Question

我正在进行一项opengl任务，我必须让一个生物（我选择了一个雪人）在一些地形上移动。我试图让它四处走动，我得到了最奇怪的错误。打印出数字后，我经常将“-1。＃QNAN0”作为数字。我甚至都不知道这意味着什么。下面是雪人的更新函数，构造函数和头文件。我正在尝试将2个数字用作速度并将其添加到位置，同时将其设置为动画（随机更改），但我不明白哪些错误导致我无法从rand（）中获取数字。< / p>

每次概率检查成功时，都会输出：

DEBUG: probability check succeeded
-1.#QNAN0 0.000000

或

DEBUG: probability check succeeded
0.000000 0.000000

每个人有大约50％的可能性。

来自Snowman.cpp

void Snowman::update(canvas_t texture){
//randomly toggle the walking variable
int probability = rand() % 100;
//printf("DEBUG: probability = %d\n", probability);
if(probability <= 10){
    printf("DEBUG: probability check succeeded\n");
    walking = !walking;
    dx = static_cast<float>(( (rand() % 10) - 5));
    dy = static_cast<float>(( (rand() % 10) - 5));
    printf("%f %f\n", dx, dy);
}
//code to control movement
if(walking){
    animate = true;
    x += dx;
    y += dy;
    constrain(x, 0, texture.width);
    constrain(y, 0, texture.height);
}else{
    animate = false;
}

//set the height after x and y are resolved
z = getHeight(texture);
}


Snowman::Snowman(canvas_t terrain)
{
wireFrame = false;
animate = false;
armSegments = 2;
animationFrameNumber = 0;
manualUserOffset = 0;

//set its initial position
x = rand() % terrain.width;
y = rand() % terrain.height;
dx = 0;
dy = 0;
}

来自Snowman.h

class Snowman
{
public:
Snowman(canvas_t);
~Snowman(void);

void setWireframe(bool);
void toggleWireframe(void);
void setAnimate(bool);
void toggleAnimate(void);
void setArmSegments(int);
void addArmSegment(void);
void subtractArmSegment(void);

void update(canvas_t);
void draw(void);

private:
bool wireFrame;
bool animate;
bool walking;
int armSegments;
int animationFrameNumber;
float manualUserOffset;

float x, y, z;
int dx, dy;

inline float f(void);
inline void drawMouth(int headRadius);
inline void drawFace(int headRadius);
void drawArm(int remainingSegments);
inline void drawBody();
inline float getHeight(canvas_t);
};

Answer 1

dx和dy为int，但您的格式说明符%f需要double或float。所以你有未定义的行为。

只处理整数和浮点数时得到NAN

1 个答案: