GLUT 键盘事件

Question

我编写了模拟选择排序操作的程序。我添加了函数 myKeyboard 来退出程序，但是由于使用函数 sleep() 来模仿动画 myKeyboard 只有在排序完成后才能工作。有什么方法可以替换函数 sleep() 以便我可以在排序过程中退出程序？这是代码：

#include <stdio.h>
#include <math.h>
#include <GL/glut.h>

using namespace std;

#define N 40

void run(void);
void display(int unused);
void selectionSort(int a[]);
void swap (int a[], int x, int y);
void mixArray (int a[]);
void myKeyboard( unsigned char key, int x, int y );
int i;
int T[N];


int main(int argc, char* argv[]){

glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(800, 800);
glutCreateWindow("Selection sort");
glEnable(GL_DEPTH_TEST);
glutKeyboardFunc(myKeyboard);
for (i = 0; i < N; i++) T[i] = i;
mixArray(T);
glutDisplayFunc(run);
glutTimerFunc(200,display,0);
glutMainLoop();
return 0;

}


void drawFigure(float x, float dx, float y, float dy, float z, float dz)
{
glBegin(GL_POLYGON);

glColor3f( 1.0f, 1.0f, 0.0f );

glVertex3f(  x + dx, y, z );
glVertex3f(  x + dx,  y + dy, z );
glVertex3f( x,  y + dy, z );
glVertex3f( x, y, z );

glEnd();


glBegin(GL_POLYGON);
glColor3f(   1.0f,  1.0f, 1.0f );

glVertex3f(  x + dx, y, z + dz );
glVertex3f(  x + dx,  y + dy, z + dz );
glVertex3f( x,  y + dy, z + dz );
glVertex3f( x, y, z + dz );
glEnd();


glBegin(GL_POLYGON);
glColor3f(  0.7f,  0.3f,  0.8f);

glVertex3f( x + dx, y, z );
glVertex3f( x + dx,  y + dy, z );
glVertex3f( x + dx,  y + dy,  z + dz );
glVertex3f( x + dx, y,  z + dz );
glEnd();


glBegin(GL_POLYGON);
glColor3f(   0.0f,  1.0f,  0.0f );


glVertex3f( x, y,  z + dz );
glVertex3f( x,  y + dy,  z + dz );
glVertex3f( x,  y + dy, z );
glVertex3f( x, y, z );
glEnd();


glBegin(GL_POLYGON);
glColor3f(0.0f,  0.0f,  1.0f );

glVertex3f(  x + dx,  y + dy,  z + dz );
glVertex3f(  x + dx,  y + dy, z );
glVertex3f( x,  y + dy, z );
glVertex3f( x,  y + dy,  z + dz );
glEnd();


glBegin(GL_POLYGON);
glColor3f(1.0f,  0.0f,  0.0f);

glVertex3f(x + dx, y, z );
glVertex3f(x + dx, y,  z + dz );
glVertex3f( x, y,  z + dz );
glVertex3f( x, y, z );
glEnd();
}


void display(int unused)
{
glLoadIdentity();

glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

for (int i = 0; i < N; i++)
{
    glRotatef(-0.4f, 1.0f, 0.0f, 0.0f );
    glRotatef( 0.1f, 0.0f, 1.0f, 0.0f );
    drawFigure(-1.0f + i * 1.9f / N, 1.0f / N, -0.5f, float(T[i]) / N, -0.8f, 0.1f);

}

glFlush();
glutSwapBuffers();
}



void run()
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0.5f, 0.2f, 0.7f);
selectionSort(T);
}


void selectionSort(int T[])
{
int minVal;
for (int i = 0; i < N; i++)
{
    minVal = i;
    for (int j = i+1; j < N; j++)
    {
        if (T[j] < T[minVal])
        {
            minVal = j;
        }
    }

    swap(T, i, minVal);
    display(minVal);
}

}


void swap (int T[], int a, int b)
{
int tmp = T[a];
T[a] = T[b];
T[b] = tmp;
}

void mixArray(int T[])
{
for (int i = 0; i < N; i++)
{
    swap(T, rand() % N, rand() % N);
}
}

void myKeyboard( unsigned char key, int x, int y )
{
if(key == 27)
{
    exit(EXIT_SUCCESS);
}
}

Answer 1

您可以使用 glutTimerFunc 设置一个每 200 毫秒调用一次的函数来执行排序步骤，而不是在 glutDisplayFunc 内运行排序。这将允许在步骤之间处理键盘事件。