1 files changed, 779 insertions, 0 deletions

diff --git a/apps/recorder/wormlet.c b/apps/recorder/wormlet.c
new file mode 100644
index 0000000000..ab8ef0aa91
--- /dev/null
+++ b/apps/recorder/wormlet.c
@@ -0,0 +1,779 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2002 Philipp Pertermann
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#include <sprintf.h>
+#include <stdlib.h>
+#include <string.h>
+#include "lcd.h"
+#include "button.h"
+#include "kernel.h"
+#include "menu.h"
+
+#define MAX_WORM_LENGTH 500    // size of the ring of the worm
+#define INITIAL_WORM_LENGTH 10 // when the game starts
+#define WORM_PER_FOOD 7 // num of pixel the worm grows by eating a food
+
+// The worm is stored in a ring of xy coordinates
+short wormx[MAX_WORM_LENGTH];
+short wormy[MAX_WORM_LENGTH];
+
+int head; // index of the head within the buffer
+short headx;
+short heady;
+
+int tail; // index of the tail within the buffer
+int growing; // number of cyles the worm still keeps growing
+
+
+#define MAX_FOOD 5  // maximal number of food items
+#define FOOD_SIZE 3 // the width and height of a food
+short foodx[MAX_FOOD];
+short foody[MAX_FOOD];
+
+#define MAX_ARGH 100 // maximal number of argh items
+#define ARGH_SIZE 4 // the width and height of a argh
+#define ARGHS_PER_FOOD 2 // number of arghs produced each time a food was eaten
+short arghx[MAX_ARGH];
+short arghy[MAX_ARGH];
+int arghCount;
+
+// direction vector in which the worm moves
+short dirx; // only values -1 0 1 allowed
+short diry; // only values -1 0 1 allowed
+
+int speed = 10;
+
+// return values of checkCollision
+#define COLLISION_NONE 0
+#define COLLISION_WORM 1
+#define COLLISION_FOOD 2
+#define COLLISION_ARGH 3
+#define COLLISION_FIELD 4
+
+// size of the field the worm lives in
+#define FIELD_RECT_X 1
+#define FIELD_RECT_Y 1
+#define FIELD_RECT_WIDTH  LCD_HEIGHT - 2
+#define FIELD_RECT_HEIGHT LCD_HEIGHT - 2
+
+/**
+ * Returns the current length of the worm.
+ * @return int a positive value
+ */
+int getWormLength(void) {
+    // initial simple calculation will be overwritten
+    // if wrong.
+    int retVal = head - tail;
+
+    // if the worm 'crosses' the boundaries of the ringbuffer
+    if (retVal < 0) {
+        retVal = head + MAX_WORM_LENGTH - tail;
+    }
+
+    return retVal;
+}
+
+/**
+ * Checks wether a specific food in the food arrays is at the
+ * specified coordinates.
+ * @param int foodIndex The index of the food in the food arrays
+ * @param int x the x coordinate.
+ * @param int y the y coordinate.
+ * @return Returns true if the coordinate hits the food specified by
+ * foodIndex.
+ */
+bool specificFoodCollision(int foodIndex, int x, int y) {
+    bool retVal = false;
+    if (x >= foodx[foodIndex]             &&
+        x <  foodx[foodIndex] + FOOD_SIZE &&
+        y >= foody[foodIndex]             &&
+        y <  foody[foodIndex] + FOOD_SIZE) {
+
+        retVal = true;
+    }
+    return retVal;
+}
+
+/**
+ * Returns the index of the food that is at the
+ * given coordinates. If no food is at the coordinates
+ * -1 is returned.
+ * @return int  -1 <= value < MAX_FOOD
+ */
+int foodCollision(int x, int y) {
+    int i = 0;
+    int retVal = -1;
+    bool collisionDetected = false;
+    for (i = 0; i < MAX_FOOD && !collisionDetected; i++) {
+        if (specificFoodCollision(i, x, y)) {
+
+            collisionDetected = true;
+            retVal = i;
+        }
+    }
+    return retVal;
+}
+
+/**
+ * Checks wether a specific argh in the argh arrays is at the
+ * specified coordinates.
+ * @param int arghIndex The index of the argh in the argh arrays
+ * @param int x the x coordinate.
+ * @param int y the y coordinate.
+ * @return Returns true if the coordinate hits the argh specified by
+ * arghIndex.
+ */
+bool specificArghCollision(int arghIndex, int x, int y) {
+    bool retVal = false;
+    if (x >= arghx[arghIndex]             &&
+        x <  arghx[arghIndex] + ARGH_SIZE &&
+        y >= arghy[arghIndex]             &&
+        y <  arghy[arghIndex] + ARGH_SIZE) {
+
+        retVal = true;
+    }
+    return retVal;
+}
+
+/**
+ * Returns the index of the argh that is at the
+ * given coordinates. If no argh is at the coordinates
+ * -1 is returned.
+ * @param int x The x coordinate.
+ * @param int y The y coordinate.
+ * @return int  -1 <= value < arghCount <= MAX_ARGH
+ */
+int arghCollision(int x, int y) {
+    int i = 0;
+    int retVal = -1;
+    bool collisionDetected = false;
+
+    // search for the argh that has the specified coords
+    for (i = 0; i < arghCount && !collisionDetected; i++) {
+        if (specificArghCollision(i, x, y)) {
+
+            collisionDetected = true;
+            retVal = i;
+        }
+    }
+    return retVal;
+}
+
+/**
+ * Checks wether the worm collides with the food at the specfied food-arrays.
+ * @param int foodIndex The index of the food in the arrays. Ensure the value is
+ * 0 <= foodIndex <= MAX_FOOD
+ * @return Returns true if the worm collides with the specified food.
+ */
+bool wormFoodCollision(int foodIndex) {
+    bool retVal = false;
+
+    // buffer wormLength because getWormLength is expensive
+    int wormLength = getWormLength();
+    int i;
+
+    // although all the worm gets iterated i is NOT the index
+    // of the worm arrays
+    for (i = 0; i < wormLength && !retVal; i++) {
+
+        // convert i to the true worm indices
+        int wormIndex = (tail + i) % MAX_WORM_LENGTH;
+
+        // The check
+        if (specificFoodCollision(foodIndex, wormx[wormIndex], wormy[wormIndex])) {
+            retVal = true;
+        }
+    }
+
+    return retVal;
+}
+
+/**
+ * Checks wether the worm collides with the argh at the specfied argh-arrays.
+ * @param int arghIndex The index of the argh in the arrays. Ensure the value is
+ * 0 <= arghIndex < arghCount <= MAX_ARGH
+ * @return Returns true if the worm collides with the specified argh.
+ */
+bool wormArghCollision(int arghIndex) {
+    bool retVal = false;
+
+    // buffer wormLength because getWormLength is expensive
+    int wormLength = getWormLength();
+    int i;
+
+    // although all the worm gets iterated i is NOT the index
+    // of the worm arrays
+    for (i = 0; i < wormLength && !retVal; i++) {
+
+        // convert i to the true worm indices
+        int wormIndex = (tail + i) % MAX_WORM_LENGTH;
+
+        // The check
+        if (specificArghCollision(arghIndex, wormx[wormIndex], wormy[wormIndex])) {
+            retVal = true;
+        }
+    }
+
+    return retVal;
+}
+
+/**
+ * Find new coordinates for the food stored in foodx[index], foody[index]
+ * that don't collide with any other food or argh
+ * @param int index 
+ * Ensure that 0 <= index < MAX_FOOD.
+ */
+void makeFood(int index) {
+
+    int x = 0;
+    int y = 0;
+    bool collisionDetected = false;
+
+    do {
+        // make coordinates for a new food so that
+        // the entire food lies within the FIELD
+        x = rand() % (FIELD_RECT_WIDTH  - FOOD_SIZE);
+        y = rand() % (FIELD_RECT_HEIGHT - FOOD_SIZE);
+
+        // Ensure that the new food doesn't collide with any
+        // existing foods or arghs.
+        // If one or more corners of the new food hit any existing
+        // argh or food a collision is detected.
+        collisionDetected = 
+           foodCollision(x                , y                ) >= 0 ||
+           foodCollision(x + FOOD_SIZE - 1, y                ) >= 0 ||
+           foodCollision(x                , y + FOOD_SIZE - 1) >= 0 ||
+           foodCollision(x + FOOD_SIZE - 1, y + FOOD_SIZE - 1) >= 0 ||
+           arghCollision(x                , y                ) >= 0 || 
+           arghCollision(x + FOOD_SIZE - 1, y                ) >= 0 ||
+           arghCollision(x                , y + FOOD_SIZE - 1) >= 0 ||
+           arghCollision(x + FOOD_SIZE - 1, y + FOOD_SIZE - 1) >= 0;
+
+        // use coordinates for further testing
+        foodx[index] = x;
+        foody[index] = y;
+
+        // now test wether we accidently hit the worm with food ;)
+        collisionDetected |= wormFoodCollision(index);
+    }
+    while (collisionDetected);
+}
+
+/**
+ * Clears a food from the lcd buffer.
+ * @param int index The index of the food arrays under which
+ * the coordinates of the desired food can be found. Ensure 
+ * that the value is 0 <= index <= MAX_FOOD.
+ */
+void clearFood(int index) {
+    // remove the old food from the screen
+    lcd_clearrect  (foodx[index] + FIELD_RECT_X, 
+                    foody[index] + FIELD_RECT_Y, 
+                    FOOD_SIZE, FOOD_SIZE);
+}
+
+/**
+ * Draws a food in the lcd buffer.
+ * @param int index The index of the food arrays under which
+ * the coordinates of the desired food can be found. Ensure 
+ * that the value is 0 <= index <= MAX_FOOD.
+ */
+void drawFood(int index) {
+    // draw the food object
+    lcd_fillrect  (foodx[index] + FIELD_RECT_X, 
+                   foody[index] + FIELD_RECT_Y, 
+                   FOOD_SIZE, FOOD_SIZE);
+    lcd_clearrect(foodx[index] + FIELD_RECT_X + 1, 
+                   foody[index] + FIELD_RECT_Y + 1, 
+                   FOOD_SIZE - 2, FOOD_SIZE - 2);
+}
+
+/**
+ * Find new coordinates for the argh stored in arghx[index], arghy[index]
+ * that don't collide with any other food or argh.
+ * @param int index 
+ * Ensure that 0 <= index < arghCount < MAX_ARGH.
+ */
+void makeArgh(int index) {
+    int x; 
+    int y; 
+    bool collisionDetected = false;
+
+    do {
+        // make coordinates for a new argh so that
+        // the entire food lies within the FIELD
+        x = rand() % (FIELD_RECT_WIDTH  - ARGH_SIZE);
+        y = rand() % (FIELD_RECT_HEIGHT - ARGH_SIZE);
+        // Ensure that the new argh doesn't intersect with any
+        // existing foods or arghs.
+        // If one or more corners of the new argh hit any existing
+        // argh or food an intersection is detected.
+        collisionDetected = 
+           foodCollision(x                , y                ) >= 0 || 
+           foodCollision(x + ARGH_SIZE - 1, y                ) >= 0 ||
+           foodCollision(x                , y + ARGH_SIZE - 1) >= 0 ||
+           foodCollision(x + ARGH_SIZE - 1, y + ARGH_SIZE - 1) >= 0 ||
+           arghCollision(x                , y                ) >= 0 || 
+           arghCollision(x + ARGH_SIZE - 1, y                ) >= 0 ||
+           arghCollision(x                , y + ARGH_SIZE - 1) >= 0 ||
+           arghCollision(x + ARGH_SIZE - 1, y + ARGH_SIZE - 1) >= 0;
+
+        // use the candidate coordinates to make a real argh
+        arghx[index] = x;
+        arghy[index] = y;
+
+        // now test wether we accidently hit the worm with argh ;)
+        collisionDetected |= wormArghCollision(index);
+    }
+    while (collisionDetected);
+}
+
+/**
+ * Draws an argh in the lcd buffer.
+ * @param int index The index of the argh arrays under which
+ * the coordinates of the desired argh can be found. Ensure 
+ * that the value is 0 <= index < arghCount <= MAX_ARGH.
+ */
+void drawArgh(int index) {
+    // draw the new argh
+    lcd_fillrect  (arghx[index] + FIELD_RECT_X, 
+                   arghy[index] + FIELD_RECT_Y, 
+                   ARGH_SIZE, ARGH_SIZE);
+}
+
+/**
+ * Initializes the worm-, food- and argh-arrays, draws a frame,
+ * makes some food and argh and display all that stuff.
+ */
+void initWormlet(void) {
+
+    // Needed when the game is restarted using BUTTON_ON
+    lcd_clear_display();
+
+    // Initialize all the worm coordinates to 0,0.
+    int i;
+    for (i = 0; i < MAX_WORM_LENGTH; i++){
+        wormx[i] = 0;
+        wormy[i] = 0;
+    }
+
+    // initialize the worm size
+    head = INITIAL_WORM_LENGTH;
+    tail = 0;
+
+    // initialize the worm start point
+    headx = 0;
+    heady = 0;
+
+    // set the initial direction the worm creeps to
+    dirx = 1;
+    diry = 0;
+
+    // make and display some food and argh
+    arghCount = MAX_FOOD;
+    for (i = 0; i < MAX_FOOD; i++) {
+        makeFood(i);
+        drawFood(i);
+        makeArgh(i);
+        drawArgh(i);
+    }
+
+    // draw the game field
+    lcd_invertrect  (0    , 0  , FIELD_RECT_WIDTH + 2, FIELD_RECT_HEIGHT + 2);
+    lcd_invertrect(0 + 1, 0 + 1, FIELD_RECT_WIDTH    , FIELD_RECT_HEIGHT);
+
+    // make everything visible
+    lcd_update();
+}
+
+/** 
+ * Move the worm one step further.
+ * The direction in which the worm moves is taken
+ * from dirx and diry. If the 
+ * worm crosses the boundaries of the field the
+ * worm is wrapped (it enters the field from the
+ * opposite side). moveWorm decreases growing if > 0.
+ */
+void moveWorm(void) {
+    // find the next array index for the head
+    head++;
+    if (head >= MAX_WORM_LENGTH){
+        head = 0;
+    }
+
+    // find the next array index for the tail
+    tail++;
+    if (tail >= MAX_WORM_LENGTH){
+        tail = 0;
+    }
+
+    // determine the new head position
+    headx += dirx;
+    heady += diry;
+
+    // Wrap the new head position if necessary
+    if (headx >= FIELD_RECT_WIDTH) {
+        headx = 0;
+    }
+
+    if (headx < 0){
+        headx = FIELD_RECT_WIDTH - 1;
+    }
+
+    if (heady >= FIELD_RECT_HEIGHT) {
+        heady = 0;
+    }
+
+    if (heady < 0) {
+        heady = FIELD_RECT_HEIGHT - 1;
+    }
+
+    // store the new head position in the 
+    // worm arrays
+    wormx[head] = headx;
+    wormy[head] = heady;
+
+    // update the worms grow state
+    if (growing > 0) growing --;
+}
+
+/**
+ * Draws the head and clears the tail of the worm in 
+ * the display buffer. lcd_update() is NOT called thus
+ * the caller has to take care that the buffer is displayed.
+ */
+void drawWorm(void) {
+    // draw the new head
+    lcd_drawpixel( wormx[head] + FIELD_RECT_X, wormy[head] + FIELD_RECT_Y);
+
+    // clear the space behind the worm
+    lcd_clearpixel(wormx[tail] + FIELD_RECT_X, wormy[tail] + FIELD_RECT_Y);
+}
+
+/**
+ * Checks wether the coordinate is part of the worm.
+ * @param x int The x coordinate 
+ * @param y int The y coordinate
+ * @return int The index of the worm arrays that contain x, y.
+ * Returns -1 if the coordinates are not part of the worm.
+ */ 
+int wormCollision(int x, int y) {
+    int retVal = -1;
+
+    // getWormLength is expensive -> buffer the value
+    int wormLength = getWormLength();
+    int i;
+
+    // test each entry that is part of the worm
+    for (i = 0; i < wormLength && retVal == -1; i++) {
+
+        // The iteration iterates the length of the worm.
+        // Here's the conversion to the true indices within
+        // the worm arrays.
+        int trueIndex = (tail + i) % MAX_WORM_LENGTH;
+
+        // The check
+        if (wormx[trueIndex] == x && wormy[trueIndex] == y) {
+            retVal = trueIndex;
+        }
+    }
+    return retVal;
+}
+
+/**
+ * Returns true if the head of the worm just has
+ * crossed the field boundaries. 
+ * @return bool true if the worm just has wrapped.
+ */ 
+bool fieldCollision(void) {
+    bool retVal = false;
+    if ((headx == FIELD_RECT_WIDTH - 1  && dirx == -1) ||
+        (headx == 0                     && dirx ==  1) ||
+        (heady == FIELD_RECT_HEIGHT - 1 && diry == -1) ||
+        (heady == 0                     && diry ==  1)) {
+
+        retVal = true;
+    }
+    return retVal;
+}
+
+/**
+ * Checks and returns wether the head of the worm
+ * is colliding with something currently.
+ * @return int One of the values
+ * <ul>
+ *   <li>COLLISION_NONE
+ *   <li>COLLISION_WORM
+ *   <li>COLLISION_FOOD
+ *   <li>COLLISION_ARGH
+ *   <li>COLLISION_FIELD
+ * </ul>
+ */
+int checkCollision(void) {
+    int retVal = COLLISION_NONE;
+
+    if (wormCollision(headx, heady) >= 0) {
+        retVal = COLLISION_WORM;
+    }
+
+    if (foodCollision(headx, heady) >= 0) {
+        retVal = COLLISION_FOOD;
+    }
+
+    if (arghCollision(headx, heady) >= 0) {
+        retVal = COLLISION_ARGH;
+    }
+
+    if (fieldCollision()) {
+        retVal = COLLISION_FIELD;
+    }
+
+    return retVal;
+}
+
+/*
+void debugOutput(void) {
+    char buf[40];
+
+    // head
+    snprintf(buf, sizeof(buf), "h:%d(%d;%d)    ", head, wormx[head], wormy[head]);
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 0, buf, 0);
+
+    // tail
+    snprintf(buf, sizeof(buf), "t:%d(%d;%d)    ", tail, wormx[tail], wormy[tail]);
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 8, buf, 0);
+
+    // speed
+    snprintf(buf, sizeof(buf), "div:%d  ", speed);
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 16, buf, 0);
+
+    // collision
+    switch (checkCollision()) {
+        case COLLISION_NONE:  snprintf(buf, sizeof(buf), "free  "); break;
+        case COLLISION_WORM:  snprintf(buf, sizeof(buf), "worm  "); break;
+        case COLLISION_FOOD:  snprintf(buf, sizeof(buf), "food  "); break;
+        case COLLISION_ARGH:  snprintf(buf, sizeof(buf), "argh  "); break;
+        case COLLISION_FIELD: snprintf(buf, sizeof(buf), "field "); break;
+    }
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 24, buf, 0);
+}
+*/
+
+/**
+ * Prints out the score board with all the status information
+ * about the game.
+ */
+void scoreBoard(void) {
+    char buf[15];
+    char buf2[15];
+
+    // Title
+    snprintf(buf, sizeof (buf), "Wormlet");
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 0, buf, 0);
+
+    // length
+    snprintf(buf, sizeof (buf), "length:");
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 12, buf, 0);
+    snprintf(buf, sizeof (buf), "%d  ", getWormLength() - growing);
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 20, buf, 0);
+
+    switch (checkCollision()) {
+        case COLLISION_NONE:  
+            snprintf(buf, sizeof(buf), "I'm hungry!  "); 
+            if (growing > 0) {
+                snprintf(buf2, sizeof(buf2), "growing");
+            }
+            else {
+                snprintf(buf2, sizeof(buf2), "             ");
+            }
+            break;
+
+        case COLLISION_WORM:  
+            snprintf(buf, sizeof(buf), "Ouch! I bit"); 
+            snprintf(buf2, sizeof(buf2), "myself!    ");
+            break;
+
+        case COLLISION_FOOD:  
+            snprintf(buf, sizeof(buf), "Yummy!  "); 
+            snprintf(buf2, sizeof(buf2), "growing");
+            break;
+
+        case COLLISION_ARGH:  
+            snprintf(buf, sizeof(buf), "Argh! I'm   "); 
+            snprintf(buf2, sizeof(buf2), "poisoned!   ");
+            break;
+
+        case COLLISION_FIELD: 
+            snprintf(buf, sizeof(buf), "Boing!        "); 
+            snprintf(buf2, sizeof(buf2), "Headcrash!");
+            break;
+    }
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 32, buf, 0);
+    lcd_putsxy(FIELD_RECT_WIDTH + 3, 40, buf2, 0);
+}
+
+/**
+ * Checks for collisions of the worm and its environment and
+ * takes appropriate actions like growing the worm or killing it.
+ * @return bool Returns true if the worm is dead. Returns
+ * false if the worm is healthy, up and creeping.
+ */
+bool processCollisions(void) {
+    bool wormDead = false;
+    int index = -1;
+
+    wormDead = fieldCollision();
+
+    if (!wormDead) {
+
+        // check if food was eaten
+        index = foodCollision(headx, heady);
+        if (index != -1){
+            clearFood(index);
+            makeFood(index);
+            drawFood(index);
+            
+            int i = 0;
+            
+            for (i = 0; i < ARGHS_PER_FOOD; i++) {
+                arghCount++;
+                if (arghCount > MAX_ARGH) {
+                    arghCount = MAX_ARGH;
+                }
+                makeArgh(arghCount - 1);
+                drawArgh(arghCount - 1);
+            }
+
+            tail -= WORM_PER_FOOD;
+            growing += WORM_PER_FOOD;
+            if (tail < 0) {
+                tail += MAX_WORM_LENGTH; 
+            }
+
+            drawWorm();
+        }
+
+        // check if argh was eaten
+        else {
+            index = arghCollision(headx, heady);
+            if (index != -1) {
+                wormDead = true;
+            }
+            else {
+                if (wormCollision(headx, heady) != -1) {
+                    wormDead = true;
+                }
+            }
+        }
+    }
+    return wormDead;
+}
+
+/**
+ * The main loop of the game.
+ * @return bool Returns true if the game ended
+ * with a dead worm. Returns false if the user
+ * aborted the game manually.
+ */ 
+bool run(void) {
+    int button = 0;
+    int wormDead = false;
+
+    // initialize the board and so on
+    initWormlet();
+
+    // change the direction of the worm
+    while (button != BUTTON_OFF && ! wormDead)
+    {
+        switch (button) {
+            case BUTTON_UP:
+                diry = -1;
+                dirx = 0;
+                break;
+
+            case BUTTON_DOWN:
+                diry = 1;
+                dirx = 0;
+                break;
+
+            case BUTTON_LEFT:
+                dirx = -1;
+                diry = 0;
+                break;
+
+            case BUTTON_RIGHT:
+                dirx = 1;
+                diry = 0;
+                break;
+
+            case BUTTON_F2:
+                speed--;
+                break;
+
+            case BUTTON_F3:
+                speed ++;
+                break;
+        }
+
+        moveWorm();
+//      debugOutput();
+        wormDead = processCollisions();
+        drawWorm();
+        scoreBoard();
+        lcd_update();
+        button = button_get_w_tmo(HZ/speed);
+    }
+    return wormDead;
+}
+
+/**
+ * Main entry point from the menu to start the game control.
+ */
+Menu wormlet(void)
+{
+    bool wormDead = false;
+    int button;
+    do {    
+
+        // button state will be overridden if
+        // the game quits with the death of the worm.
+        // Initializing button to BUTTON_OFF ensures
+        // that the user can hit BUTTON_OFF during the
+        // game to return to the menu.
+        button  = BUTTON_OFF;
+
+        // start the game
+        wormDead = run();
+
+        // if worm isn't dead the game was quit
+        // via BUTTON_OFF -> no need to wait for
+        // buttons.
+        if (wormDead) {
+            do {
+                button = button_get(true);
+            }
+            // BUTTON_ON -> start new game
+            // BUTTON_OFF -> back to game menu
+            while (button != BUTTON_OFF && button != BUTTON_ON);
+        }
+    }
+    while (button != BUTTON_OFF);
+
+    return MENU_OK;
+}