
+  if(!(maze[*px][*py] & BORDER_W)){
+    if((maze[*px-1][*py] & WALL_ALL) == WALL_ALL){
+      /* save found cell coordinates */
+      neighbours[ncount]=((*px-1)<<8)|(*py);
+      ncount++;
+    }
+  }
+
+  /* east */
+  if(!(maze[*px][*py] & BORDER_E)){
+    if((maze[*px+1][*py] & WALL_ALL) == WALL_ALL){
+      /* save found cell coordinates */
+      neighbours[ncount]=((*px+1)<<8)|(*py);
+      ncount++;
+    }
+  }
+
+  /* south */
+  if(!(maze[*px][*py] & BORDER_S)){
+    if((maze[*px][*py+1] & WALL_ALL) == WALL_ALL){
+      /* save found cell coordinates */
+      neighbours[ncount]=(*px<<8)|((*py)+1);
+      ncount++;
+    }
+  }
+ 
+  /* randomly select neighbour cell with walls */
+  if(ncount!=0){
+    found_cell = neighbours[rb->rand()%ncount];
+    *pny = found_cell &0x000000ff;
+    *pnx = (unsigned int) found_cell >> 8;
+  } 
+  return ncount;
+}
+
+void remove_walls(int *px, int *py, int *pnx, int *pny){
+
+  /* where is our neighbour? */
+
+  /* north or south */
+  if(*px==*pnx){
+    if(*py<*pny){
+      /*south*/
+      maze[*px][*py] &= ~WALL_S;
+      maze[*pnx][*pny] &= ~WALL_N;
+    } else {
+      /*north*/
+      maze[*px][*py] &= ~WALL_N;
+      maze[*pnx][*pny] &= ~WALL_S;
+    }
+  } else {
+    /* east or west */
+    if(*py==*pny){
+      if(*px<*pnx){
+        /* east */
+        maze[*px][*py] &= ~WALL_E;
+        maze[*pnx][*pny] &= ~WALL_W;
+
+      } else {
+        /*west*/
+        maze[*px][*py] &= ~WALL_W;
+        maze[*pnx][*pny] &= ~WALL_E;
+      }
+    }
+  }
+}
+
+
+void generate_maze(void){
+  int stp = 0;
+  int total_cells = MAZE_WIDTH * MAZE_HEIGHT;
+  int visited_cells;
+  int neighbour_cell;
+  int x, y;
+  int nx = 0;
+  int ny = 0;
+  int *px, *py, *pnx, *pny;
+
+  px = &x;
+  py = &y;
+  pnx = &nx;
+  pny = &ny;
+
+  x = rb->rand()%MAZE_WIDTH;
+  y = rb->rand()%MAZE_HEIGHT;
+  
+  visited_cells = 1;
+  while (visited_cells < total_cells){
+
+    neighbour_cell = random_neighbour_cell_with_walls(px, py, pnx, pny);
+    if(neighbour_cell == 0){
+
+      /* pop from stack */
+      stp--;
+      *py = stack[stp];
+      *py &= 0xff;
+      *px = (stack[stp])>>8;
+    } else {
+      remove_walls(px, py, pnx, pny);
+      
+      /* save position on the stack */
+      stack[stp] = ((*px<<8)|*py);
+      stp++;
+      /* current cell = neighbour cell */
+      x=nx;
+      y=ny;
+
+      visited_cells++;
+    }
+  }
+}
+
+
+void solve_maze(void){
+  int x, y;
+  unsigned char cell;
+  unsigned char w;
+  int dead_ends = 1;
+
+  /* dead end filler*/
+  
+  /* remove some  borders and walls on start and end point */
+  maze[0][0] &= ~(WALL_N|BORDER_N);
+  maze[MAZE_WIDTH-1][MAZE_HEIGHT-1] &= ~(WALL_S|BORDER_S);
+
+  while(dead_ends){
+    dead_ends = 0;
+    /* scan for dead ends */
+    for(y=0; y<MAZE_HEIGHT; y++){
+      for(x=0; x<MAZE_WIDTH; x++){
+        cell = maze[x][y];
+        w = ~cell & 0x0f;
+        if(w == WALL_N ||
+           w == WALL_E ||
+           w == WALL_S ||
+           w == WALL_W){
+          /* found dead end, fill it up */
+          maze[x][y] |= WALL_ALL;
+          /* don't forget the neighbours */
+          if(!(cell & BORDER_N))
+            maze[x][y-1]|=WALL_S;
+          if(!(cell & BORDER_E))
+            maze[x+1][y]|=WALL_W;
+          if(!(cell & BORDER_S))
+            maze[x][y+1]|=WALL_N;
+          if(!(cell & BORDER_W))
+            maze[x-1][y]|=WALL_E;
+          dead_ends++;
+        }
+      }
+    }
+
+    /* This could probably be removed at this point to speed up
+     * things a lot but I think it's quite entertaining to watch
+     * the algorithm * solve the maze.
+     */
+    show_maze();
+  }
+}
+
+/**********************************/
+/* this is the plugin entry point */
+/**********************************/
+enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
+{
+  int button = 0;
+  int quit = 0;
+
+  (void)parameter;
+  rb = api;
+ 
+  init_maze();
+  generate_maze();
+  show_maze();
+
+  while(!quit) {
+    button = pluginlib_getaction(rb, TIMEOUT_BLOCK, plugin_contexts, 2);
+    switch(button) {
+    case MAZE_NEW:
+      init_maze();
+      generate_maze();
+      show_maze();
+      break;
+    case MAZE_SOLVE:
+      solve_maze();
+      break;
+    case MAZE_QUIT:
+      /* quit plugin */
+      quit=true;
+      return PLUGIN_OK;
+      break;
+    default:
+      if (rb->default_event_handler(button) == SYS_USB_CONNECTED) {
+        return PLUGIN_USB_CONNECTED;
+      }
+      break;
+    }
+    rb->yield();
+  }
+  return PLUGIN_OK;
+}
+
+