C 为什么只有一个数组下标没有被分配？

真奇怪

我正在为我的游戏编写一些物理代码，一些行星间的引力。这不管用，但这不是重点

我正在运行一个游戏循环。对于主循环中的每一帧，我都调用

void calculate\u gravity（GameState*game）

。我的36面墙阵列中的四个墙对象在此功能中发挥作用，特别是

墙瓷砖[32]

到

[35]

。我使用此函数为我的播放器计算

速度x

和

速度y

。为此，我做了一个从32到35的循环，即

wall\u tiles[]

中相关墙的索引。以下代码段很长，但大部分是调试printf语句：

void calculate_gravity(GameState *game)
{
    Player *player = &game->player;
    int factor;
    float speed_x, speed_y;
    float speeds_x[16];
    float speeds_y[16];

    factor = 2000;

    for (int i = 32; i < NUMBER_OF_WALLS; ++i)
    {
        float vector_x;
        float vector_y;
        float get_vector_x(GameState*, int);
        float get_vector_y(GameState*, int);
        float this_speed_x;
        float this_speed_y;


        vector_x = get_vector_x(game, i);
        vector_y = get_vector_y(game, i);

        printf("Vector: player to object %d = [%0.3f, %0.3f]",
               i, vector_x, vector_y);



        float  gravity_pull, distance;

        distance = game->wall_tiles[i].magnitude_from_player;
        if (distance < 100)
        {
            distance = 100;
        }

        // object direction = vector
        gravity_pull = factor*(1/(distance*distance));

        this_speed_x = vector_x * gravity_pull;
        this_speed_y = vector_y * gravity_pull;

        speeds_x[i-32] = this_speed_x;
        speeds_y[i-32] = this_speed_y;
        printf("\t i-32 = %d\n", i-32);



    }

    // Calculate average speed
    speed_x = (speeds_x[0] + speeds_x[1] + speeds_x[2] + speeds_x[3]) / 4;
    speed_y = (speeds_y[0] + speeds_y[1] + speeds_y[2] + speeds_y[3]) / 4;


    printf("speeds_x = [");
    for (int i = 0; i < 4; ++i)
    {
        printf("%0.2f,", speeds_x[i]);
    }
    printf("]\n");
    printf("Speed_x: %0.3f\n", speed_x);

    printf("speeds_y = [");
    for (int i = 0; i < 4; ++i)
    {
        printf("%0.2f,", speeds_y[i]);
    }
    printf("]\n");
    printf("Speed_y: %0.3f\n\n", speed_y);


    printf("\n");

    player->x += speed_x;
    player->y += speed_y;


}

我曾尝试将

速度\ux[16]

声明为

速度\ux[4]

和

速度\ux[100]

，但这并没有什么区别。

---

我错过了什么？为什么只有

speeds\ux[2]

和

speeds\uy[2]

始终为0，而不是其他索引？

所以评论中的人都这么说。如果有人读到这篇文章，别忘了调用你的函数。。。（特别是

距离=向量大小（游戏，游戏->墙砖[i]）；

）。而%g运算符是一件好事。它也确实有助于获得更干净的调试屏幕。多亏了你们，它现在可以工作了

____________________________________________________________________________________________________

Object's ID: 32
Vector (player to object):                      [-998.6, -371.6]
Distance (player to object):                    1065.47
Object's gravity pull:                          0.00176175
Object's speed effect (x, y):                   [-1.75924, -1.75924]

Object's ID: 33
Vector (player to object):                      [-1298.6, -71.6]
Distance (player to object):                    1300.55
Object's gravity pull:                          0.00118243
Object's speed effect (x, y):                   [-1.53548, -1.53548]

Object's ID: 34
Vector (player to object):                      [-1598.6, -371.6]
Distance (player to object):                    1641.2
Object's gravity pull:                          0.00074252
Object's speed effect (x, y):                   [-1.18698, -1.18698]

Object's ID: 35
Vector (player to object):                      [-1298.6, -671.6]
Distance (player to object):                    1461.96
Object's gravity pull:                          0.000935744
Object's speed effect (x, y):                   [-1.21514, -1.21514]

Array of speed values (x):                      [-1.76,-1.54,-1.19,-1.22] |             Average: -1.42
Array of speed values (y):                      [-0.65,-0.08,-0.28,-0.63] |             Average: -0.41
____________________________________________________________________________________________________

---

你能给我们看一下

get\u vector\u x

代码吗？或者至少在循环中打印出

vector_x

和

vector_y

的值？另外，速度真的是零吗？试着用

%g

格式打印，以获得完全的精度。似乎没有披露

游戏->墙砖[i]的值。玩家
的大小。请贴一张。每面墙都有一个
距离。如果这是大的，你的价值将是非常小的。（在应用引力之前打印数值。）
game->wall_tiles[34]。玩家提供的数值
一定是一个巨大的值调试的下一步是为每个索引打印
i
、
vector\u x
、
vector\u y
、
distance
和
gravity\u pull
。这个问题的下一步是发布一篇文章。
____________________________________________________________________________________________________

Object's ID: 32
Vector (player to object):                      [-998.6, -371.6]
Distance (player to object):                    1065.47
Object's gravity pull:                          0.00176175
Object's speed effect (x, y):                   [-1.75924, -1.75924]

Object's ID: 33
Vector (player to object):                      [-1298.6, -71.6]
Distance (player to object):                    1300.55
Object's gravity pull:                          0.00118243
Object's speed effect (x, y):                   [-1.53548, -1.53548]

Object's ID: 34
Vector (player to object):                      [-1598.6, -371.6]
Distance (player to object):                    1641.2
Object's gravity pull:                          0.00074252
Object's speed effect (x, y):                   [-1.18698, -1.18698]

Object's ID: 35
Vector (player to object):                      [-1298.6, -671.6]
Distance (player to object):                    1461.96
Object's gravity pull:                          0.000935744
Object's speed effect (x, y):                   [-1.21514, -1.21514]

Array of speed values (x):                      [-1.76,-1.54,-1.19,-1.22] |             Average: -1.42
Array of speed values (y):                      [-0.65,-0.08,-0.28,-0.63] |             Average: -0.41
____________________________________________________________________________________________________