c - 我的调试文本显示垃圾

Question

我正在使用令人惊叹的 raylib 用 C 语言制作一个简单的游戏我尝试打印我的玩家坐标，但应更新的 x 值保持在 0 ，而应保持不变的 y 值会打印一个垃圾值，该值根据我的玩家的 x 值而变化

我的代码如下:( here 是一个注释版本，如果帖子中嵌入了太多代码，抱歉)

// WIP

#include "raylib.h"

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>

//#define PLATFORM_WEB
#define DEBUG

#if defined(PLATFORM_WEB)
    #include <emscripten/emscripten.h>
#endif

#define PLAYER_MAX_LIFE         5

typedef enum GameScreen { LOGO, TITLE, GAMEPLAY, ENDING } GameScreen;

typedef struct Player {
    Vector2 position;
    Vector2 size;
    int life;
} Player;

typedef struct Food {
    Vector2 position;
    int value;
} Food;

static int  screenWidth = 800;
static int  screenHeight = 450;

static int  framesCounter;
static bool gameOver;
static bool pause;

#if defined(DEBUG)
static char* debugText;
#endif

static Player player;

static void InitGame(void);         // Initialize game
static void UpdateGame(void);       // Update game (one frame)
static void DrawGame(void);         // Draw game (one frame)
static void UnloadGame(void);       // Unload game
static void UpdateDrawFrame(void);  // Update and Draw (one frame)

int main()
{
    InitWindow(screenWidth, screenHeight, "what should i name this piece of s##t game");

    InitGame();

#if defined(PLATFORM_WEB)
    emscripten_set_main_loop(UpdateDrawFrame, 0, 1);
#else

    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        UpdateGame();
        DrawGame();
    }
#endif

    UnloadGame();         // Unload loaded data (textures, sounds, models etc)

    CloseWindow();        // Close window and OpenGL context    
    return 0;
}

void InitGame(void)
{
    player.position = (Vector2){ screenWidth/2, screenHeight - screenHeight/8 };
    player.size = (Vector2){ screenWidth/10, 20 };
    player.life = PLAYER_MAX_LIFE;
    debugText = malloc(sizeof(char) * 20);
}

void UpdateGame(void)
{
    if (!gameOver)
    {
        if (IsKeyPressed('P')) pause = !pause;

        if (!pause)
        {
            if (IsKeyDown(KEY_LEFT))                                  player.position.x -= 5;
            if ((player.position.x - player.size.x/2) <= 0)           player.position.x = player.size.x/2;
            if (IsKeyDown(KEY_RIGHT))                                 player.position.x += 5;
            if ((player.position.x + player.size.x/2) >= screenWidth) player.position.x = screenWidth - player.size.x/2;

        #if defined(DEBUG)
            debugText = FormatText("screen: %dx%d\nx: %d\ny: %d", screenWidth, screenHeight, player.position.x, player.position.y);
        #endif    
            if (player.life <= 0) gameOver = true;
        }
    }
    else
    {
        if (IsKeyPressed(KEY_ENTER))
        {
            InitGame();
            gameOver = false;
        }
    }
}

void DrawGame(void)
{
    BeginDrawing();
        ClearBackground(RAYWHITE);

        if (!gameOver)
        {
        #if defined(DEBUG)
            DrawText(debugText, 50, 70, 20, BLACK);
        #endif
            DrawRectangle(0, screenHeight - screenHeight/8 + (screenHeight - screenHeight/8)/36, screenWidth, screenHeight/9, GREEN);

            DrawRectangle(player.position.x - player.size.x/2, player.position.y - player.size.y/2, player.size.x, player.size.y, BLACK);

            for (int i = 0; i < player.life; i++) DrawRectangle(20 + 40*i, screenHeight - 30, 35, 10, LIGHTGRAY);

            if (pause) DrawText("GAME PAUSED", screenWidth / 2 - MeasureText("GAME PAUSED", 40)/2, screenHeight/2 - 40, 40, GRAY);
        }
        else DrawText("PRESS [ENTER] TO PLAY AGAIN", screenWidth/2 - MeasureText("PRESS [ENTER] TO PLAY AGAIN", 20)/2, screenHeight/2 - 50, 20, GRAY);

    EndDrawing();
}

void UnloadGame(void)
{
    free(debugText);
}

void UpdateDrawFrame(void)
{
    UpdateGame();
    DrawGame();
}    

static void UpdateFood(void)
{
    //TODO: Implement logic
}

我认为有问题的部分是这样的:

debugText = FormatText("屏幕: %dx%d\nx: %d\ny: %d", screenWidth, screenHeight,player.position.x,player.position.y);

访问player.position.x和player.position.y不起作用或者可能存在某种溢出？我真的不知道，因此我们将不胜感激。

Answer 1

事实证明，问题之一是溢出，另一个问题是使用了错误的格式说明符更改这两行修复了它:

-- debugText = malloc(sizeof(char) * 20);
++ debugText = malloc(sizeof(char) * 40);

-- debugText = FormatText("screen: %dx%d\nx: %d\ny: %d", screenWidth, screenHeight, player.position.x, player.position.y);
++ debugText = FormatText("screen: %dx%d\nx: %f\ny: %f", screenWidth, screenHeight, player.position.x, player.position.y);