wormlet.c

编译后直接运行的ＭＰ３播放器全部Ｃ语言源代码 一个包含FAT文件系统、系统引导 Boot、FLASH Driver等内容的

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: wormlet.c,v 1.1 2003/06/29 16:33:04 zagor Exp $
 *
 * 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 "plugin.h"

#ifdef HAVE_LCD_BITMAP

/* size of the field the worm lives in */
#define FIELD_RECT_X 1
#define FIELD_RECT_Y 1
#define FIELD_RECT_WIDTH  (LCD_WIDTH - 45)
#define FIELD_RECT_HEIGHT (LCD_HEIGHT - 2)

/* size of the ring of the worm 
   choos a value that is a power of 2 to help 
   the compiler optimize modul operations*/
#define MAX_WORM_SEGMENTS 64   

/* when the game starts */
#define INITIAL_WORM_LENGTH 10 

/* num of pixel the worm grows per eaten food */
#define WORM_PER_FOOD 7        

/* num of worms creeping in the FIELD */
#define MAX_WORMS 3            

/* minimal distance between a worm and an argh 
   when a new argh is made */
#define MIN_ARGH_DIST 5

/**
 * All the properties that a worm has.
 */
static struct worm {
    /* The worm is stored in a ring of xy coordinates */
    char x[MAX_WORM_SEGMENTS];
    char y[MAX_WORM_SEGMENTS];

    int head;      /* index of the head within the buffer */
    int tail;      /* index of the tail within the buffer */
    int growing;   /* number of cyles the worm still keeps growing */
    bool alive;    /* the worms living state */

    /* direction vector in which the worm moves */
    int dirx; /* only values -1 0 1 allowed */
    int diry; /* only values -1 0 1 allowed */

    /* this method is used to fetch the direction the user
       has selected. It can be one of the values
       human_player1, human_player2, remote_player, virtual_player. 
       All these values are fuctions, that can change the direction 
       of the worm */
    void (*fetch_worm_direction)(struct worm *w);
} worms[MAX_WORMS];

/* stores the highscore - besides it was scored by a virtual player */
static int highscore;

#define MAX_FOOD  5 /* maximal number of food items */
#define FOOD_SIZE 3 /* the width and height of a food */

/* The arrays store the food coordinates  */
static char foodx[MAX_FOOD];
static char 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 per eaten food */

/* The arrays store the argh coordinates */
static char arghx[MAX_ARGH];
static char arghy[MAX_ARGH];

/* the number of arghs that are currently in use */ 
static int argh_count;

#ifdef DEBUG_WORMLET
/* just a buffer used for debug output */
static char debugout[15];
#endif

/* the number of ticks each game cycle should take */ 
#define SPEED 14

/* the number of active worms (dead or alive) */
static int worm_count = MAX_WORMS;

/* in multiplayer mode: en- / disables the remote worm control
   in singleplayer mode: toggles 4 / 2 button worm control */
static bool use_remote = false;

/* return values of check_collision */
#define COLLISION_NONE 0
#define COLLISION_WORM 1
#define COLLISION_FOOD 2
#define COLLISION_ARGH 3
#define COLLISION_FIELD 4

/* constants for use as directions.
   Note that the values are ordered clockwise.
   Thus increasing / decreasing the values
   is equivalent to right / left turns. */
#define WEST  0
#define NORTH 1
#define EAST  2
#define SOUTH 3

/* direction of human player 1 */
static int player1_dir = EAST; 
/* direction of human player 2 */
static int player2_dir = EAST; 
/* direction of human player 3 */
static int player3_dir = EAST;

/* the number of (human) players that currently
   control a worm */
static int players = 1;

/* the rockbox plugin api */
static struct plugin_api* rb;

#ifdef DEBUG_WORMLET
static void set_debug_out(char *str){
    strcpy(debugout, str);
}
#endif

/**
 * Returns the direction id in which the worm
 * currently is creeping.
 * @param struct worm *w The worm that is to be investigated. 
 *        w Must not be null.
 * @return int A value 0 <= value < 4
 *         Note the predefined constants NORTH, SOUTH, EAST, WEST
 */
static int get_worm_dir(struct worm *w) {
    int retVal ;
    if (w->dirx == 0) {
        if (w->diry == 1) {
            retVal = SOUTH;
        } else {
            retVal = NORTH;
        }
    } else {
        if (w->dirx == 1) {
            retVal = EAST;
        } else {
            retVal = WEST;
        }
    }
    return retVal;
}

/**
 * Set the direction of the specified worm with a direction id.
 * Increasing the value by 1 means to turn the worm direction
 * to right by 90 degree.
 * @param struct worm *w The worm that is to be altered. w Must not be null.
 * @param int dir The new direction in which the worm is to creep.
 *        dir must be  0 <= dir < 4. Use predefined constants 
 *        NORTH, SOUTH, EAST, WEST
 */
static void set_worm_dir(struct worm *w, int dir) {
    switch (dir) {
        case WEST:
            w->dirx = -1;
            w->diry = 0;
            break;
         case NORTH:
            w->dirx = 0;
            w->diry = - 1;
            break;
        case EAST:
            w->dirx = 1;
            w->diry = 0;
            break;
        case SOUTH:
            w->dirx = 0;
            w->diry = 1;
            break;
   }
}

/**
 * Returns the current length of the worm array. This
 * is also a value for the number of bends that are in the worm.
 * @return int a positive value with 0 <= value < MAX_WORM_SEGMENTS
 */
static int get_worm_array_length(struct worm *w) {
    /* initial simple calculation will be overwritten if wrong. */
    int retVal = w->head - w->tail;

    /* if the worm 'crosses' the boundaries of the ringbuffer */
    if (retVal < 0) {
        retVal = w->head + MAX_WORM_SEGMENTS - w->tail;
    }

    return retVal;
}

/**
 * Returns the score the specified worm. The score is the length
 * of the worm.
 * @param struct worm *w The worm that is to be investigated.
 *        w must not be null.
 * @return int The length of the worm (>= 0).
 */
static int get_score(struct worm *w) {
    int retval = 0;
    int length = get_worm_array_length(w);
    int i;
    for (i = 0; i < length; i++) {

        /* The iteration iterates the length of the worm.
           Here's the conversion to the true indices within the worm arrays. */
        int linestart = (w->tail + i  ) % MAX_WORM_SEGMENTS;
        int lineend   = (linestart + 1) % MAX_WORM_SEGMENTS;
        int startx = w->x[linestart];
        int starty = w->y[linestart];
        int endx = w->x[lineend];
        int endy = w->y[lineend];

        int minimum, maximum;

        if (startx == endx) {
            minimum = MIN(starty, endy);
            maximum = MAX(starty, endy);
        } else {
            minimum = MIN(startx, endx);
            maximum = MAX(startx, endx);
        }
            retval += abs(maximum - minimum);
    }
    return retval;
}

/**
 * Determines wether the line specified by startx, starty, endx, endy intersects
 * the rectangle specified by x, y, width, height. Note that the line must be exactly
 * horizontal or vertical (startx == endx or starty == endy). 
 * @param int startx The x coordinate of the start point of the line.
 * @param int starty The y coordinate of the start point of the line.
 * @param int endx The x coordinate of the end point of the line.
 * @param int endy The y coordinate of the end point of the line.
 * @param int x The x coordinate of the top left corner of the rectangle.
 * @param int y The y coordinate of the top left corner of the rectangle.
 * @param int width The width of the rectangle.
 * @param int height The height of the rectangle.
 * @return bool Returns true if the specified line intersects with the recangle.
 */
static bool line_in_rect(int startx, int starty, int endx, int endy, int x, int y, int width, int height) {
    bool retval = false;
    int simple, simplemin, simplemax;
    int compa, compb, compmin, compmax;
    int temp;
    if (startx == endx) {
        simple = startx;
        simplemin = x;
        simplemax = x + width;

        compa = starty;
        compb = endy;
        compmin = y;
        compmax = y + height;
    } else {
        simple = starty;
        simplemin = y;
        simplemax = y + height;

        compa = startx;
        compb = endx;
        compmin = x;
        compmax = x + width;
    };

    temp = compa;
    compa = MIN(compa, compb);
    compb = MAX(temp, compb);

    if (simplemin <= simple && simple <= simplemax) {
        if ((compmin <= compa && compa <= compmax) ||
            (compmin <= compb && compb <= compmax) ||
            (compa <= compmin && compb >= compmax)) {
            retval = true;
        }
    }
    return retval;
}

/** 
 * Tests wether the specified worm intersects with the rect.
 * @param struct worm *w The worm to be investigated
 * @param int x The x coordinate of the top left corner of the rect
 * @param int y The y coordinate of the top left corner of the rect
 * @param int widht The width of the rect
 * @param int height The height of the rect
 * @return bool Returns true if the worm intersects with the rect
 */
static bool worm_in_rect(struct worm *w, int x, int y, int width, int height) {
    bool retval = false;


    /* get_worm_array_length is expensive -> buffer the value */
    int wormLength = get_worm_array_length(w);
    int i;

    /* test each entry that is part of the worm */
    for (i = 0; i < wormLength && retval == false; i++) {

        /* The iteration iterates the length of the worm.
           Here's the conversion to the true indices within the worm arrays. */
        int linestart = (w->tail + i  ) % MAX_WORM_SEGMENTS;
        int lineend   = (linestart + 1) % MAX_WORM_SEGMENTS;
        int startx = w->x[linestart];
        int starty = w->y[linestart];
        int endx = w->x[lineend];
        int endy = w->y[lineend];

        retval = line_in_rect(startx, starty, endx, endy, x, y, width, height);
    }

    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.
 */
static bool specific_food_collision(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
 */
static int food_collision(int x, int y) {
    int i = 0;
    int retVal = -1;
    for (i = 0; i < MAX_FOOD; i++) {
        if (specific_food_collision(i, x, y)) {
            retVal = i;
            break;
        }
    }
    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.
 */
static bool specific_argh_collision(int arghIndex, int x, int y) {

    if ( x >= arghx[arghIndex] &&
         y >= arghy[arghIndex] &&
         x <  arghx[arghIndex] + ARGH_SIZE &&
         y <  arghy[arghIndex] + ARGH_SIZE )
    {
        return true;
    }

    return false;
}

/**
 * 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 < argh_count <= MAX_ARGH
 */
static int argh_collision(int x, int y) {
    int i = 0;
    int retVal = -1;

    /* search for the argh that has the specified coords */
    for (i = 0; i < argh_count; i++) {
        if (specific_argh_collision(i, x, y)) {
            retVal = i;
            break;
        }
    }
    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.
 */
static bool worm_food_collision(struct worm *w, int foodIndex)
{
    bool retVal = false;

    retVal = worm_in_rect(w, foodx[foodIndex], foody[foodIndex], 
                          FOOD_SIZE - 1, FOOD_SIZE - 1);

    return retVal;
}

/**
 * Returns true if the worm hits the argh within the next moves (unless
 * the worm changes it's direction).
 * @param struct worm *w - The worm to investigate
 * @param int argh_idx - The index of the argh 
 * @param int moves - The number of moves that are considered.
 * @return Returns false if the specified argh is not hit within the next
 *         moves.
 */
static bool worm_argh_collision_in_moves(struct worm *w, int argh_idx, int moves){
    bool retVal = false;
    int x1, y1, x2, y2;
    x1 = w->x[w->head];
    y1 = w->y[w->head];

    x2 = w->x[w->head] + moves * w->dirx;
    y2 = w->y[w->head] + moves * w->diry;

    retVal = line_in_rect(x1, y1, x2, y2, arghx[argh_idx], arghy[argh_idx], 
                         ARGH_SIZE, ARGH_SIZE);
    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 < argh_count <= MAX_ARGH
 * @return Returns true if the worm collides with the specified argh.
 */
static bool worm_argh_collision(struct worm *w, int arghIndex)
{
    bool retVal = false;

    retVal = worm_in_rect(w, arghx[arghIndex], arghy[arghIndex], 
                          ARGH_SIZE - 1, ARGH_SIZE - 1);

    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.
 */
static int make_food(int index) {

    int x = 0;
    int y = 0;
    bool collisionDetected = false;
    int tries = 0;
    int i;

    do {
        /* make coordinates for a new food so that
           the entire food lies within the FIELD */
        x = rb->rand() % (FIELD_RECT_WIDTH  - FOOD_SIZE);
        y = rb->rand() % (FIELD_RECT_HEIGHT - FOOD_SIZE);
        tries ++;

        /* 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.