当按下OPENGL上的一个按键时，我的形状不想移动

问题描述：

我想使用sin函数在水平移动时使形状执行跳转，但当它按下时它甚至不响应“j”按钮？我仍然在学习Opengl。任何关于错误在哪里的帮助？当按下OPENGL上的一个按键时，我的形状不想移动

#include <GLUT/glut.h> 
#include <math.h> 

float pointone = 0; 
float ydir =0; 
GLboolean turn ; 
void Display(); 
void DrawWall(); 
void Anim(); 
void Keyboard(unsigned char key, int x, int y); 

int main(int argc, char** argr) { 
    glutInit(&argc, argr); 
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); 
    glutInitWindowSize(1000, 600); 
    glutInitWindowPosition(50, 50); 
    glutKeyboardFunc(Keyboard); 
    glutIdleFunc(Anim); 
    glutCreateWindow("Kbeer El Haramiya"); 
    glutDisplayFunc(Display); 
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f); 
    glPointSize(20.0); 
    gluOrtho2D(0.0, 1000.0, 0.0, 600.0); 
    glutMainLoop(); 
} 

void Display() { 
    glClear(GL_COLOR_BUFFER_BIT); 
    DrawWall(); 
    glPushMatrix(); 
    if(pointone<=850 && turn ==true){ 
     pointone+=3; 
     turn=true;} 
    else if (pointone==0){ 
     turn=true;} 
     else { 
     turn = false; 
     pointone-=3; 
     } 
    glTranslatef(pointone, ydir, 0); 
    glBegin(GL_POLYGON); 
    glColor3f(0.97f,0.96f,0.768f); 
    glVertex2i(0.0f, 0.0f); 
    glVertex2i(50.0f, 0.0f); 
    glVertex2i(50.0f, 50.0f); 
    glColor3f(0.70f,0.196f,0.12f); 
    glVertex2i(0.0f, 50.0f); 
    glEnd(); 
    glPopMatrix(); 
    glFlush(); 

} 

void DrawWall(){ 
    glBegin(GL_POLYGON); 
    glColor3f(0.97f,0.96f,0.768f); 
    glVertex2i(999, 0); 
    glVertex2i(999,600); 
    glVertex2i(900, 600); 
    glVertex2i(900, 0); 
    glEnd(); 
    glBegin(GL_POLYGON); 
    glVertex2i(0, 200); 
    glVertex2i(700,200); 
    glVertex2i(700, 150); 
    glVertex2i(0,150); 
    glEnd(); 
} 

void Keyboard(unsigned char key, int x, int y){ 
    if(key == 'j') { 
     for(int i =0; i<361;i++){ 
     ydir =sin(i); 
     glutPostRedisplay(); 
    } 

} 

} 
void Anim(){ 
    glutPostRedisplay(); 
}

答

解决办法很简单，我应该叫Keyboardfunc之前创建的窗口！ :)

答

您必须更新ydirDisplay()函数中的某处。当您尝试在循环外对其进行更新时，在Keyboard函数结束后，只会安排一次重绘。

代码可以看看（例如）在某种程度上是这样的：

int yint = -1; //-1 means no moving 

void Display() { 
    if (yint > 360) // Reset when > 360° 
     yint = -1; 
    if (yint >= 0 && yint <= 360) //Update until 360° is reached 
     yint++; 

    float ydir = sin(yint); 

    //Draw code here 
} 

void Keyboard(unsigned char key, int x, int y){ 
    if(key == 'j') 
     yint = 0; 
}

当按下OPENGL上的一个按键时，我的形状不想移动

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