将主功能分成单独的功能

Question

我刚刚从 youtube 复制了一个非常简单的动画代码来学习如何在 raylib 中制作动画。但整个代码都是写在main函数里面的。我希望将其组织起来并分开。这是代码：

#include "include/raylib.h"

int main()
{
    const int screenWidth = 1200;
    const int screenHeight = 800;

    InitWindow(screenWidth, screenHeight, "2D Platformer");
    SetTargetFPS(60);

    Texture2D run_sprite = LoadTexture("sprites/Fighter/Run.png");
    Rectangle source = {0.f, 0.f, (float)run_sprite.width / 8.0f, (float)run_sprite.height};
    Vector2 position = {0, screenHeight / 2};

    int frame = 0;
    float runningTime{};
    const float updateTime{1.f/12.f};

    while (WindowShouldClose() == false)
    {
        //UPDATE VARIABLES
        float deltaTime = GetFrameTime();
        runningTime += deltaTime;
        if (runningTime >= updateTime)
        {
            runningTime = 0.f;
            source.x = (float)frame * source.width;
            frame++;
            if (frame > 8)
            {
                frame = 0;
            }
        }


        //START DRAWING
        BeginDrawing();
            ClearBackground(RAYWHITE);
            DrawTextureRec(run_sprite, source, position, WHITE);
        EndDrawing();
    }

    CloseWindow();
}

我尝试将其分为以下功能：

Texture2D run_sprite;

void load_textures()
{
    run_sprite = LoadTexture("sprites/Fighter/Run.png");
}

int frame = 0;
float runningTime{};
const float updateTime{1.f/12.f};

Rectangle source = {0.f, 0.f, (float)run_sprite.width / 8.0f, (float)run_sprite.height};
void update_run_animation()
{
    runningTime += deltaTime;
        if (runningTime >= updateTime)
        {
            runningTime = 0.f;
            source.x = (float)frame * source.width;
            frame++;
            if (frame > 8)
            {
                frame = 0;
            }
        }
}

Vector2 position = {0, screenHeight / 2};
void render_run_animation()
{
    DrawTextureRec(run_sprite, source, position, WHITE);
}

这是 main 函数内代码的实现版本：

int main()
{
    const int screenWidth = 1200;
    const int screenHeight = 800;

    InitWindow(screenWidth, screenHeight, "2D Platformer");
    SetTargetFPS(60);

    load_textures();

    while (WindowShouldClose() == false)
    {
        update_run_animation();

        BeginDrawing();
            ClearBackground(RAYWHITE);
            render_run_animation();
        EndDrawing();
    }

    CloseWindow();
}

但是当我运行这个时，它只是创建一个窗口而不是绘制纹理。我尝试从每个函数变量中获取输出来调试它。结论是，当涉及到“update_run_animation”函数时，“source.width”变量给出的默认值是0。我不知道到底是什么问题，所以我发布了整个代码。抱歉表达太长了。

Answer 1

全局变量的初始化发生在main函数运行之前。因此，您在初始化

source

（和

position

）时使用的值将不是您所期望的。在使用变量之前，您需要在

main

函数中显式初始化（分配）这些变量。