SFML 碰撞从未在我的系统中注册

Question

尝试在 SFML 中第一次在 SFML 中制作碰撞系统而不使用教程，使用基于数组的东西，如下所示：

    bool moright, moleft, moup, xcollision, ycollision;
float xvel, yvel;
int position, predictx, predicty, cm, arraynum;
class playerClass{
public:
    playerClass(){
    }
    void update()
{
        if (moright == true){
            xvel = 2;}
        if (moleft == true){
            xvel = -2;}
        if (!(moright || moleft)){
            if (xvel < 0)
                xvel = 0;
            if (xvel > 0)
                xvel = 0;}
}

};

int main()
{
    playerClass playerObject;
    // Create the main window
    RenderWindow window(VideoMode(1080, 720), "SFML window");

    // Load a sprite to display
    Texture texture;
    if (!texture.loadFromFile("gsquare100x100.png"))
        return EXIT_FAILURE;
    Sprite sprite(texture);
    Sprite floor(texture);
    Sprite wall(texture);
    floor.setPosition(Vector2f(0.f, 498.f));
    wall.setPosition(Vector2f(598.f,0.f));


    floor.setColor(Color(0, 255, 0));
    floor.setScale(12.f, 12.f);

    wall.setScale(12.f, 12.f);
    wall.setColor(Color(0, 0, 255));
  int collisions[2][4]{
 {0, 400, 500, 600},
 };

// Start the game loop
    while (window.isOpen())
{

        Vector2f position = sprite.getPosition();
        cout << position.y << endl;
        predictx = position.x + xvel;
        predicty = position.y + yvel;
        yvel = 1;
       for (arraynum = 0; arraynum < 2; arraynum++){
            if ((predictx > collisions[arraynum][0])&&(predictx < collisions[arraynum][1])&&(predicty > collisions[arraynum][2])&&(predicty < collisions[arraynum][3])){
                if ((position.y > collisions[arraynum][3])||(position.y < collisions[arraynum][2])){
                    xcollision = true;}
                if ((position.x > collisions[arraynum][1])||(position.x < collisions[arraynum][0])){
                    ycollision = true;}
                }
            }
        if (xcollision == true)
            xvel = 0;
            xcollision = false;
        if (ycollision == true)
            yvel = 0;
            ycollision = false;
        sprite.move(sf::Vector2f(0.f+xvel, 0.f+yvel));





        // Process events
        sf::Event event;
        while (window.pollEvent(event))
        {

          if (event.type == Event::KeyPressed)
              {if (event.key.code == Keyboard::D)
                   moright = true;
                if (event.key.code == Keyboard::A)
                   moleft = true;}

          if (event.type == Event::KeyReleased)
          {if (event.key.code == Keyboard::D)
               moright = false;
            if (event.key.code == Keyboard::A)
               moleft = false;}
         playerObject.update();

}

然而，碰撞从未被记录下来，删除检查精灵从哪个方向移动的位没有帮助。对 c++ 很陌生，如果这是一个愚蠢的问题，并且对于我可能过于复杂的碰撞系统，我们深表歉意。

Answer 1

由于声誉低，我无法发表评论。

从提供的代码来看，您似乎从未在任何地方将 xcollision 或 ycollision 设置为 true。

Answer 2

我以前用 SFML 写过简单的碰撞，这里是我给你的建议：让你的代码尽可能的可读！事情会变得更复杂，你需要有一个系统是可重用的和易于理解的。
我读过你的代码，但我不明白你为什么使用数组。我假设您正在尝试检查一个较小的矩形精灵是否即将退出 collisions 数组？

为此，我建议使用 FloatRect 对象。它具有您将来可能需要的有用功能，例如 .contains() 和 .intersects()。它的一个缺点是只有 top 和 left，为了让它更短，我们将定义一个简单的结构来为我们处理这部分，同时也适用于矩形精灵.
我留下了解释代码的评论，但没有亲自测试过。你可以这样做并将你学到的东西整合到你的项目中。祝你好运

#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
using namespace sf;
//using a struct is not necessarily faster. BUT it does give your code more readability and is reusable for future needs
//this struct just stores a floatRect of the given sprite/Floatrecct, defining some useful functions allowing for shorter code and more readability
struct rectangularShape 
{
    FloatRect containingRectangle;
    //constructor with sprite input
    rectangularShape(Sprite sprite)
    {
        this -> containingRectangle = FloatRect(Vector2f(sprite.getGlobalBounds().left, sprite.getGlobalBounds().top),
                                                Vector2f(sprite.getGlobalBounds().left + sprite.getGlobalBounds().width,sprite.getGlobalBounds().top + sprite.getGlobalBounds().height));
    }
    //constructor with floatrect
    rectangularShape(FloatRect rect)
    {
        this -> containingRectangle = rect;
    }
    //any useful functions for rectangular shapes-- you could add more if you want
    float getTop() {return containingRectangle.top;}
    float getbottom() {return containingRectangle.top + containingRectangle.height;}
    float getleft() {return containingRectangle.left;}
    float getright() {return containingRectangle.left + containingRectangle.width;}
};

//note the use of a FloatRect instead of the arrays you were using, this just makes it easier to understand
FloatRect inclusionArea(TopLeftVector, BottomRightVector);
Sprite sprite(texture);

//declare rectangularShapes, here we check if smallRectangle is exiting it's container
rectangularShape containingRectangle(inclusionArea);
rectangularShape smallRectangle(sprite);
//alternatively you can use the sprite's next position:
/*
spriteCopy = sprite;
spriteCopy.move(deltaTime * Vector2f(xSpeed, ySpeed));
rectangularShape smallRectangle(spriteCopy);
*/
//do the check:
if (smallRectangle.getTop() < containingRectangle.getTop() or smallRectangle.getBottom() > containingRectangle.getBottom())
    //exiting in Y axis
    //do something;
    ;
if (smallRectangle.getLeft() < containingRectangle.getLeft() or smallRectangle.getRight() > containingRectangle.getRight())
    //exiting in X axis
    //do something;
    ;

SFML 碰撞从未在我的系统中注册

SFML Collisions never register in my system

c++

sfml